File : sem_ch12.adb


   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             S E M _ C H 1 2                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2016, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25 
  26 with Aspects;   use Aspects;
  27 with Atree;     use Atree;
  28 with Contracts; use Contracts;
  29 with Einfo;     use Einfo;
  30 with Elists;    use Elists;
  31 with Errout;    use Errout;
  32 with Expander;  use Expander;
  33 with Exp_Disp;  use Exp_Disp;
  34 with Fname;     use Fname;
  35 with Fname.UF;  use Fname.UF;
  36 with Freeze;    use Freeze;
  37 with Ghost;     use Ghost;
  38 with Itypes;    use Itypes;
  39 with Lib;       use Lib;
  40 with Lib.Load;  use Lib.Load;
  41 with Lib.Xref;  use Lib.Xref;
  42 with Nlists;    use Nlists;
  43 with Namet;     use Namet;
  44 with Nmake;     use Nmake;
  45 with Opt;       use Opt;
  46 with Rident;    use Rident;
  47 with Restrict;  use Restrict;
  48 with Rtsfind;   use Rtsfind;
  49 with Sem;       use Sem;
  50 with Sem_Aux;   use Sem_Aux;
  51 with Sem_Cat;   use Sem_Cat;
  52 with Sem_Ch3;   use Sem_Ch3;
  53 with Sem_Ch6;   use Sem_Ch6;
  54 with Sem_Ch7;   use Sem_Ch7;
  55 with Sem_Ch8;   use Sem_Ch8;
  56 with Sem_Ch10;  use Sem_Ch10;
  57 with Sem_Ch13;  use Sem_Ch13;
  58 with Sem_Dim;   use Sem_Dim;
  59 with Sem_Disp;  use Sem_Disp;
  60 with Sem_Elab;  use Sem_Elab;
  61 with Sem_Elim;  use Sem_Elim;
  62 with Sem_Eval;  use Sem_Eval;
  63 with Sem_Prag;  use Sem_Prag;
  64 with Sem_Res;   use Sem_Res;
  65 with Sem_Type;  use Sem_Type;
  66 with Sem_Util;  use Sem_Util;
  67 with Sem_Warn;  use Sem_Warn;
  68 with Stand;     use Stand;
  69 with Sinfo;     use Sinfo;
  70 with Sinfo.CN;  use Sinfo.CN;
  71 with Sinput;    use Sinput;
  72 with Sinput.L;  use Sinput.L;
  73 with Snames;    use Snames;
  74 with Stringt;   use Stringt;
  75 with Uname;     use Uname;
  76 with Table;
  77 with Tbuild;    use Tbuild;
  78 with Uintp;     use Uintp;
  79 with Urealp;    use Urealp;
  80 with Warnsw;    use Warnsw;
  81 
  82 with GNAT.HTable;
  83 
  84 package body Sem_Ch12 is
  85 
  86    ----------------------------------------------------------
  87    -- Implementation of Generic Analysis and Instantiation --
  88    ----------------------------------------------------------
  89 
  90    --  GNAT implements generics by macro expansion. No attempt is made to share
  91    --  generic instantiations (for now). Analysis of a generic definition does
  92    --  not perform any expansion action, but the expander must be called on the
  93    --  tree for each instantiation, because the expansion may of course depend
  94    --  on the generic actuals. All of this is best achieved as follows:
  95    --
  96    --  a) Semantic analysis of a generic unit is performed on a copy of the
  97    --  tree for the generic unit. All tree modifications that follow analysis
  98    --  do not affect the original tree. Links are kept between the original
  99    --  tree and the copy, in order to recognize non-local references within
 100    --  the generic, and propagate them to each instance (recall that name
 101    --  resolution is done on the generic declaration: generics are not really
 102    --  macros). This is summarized in the following diagram:
 103 
 104    --              .-----------.               .----------.
 105    --              |  semantic |<--------------|  generic |
 106    --              |    copy   |               |    unit  |
 107    --              |           |==============>|          |
 108    --              |___________|    global     |__________|
 109    --                             references     |   |  |
 110    --                                            |   |  |
 111    --                                          .-----|--|.
 112    --                                          |  .-----|---.
 113    --                                          |  |  .----------.
 114    --                                          |  |  |  generic |
 115    --                                          |__|  |          |
 116    --                                             |__| instance |
 117    --                                                |__________|
 118 
 119    --  b) Each instantiation copies the original tree, and inserts into it a
 120    --  series of declarations that describe the mapping between generic formals
 121    --  and actuals. For example, a generic In OUT parameter is an object
 122    --  renaming of the corresponding actual, etc. Generic IN parameters are
 123    --  constant declarations.
 124 
 125    --  c) In order to give the right visibility for these renamings, we use
 126    --  a different scheme for package and subprogram instantiations. For
 127    --  packages, the list of renamings is inserted into the package
 128    --  specification, before the visible declarations of the package. The
 129    --  renamings are analyzed before any of the text of the instance, and are
 130    --  thus visible at the right place. Furthermore, outside of the instance,
 131    --  the generic parameters are visible and denote their corresponding
 132    --  actuals.
 133 
 134    --  For subprograms, we create a container package to hold the renamings
 135    --  and the subprogram instance itself. Analysis of the package makes the
 136    --  renaming declarations visible to the subprogram. After analyzing the
 137    --  package, the defining entity for the subprogram is touched-up so that
 138    --  it appears declared in the current scope, and not inside the container
 139    --  package.
 140 
 141    --  If the instantiation is a compilation unit, the container package is
 142    --  given the same name as the subprogram instance. This ensures that
 143    --  the elaboration procedure called by the binder, using the compilation
 144    --  unit name, calls in fact the elaboration procedure for the package.
 145 
 146    --  Not surprisingly, private types complicate this approach. By saving in
 147    --  the original generic object the non-local references, we guarantee that
 148    --  the proper entities are referenced at the point of instantiation.
 149    --  However, for private types, this by itself does not insure that the
 150    --  proper VIEW of the entity is used (the full type may be visible at the
 151    --  point of generic definition, but not at instantiation, or vice-versa).
 152    --  In order to reference the proper view, we special-case any reference
 153    --  to private types in the generic object, by saving both views, one in
 154    --  the generic and one in the semantic copy. At time of instantiation, we
 155    --  check whether the two views are consistent, and exchange declarations if
 156    --  necessary, in order to restore the correct visibility. Similarly, if
 157    --  the instance view is private when the generic view was not, we perform
 158    --  the exchange. After completing the instantiation, we restore the
 159    --  current visibility. The flag Has_Private_View marks identifiers in the
 160    --  the generic unit that require checking.
 161 
 162    --  Visibility within nested generic units requires special handling.
 163    --  Consider the following scheme:
 164 
 165    --  type Global is ...         --  outside of generic unit.
 166    --  generic ...
 167    --  package Outer is
 168    --     ...
 169    --     type Semi_Global is ... --  global to inner.
 170 
 171    --     generic ...                                         -- 1
 172    --     procedure inner (X1 : Global;  X2 : Semi_Global);
 173 
 174    --     procedure in2 is new inner (...);                   -- 4
 175    --  end Outer;
 176 
 177    --  package New_Outer is new Outer (...);                  -- 2
 178    --  procedure New_Inner is new New_Outer.Inner (...);      -- 3
 179 
 180    --  The semantic analysis of Outer captures all occurrences of Global.
 181    --  The semantic analysis of Inner (at 1) captures both occurrences of
 182    --  Global and Semi_Global.
 183 
 184    --  At point 2 (instantiation of Outer), we also produce a generic copy
 185    --  of Inner, even though Inner is, at that point, not being instantiated.
 186    --  (This is just part of the semantic analysis of New_Outer).
 187 
 188    --  Critically, references to Global within Inner must be preserved, while
 189    --  references to Semi_Global should not preserved, because they must now
 190    --  resolve to an entity within New_Outer. To distinguish between these, we
 191    --  use a global variable, Current_Instantiated_Parent, which is set when
 192    --  performing a generic copy during instantiation (at 2). This variable is
 193    --  used when performing a generic copy that is not an instantiation, but
 194    --  that is nested within one, as the occurrence of 1 within 2. The analysis
 195    --  of a nested generic only preserves references that are global to the
 196    --  enclosing Current_Instantiated_Parent. We use the Scope_Depth value to
 197    --  determine whether a reference is external to the given parent.
 198 
 199    --  The instantiation at point 3 requires no special treatment. The method
 200    --  works as well for further nestings of generic units, but of course the
 201    --  variable Current_Instantiated_Parent must be stacked because nested
 202    --  instantiations can occur, e.g. the occurrence of 4 within 2.
 203 
 204    --  The instantiation of package and subprogram bodies is handled in a
 205    --  similar manner, except that it is delayed until after semantic
 206    --  analysis is complete. In this fashion complex cross-dependencies
 207    --  between several package declarations and bodies containing generics
 208    --  can be compiled which otherwise would diagnose spurious circularities.
 209 
 210    --  For example, it is possible to compile two packages A and B that
 211    --  have the following structure:
 212 
 213    --    package A is                         package B is
 214    --       generic ...                          generic ...
 215    --       package G_A is                       package G_B is
 216 
 217    --    with B;                              with A;
 218    --    package body A is                    package body B is
 219    --       package N_B is new G_B (..)          package N_A is new G_A (..)
 220 
 221    --  The table Pending_Instantiations in package Inline is used to keep
 222    --  track of body instantiations that are delayed in this manner. Inline
 223    --  handles the actual calls to do the body instantiations. This activity
 224    --  is part of Inline, since the processing occurs at the same point, and
 225    --  for essentially the same reason, as the handling of inlined routines.
 226 
 227    ----------------------------------------------
 228    -- Detection of Instantiation Circularities --
 229    ----------------------------------------------
 230 
 231    --  If we have a chain of instantiations that is circular, this is static
 232    --  error which must be detected at compile time. The detection of these
 233    --  circularities is carried out at the point that we insert a generic
 234    --  instance spec or body. If there is a circularity, then the analysis of
 235    --  the offending spec or body will eventually result in trying to load the
 236    --  same unit again, and we detect this problem as we analyze the package
 237    --  instantiation for the second time.
 238 
 239    --  At least in some cases after we have detected the circularity, we get
 240    --  into trouble if we try to keep going. The following flag is set if a
 241    --  circularity is detected, and used to abandon compilation after the
 242    --  messages have been posted.
 243 
 244    -----------------------------------------
 245    -- Implementation of Generic Contracts --
 246    -----------------------------------------
 247 
 248    --  A "contract" is a collection of aspects and pragmas that either verify a
 249    --  property of a construct at runtime or classify the data flow to and from
 250    --  the construct in some fashion.
 251 
 252    --  Generic packages, subprograms and their respective bodies may be subject
 253    --  to the following contract-related aspects or pragmas collectively known
 254    --  as annotations:
 255 
 256    --     package                  subprogram [body]
 257    --       Abstract_State           Contract_Cases
 258    --       Initial_Condition        Depends
 259    --       Initializes              Extensions_Visible
 260    --                                Global
 261    --     package body               Post
 262    --       Refined_State            Post_Class
 263    --                                Postcondition
 264    --                                Pre
 265    --                                Pre_Class
 266    --                                Precondition
 267    --                                Refined_Depends
 268    --                                Refined_Global
 269    --                                Refined_Post
 270    --                                Test_Case
 271 
 272    --  Most package contract annotations utilize forward references to classify
 273    --  data declared within the package [body]. Subprogram annotations then use
 274    --  the classifications to further refine them. These inter dependencies are
 275    --  problematic with respect to the implementation of generics because their
 276    --  analysis, capture of global references and instantiation does not mesh
 277    --  well with the existing mechanism.
 278 
 279    --  1) Analysis of generic contracts is carried out the same way non-generic
 280    --  contracts are analyzed:
 281 
 282    --    1.1) General rule - a contract is analyzed after all related aspects
 283    --    and pragmas are analyzed. This is done by routines
 284 
 285    --       Analyze_Package_Body_Contract
 286    --       Analyze_Package_Contract
 287    --       Analyze_Subprogram_Body_Contract
 288    --       Analyze_Subprogram_Contract
 289 
 290    --    1.2) Compilation unit - the contract is analyzed after Pragmas_After
 291    --    are processed.
 292 
 293    --    1.3) Compilation unit body - the contract is analyzed at the end of
 294    --    the body declaration list.
 295 
 296    --    1.4) Package - the contract is analyzed at the end of the private or
 297    --    visible declarations, prior to analyzing the contracts of any nested
 298    --    packages or subprograms.
 299 
 300    --    1.5) Package body - the contract is analyzed at the end of the body
 301    --    declaration list, prior to analyzing the contracts of any nested
 302    --    packages or subprograms.
 303 
 304    --    1.6) Subprogram - if the subprogram is declared inside a block, a
 305    --    package or a subprogram, then its contract is analyzed at the end of
 306    --    the enclosing declarations, otherwise the subprogram is a compilation
 307    --    unit 1.2).
 308 
 309    --    1.7) Subprogram body - if the subprogram body is declared inside a
 310    --    block, a package body or a subprogram body, then its contract is
 311    --    analyzed at the end of the enclosing declarations, otherwise the
 312    --    subprogram is a compilation unit 1.3).
 313 
 314    --  2) Capture of global references within contracts is done after capturing
 315    --  global references within the generic template. There are two reasons for
 316    --  this delay - pragma annotations are not part of the generic template in
 317    --  the case of a generic subprogram declaration, and analysis of contracts
 318    --  is delayed.
 319 
 320    --  Contract-related source pragmas within generic templates are prepared
 321    --  for delayed capture of global references by routine
 322 
 323    --    Create_Generic_Contract
 324 
 325    --  The routine associates these pragmas with the contract of the template.
 326    --  In the case of a generic subprogram declaration, the routine creates
 327    --  generic templates for the pragmas declared after the subprogram because
 328    --  they are not part of the template.
 329 
 330    --    generic                                --  template starts
 331    --    procedure Gen_Proc (Input : Integer);  --  template ends
 332    --    pragma Precondition (Input > 0);       --  requires own template
 333 
 334    --    2.1) The capture of global references with aspect specifications and
 335    --    source pragmas that apply to a generic unit must be suppressed when
 336    --    the generic template is being processed because the contracts have not
 337    --    been analyzed yet. Any attempts to capture global references at that
 338    --    point will destroy the Associated_Node linkages and leave the template
 339    --    undecorated. This delay is controlled by routine
 340 
 341    --       Requires_Delayed_Save
 342 
 343    --    2.2) The real capture of global references within a contract is done
 344    --    after the contract has been analyzed, by routine
 345 
 346    --       Save_Global_References_In_Contract
 347 
 348    --  3) The instantiation of a generic contract occurs as part of the
 349    --  instantiation of the contract owner. Generic subprogram declarations
 350    --  require additional processing when the contract is specified by pragmas
 351    --  because the pragmas are not part of the generic template. This is done
 352    --  by routine
 353 
 354    --    Instantiate_Subprogram_Contract
 355 
 356    Circularity_Detected : Boolean := False;
 357    --  This should really be reset on encountering a new main unit, but in
 358    --  practice we are not using multiple main units so it is not critical.
 359 
 360    --------------------------------------------------
 361    -- Formal packages and partial parameterization --
 362    --------------------------------------------------
 363 
 364    --  When compiling a generic, a formal package is a local instantiation. If
 365    --  declared with a box, its generic formals are visible in the enclosing
 366    --  generic. If declared with a partial list of actuals, those actuals that
 367    --  are defaulted (covered by an Others clause, or given an explicit box
 368    --  initialization) are also visible in the enclosing generic, while those
 369    --  that have a corresponding actual are not.
 370 
 371    --  In our source model of instantiation, the same visibility must be
 372    --  present in the spec and body of an instance: the names of the formals
 373    --  that are defaulted must be made visible within the instance, and made
 374    --  invisible (hidden) after the instantiation is complete, so that they
 375    --  are not accessible outside of the instance.
 376 
 377    --  In a generic, a formal package is treated like a special instantiation.
 378    --  Our Ada 95 compiler handled formals with and without box in different
 379    --  ways. With partial parameterization, we use a single model for both.
 380    --  We create a package declaration that consists of the specification of
 381    --  the generic package, and a set of declarations that map the actuals
 382    --  into local renamings, just as we do for bona fide instantiations. For
 383    --  defaulted parameters and formals with a box, we copy directly the
 384    --  declarations of the formal into this local package. The result is a
 385    --  a package whose visible declarations may include generic formals. This
 386    --  package is only used for type checking and visibility analysis, and
 387    --  never reaches the back-end, so it can freely violate the placement
 388    --  rules for generic formal declarations.
 389 
 390    --  The list of declarations (renamings and copies of formals) is built
 391    --  by Analyze_Associations, just as for regular instantiations.
 392 
 393    --  At the point of instantiation, conformance checking must be applied only
 394    --  to those parameters that were specified in the formal. We perform this
 395    --  checking by creating another internal instantiation, this one including
 396    --  only the renamings and the formals (the rest of the package spec is not
 397    --  relevant to conformance checking). We can then traverse two lists: the
 398    --  list of actuals in the instance that corresponds to the formal package,
 399    --  and the list of actuals produced for this bogus instantiation. We apply
 400    --  the conformance rules to those actuals that are not defaulted (i.e.
 401    --  which still appear as generic formals.
 402 
 403    --  When we compile an instance body we must make the right parameters
 404    --  visible again. The predicate Is_Generic_Formal indicates which of the
 405    --  formals should have its Is_Hidden flag reset.
 406 
 407    -----------------------
 408    -- Local subprograms --
 409    -----------------------
 410 
 411    procedure Abandon_Instantiation (N : Node_Id);
 412    pragma No_Return (Abandon_Instantiation);
 413    --  Posts an error message "instantiation abandoned" at the indicated node
 414    --  and then raises the exception Instantiation_Error to do it.
 415 
 416    procedure Analyze_Formal_Array_Type
 417      (T   : in out Entity_Id;
 418       Def : Node_Id);
 419    --  A formal array type is treated like an array type declaration, and
 420    --  invokes Array_Type_Declaration (sem_ch3) whose first parameter is
 421    --  in-out, because in the case of an anonymous type the entity is
 422    --  actually created in the procedure.
 423 
 424    --  The following procedures treat other kinds of formal parameters
 425 
 426    procedure Analyze_Formal_Derived_Interface_Type
 427      (N   : Node_Id;
 428       T   : Entity_Id;
 429       Def : Node_Id);
 430 
 431    procedure Analyze_Formal_Derived_Type
 432      (N   : Node_Id;
 433       T   : Entity_Id;
 434       Def : Node_Id);
 435 
 436    procedure Analyze_Formal_Interface_Type
 437      (N   : Node_Id;
 438       T   : Entity_Id;
 439       Def : Node_Id);
 440 
 441    --  The following subprograms create abbreviated declarations for formal
 442    --  scalar types. We introduce an anonymous base of the proper class for
 443    --  each of them, and define the formals as constrained first subtypes of
 444    --  their bases. The bounds are expressions that are non-static in the
 445    --  generic.
 446 
 447    procedure Analyze_Formal_Decimal_Fixed_Point_Type
 448                                                 (T : Entity_Id; Def : Node_Id);
 449    procedure Analyze_Formal_Discrete_Type       (T : Entity_Id; Def : Node_Id);
 450    procedure Analyze_Formal_Floating_Type       (T : Entity_Id; Def : Node_Id);
 451    procedure Analyze_Formal_Signed_Integer_Type (T : Entity_Id; Def : Node_Id);
 452    procedure Analyze_Formal_Modular_Type        (T : Entity_Id; Def : Node_Id);
 453    procedure Analyze_Formal_Ordinary_Fixed_Point_Type
 454                                                 (T : Entity_Id; Def : Node_Id);
 455 
 456    procedure Analyze_Formal_Private_Type
 457      (N   : Node_Id;
 458       T   : Entity_Id;
 459       Def : Node_Id);
 460    --  Creates a new private type, which does not require completion
 461 
 462    procedure Analyze_Formal_Incomplete_Type (T : Entity_Id; Def : Node_Id);
 463    --  Ada 2012: Creates a new incomplete type whose actual does not freeze
 464 
 465    procedure Analyze_Generic_Formal_Part (N : Node_Id);
 466    --  Analyze generic formal part
 467 
 468    procedure Analyze_Generic_Access_Type (T : Entity_Id; Def : Node_Id);
 469    --  Create a new access type with the given designated type
 470 
 471    function Analyze_Associations
 472      (I_Node  : Node_Id;
 473       Formals : List_Id;
 474       F_Copy  : List_Id) return List_Id;
 475    --  At instantiation time, build the list of associations between formals
 476    --  and actuals. Each association becomes a renaming declaration for the
 477    --  formal entity. F_Copy is the analyzed list of formals in the generic
 478    --  copy. It is used to apply legality checks to the actuals. I_Node is the
 479    --  instantiation node itself.
 480 
 481    procedure Analyze_Subprogram_Instantiation
 482      (N : Node_Id;
 483       K : Entity_Kind);
 484 
 485    procedure Build_Instance_Compilation_Unit_Nodes
 486      (N        : Node_Id;
 487       Act_Body : Node_Id;
 488       Act_Decl : Node_Id);
 489    --  This procedure is used in the case where the generic instance of a
 490    --  subprogram body or package body is a library unit. In this case, the
 491    --  original library unit node for the generic instantiation must be
 492    --  replaced by the resulting generic body, and a link made to a new
 493    --  compilation unit node for the generic declaration. The argument N is
 494    --  the original generic instantiation. Act_Body and Act_Decl are the body
 495    --  and declaration of the instance (either package body and declaration
 496    --  nodes or subprogram body and declaration nodes depending on the case).
 497    --  On return, the node N has been rewritten with the actual body.
 498 
 499    procedure Check_Access_Definition (N : Node_Id);
 500    --  Subsidiary routine to null exclusion processing. Perform an assertion
 501    --  check on Ada version and the presence of an access definition in N.
 502 
 503    procedure Check_Formal_Packages (P_Id : Entity_Id);
 504    --  Apply the following to all formal packages in generic associations
 505 
 506    procedure Check_Formal_Package_Instance
 507      (Formal_Pack : Entity_Id;
 508       Actual_Pack : Entity_Id);
 509    --  Verify that the actuals of the actual instance match the actuals of
 510    --  the template for a formal package that is not declared with a box.
 511 
 512    procedure Check_Forward_Instantiation (Decl : Node_Id);
 513    --  If the generic is a local entity and the corresponding body has not
 514    --  been seen yet, flag enclosing packages to indicate that it will be
 515    --  elaborated after the generic body. Subprograms declared in the same
 516    --  package cannot be inlined by the front end because front-end inlining
 517    --  requires a strict linear order of elaboration.
 518 
 519    function Check_Hidden_Primitives (Assoc_List : List_Id) return Elist_Id;
 520    --  Check if some association between formals and actuals requires to make
 521    --  visible primitives of a tagged type, and make those primitives visible.
 522    --  Return the list of primitives whose visibility is modified (to restore
 523    --  their visibility later through Restore_Hidden_Primitives). If no
 524    --  candidate is found then return No_Elist.
 525 
 526    procedure Check_Hidden_Child_Unit
 527      (N           : Node_Id;
 528       Gen_Unit    : Entity_Id;
 529       Act_Decl_Id : Entity_Id);
 530    --  If the generic unit is an implicit child instance within a parent
 531    --  instance, we need to make an explicit test that it is not hidden by
 532    --  a child instance of the same name and parent.
 533 
 534    procedure Check_Generic_Actuals
 535      (Instance      : Entity_Id;
 536       Is_Formal_Box : Boolean);
 537    --  Similar to previous one. Check the actuals in the instantiation,
 538    --  whose views can change between the point of instantiation and the point
 539    --  of instantiation of the body. In addition, mark the generic renamings
 540    --  as generic actuals, so that they are not compatible with other actuals.
 541    --  Recurse on an actual that is a formal package whose declaration has
 542    --  a box.
 543 
 544    function Contains_Instance_Of
 545      (Inner : Entity_Id;
 546       Outer : Entity_Id;
 547       N     : Node_Id) return Boolean;
 548    --  Inner is instantiated within the generic Outer. Check whether Inner
 549    --  directly or indirectly contains an instance of Outer or of one of its
 550    --  parents, in the case of a subunit. Each generic unit holds a list of
 551    --  the entities instantiated within (at any depth). This procedure
 552    --  determines whether the set of such lists contains a cycle, i.e. an
 553    --  illegal circular instantiation.
 554 
 555    function Denotes_Formal_Package
 556      (Pack     : Entity_Id;
 557       On_Exit  : Boolean := False;
 558       Instance : Entity_Id := Empty) return Boolean;
 559    --  Returns True if E is a formal package of an enclosing generic, or
 560    --  the actual for such a formal in an enclosing instantiation. If such
 561    --  a package is used as a formal in an nested generic, or as an actual
 562    --  in a nested instantiation, the visibility of ITS formals should not
 563    --  be modified. When called from within Restore_Private_Views, the flag
 564    --  On_Exit is true, to indicate that the search for a possible enclosing
 565    --  instance should ignore the current one. In that case Instance denotes
 566    --  the declaration for which this is an actual. This declaration may be
 567    --  an instantiation in the source, or the internal instantiation that
 568    --  corresponds to the actual for a formal package.
 569 
 570    function Earlier (N1, N2 : Node_Id) return Boolean;
 571    --  Yields True if N1 and N2 appear in the same compilation unit,
 572    --  ignoring subunits, and if N1 is to the left of N2 in a left-to-right
 573    --  traversal of the tree for the unit. Used to determine the placement
 574    --  of freeze nodes for instance bodies that may depend on other instances.
 575 
 576    function Find_Actual_Type
 577      (Typ       : Entity_Id;
 578       Gen_Type  : Entity_Id) return Entity_Id;
 579    --  When validating the actual types of a child instance, check whether
 580    --  the formal is a formal type of the parent unit, and retrieve the current
 581    --  actual for it. Typ is the entity in the analyzed formal type declaration
 582    --  (component or index type of an array type, or designated type of an
 583    --  access formal) and Gen_Type is the enclosing analyzed formal array
 584    --  or access type. The desired actual may be a formal of a parent, or may
 585    --  be declared in a formal package of a parent. In both cases it is a
 586    --  generic actual type because it appears within a visible instance.
 587    --  Finally, it may be declared in a parent unit without being a formal
 588    --  of that unit, in which case it must be retrieved by visibility.
 589    --  Ambiguities may still arise if two homonyms are declared in two formal
 590    --  packages, and the prefix of the formal type may be needed to resolve
 591    --  the ambiguity in the instance ???
 592 
 593    procedure Freeze_Subprogram_Body
 594      (Inst_Node : Node_Id;
 595       Gen_Body  : Node_Id;
 596       Pack_Id   : Entity_Id);
 597    --  The generic body may appear textually after the instance, including
 598    --  in the proper body of a stub, or within a different package instance.
 599    --  Given that the instance can only be elaborated after the generic, we
 600    --  place freeze_nodes for the instance and/or for packages that may enclose
 601    --  the instance and the generic, so that the back-end can establish the
 602    --  proper order of elaboration.
 603 
 604    function Get_Associated_Node (N : Node_Id) return Node_Id;
 605    --  In order to propagate semantic information back from the analyzed copy
 606    --  to the original generic, we maintain links between selected nodes in the
 607    --  generic and their corresponding copies. At the end of generic analysis,
 608    --  the routine Save_Global_References traverses the generic tree, examines
 609    --  the semantic information, and preserves the links to those nodes that
 610    --  contain global information. At instantiation, the information from the
 611    --  associated node is placed on the new copy, so that name resolution is
 612    --  not repeated.
 613    --
 614    --  Three kinds of source nodes have associated nodes:
 615    --
 616    --    a) those that can reference (denote) entities, that is identifiers,
 617    --       character literals, expanded_names, operator symbols, operators,
 618    --       and attribute reference nodes. These nodes have an Entity field
 619    --       and are the set of nodes that are in N_Has_Entity.
 620    --
 621    --    b) aggregates (N_Aggregate and N_Extension_Aggregate)
 622    --
 623    --    c) selected components (N_Selected_Component)
 624    --
 625    --  For the first class, the associated node preserves the entity if it is
 626    --  global. If the generic contains nested instantiations, the associated
 627    --  node itself has been recopied, and a chain of them must be followed.
 628    --
 629    --  For aggregates, the associated node allows retrieval of the type, which
 630    --  may otherwise not appear in the generic. The view of this type may be
 631    --  different between generic and instantiation, and the full view can be
 632    --  installed before the instantiation is analyzed. For aggregates of type
 633    --  extensions, the same view exchange may have to be performed for some of
 634    --  the ancestor types, if their view is private at the point of
 635    --  instantiation.
 636    --
 637    --  Nodes that are selected components in the parse tree may be rewritten
 638    --  as expanded names after resolution, and must be treated as potential
 639    --  entity holders, which is why they also have an Associated_Node.
 640    --
 641    --  Nodes that do not come from source, such as freeze nodes, do not appear
 642    --  in the generic tree, and need not have an associated node.
 643    --
 644    --  The associated node is stored in the Associated_Node field. Note that
 645    --  this field overlaps Entity, which is fine, because the whole point is
 646    --  that we don't need or want the normal Entity field in this situation.
 647 
 648    function Has_Been_Exchanged (E : Entity_Id) return Boolean;
 649    --  Traverse the Exchanged_Views list to see if a type was private
 650    --  and has already been flipped during this phase of instantiation.
 651 
 652    procedure Hide_Current_Scope;
 653    --  When instantiating a generic child unit, the parent context must be
 654    --  present, but the instance and all entities that may be generated
 655    --  must be inserted in the current scope. We leave the current scope
 656    --  on the stack, but make its entities invisible to avoid visibility
 657    --  problems. This is reversed at the end of the instantiation. This is
 658    --  not done for the instantiation of the bodies, which only require the
 659    --  instances of the generic parents to be in scope.
 660 
 661    function In_Same_Declarative_Part
 662      (F_Node : Node_Id;
 663       Inst   : Node_Id) return Boolean;
 664    --  True if the instantiation Inst and the given freeze_node F_Node appear
 665    --  within the same declarative part, ignoring subunits, but with no inter-
 666    --  vening subprograms or concurrent units. Used to find the proper plave
 667    --  for the freeze node of an instance, when the generic is declared in a
 668    --  previous instance. If predicate is true, the freeze node of the instance
 669    --  can be placed after the freeze node of the previous instance, Otherwise
 670    --  it has to be placed at the end of the current declarative part.
 671 
 672    function In_Main_Context (E : Entity_Id) return Boolean;
 673    --  Check whether an instantiation is in the context of the main unit.
 674    --  Used to determine whether its body should be elaborated to allow
 675    --  front-end inlining.
 676 
 677    procedure Inherit_Context (Gen_Decl : Node_Id; Inst : Node_Id);
 678    --  Add the context clause of the unit containing a generic unit to a
 679    --  compilation unit that is, or contains, an instantiation.
 680 
 681    procedure Init_Env;
 682    --  Establish environment for subsequent instantiation. Separated from
 683    --  Save_Env because data-structures for visibility handling must be
 684    --  initialized before call to Check_Generic_Child_Unit.
 685 
 686    procedure Inline_Instance_Body
 687      (N        : Node_Id;
 688       Gen_Unit : Entity_Id;
 689       Act_Decl : Node_Id);
 690    --  If front-end inlining is requested, instantiate the package body,
 691    --  and preserve the visibility of its compilation unit, to insure
 692    --  that successive instantiations succeed.
 693 
 694    procedure Insert_Freeze_Node_For_Instance
 695      (N      : Node_Id;
 696       F_Node : Node_Id);
 697    --  N denotes a package or a subprogram instantiation and F_Node is the
 698    --  associated freeze node. Insert the freeze node before the first source
 699    --  body which follows immediately after N. If no such body is found, the
 700    --  freeze node is inserted at the end of the declarative region which
 701    --  contains N.
 702 
 703    procedure Install_Body
 704      (Act_Body : Node_Id;
 705       N        : Node_Id;
 706       Gen_Body : Node_Id;
 707       Gen_Decl : Node_Id);
 708    --  If the instantiation happens textually before the body of the generic,
 709    --  the instantiation of the body must be analyzed after the generic body,
 710    --  and not at the point of instantiation. Such early instantiations can
 711    --  happen if the generic and the instance appear in a package declaration
 712    --  because the generic body can only appear in the corresponding package
 713    --  body. Early instantiations can also appear if generic, instance and
 714    --  body are all in the declarative part of a subprogram or entry. Entities
 715    --  of packages that are early instantiations are delayed, and their freeze
 716    --  node appears after the generic body.
 717 
 718    procedure Install_Formal_Packages (Par : Entity_Id);
 719    --  Install the visible part of any formal of the parent that is a formal
 720    --  package. Note that for the case of a formal package with a box, this
 721    --  includes the formal part of the formal package (12.7(10/2)).
 722 
 723    procedure Install_Hidden_Primitives
 724      (Prims_List : in out Elist_Id;
 725       Gen_T      : Entity_Id;
 726       Act_T      : Entity_Id);
 727    --  Remove suffix 'P' from hidden primitives of Act_T to match the
 728    --  visibility of primitives of Gen_T. The list of primitives to which
 729    --  the suffix is removed is added to Prims_List to restore them later.
 730 
 731    procedure Install_Parent (P : Entity_Id; In_Body : Boolean := False);
 732    --  When compiling an instance of a child unit the parent (which is
 733    --  itself an instance) is an enclosing scope that must be made
 734    --  immediately visible. This procedure is also used to install the non-
 735    --  generic parent of a generic child unit when compiling its body, so
 736    --  that full views of types in the parent are made visible.
 737 
 738    --  The functions Instantiate_XXX perform various legality checks and build
 739    --  the declarations for instantiated generic parameters. In all of these
 740    --  Formal is the entity in the generic unit, Actual is the entity of
 741    --  expression in the generic associations, and Analyzed_Formal is the
 742    --  formal in the generic copy, which contains the semantic information to
 743    --  be used to validate the actual.
 744 
 745    function Instantiate_Object
 746      (Formal          : Node_Id;
 747       Actual          : Node_Id;
 748       Analyzed_Formal : Node_Id) return List_Id;
 749 
 750    function Instantiate_Type
 751      (Formal          : Node_Id;
 752       Actual          : Node_Id;
 753       Analyzed_Formal : Node_Id;
 754       Actual_Decls    : List_Id) return List_Id;
 755 
 756    function Instantiate_Formal_Subprogram
 757      (Formal          : Node_Id;
 758       Actual          : Node_Id;
 759       Analyzed_Formal : Node_Id) return Node_Id;
 760 
 761    function Instantiate_Formal_Package
 762      (Formal          : Node_Id;
 763       Actual          : Node_Id;
 764       Analyzed_Formal : Node_Id) return List_Id;
 765    --  If the formal package is declared with a box, special visibility rules
 766    --  apply to its formals: they are in the visible part of the package. This
 767    --  is true in the declarative region of the formal package, that is to say
 768    --  in the enclosing generic or instantiation. For an instantiation, the
 769    --  parameters of the formal package are made visible in an explicit step.
 770    --  Furthermore, if the actual has a visible USE clause, these formals must
 771    --  be made potentially use-visible as well. On exit from the enclosing
 772    --  instantiation, the reverse must be done.
 773 
 774    --  For a formal package declared without a box, there are conformance rules
 775    --  that apply to the actuals in the generic declaration and the actuals of
 776    --  the actual package in the enclosing instantiation. The simplest way to
 777    --  apply these rules is to repeat the instantiation of the formal package
 778    --  in the context of the enclosing instance, and compare the generic
 779    --  associations of this instantiation with those of the actual package.
 780    --  This internal instantiation only needs to contain the renamings of the
 781    --  formals: the visible and private declarations themselves need not be
 782    --  created.
 783 
 784    --  In Ada 2005, the formal package may be only partially parameterized.
 785    --  In that case the visibility step must make visible those actuals whose
 786    --  corresponding formals were given with a box. A final complication
 787    --  involves inherited operations from formal derived types, which must
 788    --  be visible if the type is.
 789 
 790    function Is_In_Main_Unit (N : Node_Id) return Boolean;
 791    --  Test if given node is in the main unit
 792 
 793    procedure Load_Parent_Of_Generic
 794      (N             : Node_Id;
 795       Spec          : Node_Id;
 796       Body_Optional : Boolean := False);
 797    --  If the generic appears in a separate non-generic library unit, load the
 798    --  corresponding body to retrieve the body of the generic. N is the node
 799    --  for the generic instantiation, Spec is the generic package declaration.
 800    --
 801    --  Body_Optional is a flag that indicates that the body is being loaded to
 802    --  ensure that temporaries are generated consistently when there are other
 803    --  instances in the current declarative part that precede the one being
 804    --  loaded. In that case a missing body is acceptable.
 805 
 806    procedure Map_Formal_Package_Entities (Form : Entity_Id; Act : Entity_Id);
 807    --  Within the generic part, entities in the formal package are
 808    --  visible. To validate subsequent type declarations, indicate
 809    --  the correspondence between the entities in the analyzed formal,
 810    --  and the entities in the actual package. There are three packages
 811    --  involved in the instantiation of a formal package: the parent
 812    --  generic P1 which appears in the generic declaration, the fake
 813    --  instantiation P2 which appears in the analyzed generic, and whose
 814    --  visible entities may be used in subsequent formals, and the actual
 815    --  P3 in the instance. To validate subsequent formals, me indicate
 816    --  that the entities in P2 are mapped into those of P3. The mapping of
 817    --  entities has to be done recursively for nested packages.
 818 
 819    procedure Move_Freeze_Nodes
 820      (Out_Of : Entity_Id;
 821       After  : Node_Id;
 822       L      : List_Id);
 823    --  Freeze nodes can be generated in the analysis of a generic unit, but
 824    --  will not be seen by the back-end. It is necessary to move those nodes
 825    --  to the enclosing scope if they freeze an outer entity. We place them
 826    --  at the end of the enclosing generic package, which is semantically
 827    --  neutral.
 828 
 829    procedure Preanalyze_Actuals (N : Node_Id; Inst : Entity_Id := Empty);
 830    --  Analyze actuals to perform name resolution. Full resolution is done
 831    --  later, when the expected types are known, but names have to be captured
 832    --  before installing parents of generics, that are not visible for the
 833    --  actuals themselves.
 834    --
 835    --  If Inst is present, it is the entity of the package instance. This
 836    --  entity is marked as having a limited_view actual when some actual is
 837    --  a limited view. This is used to place the instance body properly.
 838 
 839    procedure Remove_Parent (In_Body : Boolean := False);
 840    --  Reverse effect after instantiation of child is complete
 841 
 842    procedure Restore_Hidden_Primitives (Prims_List : in out Elist_Id);
 843    --  Restore suffix 'P' to primitives of Prims_List and leave Prims_List
 844    --  set to No_Elist.
 845 
 846    procedure Set_Instance_Env
 847      (Gen_Unit : Entity_Id;
 848       Act_Unit : Entity_Id);
 849    --  Save current instance on saved environment, to be used to determine
 850    --  the global status of entities in nested instances. Part of Save_Env.
 851    --  called after verifying that the generic unit is legal for the instance,
 852    --  The procedure also examines whether the generic unit is a predefined
 853    --  unit, in order to set configuration switches accordingly. As a result
 854    --  the procedure must be called after analyzing and freezing the actuals.
 855 
 856    procedure Set_Instance_Of (A : Entity_Id; B : Entity_Id);
 857    --  Associate analyzed generic parameter with corresponding instance. Used
 858    --  for semantic checks at instantiation time.
 859 
 860    function True_Parent (N : Node_Id) return Node_Id;
 861    --  For a subunit, return parent of corresponding stub, else return
 862    --  parent of node.
 863 
 864    procedure Valid_Default_Attribute (Nam : Entity_Id; Def : Node_Id);
 865    --  Verify that an attribute that appears as the default for a formal
 866    --  subprogram is a function or procedure with the correct profile.
 867 
 868    -------------------------------------------
 869    -- Data Structures for Generic Renamings --
 870    -------------------------------------------
 871 
 872    --  The map Generic_Renamings associates generic entities with their
 873    --  corresponding actuals. Currently used to validate type instances. It
 874    --  will eventually be used for all generic parameters to eliminate the
 875    --  need for overload resolution in the instance.
 876 
 877    type Assoc_Ptr is new Int;
 878 
 879    Assoc_Null : constant Assoc_Ptr := -1;
 880 
 881    type Assoc is record
 882       Gen_Id         : Entity_Id;
 883       Act_Id         : Entity_Id;
 884       Next_In_HTable : Assoc_Ptr;
 885    end record;
 886 
 887    package Generic_Renamings is new Table.Table
 888      (Table_Component_Type => Assoc,
 889       Table_Index_Type     => Assoc_Ptr,
 890       Table_Low_Bound      => 0,
 891       Table_Initial        => 10,
 892       Table_Increment      => 100,
 893       Table_Name           => "Generic_Renamings");
 894 
 895    --  Variable to hold enclosing instantiation. When the environment is
 896    --  saved for a subprogram inlining, the corresponding Act_Id is empty.
 897 
 898    Current_Instantiated_Parent : Assoc := (Empty, Empty, Assoc_Null);
 899 
 900    --  Hash table for associations
 901 
 902    HTable_Size : constant := 37;
 903    type HTable_Range is range 0 .. HTable_Size - 1;
 904 
 905    procedure Set_Next_Assoc (E : Assoc_Ptr; Next : Assoc_Ptr);
 906    function  Next_Assoc     (E : Assoc_Ptr) return Assoc_Ptr;
 907    function Get_Gen_Id      (E : Assoc_Ptr) return Entity_Id;
 908    function Hash            (F : Entity_Id) return HTable_Range;
 909 
 910    package Generic_Renamings_HTable is new GNAT.HTable.Static_HTable (
 911       Header_Num => HTable_Range,
 912       Element    => Assoc,
 913       Elmt_Ptr   => Assoc_Ptr,
 914       Null_Ptr   => Assoc_Null,
 915       Set_Next   => Set_Next_Assoc,
 916       Next       => Next_Assoc,
 917       Key        => Entity_Id,
 918       Get_Key    => Get_Gen_Id,
 919       Hash       => Hash,
 920       Equal      => "=");
 921 
 922    Exchanged_Views : Elist_Id;
 923    --  This list holds the private views that have been exchanged during
 924    --  instantiation to restore the visibility of the generic declaration.
 925    --  (see comments above). After instantiation, the current visibility is
 926    --  reestablished by means of a traversal of this list.
 927 
 928    Hidden_Entities : Elist_Id;
 929    --  This list holds the entities of the current scope that are removed
 930    --  from immediate visibility when instantiating a child unit. Their
 931    --  visibility is restored in Remove_Parent.
 932 
 933    --  Because instantiations can be recursive, the following must be saved
 934    --  on entry and restored on exit from an instantiation (spec or body).
 935    --  This is done by the two procedures Save_Env and Restore_Env. For
 936    --  package and subprogram instantiations (but not for the body instances)
 937    --  the action of Save_Env is done in two steps: Init_Env is called before
 938    --  Check_Generic_Child_Unit, because setting the parent instances requires
 939    --  that the visibility data structures be properly initialized. Once the
 940    --  generic is unit is validated, Set_Instance_Env completes Save_Env.
 941 
 942    Parent_Unit_Visible : Boolean := False;
 943    --  Parent_Unit_Visible is used when the generic is a child unit, and
 944    --  indicates whether the ultimate parent of the generic is visible in the
 945    --  instantiation environment. It is used to reset the visibility of the
 946    --  parent at the end of the instantiation (see Remove_Parent).
 947 
 948    Instance_Parent_Unit : Entity_Id := Empty;
 949    --  This records the ultimate parent unit of an instance of a generic
 950    --  child unit and is used in conjunction with Parent_Unit_Visible to
 951    --  indicate the unit to which the Parent_Unit_Visible flag corresponds.
 952 
 953    type Instance_Env is record
 954       Instantiated_Parent  : Assoc;
 955       Exchanged_Views      : Elist_Id;
 956       Hidden_Entities      : Elist_Id;
 957       Current_Sem_Unit     : Unit_Number_Type;
 958       Parent_Unit_Visible  : Boolean   := False;
 959       Instance_Parent_Unit : Entity_Id := Empty;
 960       Switches             : Config_Switches_Type;
 961    end record;
 962 
 963    package Instance_Envs is new Table.Table (
 964      Table_Component_Type => Instance_Env,
 965      Table_Index_Type     => Int,
 966      Table_Low_Bound      => 0,
 967      Table_Initial        => 32,
 968      Table_Increment      => 100,
 969      Table_Name           => "Instance_Envs");
 970 
 971    procedure Restore_Private_Views
 972      (Pack_Id    : Entity_Id;
 973       Is_Package : Boolean := True);
 974    --  Restore the private views of external types, and unmark the generic
 975    --  renamings of actuals, so that they become compatible subtypes again.
 976    --  For subprograms, Pack_Id is the package constructed to hold the
 977    --  renamings.
 978 
 979    procedure Switch_View (T : Entity_Id);
 980    --  Switch the partial and full views of a type and its private
 981    --  dependents (i.e. its subtypes and derived types).
 982 
 983    ------------------------------------
 984    -- Structures for Error Reporting --
 985    ------------------------------------
 986 
 987    Instantiation_Node : Node_Id;
 988    --  Used by subprograms that validate instantiation of formal parameters
 989    --  where there might be no actual on which to place the error message.
 990    --  Also used to locate the instantiation node for generic subunits.
 991 
 992    Instantiation_Error : exception;
 993    --  When there is a semantic error in the generic parameter matching,
 994    --  there is no point in continuing the instantiation, because the
 995    --  number of cascaded errors is unpredictable. This exception aborts
 996    --  the instantiation process altogether.
 997 
 998    S_Adjustment : Sloc_Adjustment;
 999    --  Offset created for each node in an instantiation, in order to keep
1000    --  track of the source position of the instantiation in each of its nodes.
1001    --  A subsequent semantic error or warning on a construct of the instance
1002    --  points to both places: the original generic node, and the point of
1003    --  instantiation. See Sinput and Sinput.L for additional details.
1004 
1005    ------------------------------------------------------------
1006    -- Data structure for keeping track when inside a Generic --
1007    ------------------------------------------------------------
1008 
1009    --  The following table is used to save values of the Inside_A_Generic
1010    --  flag (see spec of Sem) when they are saved by Start_Generic.
1011 
1012    package Generic_Flags is new Table.Table (
1013      Table_Component_Type => Boolean,
1014      Table_Index_Type     => Int,
1015      Table_Low_Bound      => 0,
1016      Table_Initial        => 32,
1017      Table_Increment      => 200,
1018      Table_Name           => "Generic_Flags");
1019 
1020    ---------------------------
1021    -- Abandon_Instantiation --
1022    ---------------------------
1023 
1024    procedure Abandon_Instantiation (N : Node_Id) is
1025    begin
1026       Error_Msg_N ("\instantiation abandoned!", N);
1027       raise Instantiation_Error;
1028    end Abandon_Instantiation;
1029 
1030    --------------------------------
1031    --  Add_Pending_Instantiation --
1032    --------------------------------
1033 
1034    procedure Add_Pending_Instantiation (Inst : Node_Id; Act_Decl : Node_Id) is
1035    begin
1036 
1037       --  Add to the instantiation node and the corresponding unit declaration
1038       --  the current values of global flags to be used when analyzing the
1039       --  instance body.
1040 
1041       Pending_Instantiations.Append
1042         ((Inst_Node                => Inst,
1043           Act_Decl                 => Act_Decl,
1044           Expander_Status          => Expander_Active,
1045           Current_Sem_Unit         => Current_Sem_Unit,
1046           Scope_Suppress           => Scope_Suppress,
1047           Local_Suppress_Stack_Top => Local_Suppress_Stack_Top,
1048           Version                  => Ada_Version,
1049           Version_Pragma           => Ada_Version_Pragma,
1050           Warnings                 => Save_Warnings,
1051           SPARK_Mode               => SPARK_Mode,
1052           SPARK_Mode_Pragma        => SPARK_Mode_Pragma));
1053    end Add_Pending_Instantiation;
1054 
1055    ----------------------------------
1056    -- Adjust_Inherited_Pragma_Sloc --
1057    ----------------------------------
1058 
1059    procedure Adjust_Inherited_Pragma_Sloc (N : Node_Id) is
1060    begin
1061       Adjust_Instantiation_Sloc (N, S_Adjustment);
1062    end Adjust_Inherited_Pragma_Sloc;
1063 
1064    --------------------------
1065    -- Analyze_Associations --
1066    --------------------------
1067 
1068    function Analyze_Associations
1069      (I_Node  : Node_Id;
1070       Formals : List_Id;
1071       F_Copy  : List_Id) return List_Id
1072    is
1073       Actuals_To_Freeze : constant Elist_Id  := New_Elmt_List;
1074       Assoc             : constant List_Id   := New_List;
1075       Default_Actuals   : constant List_Id   := New_List;
1076       Gen_Unit          : constant Entity_Id :=
1077                             Defining_Entity (Parent (F_Copy));
1078 
1079       Actuals         : List_Id;
1080       Actual          : Node_Id;
1081       Analyzed_Formal : Node_Id;
1082       First_Named     : Node_Id := Empty;
1083       Formal          : Node_Id;
1084       Match           : Node_Id;
1085       Named           : Node_Id;
1086       Saved_Formal    : Node_Id;
1087 
1088       Default_Formals : constant List_Id := New_List;
1089       --  If an Others_Choice is present, some of the formals may be defaulted.
1090       --  To simplify the treatment of visibility in an instance, we introduce
1091       --  individual defaults for each such formal. These defaults are
1092       --  appended to the list of associations and replace the Others_Choice.
1093 
1094       Found_Assoc : Node_Id;
1095       --  Association for the current formal being match. Empty if there are
1096       --  no remaining actuals, or if there is no named association with the
1097       --  name of the formal.
1098 
1099       Is_Named_Assoc : Boolean;
1100       Num_Matched    : Nat := 0;
1101       Num_Actuals    : Nat := 0;
1102 
1103       Others_Present : Boolean := False;
1104       Others_Choice  : Node_Id := Empty;
1105       --  In Ada 2005, indicates partial parameterization of a formal
1106       --  package. As usual an other association must be last in the list.
1107 
1108       procedure Check_Overloaded_Formal_Subprogram (Formal : Entity_Id);
1109       --  Apply RM 12.3(9): if a formal subprogram is overloaded, the instance
1110       --  cannot have a named association for it. AI05-0025 extends this rule
1111       --  to formals of formal packages by AI05-0025, and it also applies to
1112       --  box-initialized formals.
1113 
1114       function Has_Fully_Defined_Profile (Subp : Entity_Id) return Boolean;
1115       --  Determine whether the parameter types and the return type of Subp
1116       --  are fully defined at the point of instantiation.
1117 
1118       function Matching_Actual
1119         (F   : Entity_Id;
1120          A_F : Entity_Id) return Node_Id;
1121       --  Find actual that corresponds to a given a formal parameter. If the
1122       --  actuals are positional, return the next one, if any. If the actuals
1123       --  are named, scan the parameter associations to find the right one.
1124       --  A_F is the corresponding entity in the analyzed generic, which is
1125       --  placed on the selector name for ASIS use.
1126       --
1127       --  In Ada 2005, a named association may be given with a box, in which
1128       --  case Matching_Actual sets Found_Assoc to the generic association,
1129       --  but return Empty for the actual itself. In this case the code below
1130       --  creates a corresponding declaration for the formal.
1131 
1132       function Partial_Parameterization return Boolean;
1133       --  Ada 2005: if no match is found for a given formal, check if the
1134       --  association for it includes a box, or whether the associations
1135       --  include an Others clause.
1136 
1137       procedure Process_Default (F : Entity_Id);
1138       --  Add a copy of the declaration of generic formal F to the list of
1139       --  associations, and add an explicit box association for F if there
1140       --  is none yet, and the default comes from an Others_Choice.
1141 
1142       function Renames_Standard_Subprogram (Subp : Entity_Id) return Boolean;
1143       --  Determine whether Subp renames one of the subprograms defined in the
1144       --  generated package Standard.
1145 
1146       procedure Set_Analyzed_Formal;
1147       --  Find the node in the generic copy that corresponds to a given formal.
1148       --  The semantic information on this node is used to perform legality
1149       --  checks on the actuals. Because semantic analysis can introduce some
1150       --  anonymous entities or modify the declaration node itself, the
1151       --  correspondence between the two lists is not one-one. In addition to
1152       --  anonymous types, the presence a formal equality will introduce an
1153       --  implicit declaration for the corresponding inequality.
1154 
1155       ----------------------------------------
1156       -- Check_Overloaded_Formal_Subprogram --
1157       ----------------------------------------
1158 
1159       procedure Check_Overloaded_Formal_Subprogram (Formal : Entity_Id) is
1160          Temp_Formal : Entity_Id;
1161 
1162       begin
1163          Temp_Formal := First (Formals);
1164          while Present (Temp_Formal) loop
1165             if Nkind (Temp_Formal) in N_Formal_Subprogram_Declaration
1166               and then Temp_Formal /= Formal
1167               and then
1168                 Chars (Defining_Unit_Name (Specification (Formal))) =
1169                 Chars (Defining_Unit_Name (Specification (Temp_Formal)))
1170             then
1171                if Present (Found_Assoc) then
1172                   Error_Msg_N
1173                     ("named association not allowed for overloaded formal",
1174                      Found_Assoc);
1175 
1176                else
1177                   Error_Msg_N
1178                     ("named association not allowed for overloaded formal",
1179                      Others_Choice);
1180                end if;
1181 
1182                Abandon_Instantiation (Instantiation_Node);
1183             end if;
1184 
1185             Next (Temp_Formal);
1186          end loop;
1187       end Check_Overloaded_Formal_Subprogram;
1188 
1189       -------------------------------
1190       -- Has_Fully_Defined_Profile --
1191       -------------------------------
1192 
1193       function Has_Fully_Defined_Profile (Subp : Entity_Id) return Boolean is
1194          function Is_Fully_Defined_Type (Typ : Entity_Id) return Boolean;
1195          --  Determine whethet type Typ is fully defined
1196 
1197          ---------------------------
1198          -- Is_Fully_Defined_Type --
1199          ---------------------------
1200 
1201          function Is_Fully_Defined_Type (Typ : Entity_Id) return Boolean is
1202          begin
1203             --  A private type without a full view is not fully defined
1204 
1205             if Is_Private_Type (Typ)
1206               and then No (Full_View (Typ))
1207             then
1208                return False;
1209 
1210             --  An incomplete type is never fully defined
1211 
1212             elsif Is_Incomplete_Type (Typ) then
1213                return False;
1214 
1215             --  All other types are fully defined
1216 
1217             else
1218                return True;
1219             end if;
1220          end Is_Fully_Defined_Type;
1221 
1222          --  Local declarations
1223 
1224          Param : Entity_Id;
1225 
1226       --  Start of processing for Has_Fully_Defined_Profile
1227 
1228       begin
1229          --  Check the parameters
1230 
1231          Param := First_Formal (Subp);
1232          while Present (Param) loop
1233             if not Is_Fully_Defined_Type (Etype (Param)) then
1234                return False;
1235             end if;
1236 
1237             Next_Formal (Param);
1238          end loop;
1239 
1240          --  Check the return type
1241 
1242          return Is_Fully_Defined_Type (Etype (Subp));
1243       end Has_Fully_Defined_Profile;
1244 
1245       ---------------------
1246       -- Matching_Actual --
1247       ---------------------
1248 
1249       function Matching_Actual
1250         (F   : Entity_Id;
1251          A_F : Entity_Id) return Node_Id
1252       is
1253          Prev  : Node_Id;
1254          Act   : Node_Id;
1255 
1256       begin
1257          Is_Named_Assoc := False;
1258 
1259          --  End of list of purely positional parameters
1260 
1261          if No (Actual) or else Nkind (Actual) = N_Others_Choice then
1262             Found_Assoc := Empty;
1263             Act         := Empty;
1264 
1265          --  Case of positional parameter corresponding to current formal
1266 
1267          elsif No (Selector_Name (Actual)) then
1268             Found_Assoc := Actual;
1269             Act         := Explicit_Generic_Actual_Parameter (Actual);
1270             Num_Matched := Num_Matched + 1;
1271             Next (Actual);
1272 
1273          --  Otherwise scan list of named actuals to find the one with the
1274          --  desired name. All remaining actuals have explicit names.
1275 
1276          else
1277             Is_Named_Assoc := True;
1278             Found_Assoc := Empty;
1279             Act         := Empty;
1280             Prev        := Empty;
1281 
1282             while Present (Actual) loop
1283                if Nkind (Actual) = N_Others_Choice then
1284                   Found_Assoc := Empty;
1285                   Act         := Empty;
1286 
1287                elsif Chars (Selector_Name (Actual)) = Chars (F) then
1288                   Set_Entity (Selector_Name (Actual), A_F);
1289                   Set_Etype  (Selector_Name (Actual), Etype (A_F));
1290                   Generate_Reference (A_F, Selector_Name (Actual));
1291 
1292                   Found_Assoc := Actual;
1293                   Act         := Explicit_Generic_Actual_Parameter (Actual);
1294                   Num_Matched := Num_Matched + 1;
1295                   exit;
1296                end if;
1297 
1298                Prev := Actual;
1299                Next (Actual);
1300             end loop;
1301 
1302             --  Reset for subsequent searches. In most cases the named
1303             --  associations are in order. If they are not, we reorder them
1304             --  to avoid scanning twice the same actual. This is not just a
1305             --  question of efficiency: there may be multiple defaults with
1306             --  boxes that have the same name. In a nested instantiation we
1307             --  insert actuals for those defaults, and cannot rely on their
1308             --  names to disambiguate them.
1309 
1310             if Actual = First_Named then
1311                Next (First_Named);
1312 
1313             elsif Present (Actual) then
1314                Insert_Before (First_Named, Remove_Next (Prev));
1315             end if;
1316 
1317             Actual := First_Named;
1318          end if;
1319 
1320          if Is_Entity_Name (Act) and then Present (Entity (Act)) then
1321             Set_Used_As_Generic_Actual (Entity (Act));
1322          end if;
1323 
1324          return Act;
1325       end Matching_Actual;
1326 
1327       ------------------------------
1328       -- Partial_Parameterization --
1329       ------------------------------
1330 
1331       function Partial_Parameterization return Boolean is
1332       begin
1333          return Others_Present
1334           or else (Present (Found_Assoc) and then Box_Present (Found_Assoc));
1335       end Partial_Parameterization;
1336 
1337       ---------------------
1338       -- Process_Default --
1339       ---------------------
1340 
1341       procedure Process_Default (F : Entity_Id) is
1342          Loc     : constant Source_Ptr := Sloc (I_Node);
1343          F_Id    : constant Entity_Id  := Defining_Entity (F);
1344          Decl    : Node_Id;
1345          Default : Node_Id;
1346          Id      : Entity_Id;
1347 
1348       begin
1349          --  Append copy of formal declaration to associations, and create new
1350          --  defining identifier for it.
1351 
1352          Decl := New_Copy_Tree (F);
1353          Id := Make_Defining_Identifier (Sloc (F_Id), Chars (F_Id));
1354 
1355          if Nkind (F) in N_Formal_Subprogram_Declaration then
1356             Set_Defining_Unit_Name (Specification (Decl), Id);
1357 
1358          else
1359             Set_Defining_Identifier (Decl, Id);
1360          end if;
1361 
1362          Append (Decl, Assoc);
1363 
1364          if No (Found_Assoc) then
1365             Default :=
1366                Make_Generic_Association (Loc,
1367                  Selector_Name                     =>
1368                    New_Occurrence_Of (Id, Loc),
1369                  Explicit_Generic_Actual_Parameter => Empty);
1370             Set_Box_Present (Default);
1371             Append (Default, Default_Formals);
1372          end if;
1373       end Process_Default;
1374 
1375       ---------------------------------
1376       -- Renames_Standard_Subprogram --
1377       ---------------------------------
1378 
1379       function Renames_Standard_Subprogram (Subp : Entity_Id) return Boolean is
1380          Id : Entity_Id;
1381 
1382       begin
1383          Id := Alias (Subp);
1384          while Present (Id) loop
1385             if Scope (Id) = Standard_Standard then
1386                return True;
1387             end if;
1388 
1389             Id := Alias (Id);
1390          end loop;
1391 
1392          return False;
1393       end Renames_Standard_Subprogram;
1394 
1395       -------------------------
1396       -- Set_Analyzed_Formal --
1397       -------------------------
1398 
1399       procedure Set_Analyzed_Formal is
1400          Kind : Node_Kind;
1401 
1402       begin
1403          while Present (Analyzed_Formal) loop
1404             Kind := Nkind (Analyzed_Formal);
1405 
1406             case Nkind (Formal) is
1407 
1408                when N_Formal_Subprogram_Declaration =>
1409                   exit when Kind in N_Formal_Subprogram_Declaration
1410                     and then
1411                       Chars
1412                         (Defining_Unit_Name (Specification (Formal))) =
1413                       Chars
1414                         (Defining_Unit_Name (Specification (Analyzed_Formal)));
1415 
1416                when N_Formal_Package_Declaration =>
1417                   exit when Nkind_In (Kind, N_Formal_Package_Declaration,
1418                                             N_Generic_Package_Declaration,
1419                                             N_Package_Declaration);
1420 
1421                when N_Use_Package_Clause | N_Use_Type_Clause => exit;
1422 
1423                when others =>
1424 
1425                   --  Skip freeze nodes, and nodes inserted to replace
1426                   --  unrecognized pragmas.
1427 
1428                   exit when
1429                     Kind not in N_Formal_Subprogram_Declaration
1430                       and then not Nkind_In (Kind, N_Subprogram_Declaration,
1431                                                    N_Freeze_Entity,
1432                                                    N_Null_Statement,
1433                                                    N_Itype_Reference)
1434                       and then Chars (Defining_Identifier (Formal)) =
1435                                Chars (Defining_Identifier (Analyzed_Formal));
1436             end case;
1437 
1438             Next (Analyzed_Formal);
1439          end loop;
1440       end Set_Analyzed_Formal;
1441 
1442    --  Start of processing for Analyze_Associations
1443 
1444    begin
1445       Actuals := Generic_Associations (I_Node);
1446 
1447       if Present (Actuals) then
1448 
1449          --  Check for an Others choice, indicating a partial parameterization
1450          --  for a formal package.
1451 
1452          Actual := First (Actuals);
1453          while Present (Actual) loop
1454             if Nkind (Actual) = N_Others_Choice then
1455                Others_Present := True;
1456                Others_Choice  := Actual;
1457 
1458                if Present (Next (Actual)) then
1459                   Error_Msg_N ("others must be last association", Actual);
1460                end if;
1461 
1462                --  This subprogram is used both for formal packages and for
1463                --  instantiations. For the latter, associations must all be
1464                --  explicit.
1465 
1466                if Nkind (I_Node) /= N_Formal_Package_Declaration
1467                  and then Comes_From_Source (I_Node)
1468                then
1469                   Error_Msg_N
1470                     ("others association not allowed in an instance",
1471                       Actual);
1472                end if;
1473 
1474                --  In any case, nothing to do after the others association
1475 
1476                exit;
1477 
1478             elsif Box_Present (Actual)
1479               and then Comes_From_Source (I_Node)
1480               and then Nkind (I_Node) /= N_Formal_Package_Declaration
1481             then
1482                Error_Msg_N
1483                  ("box association not allowed in an instance", Actual);
1484             end if;
1485 
1486             Next (Actual);
1487          end loop;
1488 
1489          --  If named associations are present, save first named association
1490          --  (it may of course be Empty) to facilitate subsequent name search.
1491 
1492          First_Named := First (Actuals);
1493          while Present (First_Named)
1494            and then Nkind (First_Named) /= N_Others_Choice
1495            and then No (Selector_Name (First_Named))
1496          loop
1497             Num_Actuals := Num_Actuals + 1;
1498             Next (First_Named);
1499          end loop;
1500       end if;
1501 
1502       Named := First_Named;
1503       while Present (Named) loop
1504          if Nkind (Named) /= N_Others_Choice
1505            and then No (Selector_Name (Named))
1506          then
1507             Error_Msg_N ("invalid positional actual after named one", Named);
1508             Abandon_Instantiation (Named);
1509          end if;
1510 
1511          --  A named association may lack an actual parameter, if it was
1512          --  introduced for a default subprogram that turns out to be local
1513          --  to the outer instantiation. If it has a box association it must
1514          --  correspond to some formal in the generic.
1515 
1516          if Nkind (Named) /= N_Others_Choice
1517            and then (Present (Explicit_Generic_Actual_Parameter (Named))
1518                       or else Box_Present (Named))
1519          then
1520             Num_Actuals := Num_Actuals + 1;
1521          end if;
1522 
1523          Next (Named);
1524       end loop;
1525 
1526       if Present (Formals) then
1527          Formal := First_Non_Pragma (Formals);
1528          Analyzed_Formal := First_Non_Pragma (F_Copy);
1529 
1530          if Present (Actuals) then
1531             Actual := First (Actuals);
1532 
1533          --  All formals should have default values
1534 
1535          else
1536             Actual := Empty;
1537          end if;
1538 
1539          while Present (Formal) loop
1540             Set_Analyzed_Formal;
1541             Saved_Formal := Next_Non_Pragma (Formal);
1542 
1543             case Nkind (Formal) is
1544                when N_Formal_Object_Declaration =>
1545                   Match :=
1546                     Matching_Actual
1547                       (Defining_Identifier (Formal),
1548                        Defining_Identifier (Analyzed_Formal));
1549 
1550                   if No (Match) and then Partial_Parameterization then
1551                      Process_Default (Formal);
1552 
1553                   else
1554                      Append_List
1555                        (Instantiate_Object (Formal, Match, Analyzed_Formal),
1556                         Assoc);
1557 
1558                      --  For a defaulted in_parameter, create an entry in the
1559                      --  the list of defaulted actuals, for GNATProve use. Do
1560                      --  not included these defaults for an instance nested
1561                      --  within a generic, because the defaults are also used
1562                      --  in the analysis of the enclosing generic, and only
1563                      --  defaulted subprograms are relevant there.
1564 
1565                      if No (Match) and then not Inside_A_Generic then
1566                         Append_To (Default_Actuals,
1567                           Make_Generic_Association (Sloc (I_Node),
1568                             Selector_Name                     =>
1569                               New_Occurrence_Of
1570                                 (Defining_Identifier (Formal), Sloc (I_Node)),
1571                             Explicit_Generic_Actual_Parameter =>
1572                               New_Copy_Tree (Default_Expression (Formal))));
1573                      end if;
1574                   end if;
1575 
1576                   --  If the object is a call to an expression function, this
1577                   --  is a freezing point for it.
1578 
1579                   if Is_Entity_Name (Match)
1580                     and then Present (Entity (Match))
1581                     and then Nkind
1582                       (Original_Node (Unit_Declaration_Node (Entity (Match))))
1583                                                      = N_Expression_Function
1584                   then
1585                      Append_Elmt (Entity (Match), Actuals_To_Freeze);
1586                   end if;
1587 
1588                when N_Formal_Type_Declaration =>
1589                   Match :=
1590                     Matching_Actual
1591                       (Defining_Identifier (Formal),
1592                        Defining_Identifier (Analyzed_Formal));
1593 
1594                   if No (Match) then
1595                      if Partial_Parameterization then
1596                         Process_Default (Formal);
1597 
1598                      else
1599                         Error_Msg_Sloc := Sloc (Gen_Unit);
1600                         Error_Msg_NE
1601                           ("missing actual&",
1602                            Instantiation_Node, Defining_Identifier (Formal));
1603                         Error_Msg_NE
1604                           ("\in instantiation of & declared#",
1605                            Instantiation_Node, Gen_Unit);
1606                         Abandon_Instantiation (Instantiation_Node);
1607                      end if;
1608 
1609                   else
1610                      Analyze (Match);
1611                      Append_List
1612                        (Instantiate_Type
1613                           (Formal, Match, Analyzed_Formal, Assoc),
1614                         Assoc);
1615 
1616                      --  An instantiation is a freeze point for the actuals,
1617                      --  unless this is a rewritten formal package, or the
1618                      --  formal is an Ada 2012 formal incomplete type.
1619 
1620                      if Nkind (I_Node) = N_Formal_Package_Declaration
1621                        or else
1622                          (Ada_Version >= Ada_2012
1623                            and then
1624                              Ekind (Defining_Identifier (Analyzed_Formal)) =
1625                                                             E_Incomplete_Type)
1626                      then
1627                         null;
1628 
1629                      else
1630                         Append_Elmt (Entity (Match), Actuals_To_Freeze);
1631                      end if;
1632                   end if;
1633 
1634                   --  A remote access-to-class-wide type is not a legal actual
1635                   --  for a generic formal of an access type (E.2.2(17/2)).
1636                   --  In GNAT an exception to this rule is introduced when
1637                   --  the formal is marked as remote using implementation
1638                   --  defined aspect/pragma Remote_Access_Type. In that case
1639                   --  the actual must be remote as well.
1640 
1641                   --  If the current instantiation is the construction of a
1642                   --  local copy for a formal package the actuals may be
1643                   --  defaulted, and there is no matching actual to check.
1644 
1645                   if Nkind (Analyzed_Formal) = N_Formal_Type_Declaration
1646                     and then
1647                       Nkind (Formal_Type_Definition (Analyzed_Formal)) =
1648                                             N_Access_To_Object_Definition
1649                      and then Present (Match)
1650                   then
1651                      declare
1652                         Formal_Ent : constant Entity_Id :=
1653                                        Defining_Identifier (Analyzed_Formal);
1654                      begin
1655                         if Is_Remote_Access_To_Class_Wide_Type (Entity (Match))
1656                                                 = Is_Remote_Types (Formal_Ent)
1657                         then
1658                            --  Remoteness of formal and actual match
1659 
1660                            null;
1661 
1662                         elsif Is_Remote_Types (Formal_Ent) then
1663 
1664                            --  Remote formal, non-remote actual
1665 
1666                            Error_Msg_NE
1667                              ("actual for& must be remote", Match, Formal_Ent);
1668 
1669                         else
1670                            --  Non-remote formal, remote actual
1671 
1672                            Error_Msg_NE
1673                              ("actual for& may not be remote",
1674                               Match, Formal_Ent);
1675                         end if;
1676                      end;
1677                   end if;
1678 
1679                when N_Formal_Subprogram_Declaration =>
1680                   Match :=
1681                     Matching_Actual
1682                       (Defining_Unit_Name (Specification (Formal)),
1683                        Defining_Unit_Name (Specification (Analyzed_Formal)));
1684 
1685                   --  If the formal subprogram has the same name as another
1686                   --  formal subprogram of the generic, then a named
1687                   --  association is illegal (12.3(9)). Exclude named
1688                   --  associations that are generated for a nested instance.
1689 
1690                   if Present (Match)
1691                     and then Is_Named_Assoc
1692                     and then Comes_From_Source (Found_Assoc)
1693                   then
1694                      Check_Overloaded_Formal_Subprogram (Formal);
1695                   end if;
1696 
1697                   --  If there is no corresponding actual, this may be case
1698                   --  of partial parameterization, or else the formal has a
1699                   --  default or a box.
1700 
1701                   if No (Match) and then Partial_Parameterization then
1702                      Process_Default (Formal);
1703 
1704                      if Nkind (I_Node) = N_Formal_Package_Declaration then
1705                         Check_Overloaded_Formal_Subprogram (Formal);
1706                      end if;
1707 
1708                   else
1709                      Append_To (Assoc,
1710                        Instantiate_Formal_Subprogram
1711                          (Formal, Match, Analyzed_Formal));
1712 
1713                      --  An instantiation is a freeze point for the actuals,
1714                      --  unless this is a rewritten formal package.
1715 
1716                      if Nkind (I_Node) /= N_Formal_Package_Declaration
1717                        and then Nkind (Match) = N_Identifier
1718                        and then Is_Subprogram (Entity (Match))
1719 
1720                        --  The actual subprogram may rename a routine defined
1721                        --  in Standard. Avoid freezing such renamings because
1722                        --  subprograms coming from Standard cannot be frozen.
1723 
1724                        and then
1725                          not Renames_Standard_Subprogram (Entity (Match))
1726 
1727                        --  If the actual subprogram comes from a different
1728                        --  unit, it is already frozen, either by a body in
1729                        --  that unit or by the end of the declarative part
1730                        --  of the unit. This check avoids the freezing of
1731                        --  subprograms defined in Standard which are used
1732                        --  as generic actuals.
1733 
1734                        and then In_Same_Code_Unit (Entity (Match), I_Node)
1735                        and then Has_Fully_Defined_Profile (Entity (Match))
1736                      then
1737                         --  Mark the subprogram as having a delayed freeze
1738                         --  since this may be an out-of-order action.
1739 
1740                         Set_Has_Delayed_Freeze (Entity (Match));
1741                         Append_Elmt (Entity (Match), Actuals_To_Freeze);
1742                      end if;
1743                   end if;
1744 
1745                   --  If this is a nested generic, preserve default for later
1746                   --  instantiations. We do this as well for GNATProve use,
1747                   --  so that the list of generic associations is complete.
1748 
1749                   if No (Match) and then Box_Present (Formal) then
1750                      declare
1751                         Subp : constant Entity_Id :=
1752                           Defining_Unit_Name (Specification (Last (Assoc)));
1753 
1754                      begin
1755                         Append_To (Default_Actuals,
1756                           Make_Generic_Association (Sloc (I_Node),
1757                             Selector_Name                     =>
1758                               New_Occurrence_Of (Subp, Sloc (I_Node)),
1759                             Explicit_Generic_Actual_Parameter =>
1760                               New_Occurrence_Of (Subp, Sloc (I_Node))));
1761                      end;
1762                   end if;
1763 
1764                when N_Formal_Package_Declaration =>
1765                   Match :=
1766                     Matching_Actual
1767                       (Defining_Identifier (Formal),
1768                        Defining_Identifier (Original_Node (Analyzed_Formal)));
1769 
1770                   if No (Match) then
1771                      if Partial_Parameterization then
1772                         Process_Default (Formal);
1773 
1774                      else
1775                         Error_Msg_Sloc := Sloc (Gen_Unit);
1776                         Error_Msg_NE
1777                           ("missing actual&",
1778                            Instantiation_Node, Defining_Identifier (Formal));
1779                         Error_Msg_NE
1780                           ("\in instantiation of & declared#",
1781                            Instantiation_Node, Gen_Unit);
1782 
1783                         Abandon_Instantiation (Instantiation_Node);
1784                      end if;
1785 
1786                   else
1787                      Analyze (Match);
1788                      Append_List
1789                        (Instantiate_Formal_Package
1790                          (Formal, Match, Analyzed_Formal),
1791                         Assoc);
1792                   end if;
1793 
1794                --  For use type and use package appearing in the generic part,
1795                --  we have already copied them, so we can just move them where
1796                --  they belong (we mustn't recopy them since this would mess up
1797                --  the Sloc values).
1798 
1799                when N_Use_Package_Clause |
1800                     N_Use_Type_Clause    =>
1801                   if Nkind (Original_Node (I_Node)) =
1802                                      N_Formal_Package_Declaration
1803                   then
1804                      Append (New_Copy_Tree (Formal), Assoc);
1805                   else
1806                      Remove (Formal);
1807                      Append (Formal, Assoc);
1808                   end if;
1809 
1810                when others =>
1811                   raise Program_Error;
1812 
1813             end case;
1814 
1815             Formal := Saved_Formal;
1816             Next_Non_Pragma (Analyzed_Formal);
1817          end loop;
1818 
1819          if Num_Actuals > Num_Matched then
1820             Error_Msg_Sloc := Sloc (Gen_Unit);
1821 
1822             if Present (Selector_Name (Actual)) then
1823                Error_Msg_NE
1824                  ("unmatched actual &", Actual, Selector_Name (Actual));
1825                Error_Msg_NE
1826                  ("\in instantiation of & declared#", Actual, Gen_Unit);
1827             else
1828                Error_Msg_NE
1829                  ("unmatched actual in instantiation of & declared#",
1830                   Actual, Gen_Unit);
1831             end if;
1832          end if;
1833 
1834       elsif Present (Actuals) then
1835          Error_Msg_N
1836            ("too many actuals in generic instantiation", Instantiation_Node);
1837       end if;
1838 
1839       --  An instantiation freezes all generic actuals. The only exceptions
1840       --  to this are incomplete types and subprograms which are not fully
1841       --  defined at the point of instantiation.
1842 
1843       declare
1844          Elmt : Elmt_Id := First_Elmt (Actuals_To_Freeze);
1845       begin
1846          while Present (Elmt) loop
1847             Freeze_Before (I_Node, Node (Elmt));
1848             Next_Elmt (Elmt);
1849          end loop;
1850       end;
1851 
1852       --  If there are default subprograms, normalize the tree by adding
1853       --  explicit associations for them. This is required if the instance
1854       --  appears within a generic.
1855 
1856       if not Is_Empty_List (Default_Actuals) then
1857          declare
1858             Default : Node_Id;
1859 
1860          begin
1861             Default := First (Default_Actuals);
1862             while Present (Default) loop
1863                Mark_Rewrite_Insertion (Default);
1864                Next (Default);
1865             end loop;
1866 
1867             if No (Actuals) then
1868                Set_Generic_Associations (I_Node, Default_Actuals);
1869             else
1870                Append_List_To (Actuals, Default_Actuals);
1871             end if;
1872          end;
1873       end if;
1874 
1875       --  If this is a formal package, normalize the parameter list by adding
1876       --  explicit box associations for the formals that are covered by an
1877       --  Others_Choice.
1878 
1879       if not Is_Empty_List (Default_Formals) then
1880          Append_List (Default_Formals, Formals);
1881       end if;
1882 
1883       return Assoc;
1884    end Analyze_Associations;
1885 
1886    -------------------------------
1887    -- Analyze_Formal_Array_Type --
1888    -------------------------------
1889 
1890    procedure Analyze_Formal_Array_Type
1891      (T   : in out Entity_Id;
1892       Def : Node_Id)
1893    is
1894       DSS : Node_Id;
1895 
1896    begin
1897       --  Treated like a non-generic array declaration, with additional
1898       --  semantic checks.
1899 
1900       Enter_Name (T);
1901 
1902       if Nkind (Def) = N_Constrained_Array_Definition then
1903          DSS := First (Discrete_Subtype_Definitions (Def));
1904          while Present (DSS) loop
1905             if Nkind_In (DSS, N_Subtype_Indication,
1906                               N_Range,
1907                               N_Attribute_Reference)
1908             then
1909                Error_Msg_N ("only a subtype mark is allowed in a formal", DSS);
1910             end if;
1911 
1912             Next (DSS);
1913          end loop;
1914       end if;
1915 
1916       Array_Type_Declaration (T, Def);
1917       Set_Is_Generic_Type (Base_Type (T));
1918 
1919       if Ekind (Component_Type (T)) = E_Incomplete_Type
1920         and then No (Full_View (Component_Type (T)))
1921       then
1922          Error_Msg_N ("premature usage of incomplete type", Def);
1923 
1924       --  Check that range constraint is not allowed on the component type
1925       --  of a generic formal array type (AARM 12.5.3(3))
1926 
1927       elsif Is_Internal (Component_Type (T))
1928         and then Present (Subtype_Indication (Component_Definition (Def)))
1929         and then Nkind (Original_Node
1930                          (Subtype_Indication (Component_Definition (Def)))) =
1931                                                          N_Subtype_Indication
1932       then
1933          Error_Msg_N
1934            ("in a formal, a subtype indication can only be "
1935             & "a subtype mark (RM 12.5.3(3))",
1936             Subtype_Indication (Component_Definition (Def)));
1937       end if;
1938 
1939    end Analyze_Formal_Array_Type;
1940 
1941    ---------------------------------------------
1942    -- Analyze_Formal_Decimal_Fixed_Point_Type --
1943    ---------------------------------------------
1944 
1945    --  As for other generic types, we create a valid type representation with
1946    --  legal but arbitrary attributes, whose values are never considered
1947    --  static. For all scalar types we introduce an anonymous base type, with
1948    --  the same attributes. We choose the corresponding integer type to be
1949    --  Standard_Integer.
1950    --  Here and in other similar routines, the Sloc of the generated internal
1951    --  type must be the same as the sloc of the defining identifier of the
1952    --  formal type declaration, to provide proper source navigation.
1953 
1954    procedure Analyze_Formal_Decimal_Fixed_Point_Type
1955      (T   : Entity_Id;
1956       Def : Node_Id)
1957    is
1958       Loc : constant Source_Ptr := Sloc (Def);
1959 
1960       Base : constant Entity_Id :=
1961                New_Internal_Entity
1962                  (E_Decimal_Fixed_Point_Type,
1963                   Current_Scope,
1964                   Sloc (Defining_Identifier (Parent (Def))), 'G');
1965 
1966       Int_Base  : constant Entity_Id := Standard_Integer;
1967       Delta_Val : constant Ureal := Ureal_1;
1968       Digs_Val  : constant Uint  := Uint_6;
1969 
1970       function Make_Dummy_Bound return Node_Id;
1971       --  Return a properly typed universal real literal to use as a bound
1972 
1973       ----------------------
1974       -- Make_Dummy_Bound --
1975       ----------------------
1976 
1977       function Make_Dummy_Bound return Node_Id is
1978          Bound : constant Node_Id := Make_Real_Literal (Loc, Ureal_1);
1979       begin
1980          Set_Etype (Bound, Universal_Real);
1981          return Bound;
1982       end Make_Dummy_Bound;
1983 
1984    --  Start of processing for Analyze_Formal_Decimal_Fixed_Point_Type
1985 
1986    begin
1987       Enter_Name (T);
1988 
1989       Set_Etype          (Base, Base);
1990       Set_Size_Info      (Base, Int_Base);
1991       Set_RM_Size        (Base, RM_Size (Int_Base));
1992       Set_First_Rep_Item (Base, First_Rep_Item (Int_Base));
1993       Set_Digits_Value   (Base, Digs_Val);
1994       Set_Delta_Value    (Base, Delta_Val);
1995       Set_Small_Value    (Base, Delta_Val);
1996       Set_Scalar_Range   (Base,
1997         Make_Range (Loc,
1998           Low_Bound  => Make_Dummy_Bound,
1999           High_Bound => Make_Dummy_Bound));
2000 
2001       Set_Is_Generic_Type (Base);
2002       Set_Parent          (Base, Parent (Def));
2003 
2004       Set_Ekind          (T, E_Decimal_Fixed_Point_Subtype);
2005       Set_Etype          (T, Base);
2006       Set_Size_Info      (T, Int_Base);
2007       Set_RM_Size        (T, RM_Size (Int_Base));
2008       Set_First_Rep_Item (T, First_Rep_Item (Int_Base));
2009       Set_Digits_Value   (T, Digs_Val);
2010       Set_Delta_Value    (T, Delta_Val);
2011       Set_Small_Value    (T, Delta_Val);
2012       Set_Scalar_Range   (T, Scalar_Range (Base));
2013       Set_Is_Constrained (T);
2014 
2015       Check_Restriction (No_Fixed_Point, Def);
2016    end Analyze_Formal_Decimal_Fixed_Point_Type;
2017 
2018    -------------------------------------------
2019    -- Analyze_Formal_Derived_Interface_Type --
2020    -------------------------------------------
2021 
2022    procedure Analyze_Formal_Derived_Interface_Type
2023      (N   : Node_Id;
2024       T   : Entity_Id;
2025       Def : Node_Id)
2026    is
2027       Loc   : constant Source_Ptr := Sloc (Def);
2028 
2029    begin
2030       --  Rewrite as a type declaration of a derived type. This ensures that
2031       --  the interface list and primitive operations are properly captured.
2032 
2033       Rewrite (N,
2034         Make_Full_Type_Declaration (Loc,
2035           Defining_Identifier => T,
2036           Type_Definition     => Def));
2037       Analyze (N);
2038       Set_Is_Generic_Type (T);
2039    end Analyze_Formal_Derived_Interface_Type;
2040 
2041    ---------------------------------
2042    -- Analyze_Formal_Derived_Type --
2043    ---------------------------------
2044 
2045    procedure Analyze_Formal_Derived_Type
2046      (N   : Node_Id;
2047       T   : Entity_Id;
2048       Def : Node_Id)
2049    is
2050       Loc      : constant Source_Ptr := Sloc (Def);
2051       Unk_Disc : constant Boolean    := Unknown_Discriminants_Present (N);
2052       New_N    : Node_Id;
2053 
2054    begin
2055       Set_Is_Generic_Type (T);
2056 
2057       if Private_Present (Def) then
2058          New_N :=
2059            Make_Private_Extension_Declaration (Loc,
2060              Defining_Identifier           => T,
2061              Discriminant_Specifications   => Discriminant_Specifications (N),
2062              Unknown_Discriminants_Present => Unk_Disc,
2063              Subtype_Indication            => Subtype_Mark (Def),
2064              Interface_List                => Interface_List (Def));
2065 
2066          Set_Abstract_Present     (New_N, Abstract_Present     (Def));
2067          Set_Limited_Present      (New_N, Limited_Present      (Def));
2068          Set_Synchronized_Present (New_N, Synchronized_Present (Def));
2069 
2070       else
2071          New_N :=
2072            Make_Full_Type_Declaration (Loc,
2073              Defining_Identifier         => T,
2074              Discriminant_Specifications =>
2075                Discriminant_Specifications (Parent (T)),
2076              Type_Definition             =>
2077                Make_Derived_Type_Definition (Loc,
2078                  Subtype_Indication => Subtype_Mark (Def)));
2079 
2080          Set_Abstract_Present
2081            (Type_Definition (New_N), Abstract_Present (Def));
2082          Set_Limited_Present
2083            (Type_Definition (New_N), Limited_Present  (Def));
2084       end if;
2085 
2086       Rewrite (N, New_N);
2087       Analyze (N);
2088 
2089       if Unk_Disc then
2090          if not Is_Composite_Type (T) then
2091             Error_Msg_N
2092               ("unknown discriminants not allowed for elementary types", N);
2093          else
2094             Set_Has_Unknown_Discriminants (T);
2095             Set_Is_Constrained (T, False);
2096          end if;
2097       end if;
2098 
2099       --  If the parent type has a known size, so does the formal, which makes
2100       --  legal representation clauses that involve the formal.
2101 
2102       Set_Size_Known_At_Compile_Time
2103         (T, Size_Known_At_Compile_Time (Entity (Subtype_Mark (Def))));
2104    end Analyze_Formal_Derived_Type;
2105 
2106    ----------------------------------
2107    -- Analyze_Formal_Discrete_Type --
2108    ----------------------------------
2109 
2110    --  The operations defined for a discrete types are those of an enumeration
2111    --  type. The size is set to an arbitrary value, for use in analyzing the
2112    --  generic unit.
2113 
2114    procedure Analyze_Formal_Discrete_Type (T : Entity_Id; Def : Node_Id) is
2115       Loc : constant Source_Ptr := Sloc (Def);
2116       Lo  : Node_Id;
2117       Hi  : Node_Id;
2118 
2119       Base : constant Entity_Id :=
2120                New_Internal_Entity
2121                  (E_Floating_Point_Type, Current_Scope,
2122                   Sloc (Defining_Identifier (Parent (Def))), 'G');
2123 
2124    begin
2125       Enter_Name          (T);
2126       Set_Ekind           (T, E_Enumeration_Subtype);
2127       Set_Etype           (T, Base);
2128       Init_Size           (T, 8);
2129       Init_Alignment      (T);
2130       Set_Is_Generic_Type (T);
2131       Set_Is_Constrained  (T);
2132 
2133       --  For semantic analysis, the bounds of the type must be set to some
2134       --  non-static value. The simplest is to create attribute nodes for those
2135       --  bounds, that refer to the type itself. These bounds are never
2136       --  analyzed but serve as place-holders.
2137 
2138       Lo :=
2139         Make_Attribute_Reference (Loc,
2140           Attribute_Name => Name_First,
2141           Prefix         => New_Occurrence_Of (T, Loc));
2142       Set_Etype (Lo, T);
2143 
2144       Hi :=
2145         Make_Attribute_Reference (Loc,
2146           Attribute_Name => Name_Last,
2147           Prefix         => New_Occurrence_Of (T, Loc));
2148       Set_Etype (Hi, T);
2149 
2150       Set_Scalar_Range (T,
2151         Make_Range (Loc,
2152           Low_Bound  => Lo,
2153           High_Bound => Hi));
2154 
2155       Set_Ekind           (Base, E_Enumeration_Type);
2156       Set_Etype           (Base, Base);
2157       Init_Size           (Base, 8);
2158       Init_Alignment      (Base);
2159       Set_Is_Generic_Type (Base);
2160       Set_Scalar_Range    (Base, Scalar_Range (T));
2161       Set_Parent          (Base, Parent (Def));
2162    end Analyze_Formal_Discrete_Type;
2163 
2164    ----------------------------------
2165    -- Analyze_Formal_Floating_Type --
2166    ---------------------------------
2167 
2168    procedure Analyze_Formal_Floating_Type (T : Entity_Id; Def : Node_Id) is
2169       Base : constant Entity_Id :=
2170                New_Internal_Entity
2171                  (E_Floating_Point_Type, Current_Scope,
2172                   Sloc (Defining_Identifier (Parent (Def))), 'G');
2173 
2174    begin
2175       --  The various semantic attributes are taken from the predefined type
2176       --  Float, just so that all of them are initialized. Their values are
2177       --  never used because no constant folding or expansion takes place in
2178       --  the generic itself.
2179 
2180       Enter_Name (T);
2181       Set_Ekind          (T, E_Floating_Point_Subtype);
2182       Set_Etype          (T, Base);
2183       Set_Size_Info      (T,              (Standard_Float));
2184       Set_RM_Size        (T, RM_Size      (Standard_Float));
2185       Set_Digits_Value   (T, Digits_Value (Standard_Float));
2186       Set_Scalar_Range   (T, Scalar_Range (Standard_Float));
2187       Set_Is_Constrained (T);
2188 
2189       Set_Is_Generic_Type (Base);
2190       Set_Etype           (Base, Base);
2191       Set_Size_Info       (Base,              (Standard_Float));
2192       Set_RM_Size         (Base, RM_Size      (Standard_Float));
2193       Set_Digits_Value    (Base, Digits_Value (Standard_Float));
2194       Set_Scalar_Range    (Base, Scalar_Range (Standard_Float));
2195       Set_Parent          (Base, Parent (Def));
2196 
2197       Check_Restriction (No_Floating_Point, Def);
2198    end Analyze_Formal_Floating_Type;
2199 
2200    -----------------------------------
2201    -- Analyze_Formal_Interface_Type;--
2202    -----------------------------------
2203 
2204    procedure Analyze_Formal_Interface_Type
2205       (N   : Node_Id;
2206        T   : Entity_Id;
2207        Def : Node_Id)
2208    is
2209       Loc   : constant Source_Ptr := Sloc (N);
2210       New_N : Node_Id;
2211 
2212    begin
2213       New_N :=
2214         Make_Full_Type_Declaration (Loc,
2215           Defining_Identifier => T,
2216           Type_Definition     => Def);
2217 
2218       Rewrite (N, New_N);
2219       Analyze (N);
2220       Set_Is_Generic_Type (T);
2221    end Analyze_Formal_Interface_Type;
2222 
2223    ---------------------------------
2224    -- Analyze_Formal_Modular_Type --
2225    ---------------------------------
2226 
2227    procedure Analyze_Formal_Modular_Type (T : Entity_Id; Def : Node_Id) is
2228    begin
2229       --  Apart from their entity kind, generic modular types are treated like
2230       --  signed integer types, and have the same attributes.
2231 
2232       Analyze_Formal_Signed_Integer_Type (T, Def);
2233       Set_Ekind (T, E_Modular_Integer_Subtype);
2234       Set_Ekind (Etype (T), E_Modular_Integer_Type);
2235 
2236    end Analyze_Formal_Modular_Type;
2237 
2238    ---------------------------------------
2239    -- Analyze_Formal_Object_Declaration --
2240    ---------------------------------------
2241 
2242    procedure Analyze_Formal_Object_Declaration (N : Node_Id) is
2243       E  : constant Node_Id := Default_Expression (N);
2244       Id : constant Node_Id := Defining_Identifier (N);
2245       K  : Entity_Kind;
2246       T  : Node_Id;
2247 
2248    begin
2249       Enter_Name (Id);
2250 
2251       --  Determine the mode of the formal object
2252 
2253       if Out_Present (N) then
2254          K := E_Generic_In_Out_Parameter;
2255 
2256          if not In_Present (N) then
2257             Error_Msg_N ("formal generic objects cannot have mode OUT", N);
2258          end if;
2259 
2260       else
2261          K := E_Generic_In_Parameter;
2262       end if;
2263 
2264       if Present (Subtype_Mark (N)) then
2265          Find_Type (Subtype_Mark (N));
2266          T := Entity (Subtype_Mark (N));
2267 
2268          --  Verify that there is no redundant null exclusion
2269 
2270          if Null_Exclusion_Present (N) then
2271             if not Is_Access_Type (T) then
2272                Error_Msg_N
2273                  ("null exclusion can only apply to an access type", N);
2274 
2275             elsif Can_Never_Be_Null (T) then
2276                Error_Msg_NE
2277                  ("`NOT NULL` not allowed (& already excludes null)", N, T);
2278             end if;
2279          end if;
2280 
2281       --  Ada 2005 (AI-423): Formal object with an access definition
2282 
2283       else
2284          Check_Access_Definition (N);
2285          T := Access_Definition
2286                 (Related_Nod => N,
2287                  N           => Access_Definition (N));
2288       end if;
2289 
2290       if Ekind (T) = E_Incomplete_Type then
2291          declare
2292             Error_Node : Node_Id;
2293 
2294          begin
2295             if Present (Subtype_Mark (N)) then
2296                Error_Node := Subtype_Mark (N);
2297             else
2298                Check_Access_Definition (N);
2299                Error_Node := Access_Definition (N);
2300             end if;
2301 
2302             Error_Msg_N ("premature usage of incomplete type", Error_Node);
2303          end;
2304       end if;
2305 
2306       if K = E_Generic_In_Parameter then
2307 
2308          --  Ada 2005 (AI-287): Limited aggregates allowed in generic formals
2309 
2310          if Ada_Version < Ada_2005 and then Is_Limited_Type (T) then
2311             Error_Msg_N
2312               ("generic formal of mode IN must not be of limited type", N);
2313             Explain_Limited_Type (T, N);
2314          end if;
2315 
2316          if Is_Abstract_Type (T) then
2317             Error_Msg_N
2318               ("generic formal of mode IN must not be of abstract type", N);
2319          end if;
2320 
2321          if Present (E) then
2322             Preanalyze_Spec_Expression (E, T);
2323 
2324             if Is_Limited_Type (T) and then not OK_For_Limited_Init (T, E) then
2325                Error_Msg_N
2326                  ("initialization not allowed for limited types", E);
2327                Explain_Limited_Type (T, E);
2328             end if;
2329          end if;
2330 
2331          Set_Ekind (Id, K);
2332          Set_Etype (Id, T);
2333 
2334       --  Case of generic IN OUT parameter
2335 
2336       else
2337          --  If the formal has an unconstrained type, construct its actual
2338          --  subtype, as is done for subprogram formals. In this fashion, all
2339          --  its uses can refer to specific bounds.
2340 
2341          Set_Ekind (Id, K);
2342          Set_Etype (Id, T);
2343 
2344          if (Is_Array_Type (T) and then not Is_Constrained (T))
2345            or else (Ekind (T) = E_Record_Type and then Has_Discriminants (T))
2346          then
2347             declare
2348                Non_Freezing_Ref : constant Node_Id :=
2349                                     New_Occurrence_Of (Id, Sloc (Id));
2350                Decl : Node_Id;
2351 
2352             begin
2353                --  Make sure the actual subtype doesn't generate bogus freezing
2354 
2355                Set_Must_Not_Freeze (Non_Freezing_Ref);
2356                Decl := Build_Actual_Subtype (T, Non_Freezing_Ref);
2357                Insert_Before_And_Analyze (N, Decl);
2358                Set_Actual_Subtype (Id, Defining_Identifier (Decl));
2359             end;
2360          else
2361             Set_Actual_Subtype (Id, T);
2362          end if;
2363 
2364          if Present (E) then
2365             Error_Msg_N
2366               ("initialization not allowed for `IN OUT` formals", N);
2367          end if;
2368       end if;
2369 
2370       if Has_Aspects (N) then
2371          Analyze_Aspect_Specifications (N, Id);
2372       end if;
2373    end Analyze_Formal_Object_Declaration;
2374 
2375    ----------------------------------------------
2376    -- Analyze_Formal_Ordinary_Fixed_Point_Type --
2377    ----------------------------------------------
2378 
2379    procedure Analyze_Formal_Ordinary_Fixed_Point_Type
2380      (T   : Entity_Id;
2381       Def : Node_Id)
2382    is
2383       Loc  : constant Source_Ptr := Sloc (Def);
2384       Base : constant Entity_Id :=
2385                New_Internal_Entity
2386                  (E_Ordinary_Fixed_Point_Type, Current_Scope,
2387                   Sloc (Defining_Identifier (Parent (Def))), 'G');
2388 
2389    begin
2390       --  The semantic attributes are set for completeness only, their values
2391       --  will never be used, since all properties of the type are non-static.
2392 
2393       Enter_Name (T);
2394       Set_Ekind            (T, E_Ordinary_Fixed_Point_Subtype);
2395       Set_Etype            (T, Base);
2396       Set_Size_Info        (T, Standard_Integer);
2397       Set_RM_Size          (T, RM_Size (Standard_Integer));
2398       Set_Small_Value      (T, Ureal_1);
2399       Set_Delta_Value      (T, Ureal_1);
2400       Set_Scalar_Range     (T,
2401         Make_Range (Loc,
2402           Low_Bound  => Make_Real_Literal (Loc, Ureal_1),
2403           High_Bound => Make_Real_Literal (Loc, Ureal_1)));
2404       Set_Is_Constrained   (T);
2405 
2406       Set_Is_Generic_Type (Base);
2407       Set_Etype           (Base, Base);
2408       Set_Size_Info       (Base, Standard_Integer);
2409       Set_RM_Size         (Base, RM_Size (Standard_Integer));
2410       Set_Small_Value     (Base, Ureal_1);
2411       Set_Delta_Value     (Base, Ureal_1);
2412       Set_Scalar_Range    (Base, Scalar_Range (T));
2413       Set_Parent          (Base, Parent (Def));
2414 
2415       Check_Restriction (No_Fixed_Point, Def);
2416    end Analyze_Formal_Ordinary_Fixed_Point_Type;
2417 
2418    ----------------------------------------
2419    -- Analyze_Formal_Package_Declaration --
2420    ----------------------------------------
2421 
2422    procedure Analyze_Formal_Package_Declaration (N : Node_Id) is
2423       Gen_Id   : constant Node_Id    := Name (N);
2424       Loc      : constant Source_Ptr := Sloc (N);
2425       Pack_Id  : constant Entity_Id  := Defining_Identifier (N);
2426       Formal   : Entity_Id;
2427       Gen_Decl : Node_Id;
2428       Gen_Unit : Entity_Id;
2429       Renaming : Node_Id;
2430 
2431       Vis_Prims_List : Elist_Id := No_Elist;
2432       --  List of primitives made temporarily visible in the instantiation
2433       --  to match the visibility of the formal type.
2434 
2435       function Build_Local_Package return Node_Id;
2436       --  The formal package is rewritten so that its parameters are replaced
2437       --  with corresponding declarations. For parameters with bona fide
2438       --  associations these declarations are created by Analyze_Associations
2439       --  as for a regular instantiation. For boxed parameters, we preserve
2440       --  the formal declarations and analyze them, in order to introduce
2441       --  entities of the right kind in the environment of the formal.
2442 
2443       -------------------------
2444       -- Build_Local_Package --
2445       -------------------------
2446 
2447       function Build_Local_Package return Node_Id is
2448          Decls     : List_Id;
2449          Pack_Decl : Node_Id;
2450 
2451       begin
2452          --  Within the formal, the name of the generic package is a renaming
2453          --  of the formal (as for a regular instantiation).
2454 
2455          Pack_Decl :=
2456            Make_Package_Declaration (Loc,
2457              Specification =>
2458                Copy_Generic_Node
2459                  (Specification (Original_Node (Gen_Decl)),
2460                     Empty, Instantiating => True));
2461 
2462          Renaming :=
2463            Make_Package_Renaming_Declaration (Loc,
2464              Defining_Unit_Name =>
2465                Make_Defining_Identifier (Loc, Chars (Gen_Unit)),
2466              Name               => New_Occurrence_Of (Formal, Loc));
2467 
2468          if Nkind (Gen_Id) = N_Identifier
2469            and then Chars (Gen_Id) = Chars (Pack_Id)
2470          then
2471             Error_Msg_NE
2472               ("& is hidden within declaration of instance", Gen_Id, Gen_Unit);
2473          end if;
2474 
2475          --  If the formal is declared with a box, or with an others choice,
2476          --  create corresponding declarations for all entities in the formal
2477          --  part, so that names with the proper types are available in the
2478          --  specification of the formal package.
2479 
2480          --  On the other hand, if there are no associations, then all the
2481          --  formals must have defaults, and this will be checked by the
2482          --  call to Analyze_Associations.
2483 
2484          if Box_Present (N)
2485            or else Nkind (First (Generic_Associations (N))) = N_Others_Choice
2486          then
2487             declare
2488                Formal_Decl : Node_Id;
2489 
2490             begin
2491                --  TBA : for a formal package, need to recurse ???
2492 
2493                Decls := New_List;
2494                Formal_Decl :=
2495                  First
2496                    (Generic_Formal_Declarations (Original_Node (Gen_Decl)));
2497                while Present (Formal_Decl) loop
2498                   Append_To
2499                     (Decls, Copy_Generic_Node (Formal_Decl, Empty, True));
2500                   Next (Formal_Decl);
2501                end loop;
2502             end;
2503 
2504          --  If generic associations are present, use Analyze_Associations to
2505          --  create the proper renaming declarations.
2506 
2507          else
2508             declare
2509                Act_Tree : constant Node_Id :=
2510                             Copy_Generic_Node
2511                               (Original_Node (Gen_Decl), Empty,
2512                                Instantiating => True);
2513 
2514             begin
2515                Generic_Renamings.Set_Last (0);
2516                Generic_Renamings_HTable.Reset;
2517                Instantiation_Node := N;
2518 
2519                Decls :=
2520                  Analyze_Associations
2521                    (I_Node  => Original_Node (N),
2522                     Formals => Generic_Formal_Declarations (Act_Tree),
2523                     F_Copy  => Generic_Formal_Declarations (Gen_Decl));
2524 
2525                Vis_Prims_List := Check_Hidden_Primitives (Decls);
2526             end;
2527          end if;
2528 
2529          Append (Renaming, To => Decls);
2530 
2531          --  Add generated declarations ahead of local declarations in
2532          --  the package.
2533 
2534          if No (Visible_Declarations (Specification (Pack_Decl))) then
2535             Set_Visible_Declarations (Specification (Pack_Decl), Decls);
2536          else
2537             Insert_List_Before
2538               (First (Visible_Declarations (Specification (Pack_Decl))),
2539                  Decls);
2540          end if;
2541 
2542          return Pack_Decl;
2543       end Build_Local_Package;
2544 
2545       --  Local variables
2546 
2547       Save_IPSM : constant Boolean := Ignore_Pragma_SPARK_Mode;
2548       --  Save flag Ignore_Pragma_SPARK_Mode for restore on exit
2549 
2550       Associations     : Boolean := True;
2551       New_N            : Node_Id;
2552       Parent_Installed : Boolean := False;
2553       Parent_Instance  : Entity_Id;
2554       Renaming_In_Par  : Entity_Id;
2555 
2556    --  Start of processing for Analyze_Formal_Package_Declaration
2557 
2558    begin
2559       Check_Text_IO_Special_Unit (Gen_Id);
2560 
2561       Init_Env;
2562       Check_Generic_Child_Unit (Gen_Id, Parent_Installed);
2563       Gen_Unit := Entity (Gen_Id);
2564 
2565       --  Check for a formal package that is a package renaming
2566 
2567       if Present (Renamed_Object (Gen_Unit)) then
2568 
2569          --  Indicate that unit is used, before replacing it with renamed
2570          --  entity for use below.
2571 
2572          if In_Extended_Main_Source_Unit (N) then
2573             Set_Is_Instantiated (Gen_Unit);
2574             Generate_Reference  (Gen_Unit, N);
2575          end if;
2576 
2577          Gen_Unit := Renamed_Object (Gen_Unit);
2578       end if;
2579 
2580       if Ekind (Gen_Unit) /= E_Generic_Package then
2581          Error_Msg_N ("expect generic package name", Gen_Id);
2582          Restore_Env;
2583          goto Leave;
2584 
2585       elsif Gen_Unit = Current_Scope then
2586          Error_Msg_N
2587            ("generic package cannot be used as a formal package of itself",
2588             Gen_Id);
2589          Restore_Env;
2590          goto Leave;
2591 
2592       elsif In_Open_Scopes (Gen_Unit) then
2593          if Is_Compilation_Unit (Gen_Unit)
2594            and then Is_Child_Unit (Current_Scope)
2595          then
2596             --  Special-case the error when the formal is a parent, and
2597             --  continue analysis to minimize cascaded errors.
2598 
2599             Error_Msg_N
2600               ("generic parent cannot be used as formal package "
2601                & "of a child unit", Gen_Id);
2602 
2603          else
2604             Error_Msg_N
2605               ("generic package cannot be used as a formal package "
2606                & "within itself", Gen_Id);
2607             Restore_Env;
2608             goto Leave;
2609          end if;
2610       end if;
2611 
2612       --  Check that name of formal package does not hide name of generic,
2613       --  or its leading prefix. This check must be done separately because
2614       --  the name of the generic has already been analyzed.
2615 
2616       declare
2617          Gen_Name : Entity_Id;
2618 
2619       begin
2620          Gen_Name := Gen_Id;
2621          while Nkind (Gen_Name) = N_Expanded_Name loop
2622             Gen_Name := Prefix (Gen_Name);
2623          end loop;
2624 
2625          if Chars (Gen_Name) = Chars (Pack_Id) then
2626             Error_Msg_NE
2627              ("& is hidden within declaration of formal package",
2628               Gen_Id, Gen_Name);
2629          end if;
2630       end;
2631 
2632       if Box_Present (N)
2633         or else No (Generic_Associations (N))
2634         or else Nkind (First (Generic_Associations (N))) = N_Others_Choice
2635       then
2636          Associations := False;
2637       end if;
2638 
2639       --  If there are no generic associations, the generic parameters appear
2640       --  as local entities and are instantiated like them. We copy the generic
2641       --  package declaration as if it were an instantiation, and analyze it
2642       --  like a regular package, except that we treat the formals as
2643       --  additional visible components.
2644 
2645       Gen_Decl := Unit_Declaration_Node (Gen_Unit);
2646 
2647       if In_Extended_Main_Source_Unit (N) then
2648          Set_Is_Instantiated (Gen_Unit);
2649          Generate_Reference  (Gen_Unit, N);
2650       end if;
2651 
2652       Formal := New_Copy (Pack_Id);
2653       Create_Instantiation_Source (N, Gen_Unit, S_Adjustment);
2654 
2655       --  Make local generic without formals. The formals will be replaced with
2656       --  internal declarations.
2657 
2658       begin
2659          New_N := Build_Local_Package;
2660 
2661       --  If there are errors in the parameter list, Analyze_Associations
2662       --  raises Instantiation_Error. Patch the declaration to prevent further
2663       --  exception propagation.
2664 
2665       exception
2666          when Instantiation_Error =>
2667             Enter_Name (Formal);
2668             Set_Ekind  (Formal, E_Variable);
2669             Set_Etype  (Formal, Any_Type);
2670             Restore_Hidden_Primitives (Vis_Prims_List);
2671 
2672             if Parent_Installed then
2673                Remove_Parent;
2674             end if;
2675 
2676             goto Leave;
2677       end;
2678 
2679       Rewrite (N, New_N);
2680       Set_Defining_Unit_Name (Specification (New_N), Formal);
2681       Set_Generic_Parent (Specification (N), Gen_Unit);
2682       Set_Instance_Env (Gen_Unit, Formal);
2683       Set_Is_Generic_Instance (Formal);
2684 
2685       Enter_Name (Formal);
2686       Set_Ekind  (Formal, E_Package);
2687       Set_Etype  (Formal, Standard_Void_Type);
2688       Set_Inner_Instances (Formal, New_Elmt_List);
2689       Push_Scope  (Formal);
2690 
2691       --  Manually set the SPARK_Mode from the context because the package
2692       --  declaration is never analyzed.
2693 
2694       Set_SPARK_Pragma               (Formal, SPARK_Mode_Pragma);
2695       Set_SPARK_Aux_Pragma           (Formal, SPARK_Mode_Pragma);
2696       Set_SPARK_Pragma_Inherited     (Formal);
2697       Set_SPARK_Aux_Pragma_Inherited (Formal);
2698 
2699       if Is_Child_Unit (Gen_Unit) and then Parent_Installed then
2700 
2701          --  Similarly, we have to make the name of the formal visible in the
2702          --  parent instance, to resolve properly fully qualified names that
2703          --  may appear in the generic unit. The parent instance has been
2704          --  placed on the scope stack ahead of the current scope.
2705 
2706          Parent_Instance := Scope_Stack.Table (Scope_Stack.Last - 1).Entity;
2707 
2708          Renaming_In_Par :=
2709            Make_Defining_Identifier (Loc, Chars (Gen_Unit));
2710          Set_Ekind (Renaming_In_Par, E_Package);
2711          Set_Etype (Renaming_In_Par, Standard_Void_Type);
2712          Set_Scope (Renaming_In_Par, Parent_Instance);
2713          Set_Parent (Renaming_In_Par, Parent (Formal));
2714          Set_Renamed_Object (Renaming_In_Par, Formal);
2715          Append_Entity (Renaming_In_Par, Parent_Instance);
2716       end if;
2717 
2718       --  A formal package declaration behaves as a package instantiation with
2719       --  respect to SPARK_Mode "off". If the annotation is "off" or altogether
2720       --  missing, set the global flag which signals Analyze_Pragma to ingnore
2721       --  all SPARK_Mode pragmas within the generic_package_name.
2722 
2723       if SPARK_Mode /= On then
2724          Ignore_Pragma_SPARK_Mode := True;
2725       end if;
2726 
2727       Analyze (Specification (N));
2728 
2729       --  The formals for which associations are provided are not visible
2730       --  outside of the formal package. The others are still declared by a
2731       --  formal parameter declaration.
2732 
2733       --  If there are no associations, the only local entity to hide is the
2734       --  generated package renaming itself.
2735 
2736       declare
2737          E : Entity_Id;
2738 
2739       begin
2740          E := First_Entity (Formal);
2741          while Present (E) loop
2742             if Associations and then not Is_Generic_Formal (E) then
2743                Set_Is_Hidden (E);
2744             end if;
2745 
2746             if Ekind (E) = E_Package and then Renamed_Entity (E) = Formal then
2747                Set_Is_Hidden (E);
2748                exit;
2749             end if;
2750 
2751             Next_Entity (E);
2752          end loop;
2753       end;
2754 
2755       End_Package_Scope (Formal);
2756       Restore_Hidden_Primitives (Vis_Prims_List);
2757 
2758       if Parent_Installed then
2759          Remove_Parent;
2760       end if;
2761 
2762       Restore_Env;
2763 
2764       --  Inside the generic unit, the formal package is a regular package, but
2765       --  no body is needed for it. Note that after instantiation, the defining
2766       --  unit name we need is in the new tree and not in the original (see
2767       --  Package_Instantiation). A generic formal package is an instance, and
2768       --  can be used as an actual for an inner instance.
2769 
2770       Set_Has_Completion (Formal, True);
2771 
2772       --  Add semantic information to the original defining identifier for ASIS
2773       --  use.
2774 
2775       Set_Ekind (Pack_Id, E_Package);
2776       Set_Etype (Pack_Id, Standard_Void_Type);
2777       Set_Scope (Pack_Id, Scope (Formal));
2778       Set_Has_Completion (Pack_Id, True);
2779 
2780    <<Leave>>
2781       if Has_Aspects (N) then
2782          Analyze_Aspect_Specifications (N, Pack_Id);
2783       end if;
2784 
2785       Ignore_Pragma_SPARK_Mode := Save_IPSM;
2786    end Analyze_Formal_Package_Declaration;
2787 
2788    ---------------------------------
2789    -- Analyze_Formal_Private_Type --
2790    ---------------------------------
2791 
2792    procedure Analyze_Formal_Private_Type
2793      (N   : Node_Id;
2794       T   : Entity_Id;
2795       Def : Node_Id)
2796    is
2797    begin
2798       New_Private_Type (N, T, Def);
2799 
2800       --  Set the size to an arbitrary but legal value
2801 
2802       Set_Size_Info (T, Standard_Integer);
2803       Set_RM_Size   (T, RM_Size (Standard_Integer));
2804    end Analyze_Formal_Private_Type;
2805 
2806    ------------------------------------
2807    -- Analyze_Formal_Incomplete_Type --
2808    ------------------------------------
2809 
2810    procedure Analyze_Formal_Incomplete_Type
2811      (T   : Entity_Id;
2812       Def : Node_Id)
2813    is
2814    begin
2815       Enter_Name (T);
2816       Set_Ekind (T, E_Incomplete_Type);
2817       Set_Etype (T, T);
2818       Set_Private_Dependents (T, New_Elmt_List);
2819 
2820       if Tagged_Present (Def) then
2821          Set_Is_Tagged_Type (T);
2822          Make_Class_Wide_Type (T);
2823          Set_Direct_Primitive_Operations (T, New_Elmt_List);
2824       end if;
2825    end Analyze_Formal_Incomplete_Type;
2826 
2827    ----------------------------------------
2828    -- Analyze_Formal_Signed_Integer_Type --
2829    ----------------------------------------
2830 
2831    procedure Analyze_Formal_Signed_Integer_Type
2832      (T   : Entity_Id;
2833       Def : Node_Id)
2834    is
2835       Base : constant Entity_Id :=
2836                New_Internal_Entity
2837                  (E_Signed_Integer_Type,
2838                   Current_Scope,
2839                   Sloc (Defining_Identifier (Parent (Def))), 'G');
2840 
2841    begin
2842       Enter_Name (T);
2843 
2844       Set_Ekind          (T, E_Signed_Integer_Subtype);
2845       Set_Etype          (T, Base);
2846       Set_Size_Info      (T, Standard_Integer);
2847       Set_RM_Size        (T, RM_Size (Standard_Integer));
2848       Set_Scalar_Range   (T, Scalar_Range (Standard_Integer));
2849       Set_Is_Constrained (T);
2850 
2851       Set_Is_Generic_Type (Base);
2852       Set_Size_Info       (Base, Standard_Integer);
2853       Set_RM_Size         (Base, RM_Size (Standard_Integer));
2854       Set_Etype           (Base, Base);
2855       Set_Scalar_Range    (Base, Scalar_Range (Standard_Integer));
2856       Set_Parent          (Base, Parent (Def));
2857    end Analyze_Formal_Signed_Integer_Type;
2858 
2859    -------------------------------------------
2860    -- Analyze_Formal_Subprogram_Declaration --
2861    -------------------------------------------
2862 
2863    procedure Analyze_Formal_Subprogram_Declaration (N : Node_Id) is
2864       Spec : constant Node_Id   := Specification (N);
2865       Def  : constant Node_Id   := Default_Name (N);
2866       Nam  : constant Entity_Id := Defining_Unit_Name (Spec);
2867       Subp : Entity_Id;
2868 
2869    begin
2870       if Nam = Error then
2871          return;
2872       end if;
2873 
2874       if Nkind (Nam) = N_Defining_Program_Unit_Name then
2875          Error_Msg_N ("name of formal subprogram must be a direct name", Nam);
2876          goto Leave;
2877       end if;
2878 
2879       Analyze_Subprogram_Declaration (N);
2880       Set_Is_Formal_Subprogram (Nam);
2881       Set_Has_Completion (Nam);
2882 
2883       if Nkind (N) = N_Formal_Abstract_Subprogram_Declaration then
2884          Set_Is_Abstract_Subprogram (Nam);
2885 
2886          Set_Is_Dispatching_Operation (Nam);
2887 
2888          --  A formal abstract procedure cannot have a null default
2889          --  (RM 12.6(4.1/2)).
2890 
2891          if Nkind (Spec) = N_Procedure_Specification
2892            and then Null_Present (Spec)
2893          then
2894             Error_Msg_N
2895               ("a formal abstract subprogram cannot default to null", Spec);
2896          end if;
2897 
2898          declare
2899             Ctrl_Type : constant Entity_Id := Find_Dispatching_Type (Nam);
2900          begin
2901             if No (Ctrl_Type) then
2902                Error_Msg_N
2903                  ("abstract formal subprogram must have a controlling type",
2904                   N);
2905 
2906             elsif Ada_Version >= Ada_2012
2907               and then Is_Incomplete_Type (Ctrl_Type)
2908             then
2909                Error_Msg_NE
2910                  ("controlling type of abstract formal subprogram cannot "
2911                   & "be incomplete type", N, Ctrl_Type);
2912 
2913             else
2914                Check_Controlling_Formals (Ctrl_Type, Nam);
2915             end if;
2916          end;
2917       end if;
2918 
2919       --  Default name is resolved at the point of instantiation
2920 
2921       if Box_Present (N) then
2922          null;
2923 
2924       --  Else default is bound at the point of generic declaration
2925 
2926       elsif Present (Def) then
2927          if Nkind (Def) = N_Operator_Symbol then
2928             Find_Direct_Name (Def);
2929 
2930          elsif Nkind (Def) /= N_Attribute_Reference then
2931             Analyze (Def);
2932 
2933          else
2934             --  For an attribute reference, analyze the prefix and verify
2935             --  that it has the proper profile for the subprogram.
2936 
2937             Analyze (Prefix (Def));
2938             Valid_Default_Attribute (Nam, Def);
2939             goto Leave;
2940          end if;
2941 
2942          --  Default name may be overloaded, in which case the interpretation
2943          --  with the correct profile must be selected, as for a renaming.
2944          --  If the definition is an indexed component, it must denote a
2945          --  member of an entry family. If it is a selected component, it
2946          --  can be a protected operation.
2947 
2948          if Etype (Def) = Any_Type then
2949             goto Leave;
2950 
2951          elsif Nkind (Def) = N_Selected_Component then
2952             if not Is_Overloadable (Entity (Selector_Name (Def))) then
2953                Error_Msg_N ("expect valid subprogram name as default", Def);
2954             end if;
2955 
2956          elsif Nkind (Def) = N_Indexed_Component then
2957             if Is_Entity_Name (Prefix (Def)) then
2958                if Ekind (Entity (Prefix (Def))) /= E_Entry_Family then
2959                   Error_Msg_N ("expect valid subprogram name as default", Def);
2960                end if;
2961 
2962             elsif Nkind (Prefix (Def)) = N_Selected_Component then
2963                if Ekind (Entity (Selector_Name (Prefix (Def)))) /=
2964                                                           E_Entry_Family
2965                then
2966                   Error_Msg_N ("expect valid subprogram name as default", Def);
2967                end if;
2968 
2969             else
2970                Error_Msg_N ("expect valid subprogram name as default", Def);
2971                goto Leave;
2972             end if;
2973 
2974          elsif Nkind (Def) = N_Character_Literal then
2975 
2976             --  Needs some type checks: subprogram should be parameterless???
2977 
2978             Resolve (Def, (Etype (Nam)));
2979 
2980          elsif not Is_Entity_Name (Def)
2981            or else not Is_Overloadable (Entity (Def))
2982          then
2983             Error_Msg_N ("expect valid subprogram name as default", Def);
2984             goto Leave;
2985 
2986          elsif not Is_Overloaded (Def) then
2987             Subp := Entity (Def);
2988 
2989             if Subp = Nam then
2990                Error_Msg_N ("premature usage of formal subprogram", Def);
2991 
2992             elsif not Entity_Matches_Spec (Subp, Nam) then
2993                Error_Msg_N ("no visible entity matches specification", Def);
2994             end if;
2995 
2996          --  More than one interpretation, so disambiguate as for a renaming
2997 
2998          else
2999             declare
3000                I   : Interp_Index;
3001                I1  : Interp_Index := 0;
3002                It  : Interp;
3003                It1 : Interp;
3004 
3005             begin
3006                Subp := Any_Id;
3007                Get_First_Interp (Def, I, It);
3008                while Present (It.Nam) loop
3009                   if Entity_Matches_Spec (It.Nam, Nam) then
3010                      if Subp /= Any_Id then
3011                         It1 := Disambiguate (Def, I1, I, Etype (Subp));
3012 
3013                         if It1 = No_Interp then
3014                            Error_Msg_N ("ambiguous default subprogram", Def);
3015                         else
3016                            Subp := It1.Nam;
3017                         end if;
3018 
3019                         exit;
3020 
3021                      else
3022                         I1  := I;
3023                         Subp := It.Nam;
3024                      end if;
3025                   end if;
3026 
3027                   Get_Next_Interp (I, It);
3028                end loop;
3029             end;
3030 
3031             if Subp /= Any_Id then
3032 
3033                --  Subprogram found, generate reference to it
3034 
3035                Set_Entity (Def, Subp);
3036                Generate_Reference (Subp, Def);
3037 
3038                if Subp = Nam then
3039                   Error_Msg_N ("premature usage of formal subprogram", Def);
3040 
3041                elsif Ekind (Subp) /= E_Operator then
3042                   Check_Mode_Conformant (Subp, Nam);
3043                end if;
3044 
3045             else
3046                Error_Msg_N ("no visible subprogram matches specification", N);
3047             end if;
3048          end if;
3049       end if;
3050 
3051    <<Leave>>
3052       if Has_Aspects (N) then
3053          Analyze_Aspect_Specifications (N, Nam);
3054       end if;
3055 
3056    end Analyze_Formal_Subprogram_Declaration;
3057 
3058    -------------------------------------
3059    -- Analyze_Formal_Type_Declaration --
3060    -------------------------------------
3061 
3062    procedure Analyze_Formal_Type_Declaration (N : Node_Id) is
3063       Def : constant Node_Id := Formal_Type_Definition (N);
3064       T   : Entity_Id;
3065 
3066    begin
3067       T := Defining_Identifier (N);
3068 
3069       if Present (Discriminant_Specifications (N))
3070         and then Nkind (Def) /= N_Formal_Private_Type_Definition
3071       then
3072          Error_Msg_N
3073            ("discriminants not allowed for this formal type", T);
3074       end if;
3075 
3076       --  Enter the new name, and branch to specific routine
3077 
3078       case Nkind (Def) is
3079          when N_Formal_Private_Type_Definition         =>
3080             Analyze_Formal_Private_Type (N, T, Def);
3081 
3082          when N_Formal_Derived_Type_Definition         =>
3083             Analyze_Formal_Derived_Type (N, T, Def);
3084 
3085          when N_Formal_Incomplete_Type_Definition         =>
3086             Analyze_Formal_Incomplete_Type (T, Def);
3087 
3088          when N_Formal_Discrete_Type_Definition        =>
3089             Analyze_Formal_Discrete_Type (T, Def);
3090 
3091          when N_Formal_Signed_Integer_Type_Definition  =>
3092             Analyze_Formal_Signed_Integer_Type (T, Def);
3093 
3094          when N_Formal_Modular_Type_Definition         =>
3095             Analyze_Formal_Modular_Type (T, Def);
3096 
3097          when N_Formal_Floating_Point_Definition       =>
3098             Analyze_Formal_Floating_Type (T, Def);
3099 
3100          when N_Formal_Ordinary_Fixed_Point_Definition =>
3101             Analyze_Formal_Ordinary_Fixed_Point_Type (T, Def);
3102 
3103          when N_Formal_Decimal_Fixed_Point_Definition  =>
3104             Analyze_Formal_Decimal_Fixed_Point_Type (T, Def);
3105 
3106          when N_Array_Type_Definition =>
3107             Analyze_Formal_Array_Type (T, Def);
3108 
3109          when N_Access_To_Object_Definition            |
3110               N_Access_Function_Definition             |
3111               N_Access_Procedure_Definition            =>
3112             Analyze_Generic_Access_Type (T, Def);
3113 
3114          --  Ada 2005: a interface declaration is encoded as an abstract
3115          --  record declaration or a abstract type derivation.
3116 
3117          when N_Record_Definition                      =>
3118             Analyze_Formal_Interface_Type (N, T, Def);
3119 
3120          when N_Derived_Type_Definition                =>
3121             Analyze_Formal_Derived_Interface_Type (N, T, Def);
3122 
3123          when N_Error                                  =>
3124             null;
3125 
3126          when others                                   =>
3127             raise Program_Error;
3128 
3129       end case;
3130 
3131       Set_Is_Generic_Type (T);
3132 
3133       if Has_Aspects (N) then
3134          Analyze_Aspect_Specifications (N, T);
3135       end if;
3136    end Analyze_Formal_Type_Declaration;
3137 
3138    ------------------------------------
3139    -- Analyze_Function_Instantiation --
3140    ------------------------------------
3141 
3142    procedure Analyze_Function_Instantiation (N : Node_Id) is
3143    begin
3144       Analyze_Subprogram_Instantiation (N, E_Function);
3145    end Analyze_Function_Instantiation;
3146 
3147    ---------------------------------
3148    -- Analyze_Generic_Access_Type --
3149    ---------------------------------
3150 
3151    procedure Analyze_Generic_Access_Type (T : Entity_Id; Def : Node_Id) is
3152    begin
3153       Enter_Name (T);
3154 
3155       if Nkind (Def) = N_Access_To_Object_Definition then
3156          Access_Type_Declaration (T, Def);
3157 
3158          if Is_Incomplete_Or_Private_Type (Designated_Type (T))
3159            and then No (Full_View (Designated_Type (T)))
3160            and then not Is_Generic_Type (Designated_Type (T))
3161          then
3162             Error_Msg_N ("premature usage of incomplete type", Def);
3163 
3164          elsif not Is_Entity_Name (Subtype_Indication (Def)) then
3165             Error_Msg_N
3166               ("only a subtype mark is allowed in a formal", Def);
3167          end if;
3168 
3169       else
3170          Access_Subprogram_Declaration (T, Def);
3171       end if;
3172    end Analyze_Generic_Access_Type;
3173 
3174    ---------------------------------
3175    -- Analyze_Generic_Formal_Part --
3176    ---------------------------------
3177 
3178    procedure Analyze_Generic_Formal_Part (N : Node_Id) is
3179       Gen_Parm_Decl : Node_Id;
3180 
3181    begin
3182       --  The generic formals are processed in the scope of the generic unit,
3183       --  where they are immediately visible. The scope is installed by the
3184       --  caller.
3185 
3186       Gen_Parm_Decl := First (Generic_Formal_Declarations (N));
3187       while Present (Gen_Parm_Decl) loop
3188          Analyze (Gen_Parm_Decl);
3189          Next (Gen_Parm_Decl);
3190       end loop;
3191 
3192       Generate_Reference_To_Generic_Formals (Current_Scope);
3193    end Analyze_Generic_Formal_Part;
3194 
3195    ------------------------------------------
3196    -- Analyze_Generic_Package_Declaration  --
3197    ------------------------------------------
3198 
3199    procedure Analyze_Generic_Package_Declaration (N : Node_Id) is
3200       Loc         : constant Source_Ptr := Sloc (N);
3201       Decls       : constant List_Id :=
3202                       Visible_Declarations (Specification (N));
3203       Decl        : Node_Id;
3204       Id          : Entity_Id;
3205       New_N       : Node_Id;
3206       Renaming    : Node_Id;
3207       Save_Parent : Node_Id;
3208 
3209    begin
3210       Check_SPARK_05_Restriction ("generic is not allowed", N);
3211 
3212       --  We introduce a renaming of the enclosing package, to have a usable
3213       --  entity as the prefix of an expanded name for a local entity of the
3214       --  form Par.P.Q, where P is the generic package. This is because a local
3215       --  entity named P may hide it, so that the usual visibility rules in
3216       --  the instance will not resolve properly.
3217 
3218       Renaming :=
3219         Make_Package_Renaming_Declaration (Loc,
3220           Defining_Unit_Name =>
3221             Make_Defining_Identifier (Loc,
3222              Chars => New_External_Name (Chars (Defining_Entity (N)), "GH")),
3223           Name               =>
3224             Make_Identifier (Loc, Chars (Defining_Entity (N))));
3225 
3226       if Present (Decls) then
3227          Decl := First (Decls);
3228          while Present (Decl) and then Nkind (Decl) = N_Pragma loop
3229             Next (Decl);
3230          end loop;
3231 
3232          if Present (Decl) then
3233             Insert_Before (Decl, Renaming);
3234          else
3235             Append (Renaming, Visible_Declarations (Specification (N)));
3236          end if;
3237 
3238       else
3239          Set_Visible_Declarations (Specification (N), New_List (Renaming));
3240       end if;
3241 
3242       --  Create copy of generic unit, and save for instantiation. If the unit
3243       --  is a child unit, do not copy the specifications for the parent, which
3244       --  are not part of the generic tree.
3245 
3246       Save_Parent := Parent_Spec (N);
3247       Set_Parent_Spec (N, Empty);
3248 
3249       New_N := Copy_Generic_Node (N, Empty, Instantiating => False);
3250       Set_Parent_Spec (New_N, Save_Parent);
3251       Rewrite (N, New_N);
3252 
3253       --  Once the contents of the generic copy and the template are swapped,
3254       --  do the same for their respective aspect specifications.
3255 
3256       Exchange_Aspects (N, New_N);
3257 
3258       --  Collect all contract-related source pragmas found within the template
3259       --  and attach them to the contract of the package spec. This contract is
3260       --  used in the capture of global references within annotations.
3261 
3262       Create_Generic_Contract (N);
3263 
3264       Id := Defining_Entity (N);
3265       Generate_Definition (Id);
3266 
3267       --  Expansion is not applied to generic units
3268 
3269       Start_Generic;
3270 
3271       Enter_Name (Id);
3272       Set_Ekind  (Id, E_Generic_Package);
3273       Set_Etype  (Id, Standard_Void_Type);
3274 
3275       --  A generic package declared within a Ghost region is rendered Ghost
3276       --  (SPARK RM 6.9(2)).
3277 
3278       if Ghost_Mode > None then
3279          Set_Is_Ghost_Entity (Id);
3280       end if;
3281 
3282       --  Analyze aspects now, so that generated pragmas appear in the
3283       --  declarations before building and analyzing the generic copy.
3284 
3285       if Has_Aspects (N) then
3286          Analyze_Aspect_Specifications (N, Id);
3287       end if;
3288 
3289       Push_Scope (Id);
3290       Enter_Generic_Scope (Id);
3291       Set_Inner_Instances (Id, New_Elmt_List);
3292 
3293       Set_Categorization_From_Pragmas (N);
3294       Set_Is_Pure (Id, Is_Pure (Current_Scope));
3295 
3296       --  Link the declaration of the generic homonym in the generic copy to
3297       --  the package it renames, so that it is always resolved properly.
3298 
3299       Set_Generic_Homonym (Id, Defining_Unit_Name (Renaming));
3300       Set_Entity (Associated_Node (Name (Renaming)), Id);
3301 
3302       --  For a library unit, we have reconstructed the entity for the unit,
3303       --  and must reset it in the library tables.
3304 
3305       if Nkind (Parent (N)) = N_Compilation_Unit then
3306          Set_Cunit_Entity (Current_Sem_Unit, Id);
3307       end if;
3308 
3309       Analyze_Generic_Formal_Part (N);
3310 
3311       --  After processing the generic formals, analysis proceeds as for a
3312       --  non-generic package.
3313 
3314       Analyze (Specification (N));
3315 
3316       Validate_Categorization_Dependency (N, Id);
3317 
3318       End_Generic;
3319 
3320       End_Package_Scope (Id);
3321       Exit_Generic_Scope (Id);
3322 
3323       if Nkind (Parent (N)) /= N_Compilation_Unit then
3324          Move_Freeze_Nodes (Id, N, Visible_Declarations (Specification (N)));
3325          Move_Freeze_Nodes (Id, N, Private_Declarations (Specification (N)));
3326          Move_Freeze_Nodes (Id, N, Generic_Formal_Declarations (N));
3327 
3328       else
3329          Set_Body_Required (Parent (N), Unit_Requires_Body (Id));
3330          Validate_RT_RAT_Component (N);
3331 
3332          --  If this is a spec without a body, check that generic parameters
3333          --  are referenced.
3334 
3335          if not Body_Required (Parent (N)) then
3336             Check_References (Id);
3337          end if;
3338       end if;
3339 
3340       --  If there is a specified storage pool in the context, create an
3341       --  aspect on the package declaration, so that it is used in any
3342       --  instance that does not override it.
3343 
3344       if Present (Default_Pool) then
3345          declare
3346             ASN : Node_Id;
3347 
3348          begin
3349             ASN :=
3350               Make_Aspect_Specification (Loc,
3351                 Identifier => Make_Identifier (Loc, Name_Default_Storage_Pool),
3352                 Expression => New_Copy (Default_Pool));
3353 
3354             if No (Aspect_Specifications (Specification (N))) then
3355                Set_Aspect_Specifications (Specification (N), New_List (ASN));
3356             else
3357                Append (ASN, Aspect_Specifications (Specification (N)));
3358             end if;
3359          end;
3360       end if;
3361    end Analyze_Generic_Package_Declaration;
3362 
3363    --------------------------------------------
3364    -- Analyze_Generic_Subprogram_Declaration --
3365    --------------------------------------------
3366 
3367    procedure Analyze_Generic_Subprogram_Declaration (N : Node_Id) is
3368       Formals     : List_Id;
3369       Id          : Entity_Id;
3370       New_N       : Node_Id;
3371       Result_Type : Entity_Id;
3372       Save_Parent : Node_Id;
3373       Spec        : Node_Id;
3374       Typ         : Entity_Id;
3375 
3376    begin
3377       Check_SPARK_05_Restriction ("generic is not allowed", N);
3378 
3379       --  Create copy of generic unit, and save for instantiation. If the unit
3380       --  is a child unit, do not copy the specifications for the parent, which
3381       --  are not part of the generic tree.
3382 
3383       Save_Parent := Parent_Spec (N);
3384       Set_Parent_Spec (N, Empty);
3385 
3386       New_N := Copy_Generic_Node (N, Empty, Instantiating => False);
3387       Set_Parent_Spec (New_N, Save_Parent);
3388       Rewrite (N, New_N);
3389 
3390       --  Once the contents of the generic copy and the template are swapped,
3391       --  do the same for their respective aspect specifications.
3392 
3393       Exchange_Aspects (N, New_N);
3394 
3395       --  Collect all contract-related source pragmas found within the template
3396       --  and attach them to the contract of the subprogram spec. This contract
3397       --  is used in the capture of global references within annotations.
3398 
3399       Create_Generic_Contract (N);
3400 
3401       Spec := Specification (N);
3402       Id := Defining_Entity (Spec);
3403       Generate_Definition (Id);
3404 
3405       if Nkind (Id) = N_Defining_Operator_Symbol then
3406          Error_Msg_N
3407            ("operator symbol not allowed for generic subprogram", Id);
3408       end if;
3409 
3410       Start_Generic;
3411 
3412       Enter_Name (Id);
3413       Set_Scope_Depth_Value (Id, Scope_Depth (Current_Scope) + 1);
3414 
3415       --  Analyze the aspects of the generic copy to ensure that all generated
3416       --  pragmas (if any) perform their semantic effects.
3417 
3418       if Has_Aspects (N) then
3419          Analyze_Aspect_Specifications (N, Id);
3420       end if;
3421 
3422       Push_Scope (Id);
3423       Enter_Generic_Scope (Id);
3424       Set_Inner_Instances (Id, New_Elmt_List);
3425       Set_Is_Pure (Id, Is_Pure (Current_Scope));
3426 
3427       Analyze_Generic_Formal_Part (N);
3428 
3429       Formals := Parameter_Specifications (Spec);
3430 
3431       if Nkind (Spec) = N_Function_Specification then
3432          Set_Ekind (Id, E_Generic_Function);
3433       else
3434          Set_Ekind (Id, E_Generic_Procedure);
3435       end if;
3436 
3437       if Present (Formals) then
3438          Process_Formals (Formals, Spec);
3439       end if;
3440 
3441       if Nkind (Spec) = N_Function_Specification then
3442          if Nkind (Result_Definition (Spec)) = N_Access_Definition then
3443             Result_Type := Access_Definition (Spec, Result_Definition (Spec));
3444             Set_Etype (Id, Result_Type);
3445 
3446             --  Check restriction imposed by AI05-073: a generic function
3447             --  cannot return an abstract type or an access to such.
3448 
3449             --  This is a binding interpretation should it apply to earlier
3450             --  versions of Ada as well as Ada 2012???
3451 
3452             if Is_Abstract_Type (Designated_Type (Result_Type))
3453               and then Ada_Version >= Ada_2012
3454             then
3455                Error_Msg_N
3456                  ("generic function cannot have an access result "
3457                   & "that designates an abstract type", Spec);
3458             end if;
3459 
3460          else
3461             Find_Type (Result_Definition (Spec));
3462             Typ := Entity (Result_Definition (Spec));
3463 
3464             if Is_Abstract_Type (Typ)
3465               and then Ada_Version >= Ada_2012
3466             then
3467                Error_Msg_N
3468                  ("generic function cannot have abstract result type", Spec);
3469             end if;
3470 
3471             --  If a null exclusion is imposed on the result type, then create
3472             --  a null-excluding itype (an access subtype) and use it as the
3473             --  function's Etype.
3474 
3475             if Is_Access_Type (Typ)
3476               and then Null_Exclusion_Present (Spec)
3477             then
3478                Set_Etype  (Id,
3479                  Create_Null_Excluding_Itype
3480                    (T           => Typ,
3481                     Related_Nod => Spec,
3482                     Scope_Id    => Defining_Unit_Name (Spec)));
3483             else
3484                Set_Etype (Id, Typ);
3485             end if;
3486          end if;
3487 
3488       else
3489          Set_Etype (Id, Standard_Void_Type);
3490       end if;
3491 
3492       --  A generic subprogram declared within a Ghost region is rendered Ghost
3493       --  (SPARK RM 6.9(2)).
3494 
3495       if Ghost_Mode > None then
3496          Set_Is_Ghost_Entity (Id);
3497       end if;
3498 
3499       --  For a library unit, we have reconstructed the entity for the unit,
3500       --  and must reset it in the library tables. We also make sure that
3501       --  Body_Required is set properly in the original compilation unit node.
3502 
3503       if Nkind (Parent (N)) = N_Compilation_Unit then
3504          Set_Cunit_Entity (Current_Sem_Unit, Id);
3505          Set_Body_Required (Parent (N), Unit_Requires_Body (Id));
3506       end if;
3507 
3508       Set_Categorization_From_Pragmas (N);
3509       Validate_Categorization_Dependency (N, Id);
3510 
3511       --  Capture all global references that occur within the profile of the
3512       --  generic subprogram. Aspects are not part of this processing because
3513       --  they must be delayed. If processed now, Save_Global_References will
3514       --  destroy the Associated_Node links and prevent the capture of global
3515       --  references when the contract of the generic subprogram is analyzed.
3516 
3517       Save_Global_References (Original_Node (N));
3518 
3519       End_Generic;
3520       End_Scope;
3521       Exit_Generic_Scope (Id);
3522       Generate_Reference_To_Formals (Id);
3523 
3524       List_Inherited_Pre_Post_Aspects (Id);
3525    end Analyze_Generic_Subprogram_Declaration;
3526 
3527    -----------------------------------
3528    -- Analyze_Package_Instantiation --
3529    -----------------------------------
3530 
3531    procedure Analyze_Package_Instantiation (N : Node_Id) is
3532       Loc    : constant Source_Ptr := Sloc (N);
3533       Gen_Id : constant Node_Id    := Name (N);
3534 
3535       Act_Decl      : Node_Id;
3536       Act_Decl_Name : Node_Id;
3537       Act_Decl_Id   : Entity_Id;
3538       Act_Spec      : Node_Id;
3539       Act_Tree      : Node_Id;
3540 
3541       Gen_Decl : Node_Id;
3542       Gen_Spec : Node_Id;
3543       Gen_Unit : Entity_Id;
3544 
3545       Is_Actual_Pack : constant Boolean :=
3546                          Is_Internal (Defining_Entity (N));
3547 
3548       Env_Installed     : Boolean := False;
3549       Parent_Installed  : Boolean := False;
3550       Renaming_List     : List_Id;
3551       Unit_Renaming     : Node_Id;
3552       Needs_Body        : Boolean;
3553       Inline_Now        : Boolean := False;
3554       Has_Inline_Always : Boolean := False;
3555 
3556       Save_IPSM : constant Boolean := Ignore_Pragma_SPARK_Mode;
3557       --  Save flag Ignore_Pragma_SPARK_Mode for restore on exit
3558 
3559       Save_SM  : constant SPARK_Mode_Type := SPARK_Mode;
3560       Save_SMP : constant Node_Id         := SPARK_Mode_Pragma;
3561       --  Save the SPARK_Mode-related data for restore on exit
3562 
3563       Save_Style_Check : constant Boolean := Style_Check;
3564       --  Save style check mode for restore on exit
3565 
3566       procedure Delay_Descriptors (E : Entity_Id);
3567       --  Delay generation of subprogram descriptors for given entity
3568 
3569       function Might_Inline_Subp return Boolean;
3570       --  If inlining is active and the generic contains inlined subprograms,
3571       --  we instantiate the body. This may cause superfluous instantiations,
3572       --  but it is simpler than detecting the need for the body at the point
3573       --  of inlining, when the context of the instance is not available.
3574 
3575       -----------------------
3576       -- Delay_Descriptors --
3577       -----------------------
3578 
3579       procedure Delay_Descriptors (E : Entity_Id) is
3580       begin
3581          if not Delay_Subprogram_Descriptors (E) then
3582             Set_Delay_Subprogram_Descriptors (E);
3583             Pending_Descriptor.Append (E);
3584          end if;
3585       end Delay_Descriptors;
3586 
3587       -----------------------
3588       -- Might_Inline_Subp --
3589       -----------------------
3590 
3591       function Might_Inline_Subp return Boolean is
3592          E : Entity_Id;
3593 
3594       begin
3595          if not Inline_Processing_Required then
3596             return False;
3597 
3598          else
3599             E := First_Entity (Gen_Unit);
3600             while Present (E) loop
3601                if Is_Subprogram (E) and then Is_Inlined (E) then
3602                   --  Remember if there are any subprograms with Inline_Always
3603 
3604                   if Has_Pragma_Inline_Always (E) then
3605                      Has_Inline_Always := True;
3606                   end if;
3607 
3608                   return True;
3609                end if;
3610 
3611                Next_Entity (E);
3612             end loop;
3613          end if;
3614 
3615          return False;
3616       end Might_Inline_Subp;
3617 
3618       --  Local declarations
3619 
3620       Vis_Prims_List : Elist_Id := No_Elist;
3621       --  List of primitives made temporarily visible in the instantiation
3622       --  to match the visibility of the formal type
3623 
3624    --  Start of processing for Analyze_Package_Instantiation
3625 
3626    begin
3627       Check_SPARK_05_Restriction ("generic is not allowed", N);
3628 
3629       --  Very first thing: check for Text_IO special unit in case we are
3630       --  instantiating one of the children of [[Wide_]Wide_]Text_IO.
3631 
3632       Check_Text_IO_Special_Unit (Name (N));
3633 
3634       --  Make node global for error reporting
3635 
3636       Instantiation_Node := N;
3637 
3638       --  Turn off style checking in instances. If the check is enabled on the
3639       --  generic unit, a warning in an instance would just be noise. If not
3640       --  enabled on the generic, then a warning in an instance is just wrong.
3641 
3642       Style_Check := False;
3643 
3644       --  Case of instantiation of a generic package
3645 
3646       if Nkind (N) = N_Package_Instantiation then
3647          Act_Decl_Id := New_Copy (Defining_Entity (N));
3648          Set_Comes_From_Source (Act_Decl_Id, True);
3649 
3650          if Nkind (Defining_Unit_Name (N)) = N_Defining_Program_Unit_Name then
3651             Act_Decl_Name :=
3652               Make_Defining_Program_Unit_Name (Loc,
3653                 Name                =>
3654                   New_Copy_Tree (Name (Defining_Unit_Name (N))),
3655                 Defining_Identifier => Act_Decl_Id);
3656          else
3657             Act_Decl_Name := Act_Decl_Id;
3658          end if;
3659 
3660       --  Case of instantiation of a formal package
3661 
3662       else
3663          Act_Decl_Id   := Defining_Identifier (N);
3664          Act_Decl_Name := Act_Decl_Id;
3665       end if;
3666 
3667       Generate_Definition (Act_Decl_Id);
3668       Set_Ekind (Act_Decl_Id, E_Package);
3669 
3670       --  Initialize list of incomplete actuals before analysis
3671 
3672       Set_Incomplete_Actuals (Act_Decl_Id, New_Elmt_List);
3673 
3674       Preanalyze_Actuals (N, Act_Decl_Id);
3675 
3676       Init_Env;
3677       Env_Installed := True;
3678 
3679       --  Reset renaming map for formal types. The mapping is established
3680       --  when analyzing the generic associations, but some mappings are
3681       --  inherited from formal packages of parent units, and these are
3682       --  constructed when the parents are installed.
3683 
3684       Generic_Renamings.Set_Last (0);
3685       Generic_Renamings_HTable.Reset;
3686 
3687       Check_Generic_Child_Unit (Gen_Id, Parent_Installed);
3688       Gen_Unit := Entity (Gen_Id);
3689 
3690       --  Verify that it is the name of a generic package
3691 
3692       --  A visibility glitch: if the instance is a child unit and the generic
3693       --  is the generic unit of a parent instance (i.e. both the parent and
3694       --  the child units are instances of the same package) the name now
3695       --  denotes the renaming within the parent, not the intended generic
3696       --  unit. See if there is a homonym that is the desired generic. The
3697       --  renaming declaration must be visible inside the instance of the
3698       --  child, but not when analyzing the name in the instantiation itself.
3699 
3700       if Ekind (Gen_Unit) = E_Package
3701         and then Present (Renamed_Entity (Gen_Unit))
3702         and then In_Open_Scopes (Renamed_Entity (Gen_Unit))
3703         and then Is_Generic_Instance (Renamed_Entity (Gen_Unit))
3704         and then Present (Homonym (Gen_Unit))
3705       then
3706          Gen_Unit := Homonym (Gen_Unit);
3707       end if;
3708 
3709       if Etype (Gen_Unit) = Any_Type then
3710          Restore_Env;
3711          goto Leave;
3712 
3713       elsif Ekind (Gen_Unit) /= E_Generic_Package then
3714 
3715          --  Ada 2005 (AI-50217): Cannot use instance in limited with_clause
3716 
3717          if From_Limited_With (Gen_Unit) then
3718             Error_Msg_N
3719               ("cannot instantiate a limited withed package", Gen_Id);
3720          else
3721             Error_Msg_NE
3722               ("& is not the name of a generic package", Gen_Id, Gen_Unit);
3723          end if;
3724 
3725          Restore_Env;
3726          goto Leave;
3727       end if;
3728 
3729       if In_Extended_Main_Source_Unit (N) then
3730          Set_Is_Instantiated (Gen_Unit);
3731          Generate_Reference  (Gen_Unit, N);
3732 
3733          if Present (Renamed_Object (Gen_Unit)) then
3734             Set_Is_Instantiated (Renamed_Object (Gen_Unit));
3735             Generate_Reference  (Renamed_Object (Gen_Unit), N);
3736          end if;
3737       end if;
3738 
3739       if Nkind (Gen_Id) = N_Identifier
3740         and then Chars (Gen_Unit) = Chars (Defining_Entity (N))
3741       then
3742          Error_Msg_NE
3743            ("& is hidden within declaration of instance", Gen_Id, Gen_Unit);
3744 
3745       elsif Nkind (Gen_Id) = N_Expanded_Name
3746         and then Is_Child_Unit (Gen_Unit)
3747         and then Nkind (Prefix (Gen_Id)) = N_Identifier
3748         and then Chars (Act_Decl_Id) = Chars (Prefix (Gen_Id))
3749       then
3750          Error_Msg_N
3751            ("& is hidden within declaration of instance ", Prefix (Gen_Id));
3752       end if;
3753 
3754       Set_Entity (Gen_Id, Gen_Unit);
3755 
3756       --  If generic is a renaming, get original generic unit
3757 
3758       if Present (Renamed_Object (Gen_Unit))
3759         and then Ekind (Renamed_Object (Gen_Unit)) = E_Generic_Package
3760       then
3761          Gen_Unit := Renamed_Object (Gen_Unit);
3762       end if;
3763 
3764       --  Verify that there are no circular instantiations
3765 
3766       if In_Open_Scopes (Gen_Unit) then
3767          Error_Msg_NE ("instantiation of & within itself", N, Gen_Unit);
3768          Restore_Env;
3769          goto Leave;
3770 
3771       elsif Contains_Instance_Of (Gen_Unit, Current_Scope, Gen_Id) then
3772          Error_Msg_Node_2 := Current_Scope;
3773          Error_Msg_NE
3774            ("circular Instantiation: & instantiated in &!", N, Gen_Unit);
3775          Circularity_Detected := True;
3776          Restore_Env;
3777          goto Leave;
3778 
3779       else
3780          --  If the context of the instance is subject to SPARK_Mode "off" or
3781          --  the annotation is altogether missing, set the global flag which
3782          --  signals Analyze_Pragma to ignore all SPARK_Mode pragmas within
3783          --  the instance.
3784 
3785          if SPARK_Mode /= On then
3786             Ignore_Pragma_SPARK_Mode := True;
3787          end if;
3788 
3789          Gen_Decl := Unit_Declaration_Node (Gen_Unit);
3790          Gen_Spec := Specification (Gen_Decl);
3791 
3792          --  Initialize renamings map, for error checking, and the list that
3793          --  holds private entities whose views have changed between generic
3794          --  definition and instantiation. If this is the instance created to
3795          --  validate an actual package, the instantiation environment is that
3796          --  of the enclosing instance.
3797 
3798          Create_Instantiation_Source (N, Gen_Unit, S_Adjustment);
3799 
3800          --  Copy original generic tree, to produce text for instantiation
3801 
3802          Act_Tree :=
3803            Copy_Generic_Node
3804              (Original_Node (Gen_Decl), Empty, Instantiating => True);
3805 
3806          Act_Spec := Specification (Act_Tree);
3807 
3808          --  If this is the instance created to validate an actual package,
3809          --  only the formals matter, do not examine the package spec itself.
3810 
3811          if Is_Actual_Pack then
3812             Set_Visible_Declarations (Act_Spec, New_List);
3813             Set_Private_Declarations (Act_Spec, New_List);
3814          end if;
3815 
3816          Renaming_List :=
3817            Analyze_Associations
3818              (I_Node  => N,
3819               Formals => Generic_Formal_Declarations (Act_Tree),
3820               F_Copy  => Generic_Formal_Declarations (Gen_Decl));
3821 
3822          Vis_Prims_List := Check_Hidden_Primitives (Renaming_List);
3823 
3824          Set_Instance_Env (Gen_Unit, Act_Decl_Id);
3825          Set_Defining_Unit_Name (Act_Spec, Act_Decl_Name);
3826          Set_Is_Generic_Instance (Act_Decl_Id);
3827          Set_Generic_Parent (Act_Spec, Gen_Unit);
3828 
3829          --  References to the generic in its own declaration or its body are
3830          --  references to the instance. Add a renaming declaration for the
3831          --  generic unit itself. This declaration, as well as the renaming
3832          --  declarations for the generic formals, must remain private to the
3833          --  unit: the formals, because this is the language semantics, and
3834          --  the unit because its use is an artifact of the implementation.
3835 
3836          Unit_Renaming :=
3837            Make_Package_Renaming_Declaration (Loc,
3838              Defining_Unit_Name =>
3839                Make_Defining_Identifier (Loc, Chars (Gen_Unit)),
3840              Name               => New_Occurrence_Of (Act_Decl_Id, Loc));
3841 
3842          Append (Unit_Renaming, Renaming_List);
3843 
3844          --  The renaming declarations are the first local declarations of the
3845          --  new unit.
3846 
3847          if Is_Non_Empty_List (Visible_Declarations (Act_Spec)) then
3848             Insert_List_Before
3849               (First (Visible_Declarations (Act_Spec)), Renaming_List);
3850          else
3851             Set_Visible_Declarations (Act_Spec, Renaming_List);
3852          end if;
3853 
3854          Act_Decl := Make_Package_Declaration (Loc, Specification => Act_Spec);
3855 
3856          --  Propagate the aspect specifications from the package declaration
3857          --  template to the instantiated version of the package declaration.
3858 
3859          if Has_Aspects (Act_Tree) then
3860             Set_Aspect_Specifications (Act_Decl,
3861               New_Copy_List_Tree (Aspect_Specifications (Act_Tree)));
3862          end if;
3863 
3864          --  The generic may have a generated Default_Storage_Pool aspect,
3865          --  set at the point of generic declaration. If the instance has
3866          --  that aspect, it overrides the one inherited from the generic.
3867 
3868          if Has_Aspects (Gen_Spec) then
3869             if No (Aspect_Specifications (N)) then
3870                Set_Aspect_Specifications (N,
3871                  (New_Copy_List_Tree
3872                    (Aspect_Specifications (Gen_Spec))));
3873 
3874             else
3875                declare
3876                   ASN1, ASN2 : Node_Id;
3877 
3878                begin
3879                   ASN1 := First (Aspect_Specifications (N));
3880                   while Present (ASN1) loop
3881                      if Chars (Identifier (ASN1)) = Name_Default_Storage_Pool
3882                      then
3883                         --  If generic carries a default storage pool, remove
3884                         --  it in favor of the instance one.
3885 
3886                         ASN2 := First (Aspect_Specifications (Gen_Spec));
3887                         while Present (ASN2) loop
3888                            if Chars (Identifier (ASN2)) =
3889                                                     Name_Default_Storage_Pool
3890                            then
3891                               Remove (ASN2);
3892                               exit;
3893                            end if;
3894 
3895                            Next (ASN2);
3896                         end loop;
3897                      end if;
3898 
3899                      Next (ASN1);
3900                   end loop;
3901 
3902                   Prepend_List_To (Aspect_Specifications (N),
3903                     (New_Copy_List_Tree
3904                       (Aspect_Specifications (Gen_Spec))));
3905                end;
3906             end if;
3907          end if;
3908 
3909          --  Save the instantiation node, for subsequent instantiation of the
3910          --  body, if there is one and we are generating code for the current
3911          --  unit. Mark unit as having a body (avoids premature error message).
3912 
3913          --  We instantiate the body if we are generating code, if we are
3914          --  generating cross-reference information, or if we are building
3915          --  trees for ASIS use or GNATprove use.
3916 
3917          declare
3918             Enclosing_Body_Present : Boolean := False;
3919             --  If the generic unit is not a compilation unit, then a body may
3920             --  be present in its parent even if none is required. We create a
3921             --  tentative pending instantiation for the body, which will be
3922             --  discarded if none is actually present.
3923 
3924             Scop : Entity_Id;
3925 
3926          begin
3927             if Scope (Gen_Unit) /= Standard_Standard
3928               and then not Is_Child_Unit (Gen_Unit)
3929             then
3930                Scop := Scope (Gen_Unit);
3931                while Present (Scop) and then Scop /= Standard_Standard loop
3932                   if Unit_Requires_Body (Scop) then
3933                      Enclosing_Body_Present := True;
3934                      exit;
3935 
3936                   elsif In_Open_Scopes (Scop)
3937                     and then In_Package_Body (Scop)
3938                   then
3939                      Enclosing_Body_Present := True;
3940                      exit;
3941                   end if;
3942 
3943                   exit when Is_Compilation_Unit (Scop);
3944                   Scop := Scope (Scop);
3945                end loop;
3946             end if;
3947 
3948             --  If front-end inlining is enabled or there are any subprograms
3949             --  marked with Inline_Always, and this is a unit for which code
3950             --  will be generated, we instantiate the body at once.
3951 
3952             --  This is done if the instance is not the main unit, and if the
3953             --  generic is not a child unit of another generic, to avoid scope
3954             --  problems and the reinstallation of parent instances.
3955 
3956             if Expander_Active
3957               and then (not Is_Child_Unit (Gen_Unit)
3958                          or else not Is_Generic_Unit (Scope (Gen_Unit)))
3959               and then Might_Inline_Subp
3960               and then not Is_Actual_Pack
3961             then
3962                if not Back_End_Inlining
3963                  and then (Front_End_Inlining or else Has_Inline_Always)
3964                  and then (Is_In_Main_Unit (N)
3965                             or else In_Main_Context (Current_Scope))
3966                  and then Nkind (Parent (N)) /= N_Compilation_Unit
3967                then
3968                   Inline_Now := True;
3969 
3970                --  In configurable_run_time mode we force the inlining of
3971                --  predefined subprograms marked Inline_Always, to minimize
3972                --  the use of the run-time library.
3973 
3974                elsif Is_Predefined_File_Name
3975                        (Unit_File_Name (Get_Source_Unit (Gen_Decl)))
3976                  and then Configurable_Run_Time_Mode
3977                  and then Nkind (Parent (N)) /= N_Compilation_Unit
3978                then
3979                   Inline_Now := True;
3980                end if;
3981 
3982                --  If the current scope is itself an instance within a child
3983                --  unit, there will be duplications in the scope stack, and the
3984                --  unstacking mechanism in Inline_Instance_Body will fail.
3985                --  This loses some rare cases of optimization, and might be
3986                --  improved some day, if we can find a proper abstraction for
3987                --  "the complete compilation context" that can be saved and
3988                --  restored. ???
3989 
3990                if Is_Generic_Instance (Current_Scope) then
3991                   declare
3992                      Curr_Unit : constant Entity_Id :=
3993                                    Cunit_Entity (Current_Sem_Unit);
3994                   begin
3995                      if Curr_Unit /= Current_Scope
3996                        and then Is_Child_Unit (Curr_Unit)
3997                      then
3998                         Inline_Now := False;
3999                      end if;
4000                   end;
4001                end if;
4002             end if;
4003 
4004             Needs_Body :=
4005               (Unit_Requires_Body (Gen_Unit)
4006                 or else Enclosing_Body_Present
4007                 or else Present (Corresponding_Body (Gen_Decl)))
4008                and then (Is_In_Main_Unit (N) or else Might_Inline_Subp)
4009                and then not Is_Actual_Pack
4010                and then not Inline_Now
4011                and then (Operating_Mode = Generate_Code
4012 
4013                           --  Need comment for this check ???
4014 
4015                           or else (Operating_Mode = Check_Semantics
4016                                     and then (ASIS_Mode or GNATprove_Mode)));
4017 
4018             --  If front-end inlining is enabled or there are any subprograms
4019             --  marked with Inline_Always, do not instantiate body when within
4020             --  a generic context.
4021 
4022             if ((Front_End_Inlining or else Has_Inline_Always)
4023                   and then not Expander_Active)
4024               or else Is_Generic_Unit (Cunit_Entity (Main_Unit))
4025             then
4026                Needs_Body := False;
4027             end if;
4028 
4029             --  If the current context is generic, and the package being
4030             --  instantiated is declared within a formal package, there is no
4031             --  body to instantiate until the enclosing generic is instantiated
4032             --  and there is an actual for the formal package. If the formal
4033             --  package has parameters, we build a regular package instance for
4034             --  it, that precedes the original formal package declaration.
4035 
4036             if In_Open_Scopes (Scope (Scope (Gen_Unit))) then
4037                declare
4038                   Decl : constant Node_Id :=
4039                            Original_Node
4040                              (Unit_Declaration_Node (Scope (Gen_Unit)));
4041                begin
4042                   if Nkind (Decl) = N_Formal_Package_Declaration
4043                     or else (Nkind (Decl) = N_Package_Declaration
4044                               and then Is_List_Member (Decl)
4045                               and then Present (Next (Decl))
4046                               and then
4047                                 Nkind (Next (Decl)) =
4048                                                 N_Formal_Package_Declaration)
4049                   then
4050                      Needs_Body := False;
4051                   end if;
4052                end;
4053             end if;
4054          end;
4055 
4056          --  For RCI unit calling stubs, we omit the instance body if the
4057          --  instance is the RCI library unit itself.
4058 
4059          --  However there is a special case for nested instances: in this case
4060          --  we do generate the instance body, as it might be required, e.g.
4061          --  because it provides stream attributes for some type used in the
4062          --  profile of a remote subprogram. This is consistent with 12.3(12),
4063          --  which indicates that the instance body occurs at the place of the
4064          --  instantiation, and thus is part of the RCI declaration, which is
4065          --  present on all client partitions (this is E.2.3(18)).
4066 
4067          --  Note that AI12-0002 may make it illegal at some point to have
4068          --  stream attributes defined in an RCI unit, in which case this
4069          --  special case will become unnecessary. In the meantime, there
4070          --  is known application code in production that depends on this
4071          --  being possible, so we definitely cannot eliminate the body in
4072          --  the case of nested instances for the time being.
4073 
4074          --  When we generate a nested instance body, calling stubs for any
4075          --  relevant subprogram will be be inserted immediately after the
4076          --  subprogram declarations, and will take precedence over the
4077          --  subsequent (original) body. (The stub and original body will be
4078          --  complete homographs, but this is permitted in an instance).
4079          --  (Could we do better and remove the original body???)
4080 
4081          if Distribution_Stub_Mode = Generate_Caller_Stub_Body
4082            and then Comes_From_Source (N)
4083            and then Nkind (Parent (N)) = N_Compilation_Unit
4084          then
4085             Needs_Body := False;
4086          end if;
4087 
4088          if Needs_Body then
4089 
4090             --  Here is a defence against a ludicrous number of instantiations
4091             --  caused by a circular set of instantiation attempts.
4092 
4093             if Pending_Instantiations.Last > Maximum_Instantiations then
4094                Error_Msg_Uint_1 := UI_From_Int (Maximum_Instantiations);
4095                Error_Msg_N ("too many instantiations, exceeds max of^", N);
4096                Error_Msg_N ("\limit can be changed using -gnateinn switch", N);
4097                raise Unrecoverable_Error;
4098             end if;
4099 
4100             --  Indicate that the enclosing scopes contain an instantiation,
4101             --  and that cleanup actions should be delayed until after the
4102             --  instance body is expanded.
4103 
4104             Check_Forward_Instantiation (Gen_Decl);
4105             if Nkind (N) = N_Package_Instantiation then
4106                declare
4107                   Enclosing_Master : Entity_Id;
4108 
4109                begin
4110                   --  Loop to search enclosing masters
4111 
4112                   Enclosing_Master := Current_Scope;
4113                   Scope_Loop : while Enclosing_Master /= Standard_Standard loop
4114                      if Ekind (Enclosing_Master) = E_Package then
4115                         if Is_Compilation_Unit (Enclosing_Master) then
4116                            if In_Package_Body (Enclosing_Master) then
4117                               Delay_Descriptors
4118                                 (Body_Entity (Enclosing_Master));
4119                            else
4120                               Delay_Descriptors
4121                                 (Enclosing_Master);
4122                            end if;
4123 
4124                            exit Scope_Loop;
4125 
4126                         else
4127                            Enclosing_Master := Scope (Enclosing_Master);
4128                         end if;
4129 
4130                      elsif Is_Generic_Unit (Enclosing_Master)
4131                        or else Ekind (Enclosing_Master) = E_Void
4132                      then
4133                         --  Cleanup actions will eventually be performed on the
4134                         --  enclosing subprogram or package instance, if any.
4135                         --  Enclosing scope is void in the formal part of a
4136                         --  generic subprogram.
4137 
4138                         exit Scope_Loop;
4139 
4140                      else
4141                         if Ekind (Enclosing_Master) = E_Entry
4142                           and then
4143                             Ekind (Scope (Enclosing_Master)) = E_Protected_Type
4144                         then
4145                            if not Expander_Active then
4146                               exit Scope_Loop;
4147                            else
4148                               Enclosing_Master :=
4149                                 Protected_Body_Subprogram (Enclosing_Master);
4150                            end if;
4151                         end if;
4152 
4153                         Set_Delay_Cleanups (Enclosing_Master);
4154 
4155                         while Ekind (Enclosing_Master) = E_Block loop
4156                            Enclosing_Master := Scope (Enclosing_Master);
4157                         end loop;
4158 
4159                         if Is_Subprogram (Enclosing_Master) then
4160                            Delay_Descriptors (Enclosing_Master);
4161 
4162                         elsif Is_Task_Type (Enclosing_Master) then
4163                            declare
4164                               TBP : constant Node_Id :=
4165                                       Get_Task_Body_Procedure
4166                                         (Enclosing_Master);
4167                            begin
4168                               if Present (TBP) then
4169                                  Delay_Descriptors  (TBP);
4170                                  Set_Delay_Cleanups (TBP);
4171                               end if;
4172                            end;
4173                         end if;
4174 
4175                         exit Scope_Loop;
4176                      end if;
4177                   end loop Scope_Loop;
4178                end;
4179 
4180                --  Make entry in table
4181 
4182                Add_Pending_Instantiation (N, Act_Decl);
4183             end if;
4184          end if;
4185 
4186          Set_Categorization_From_Pragmas (Act_Decl);
4187 
4188          if Parent_Installed then
4189             Hide_Current_Scope;
4190          end if;
4191 
4192          Set_Instance_Spec (N, Act_Decl);
4193 
4194          --  If not a compilation unit, insert the package declaration before
4195          --  the original instantiation node.
4196 
4197          if Nkind (Parent (N)) /= N_Compilation_Unit then
4198             Mark_Rewrite_Insertion (Act_Decl);
4199             Insert_Before (N, Act_Decl);
4200 
4201             if Has_Aspects (N) then
4202                Analyze_Aspect_Specifications (N, Act_Decl_Id);
4203 
4204                --  The pragma created for a Default_Storage_Pool aspect must
4205                --  appear ahead of the declarations in the instance spec.
4206                --  Analysis has placed it after the instance node, so remove
4207                --  it and reinsert it properly now.
4208 
4209                declare
4210                   ASN : constant Node_Id := First (Aspect_Specifications (N));
4211                   A_Name : constant Name_Id := Chars (Identifier (ASN));
4212                   Decl : Node_Id;
4213 
4214                begin
4215                   if A_Name = Name_Default_Storage_Pool then
4216                      if No (Visible_Declarations (Act_Spec)) then
4217                         Set_Visible_Declarations (Act_Spec, New_List);
4218                      end if;
4219 
4220                      Decl := Next (N);
4221                      while Present (Decl) loop
4222                         if Nkind (Decl) = N_Pragma then
4223                            Remove (Decl);
4224                            Prepend (Decl, Visible_Declarations (Act_Spec));
4225                            exit;
4226                         end if;
4227 
4228                         Next (Decl);
4229                      end loop;
4230                   end if;
4231                end;
4232             end if;
4233 
4234             Analyze (Act_Decl);
4235 
4236          --  For an instantiation that is a compilation unit, place
4237          --  declaration on current node so context is complete for analysis
4238          --  (including nested instantiations). If this is the main unit,
4239          --  the declaration eventually replaces the instantiation node.
4240          --  If the instance body is created later, it replaces the
4241          --  instance node, and the declaration is attached to it
4242          --  (see Build_Instance_Compilation_Unit_Nodes).
4243 
4244          else
4245             if Cunit_Entity (Current_Sem_Unit) = Defining_Entity (N) then
4246 
4247                --  The entity for the current unit is the newly created one,
4248                --  and all semantic information is attached to it.
4249 
4250                Set_Cunit_Entity (Current_Sem_Unit, Act_Decl_Id);
4251 
4252                --  If this is the main unit, replace the main entity as well
4253 
4254                if Current_Sem_Unit = Main_Unit then
4255                   Main_Unit_Entity := Act_Decl_Id;
4256                end if;
4257             end if;
4258 
4259             Set_Unit (Parent (N), Act_Decl);
4260             Set_Parent_Spec (Act_Decl, Parent_Spec (N));
4261             Set_Package_Instantiation (Act_Decl_Id, N);
4262 
4263             --  Process aspect specifications of the instance node, if any, to
4264             --  take into account categorization pragmas before analyzing the
4265             --  instance.
4266 
4267             if Has_Aspects (N) then
4268                Analyze_Aspect_Specifications (N, Act_Decl_Id);
4269             end if;
4270 
4271             Analyze (Act_Decl);
4272             Set_Unit (Parent (N), N);
4273             Set_Body_Required (Parent (N), False);
4274 
4275             --  We never need elaboration checks on instantiations, since by
4276             --  definition, the body instantiation is elaborated at the same
4277             --  time as the spec instantiation.
4278 
4279             Set_Suppress_Elaboration_Warnings (Act_Decl_Id);
4280             Set_Kill_Elaboration_Checks       (Act_Decl_Id);
4281          end if;
4282 
4283          Check_Elab_Instantiation (N);
4284 
4285          if ABE_Is_Certain (N) and then Needs_Body then
4286             Pending_Instantiations.Decrement_Last;
4287          end if;
4288 
4289          Check_Hidden_Child_Unit (N, Gen_Unit, Act_Decl_Id);
4290 
4291          Set_First_Private_Entity (Defining_Unit_Name (Unit_Renaming),
4292            First_Private_Entity (Act_Decl_Id));
4293 
4294          --  If the instantiation will receive a body, the unit will be
4295          --  transformed into a package body, and receive its own elaboration
4296          --  entity. Otherwise, the nature of the unit is now a package
4297          --  declaration.
4298 
4299          if Nkind (Parent (N)) = N_Compilation_Unit
4300            and then not Needs_Body
4301          then
4302             Rewrite (N, Act_Decl);
4303          end if;
4304 
4305          if Present (Corresponding_Body (Gen_Decl))
4306            or else Unit_Requires_Body (Gen_Unit)
4307          then
4308             Set_Has_Completion (Act_Decl_Id);
4309          end if;
4310 
4311          Check_Formal_Packages (Act_Decl_Id);
4312 
4313          Restore_Hidden_Primitives (Vis_Prims_List);
4314          Restore_Private_Views (Act_Decl_Id);
4315 
4316          Inherit_Context (Gen_Decl, N);
4317 
4318          if Parent_Installed then
4319             Remove_Parent;
4320          end if;
4321 
4322          Restore_Env;
4323          Env_Installed := False;
4324       end if;
4325 
4326       Validate_Categorization_Dependency (N, Act_Decl_Id);
4327 
4328       --  There used to be a check here to prevent instantiations in local
4329       --  contexts if the No_Local_Allocators restriction was active. This
4330       --  check was removed by a binding interpretation in AI-95-00130/07,
4331       --  but we retain the code for documentation purposes.
4332 
4333       --  if Ekind (Act_Decl_Id) /= E_Void
4334       --    and then not Is_Library_Level_Entity (Act_Decl_Id)
4335       --  then
4336       --     Check_Restriction (No_Local_Allocators, N);
4337       --  end if;
4338 
4339       if Inline_Now then
4340          Inline_Instance_Body (N, Gen_Unit, Act_Decl);
4341       end if;
4342 
4343       --  The following is a tree patch for ASIS: ASIS needs separate nodes to
4344       --  be used as defining identifiers for a formal package and for the
4345       --  corresponding expanded package.
4346 
4347       if Nkind (N) = N_Formal_Package_Declaration then
4348          Act_Decl_Id := New_Copy (Defining_Entity (N));
4349          Set_Comes_From_Source (Act_Decl_Id, True);
4350          Set_Is_Generic_Instance (Act_Decl_Id, False);
4351          Set_Defining_Identifier (N, Act_Decl_Id);
4352       end if;
4353 
4354       Ignore_Pragma_SPARK_Mode := Save_IPSM;
4355       SPARK_Mode               := Save_SM;
4356       SPARK_Mode_Pragma        := Save_SMP;
4357       Style_Check              := Save_Style_Check;
4358 
4359       --  Check that if N is an instantiation of System.Dim_Float_IO or
4360       --  System.Dim_Integer_IO, the formal type has a dimension system.
4361 
4362       if Nkind (N) = N_Package_Instantiation
4363         and then Is_Dim_IO_Package_Instantiation (N)
4364       then
4365          declare
4366             Assoc : constant Node_Id := First (Generic_Associations (N));
4367          begin
4368             if not Has_Dimension_System
4369                      (Etype (Explicit_Generic_Actual_Parameter (Assoc)))
4370             then
4371                Error_Msg_N ("type with a dimension system expected", Assoc);
4372             end if;
4373          end;
4374       end if;
4375 
4376    <<Leave>>
4377       if Has_Aspects (N) and then Nkind (Parent (N)) /= N_Compilation_Unit then
4378          Analyze_Aspect_Specifications (N, Act_Decl_Id);
4379       end if;
4380 
4381    exception
4382       when Instantiation_Error =>
4383          if Parent_Installed then
4384             Remove_Parent;
4385          end if;
4386 
4387          if Env_Installed then
4388             Restore_Env;
4389          end if;
4390 
4391          Ignore_Pragma_SPARK_Mode := Save_IPSM;
4392          SPARK_Mode               := Save_SM;
4393          SPARK_Mode_Pragma        := Save_SMP;
4394          Style_Check              := Save_Style_Check;
4395    end Analyze_Package_Instantiation;
4396 
4397    --------------------------
4398    -- Inline_Instance_Body --
4399    --------------------------
4400 
4401    procedure Inline_Instance_Body
4402      (N        : Node_Id;
4403       Gen_Unit : Entity_Id;
4404       Act_Decl : Node_Id)
4405    is
4406       Curr_Comp : constant Node_Id   := Cunit (Current_Sem_Unit);
4407       Curr_Unit : constant Entity_Id := Cunit_Entity (Current_Sem_Unit);
4408       Gen_Comp  : constant Entity_Id :=
4409                     Cunit_Entity (Get_Source_Unit (Gen_Unit));
4410 
4411       Save_SM  : constant SPARK_Mode_Type := SPARK_Mode;
4412       Save_SMP : constant Node_Id         := SPARK_Mode_Pragma;
4413       --  Save all SPARK_Mode-related attributes as removing enclosing scopes
4414       --  to provide a clean environment for analysis of the inlined body will
4415       --  eliminate any previously set SPARK_Mode.
4416 
4417       Scope_Stack_Depth : constant Pos :=
4418                             Scope_Stack.Last - Scope_Stack.First + 1;
4419 
4420       Use_Clauses  : array (1 .. Scope_Stack_Depth) of Node_Id;
4421       Instances    : array (1 .. Scope_Stack_Depth) of Entity_Id;
4422       Inner_Scopes : array (1 .. Scope_Stack_Depth) of Entity_Id;
4423       Curr_Scope   : Entity_Id := Empty;
4424       List         : Elist_Id;
4425       Num_Inner    : Nat := 0;
4426       Num_Scopes   : Nat := 0;
4427       N_Instances  : Nat := 0;
4428       Removed      : Boolean := False;
4429       S            : Entity_Id;
4430       Vis          : Boolean;
4431 
4432    begin
4433       --  Case of generic unit defined in another unit. We must remove the
4434       --  complete context of the current unit to install that of the generic.
4435 
4436       if Gen_Comp /= Cunit_Entity (Current_Sem_Unit) then
4437 
4438          --  Add some comments for the following two loops ???
4439 
4440          S := Current_Scope;
4441          while Present (S) and then S /= Standard_Standard loop
4442             loop
4443                Num_Scopes := Num_Scopes + 1;
4444 
4445                Use_Clauses (Num_Scopes) :=
4446                  (Scope_Stack.Table
4447                     (Scope_Stack.Last - Num_Scopes + 1).
4448                        First_Use_Clause);
4449                End_Use_Clauses (Use_Clauses (Num_Scopes));
4450 
4451                exit when Scope_Stack.Last - Num_Scopes + 1 = Scope_Stack.First
4452                  or else Scope_Stack.Table
4453                            (Scope_Stack.Last - Num_Scopes).Entity = Scope (S);
4454             end loop;
4455 
4456             exit when Is_Generic_Instance (S)
4457               and then (In_Package_Body (S)
4458                          or else Ekind (S) = E_Procedure
4459                          or else Ekind (S) = E_Function);
4460             S := Scope (S);
4461          end loop;
4462 
4463          Vis := Is_Immediately_Visible (Gen_Comp);
4464 
4465          --  Find and save all enclosing instances
4466 
4467          S := Current_Scope;
4468 
4469          while Present (S)
4470            and then S /= Standard_Standard
4471          loop
4472             if Is_Generic_Instance (S) then
4473                N_Instances := N_Instances + 1;
4474                Instances (N_Instances) := S;
4475 
4476                exit when In_Package_Body (S);
4477             end if;
4478 
4479             S := Scope (S);
4480          end loop;
4481 
4482          --  Remove context of current compilation unit, unless we are within a
4483          --  nested package instantiation, in which case the context has been
4484          --  removed previously.
4485 
4486          --  If current scope is the body of a child unit, remove context of
4487          --  spec as well. If an enclosing scope is an instance body, the
4488          --  context has already been removed, but the entities in the body
4489          --  must be made invisible as well.
4490 
4491          S := Current_Scope;
4492          while Present (S) and then S /= Standard_Standard loop
4493             if Is_Generic_Instance (S)
4494               and then (In_Package_Body (S)
4495                          or else Ekind_In (S, E_Procedure, E_Function))
4496             then
4497                --  We still have to remove the entities of the enclosing
4498                --  instance from direct visibility.
4499 
4500                declare
4501                   E : Entity_Id;
4502                begin
4503                   E := First_Entity (S);
4504                   while Present (E) loop
4505                      Set_Is_Immediately_Visible (E, False);
4506                      Next_Entity (E);
4507                   end loop;
4508                end;
4509 
4510                exit;
4511             end if;
4512 
4513             if S = Curr_Unit
4514               or else (Ekind (Curr_Unit) = E_Package_Body
4515                         and then S = Spec_Entity (Curr_Unit))
4516               or else (Ekind (Curr_Unit) = E_Subprogram_Body
4517                         and then S = Corresponding_Spec
4518                                        (Unit_Declaration_Node (Curr_Unit)))
4519             then
4520                Removed := True;
4521 
4522                --  Remove entities in current scopes from visibility, so that
4523                --  instance body is compiled in a clean environment.
4524 
4525                List := Save_Scope_Stack (Handle_Use => False);
4526 
4527                if Is_Child_Unit (S) then
4528 
4529                   --  Remove child unit from stack, as well as inner scopes.
4530                   --  Removing the context of a child unit removes parent units
4531                   --  as well.
4532 
4533                   while Current_Scope /= S loop
4534                      Num_Inner := Num_Inner + 1;
4535                      Inner_Scopes (Num_Inner) := Current_Scope;
4536                      Pop_Scope;
4537                   end loop;
4538 
4539                   Pop_Scope;
4540                   Remove_Context (Curr_Comp);
4541                   Curr_Scope := S;
4542 
4543                else
4544                   Remove_Context (Curr_Comp);
4545                end if;
4546 
4547                if Ekind (Curr_Unit) = E_Package_Body then
4548                   Remove_Context (Library_Unit (Curr_Comp));
4549                end if;
4550             end if;
4551 
4552             S := Scope (S);
4553          end loop;
4554 
4555          pragma Assert (Num_Inner < Num_Scopes);
4556 
4557          --  The inlined package body must be analyzed with the SPARK_Mode of
4558          --  the enclosing context, otherwise the body may cause bogus errors
4559          --  if a configuration SPARK_Mode pragma in in effect.
4560 
4561          Push_Scope (Standard_Standard);
4562          Scope_Stack.Table (Scope_Stack.Last).Is_Active_Stack_Base := True;
4563          Instantiate_Package_Body
4564            (Body_Info =>
4565              ((Inst_Node                => N,
4566                Act_Decl                 => Act_Decl,
4567                Expander_Status          => Expander_Active,
4568                Current_Sem_Unit         => Current_Sem_Unit,
4569                Scope_Suppress           => Scope_Suppress,
4570                Local_Suppress_Stack_Top => Local_Suppress_Stack_Top,
4571                Version                  => Ada_Version,
4572                Version_Pragma           => Ada_Version_Pragma,
4573                Warnings                 => Save_Warnings,
4574                SPARK_Mode               => Save_SM,
4575                SPARK_Mode_Pragma        => Save_SMP)),
4576             Inlined_Body => True);
4577 
4578          Pop_Scope;
4579 
4580          --  Restore context
4581 
4582          Set_Is_Immediately_Visible (Gen_Comp, Vis);
4583 
4584          --  Reset Generic_Instance flag so that use clauses can be installed
4585          --  in the proper order. (See Use_One_Package for effect of enclosing
4586          --  instances on processing of use clauses).
4587 
4588          for J in 1 .. N_Instances loop
4589             Set_Is_Generic_Instance (Instances (J), False);
4590          end loop;
4591 
4592          if Removed then
4593             Install_Context (Curr_Comp);
4594 
4595             if Present (Curr_Scope)
4596               and then Is_Child_Unit (Curr_Scope)
4597             then
4598                Push_Scope (Curr_Scope);
4599                Set_Is_Immediately_Visible (Curr_Scope);
4600 
4601                --  Finally, restore inner scopes as well
4602 
4603                for J in reverse 1 .. Num_Inner loop
4604                   Push_Scope (Inner_Scopes (J));
4605                end loop;
4606             end if;
4607 
4608             Restore_Scope_Stack (List, Handle_Use => False);
4609 
4610             if Present (Curr_Scope)
4611               and then
4612                 (In_Private_Part (Curr_Scope)
4613                   or else In_Package_Body (Curr_Scope))
4614             then
4615                --  Install private declaration of ancestor units, which are
4616                --  currently available. Restore_Scope_Stack and Install_Context
4617                --  only install the visible part of parents.
4618 
4619                declare
4620                   Par : Entity_Id;
4621                begin
4622                   Par := Scope (Curr_Scope);
4623                   while (Present (Par)) and then Par /= Standard_Standard loop
4624                      Install_Private_Declarations (Par);
4625                      Par := Scope (Par);
4626                   end loop;
4627                end;
4628             end if;
4629          end if;
4630 
4631          --  Restore use clauses. For a child unit, use clauses in the parents
4632          --  are restored when installing the context, so only those in inner
4633          --  scopes (and those local to the child unit itself) need to be
4634          --  installed explicitly.
4635 
4636          if Is_Child_Unit (Curr_Unit) and then Removed then
4637             for J in reverse 1 .. Num_Inner + 1 loop
4638                Scope_Stack.Table (Scope_Stack.Last - J + 1).First_Use_Clause :=
4639                  Use_Clauses (J);
4640                Install_Use_Clauses (Use_Clauses (J));
4641             end loop;
4642 
4643          else
4644             for J in reverse 1 .. Num_Scopes loop
4645                Scope_Stack.Table (Scope_Stack.Last - J + 1).First_Use_Clause :=
4646                  Use_Clauses (J);
4647                Install_Use_Clauses (Use_Clauses (J));
4648             end loop;
4649          end if;
4650 
4651          --  Restore status of instances. If one of them is a body, make its
4652          --  local entities visible again.
4653 
4654          declare
4655             E    : Entity_Id;
4656             Inst : Entity_Id;
4657 
4658          begin
4659             for J in 1 .. N_Instances loop
4660                Inst := Instances (J);
4661                Set_Is_Generic_Instance (Inst, True);
4662 
4663                if In_Package_Body (Inst)
4664                  or else Ekind_In (S, E_Procedure, E_Function)
4665                then
4666                   E := First_Entity (Instances (J));
4667                   while Present (E) loop
4668                      Set_Is_Immediately_Visible (E);
4669                      Next_Entity (E);
4670                   end loop;
4671                end if;
4672             end loop;
4673          end;
4674 
4675       --  If generic unit is in current unit, current context is correct. Note
4676       --  that the context is guaranteed to carry the correct SPARK_Mode as no
4677       --  enclosing scopes were removed.
4678 
4679       else
4680          Instantiate_Package_Body
4681            (Body_Info =>
4682              ((Inst_Node                => N,
4683                Act_Decl                 => Act_Decl,
4684                Expander_Status          => Expander_Active,
4685                Current_Sem_Unit         => Current_Sem_Unit,
4686                Scope_Suppress           => Scope_Suppress,
4687                Local_Suppress_Stack_Top => Local_Suppress_Stack_Top,
4688                Version                  => Ada_Version,
4689                Version_Pragma           => Ada_Version_Pragma,
4690                Warnings                 => Save_Warnings,
4691                SPARK_Mode               => SPARK_Mode,
4692                SPARK_Mode_Pragma        => SPARK_Mode_Pragma)),
4693             Inlined_Body => True);
4694       end if;
4695    end Inline_Instance_Body;
4696 
4697    -------------------------------------
4698    -- Analyze_Procedure_Instantiation --
4699    -------------------------------------
4700 
4701    procedure Analyze_Procedure_Instantiation (N : Node_Id) is
4702    begin
4703       Analyze_Subprogram_Instantiation (N, E_Procedure);
4704    end Analyze_Procedure_Instantiation;
4705 
4706    -----------------------------------
4707    -- Need_Subprogram_Instance_Body --
4708    -----------------------------------
4709 
4710    function Need_Subprogram_Instance_Body
4711      (N    : Node_Id;
4712       Subp : Entity_Id) return Boolean
4713    is
4714 
4715       function Is_Inlined_Or_Child_Of_Inlined (E : Entity_Id) return Boolean;
4716       --  Return True if E is an inlined subprogram, an inlined renaming or a
4717       --  subprogram nested in an inlined subprogram. The inlining machinery
4718       --  totally disregards nested subprograms since it considers that they
4719       --  will always be compiled if the parent is (see Inline.Is_Nested).
4720 
4721       ------------------------------------
4722       -- Is_Inlined_Or_Child_Of_Inlined --
4723       ------------------------------------
4724 
4725       function Is_Inlined_Or_Child_Of_Inlined (E : Entity_Id) return Boolean is
4726          Scop : Entity_Id;
4727 
4728       begin
4729          if Is_Inlined (E) or else Is_Inlined (Alias (E)) then
4730             return True;
4731          end if;
4732 
4733          Scop := Scope (E);
4734          while Scop /= Standard_Standard loop
4735             if Ekind (Scop) in Subprogram_Kind and then Is_Inlined (Scop) then
4736                return True;
4737             end if;
4738 
4739             Scop := Scope (Scop);
4740          end loop;
4741 
4742          return False;
4743       end Is_Inlined_Or_Child_Of_Inlined;
4744 
4745    begin
4746       --  Must be in the main unit or inlined (or child of inlined)
4747 
4748       if (Is_In_Main_Unit (N) or else Is_Inlined_Or_Child_Of_Inlined (Subp))
4749 
4750         --  Must be generating code or analyzing code in ASIS/GNATprove mode
4751 
4752         and then (Operating_Mode = Generate_Code
4753                    or else (Operating_Mode = Check_Semantics
4754                              and then (ASIS_Mode or GNATprove_Mode)))
4755 
4756         --  The body is needed when generating code (full expansion), in ASIS
4757         --  mode for other tools, and in GNATprove mode (special expansion) for
4758         --  formal verification of the body itself.
4759 
4760         and then (Expander_Active or ASIS_Mode or GNATprove_Mode)
4761 
4762         --  No point in inlining if ABE is inevitable
4763 
4764         and then not ABE_Is_Certain (N)
4765 
4766         --  Or if subprogram is eliminated
4767 
4768         and then not Is_Eliminated (Subp)
4769       then
4770          Add_Pending_Instantiation (N, Unit_Declaration_Node (Subp));
4771          return True;
4772 
4773       --  Here if not inlined, or we ignore the inlining
4774 
4775       else
4776          return False;
4777       end if;
4778    end Need_Subprogram_Instance_Body;
4779 
4780    --------------------------------------
4781    -- Analyze_Subprogram_Instantiation --
4782    --------------------------------------
4783 
4784    procedure Analyze_Subprogram_Instantiation
4785      (N : Node_Id;
4786       K : Entity_Kind)
4787    is
4788       Loc    : constant Source_Ptr := Sloc (N);
4789       Gen_Id : constant Node_Id    := Name (N);
4790 
4791       Anon_Id : constant Entity_Id :=
4792                   Make_Defining_Identifier (Sloc (Defining_Entity (N)),
4793                     Chars => New_External_Name
4794                                (Chars (Defining_Entity (N)), 'R'));
4795 
4796       Act_Decl_Id : Entity_Id;
4797       Act_Decl    : Node_Id;
4798       Act_Spec    : Node_Id;
4799       Act_Tree    : Node_Id;
4800 
4801       Env_Installed    : Boolean := False;
4802       Gen_Unit         : Entity_Id;
4803       Gen_Decl         : Node_Id;
4804       Pack_Id          : Entity_Id;
4805       Parent_Installed : Boolean := False;
4806 
4807       Renaming_List : List_Id;
4808       --  The list of declarations that link formals and actuals of the
4809       --  instance. These are subtype declarations for formal types, and
4810       --  renaming declarations for other formals. The subprogram declaration
4811       --  for the instance is then appended to the list, and the last item on
4812       --  the list is the renaming declaration for the instance.
4813 
4814       procedure Analyze_Instance_And_Renamings;
4815       --  The instance must be analyzed in a context that includes the mappings
4816       --  of generic parameters into actuals. We create a package declaration
4817       --  for this purpose, and a subprogram with an internal name within the
4818       --  package. The subprogram instance is simply an alias for the internal
4819       --  subprogram, declared in the current scope.
4820 
4821       procedure Build_Subprogram_Renaming;
4822       --  If the subprogram is recursive, there are occurrences of the name of
4823       --  the generic within the body, which must resolve to the current
4824       --  instance. We add a renaming declaration after the declaration, which
4825       --  is available in the instance body, as well as in the analysis of
4826       --  aspects that appear in the generic. This renaming declaration is
4827       --  inserted after the instance declaration which it renames.
4828 
4829       ------------------------------------
4830       -- Analyze_Instance_And_Renamings --
4831       ------------------------------------
4832 
4833       procedure Analyze_Instance_And_Renamings is
4834          Def_Ent   : constant Entity_Id := Defining_Entity (N);
4835          Pack_Decl : Node_Id;
4836 
4837       begin
4838          if Nkind (Parent (N)) = N_Compilation_Unit then
4839 
4840             --  For the case of a compilation unit, the container package has
4841             --  the same name as the instantiation, to insure that the binder
4842             --  calls the elaboration procedure with the right name. Copy the
4843             --  entity of the instance, which may have compilation level flags
4844             --  (e.g. Is_Child_Unit) set.
4845 
4846             Pack_Id := New_Copy (Def_Ent);
4847 
4848          else
4849             --  Otherwise we use the name of the instantiation concatenated
4850             --  with its source position to ensure uniqueness if there are
4851             --  several instantiations with the same name.
4852 
4853             Pack_Id :=
4854               Make_Defining_Identifier (Loc,
4855                 Chars => New_External_Name
4856                            (Related_Id   => Chars (Def_Ent),
4857                             Suffix       => "GP",
4858                             Suffix_Index => Source_Offset (Sloc (Def_Ent))));
4859          end if;
4860 
4861          Pack_Decl :=
4862            Make_Package_Declaration (Loc,
4863              Specification => Make_Package_Specification (Loc,
4864                Defining_Unit_Name   => Pack_Id,
4865                Visible_Declarations => Renaming_List,
4866                End_Label            => Empty));
4867 
4868          Set_Instance_Spec (N, Pack_Decl);
4869          Set_Is_Generic_Instance (Pack_Id);
4870          Set_Debug_Info_Needed (Pack_Id);
4871 
4872          --  Case of not a compilation unit
4873 
4874          if Nkind (Parent (N)) /= N_Compilation_Unit then
4875             Mark_Rewrite_Insertion (Pack_Decl);
4876             Insert_Before (N, Pack_Decl);
4877             Set_Has_Completion (Pack_Id);
4878 
4879          --  Case of an instantiation that is a compilation unit
4880 
4881          --  Place declaration on current node so context is complete for
4882          --  analysis (including nested instantiations), and for use in a
4883          --  context_clause (see Analyze_With_Clause).
4884 
4885          else
4886             Set_Unit (Parent (N), Pack_Decl);
4887             Set_Parent_Spec (Pack_Decl, Parent_Spec (N));
4888          end if;
4889 
4890          Analyze (Pack_Decl);
4891          Check_Formal_Packages (Pack_Id);
4892          Set_Is_Generic_Instance (Pack_Id, False);
4893 
4894          --  Why do we clear Is_Generic_Instance??? We set it 20 lines
4895          --  above???
4896 
4897          --  Body of the enclosing package is supplied when instantiating the
4898          --  subprogram body, after semantic analysis is completed.
4899 
4900          if Nkind (Parent (N)) = N_Compilation_Unit then
4901 
4902             --  Remove package itself from visibility, so it does not
4903             --  conflict with subprogram.
4904 
4905             Set_Name_Entity_Id (Chars (Pack_Id), Homonym (Pack_Id));
4906 
4907             --  Set name and scope of internal subprogram so that the proper
4908             --  external name will be generated. The proper scope is the scope
4909             --  of the wrapper package. We need to generate debugging info for
4910             --  the internal subprogram, so set flag accordingly.
4911 
4912             Set_Chars (Anon_Id, Chars (Defining_Entity (N)));
4913             Set_Scope (Anon_Id, Scope (Pack_Id));
4914 
4915             --  Mark wrapper package as referenced, to avoid spurious warnings
4916             --  if the instantiation appears in various with_ clauses of
4917             --  subunits of the main unit.
4918 
4919             Set_Referenced (Pack_Id);
4920          end if;
4921 
4922          Set_Is_Generic_Instance (Anon_Id);
4923          Set_Debug_Info_Needed   (Anon_Id);
4924          Act_Decl_Id := New_Copy (Anon_Id);
4925 
4926          Set_Parent (Act_Decl_Id, Parent (Anon_Id));
4927          Set_Chars  (Act_Decl_Id, Chars (Defining_Entity (N)));
4928          Set_Sloc   (Act_Decl_Id, Sloc (Defining_Entity (N)));
4929 
4930          --  Subprogram instance comes from source only if generic does
4931 
4932          Set_Comes_From_Source (Act_Decl_Id, Comes_From_Source (Gen_Unit));
4933 
4934          --  If the instance is a child unit, mark the Id accordingly. Mark
4935          --  the anonymous entity as well, which is the real subprogram and
4936          --  which is used when the instance appears in a context clause.
4937          --  Similarly, propagate the Is_Eliminated flag to handle properly
4938          --  nested eliminated subprograms.
4939 
4940          Set_Is_Child_Unit (Act_Decl_Id, Is_Child_Unit (Defining_Entity (N)));
4941          Set_Is_Child_Unit (Anon_Id, Is_Child_Unit (Defining_Entity (N)));
4942          New_Overloaded_Entity (Act_Decl_Id);
4943          Check_Eliminated  (Act_Decl_Id);
4944          Set_Is_Eliminated (Anon_Id, Is_Eliminated (Act_Decl_Id));
4945 
4946          --  In compilation unit case, kill elaboration checks on the
4947          --  instantiation, since they are never needed -- the body is
4948          --  instantiated at the same point as the spec.
4949 
4950          if Nkind (Parent (N)) = N_Compilation_Unit then
4951             Set_Suppress_Elaboration_Warnings (Act_Decl_Id);
4952             Set_Kill_Elaboration_Checks       (Act_Decl_Id);
4953             Set_Is_Compilation_Unit (Anon_Id);
4954 
4955             Set_Cunit_Entity (Current_Sem_Unit, Pack_Id);
4956          end if;
4957 
4958          --  The instance is not a freezing point for the new subprogram.
4959          --  The anonymous subprogram may have a freeze node, created for
4960          --  some delayed aspects. This freeze node must not be inherited
4961          --  by the visible subprogram entity.
4962 
4963          Set_Is_Frozen   (Act_Decl_Id, False);
4964          Set_Freeze_Node (Act_Decl_Id, Empty);
4965 
4966          if Nkind (Defining_Entity (N)) = N_Defining_Operator_Symbol then
4967             Valid_Operator_Definition (Act_Decl_Id);
4968          end if;
4969 
4970          Set_Alias  (Act_Decl_Id, Anon_Id);
4971          Set_Parent (Act_Decl_Id, Parent (Anon_Id));
4972          Set_Has_Completion (Act_Decl_Id);
4973          Set_Related_Instance (Pack_Id, Act_Decl_Id);
4974 
4975          if Nkind (Parent (N)) = N_Compilation_Unit then
4976             Set_Body_Required (Parent (N), False);
4977          end if;
4978       end Analyze_Instance_And_Renamings;
4979 
4980       -------------------------------
4981       -- Build_Subprogram_Renaming --
4982       -------------------------------
4983 
4984       procedure Build_Subprogram_Renaming is
4985          Renaming_Decl : Node_Id;
4986          Unit_Renaming : Node_Id;
4987 
4988       begin
4989          Unit_Renaming :=
4990            Make_Subprogram_Renaming_Declaration (Loc,
4991              Specification =>
4992                Copy_Generic_Node
4993                  (Specification (Original_Node (Gen_Decl)),
4994                   Empty,
4995                   Instantiating => True),
4996              Name          => New_Occurrence_Of (Anon_Id, Loc));
4997 
4998          --  The generic may be a a child unit. The renaming needs an
4999          --  identifier with the proper name.
5000 
5001          Set_Defining_Unit_Name (Specification (Unit_Renaming),
5002             Make_Defining_Identifier (Loc, Chars (Gen_Unit)));
5003 
5004          --  If there is a formal subprogram with the same name as the unit
5005          --  itself, do not add this renaming declaration, to prevent
5006          --  ambiguities when there is a call with that name in the body.
5007          --  This is a partial and ugly fix for one ACATS test. ???
5008 
5009          Renaming_Decl := First (Renaming_List);
5010          while Present (Renaming_Decl) loop
5011             if Nkind (Renaming_Decl) = N_Subprogram_Renaming_Declaration
5012               and then
5013                 Chars (Defining_Entity (Renaming_Decl)) = Chars (Gen_Unit)
5014             then
5015                exit;
5016             end if;
5017 
5018             Next (Renaming_Decl);
5019          end loop;
5020 
5021          if No (Renaming_Decl) then
5022             Append (Unit_Renaming, Renaming_List);
5023          end if;
5024       end Build_Subprogram_Renaming;
5025 
5026       --  Local variables
5027 
5028       Save_IPSM : constant Boolean := Ignore_Pragma_SPARK_Mode;
5029       --  Save flag Ignore_Pragma_SPARK_Mode for restore on exit
5030 
5031       Save_SM  : constant SPARK_Mode_Type := SPARK_Mode;
5032       Save_SMP : constant Node_Id         := SPARK_Mode_Pragma;
5033       --  Save the SPARK_Mode-related data for restore on exit
5034 
5035       Vis_Prims_List : Elist_Id := No_Elist;
5036       --  List of primitives made temporarily visible in the instantiation
5037       --  to match the visibility of the formal type
5038 
5039    --  Start of processing for Analyze_Subprogram_Instantiation
5040 
5041    begin
5042       Check_SPARK_05_Restriction ("generic is not allowed", N);
5043 
5044       --  Very first thing: check for special Text_IO unit in case we are
5045       --  instantiating one of the children of [[Wide_]Wide_]Text_IO. Of course
5046       --  such an instantiation is bogus (these are packages, not subprograms),
5047       --  but we get a better error message if we do this.
5048 
5049       Check_Text_IO_Special_Unit (Gen_Id);
5050 
5051       --  Make node global for error reporting
5052 
5053       Instantiation_Node := N;
5054 
5055       --  For package instantiations we turn off style checks, because they
5056       --  will have been emitted in the generic. For subprogram instantiations
5057       --  we want to apply at least the check on overriding indicators so we
5058       --  do not modify the style check status.
5059 
5060       --  The renaming declarations for the actuals do not come from source and
5061       --  will not generate spurious warnings.
5062 
5063       Preanalyze_Actuals (N);
5064 
5065       Init_Env;
5066       Env_Installed := True;
5067       Check_Generic_Child_Unit (Gen_Id, Parent_Installed);
5068       Gen_Unit := Entity (Gen_Id);
5069 
5070       Generate_Reference (Gen_Unit, Gen_Id);
5071 
5072       if Nkind (Gen_Id) = N_Identifier
5073         and then Chars (Gen_Unit) = Chars (Defining_Entity (N))
5074       then
5075          Error_Msg_NE
5076            ("& is hidden within declaration of instance", Gen_Id, Gen_Unit);
5077       end if;
5078 
5079       if Etype (Gen_Unit) = Any_Type then
5080          Restore_Env;
5081          return;
5082       end if;
5083 
5084       --  Verify that it is a generic subprogram of the right kind, and that
5085       --  it does not lead to a circular instantiation.
5086 
5087       if K = E_Procedure and then Ekind (Gen_Unit) /= E_Generic_Procedure then
5088          Error_Msg_NE
5089            ("& is not the name of a generic procedure", Gen_Id, Gen_Unit);
5090 
5091       elsif K = E_Function and then Ekind (Gen_Unit) /= E_Generic_Function then
5092          Error_Msg_NE
5093            ("& is not the name of a generic function", Gen_Id, Gen_Unit);
5094 
5095       elsif In_Open_Scopes (Gen_Unit) then
5096          Error_Msg_NE ("instantiation of & within itself", N, Gen_Unit);
5097 
5098       else
5099          --  If the context of the instance is subject to SPARK_Mode "off" or
5100          --  the annotation is altogether missing, set the global flag which
5101          --  signals Analyze_Pragma to ignore all SPARK_Mode pragmas within
5102          --  the instance.
5103 
5104          if SPARK_Mode /= On then
5105             Ignore_Pragma_SPARK_Mode := True;
5106          end if;
5107 
5108          Set_Entity (Gen_Id, Gen_Unit);
5109          Set_Is_Instantiated (Gen_Unit);
5110 
5111          if In_Extended_Main_Source_Unit (N) then
5112             Generate_Reference (Gen_Unit, N);
5113          end if;
5114 
5115          --  If renaming, get original unit
5116 
5117          if Present (Renamed_Object (Gen_Unit))
5118            and then Ekind_In (Renamed_Object (Gen_Unit), E_Generic_Procedure,
5119                                                          E_Generic_Function)
5120          then
5121             Gen_Unit := Renamed_Object (Gen_Unit);
5122             Set_Is_Instantiated (Gen_Unit);
5123             Generate_Reference  (Gen_Unit, N);
5124          end if;
5125 
5126          if Contains_Instance_Of (Gen_Unit, Current_Scope, Gen_Id) then
5127             Error_Msg_Node_2 := Current_Scope;
5128             Error_Msg_NE
5129               ("circular Instantiation: & instantiated in &!", N, Gen_Unit);
5130             Circularity_Detected := True;
5131             Restore_Hidden_Primitives (Vis_Prims_List);
5132             goto Leave;
5133          end if;
5134 
5135          Gen_Decl := Unit_Declaration_Node (Gen_Unit);
5136 
5137          --  Initialize renamings map, for error checking
5138 
5139          Generic_Renamings.Set_Last (0);
5140          Generic_Renamings_HTable.Reset;
5141 
5142          Create_Instantiation_Source (N, Gen_Unit, S_Adjustment);
5143 
5144          --  Copy original generic tree, to produce text for instantiation
5145 
5146          Act_Tree :=
5147            Copy_Generic_Node
5148              (Original_Node (Gen_Decl), Empty, Instantiating => True);
5149 
5150          --  Inherit overriding indicator from instance node
5151 
5152          Act_Spec := Specification (Act_Tree);
5153          Set_Must_Override     (Act_Spec, Must_Override (N));
5154          Set_Must_Not_Override (Act_Spec, Must_Not_Override (N));
5155 
5156          Renaming_List :=
5157            Analyze_Associations
5158              (I_Node  => N,
5159               Formals => Generic_Formal_Declarations (Act_Tree),
5160               F_Copy  => Generic_Formal_Declarations (Gen_Decl));
5161 
5162          Vis_Prims_List := Check_Hidden_Primitives (Renaming_List);
5163 
5164          --  The subprogram itself cannot contain a nested instance, so the
5165          --  current parent is left empty.
5166 
5167          Set_Instance_Env (Gen_Unit, Empty);
5168 
5169          --  Build the subprogram declaration, which does not appear in the
5170          --  generic template, and give it a sloc consistent with that of the
5171          --  template.
5172 
5173          Set_Defining_Unit_Name (Act_Spec, Anon_Id);
5174          Set_Generic_Parent (Act_Spec, Gen_Unit);
5175          Act_Decl :=
5176            Make_Subprogram_Declaration (Sloc (Act_Spec),
5177              Specification => Act_Spec);
5178 
5179          --  The aspects have been copied previously, but they have to be
5180          --  linked explicitly to the new subprogram declaration. Explicit
5181          --  pre/postconditions on the instance are analyzed below, in a
5182          --  separate step.
5183 
5184          Move_Aspects (Act_Tree, To => Act_Decl);
5185          Set_Categorization_From_Pragmas (Act_Decl);
5186 
5187          if Parent_Installed then
5188             Hide_Current_Scope;
5189          end if;
5190 
5191          Append (Act_Decl, Renaming_List);
5192 
5193          --  Contract-related source pragmas that follow a generic subprogram
5194          --  must be instantiated explicitly because they are not part of the
5195          --  subprogram template.
5196 
5197          Instantiate_Subprogram_Contract
5198            (Original_Node (Gen_Decl), Renaming_List);
5199 
5200          Build_Subprogram_Renaming;
5201          Analyze_Instance_And_Renamings;
5202 
5203          --  If the generic is marked Import (Intrinsic), then so is the
5204          --  instance. This indicates that there is no body to instantiate. If
5205          --  generic is marked inline, so it the instance, and the anonymous
5206          --  subprogram it renames. If inlined, or else if inlining is enabled
5207          --  for the compilation, we generate the instance body even if it is
5208          --  not within the main unit.
5209 
5210          if Is_Intrinsic_Subprogram (Gen_Unit) then
5211             Set_Is_Intrinsic_Subprogram (Anon_Id);
5212             Set_Is_Intrinsic_Subprogram (Act_Decl_Id);
5213 
5214             if Chars (Gen_Unit) = Name_Unchecked_Conversion then
5215                Validate_Unchecked_Conversion (N, Act_Decl_Id);
5216             end if;
5217          end if;
5218 
5219          --  Inherit convention from generic unit. Intrinsic convention, as for
5220          --  an instance of unchecked conversion, is not inherited because an
5221          --  explicit Ada instance has been created.
5222 
5223          if Has_Convention_Pragma (Gen_Unit)
5224            and then Convention (Gen_Unit) /= Convention_Intrinsic
5225          then
5226             Set_Convention (Act_Decl_Id, Convention (Gen_Unit));
5227             Set_Is_Exported (Act_Decl_Id, Is_Exported (Gen_Unit));
5228          end if;
5229 
5230          Generate_Definition (Act_Decl_Id);
5231 
5232          --  Inherit all inlining-related flags which apply to the generic in
5233          --  the subprogram and its declaration.
5234 
5235          Set_Is_Inlined (Act_Decl_Id, Is_Inlined (Gen_Unit));
5236          Set_Is_Inlined (Anon_Id,     Is_Inlined (Gen_Unit));
5237 
5238          Set_Has_Pragma_Inline (Act_Decl_Id, Has_Pragma_Inline (Gen_Unit));
5239          Set_Has_Pragma_Inline (Anon_Id,     Has_Pragma_Inline (Gen_Unit));
5240 
5241          Set_Has_Pragma_Inline_Always
5242            (Act_Decl_Id, Has_Pragma_Inline_Always (Gen_Unit));
5243          Set_Has_Pragma_Inline_Always
5244            (Anon_Id,     Has_Pragma_Inline_Always (Gen_Unit));
5245 
5246          if not Is_Intrinsic_Subprogram (Gen_Unit) then
5247             Check_Elab_Instantiation (N);
5248          end if;
5249 
5250          if Is_Dispatching_Operation (Act_Decl_Id)
5251            and then Ada_Version >= Ada_2005
5252          then
5253             declare
5254                Formal : Entity_Id;
5255 
5256             begin
5257                Formal := First_Formal (Act_Decl_Id);
5258                while Present (Formal) loop
5259                   if Ekind (Etype (Formal)) = E_Anonymous_Access_Type
5260                     and then Is_Controlling_Formal (Formal)
5261                     and then not Can_Never_Be_Null (Formal)
5262                   then
5263                      Error_Msg_NE
5264                        ("access parameter& is controlling,", N, Formal);
5265                      Error_Msg_NE
5266                        ("\corresponding parameter of & must be "
5267                        & "explicitly null-excluding", N, Gen_Id);
5268                   end if;
5269 
5270                   Next_Formal (Formal);
5271                end loop;
5272             end;
5273          end if;
5274 
5275          Check_Hidden_Child_Unit (N, Gen_Unit, Act_Decl_Id);
5276 
5277          Validate_Categorization_Dependency (N, Act_Decl_Id);
5278 
5279          if not Is_Intrinsic_Subprogram (Act_Decl_Id) then
5280             Inherit_Context (Gen_Decl, N);
5281 
5282             Restore_Private_Views (Pack_Id, False);
5283 
5284             --  If the context requires a full instantiation, mark node for
5285             --  subsequent construction of the body.
5286 
5287             if Need_Subprogram_Instance_Body (N, Act_Decl_Id) then
5288                Check_Forward_Instantiation (Gen_Decl);
5289 
5290             --  The wrapper package is always delayed, because it does not
5291             --  constitute a freeze point, but to insure that the freeze node
5292             --  is placed properly, it is created directly when instantiating
5293             --  the body (otherwise the freeze node might appear to early for
5294             --  nested instantiations). For ASIS purposes, indicate that the
5295             --  wrapper package has replaced the instantiation node.
5296 
5297             elsif Nkind (Parent (N)) = N_Compilation_Unit then
5298                Rewrite (N, Unit (Parent (N)));
5299                Set_Unit (Parent (N), N);
5300             end if;
5301 
5302          --  Replace instance node for library-level instantiations of
5303          --  intrinsic subprograms, for ASIS use.
5304 
5305          elsif Nkind (Parent (N)) = N_Compilation_Unit then
5306             Rewrite (N, Unit (Parent (N)));
5307             Set_Unit (Parent (N), N);
5308          end if;
5309 
5310          if Parent_Installed then
5311             Remove_Parent;
5312          end if;
5313 
5314          Restore_Hidden_Primitives (Vis_Prims_List);
5315          Restore_Env;
5316          Env_Installed := False;
5317          Generic_Renamings.Set_Last (0);
5318          Generic_Renamings_HTable.Reset;
5319 
5320          Ignore_Pragma_SPARK_Mode := Save_IPSM;
5321          SPARK_Mode               := Save_SM;
5322          SPARK_Mode_Pragma        := Save_SMP;
5323       end if;
5324 
5325    <<Leave>>
5326       if Has_Aspects (N) then
5327          Analyze_Aspect_Specifications (N, Act_Decl_Id);
5328       end if;
5329 
5330    exception
5331       when Instantiation_Error =>
5332          if Parent_Installed then
5333             Remove_Parent;
5334          end if;
5335 
5336          if Env_Installed then
5337             Restore_Env;
5338          end if;
5339 
5340          Ignore_Pragma_SPARK_Mode := Save_IPSM;
5341          SPARK_Mode               := Save_SM;
5342          SPARK_Mode_Pragma        := Save_SMP;
5343    end Analyze_Subprogram_Instantiation;
5344 
5345    -------------------------
5346    -- Get_Associated_Node --
5347    -------------------------
5348 
5349    function Get_Associated_Node (N : Node_Id) return Node_Id is
5350       Assoc : Node_Id;
5351 
5352    begin
5353       Assoc := Associated_Node (N);
5354 
5355       if Nkind (Assoc) /= Nkind (N) then
5356          return Assoc;
5357 
5358       elsif Nkind_In (Assoc, N_Aggregate, N_Extension_Aggregate) then
5359          return Assoc;
5360 
5361       else
5362          --  If the node is part of an inner generic, it may itself have been
5363          --  remapped into a further generic copy. Associated_Node is otherwise
5364          --  used for the entity of the node, and will be of a different node
5365          --  kind, or else N has been rewritten as a literal or function call.
5366 
5367          while Present (Associated_Node (Assoc))
5368            and then Nkind (Associated_Node (Assoc)) = Nkind (Assoc)
5369          loop
5370             Assoc := Associated_Node (Assoc);
5371          end loop;
5372 
5373          --  Follow and additional link in case the final node was rewritten.
5374          --  This can only happen with nested generic units.
5375 
5376          if (Nkind (Assoc) = N_Identifier or else Nkind (Assoc) in N_Op)
5377            and then Present (Associated_Node (Assoc))
5378            and then (Nkind_In (Associated_Node (Assoc), N_Function_Call,
5379                                                         N_Explicit_Dereference,
5380                                                         N_Integer_Literal,
5381                                                         N_Real_Literal,
5382                                                         N_String_Literal))
5383          then
5384             Assoc := Associated_Node (Assoc);
5385          end if;
5386 
5387          --  An additional special case: an unconstrained type in an object
5388          --  declaration may have been rewritten as a local subtype constrained
5389          --  by the expression in the declaration. We need to recover the
5390          --  original entity which may be global.
5391 
5392          if Present (Original_Node (Assoc))
5393            and then Nkind (Parent (N)) = N_Object_Declaration
5394          then
5395             Assoc := Original_Node (Assoc);
5396          end if;
5397 
5398          return Assoc;
5399       end if;
5400    end Get_Associated_Node;
5401 
5402    ----------------------------
5403    -- Build_Function_Wrapper --
5404    ----------------------------
5405 
5406    function Build_Function_Wrapper
5407      (Formal_Subp : Entity_Id;
5408       Actual_Subp : Entity_Id) return Node_Id
5409    is
5410       Loc       : constant Source_Ptr := Sloc (Current_Scope);
5411       Ret_Type  : constant Entity_Id  := Get_Instance_Of (Etype (Formal_Subp));
5412       Actuals   : List_Id;
5413       Decl      : Node_Id;
5414       Func_Name : Node_Id;
5415       Func      : Entity_Id;
5416       Parm_Type : Node_Id;
5417       Profile   : List_Id := New_List;
5418       Spec      : Node_Id;
5419       Act_F     : Entity_Id;
5420       Form_F    : Entity_Id;
5421       New_F     : Entity_Id;
5422 
5423    begin
5424       Func_Name := New_Occurrence_Of (Actual_Subp, Loc);
5425 
5426       Func := Make_Defining_Identifier (Loc, Chars (Formal_Subp));
5427       Set_Ekind (Func, E_Function);
5428       Set_Is_Generic_Actual_Subprogram (Func);
5429 
5430       Actuals := New_List;
5431       Profile := New_List;
5432 
5433       Act_F  := First_Formal (Actual_Subp);
5434       Form_F := First_Formal (Formal_Subp);
5435       while Present (Form_F) loop
5436 
5437          --  Create new formal for profile of wrapper, and add a reference
5438          --  to it in the list of actuals for the enclosing call. The name
5439          --  must be that of the formal in the formal subprogram, because
5440          --  calls to it in the generic body may use named associations.
5441 
5442          New_F := Make_Defining_Identifier (Loc, Chars (Form_F));
5443 
5444          Parm_Type :=
5445            New_Occurrence_Of (Get_Instance_Of (Etype (Form_F)), Loc);
5446 
5447          Append_To (Profile,
5448            Make_Parameter_Specification (Loc,
5449              Defining_Identifier => New_F,
5450              Parameter_Type      => Parm_Type));
5451 
5452          Append_To (Actuals, New_Occurrence_Of (New_F, Loc));
5453          Next_Formal (Form_F);
5454 
5455          if Present (Act_F) then
5456             Next_Formal (Act_F);
5457          end if;
5458       end loop;
5459 
5460       Spec :=
5461         Make_Function_Specification (Loc,
5462           Defining_Unit_Name       => Func,
5463           Parameter_Specifications => Profile,
5464           Result_Definition        => New_Occurrence_Of (Ret_Type, Loc));
5465 
5466       Decl :=
5467         Make_Expression_Function (Loc,
5468           Specification => Spec,
5469           Expression    =>
5470             Make_Function_Call (Loc,
5471               Name                   => Func_Name,
5472               Parameter_Associations => Actuals));
5473 
5474       return Decl;
5475    end Build_Function_Wrapper;
5476 
5477    ----------------------------
5478    -- Build_Operator_Wrapper --
5479    ----------------------------
5480 
5481    function Build_Operator_Wrapper
5482      (Formal_Subp : Entity_Id;
5483       Actual_Subp : Entity_Id) return Node_Id
5484    is
5485       Loc       : constant Source_Ptr := Sloc (Current_Scope);
5486       Ret_Type  : constant Entity_Id  :=
5487                     Get_Instance_Of (Etype (Formal_Subp));
5488       Op_Type   : constant Entity_Id  :=
5489                     Get_Instance_Of (Etype (First_Formal (Formal_Subp)));
5490       Is_Binary : constant Boolean    :=
5491                     Present (Next_Formal (First_Formal (Formal_Subp)));
5492 
5493       Decl    : Node_Id;
5494       Expr    : Node_Id;
5495       F1, F2  : Entity_Id;
5496       Func    : Entity_Id;
5497       Op_Name : Name_Id;
5498       Spec    : Node_Id;
5499       L, R    : Node_Id;
5500 
5501    begin
5502       Op_Name := Chars (Actual_Subp);
5503 
5504       --  Create entities for wrapper function and its formals
5505 
5506       F1 := Make_Temporary (Loc, 'A');
5507       F2 := Make_Temporary (Loc, 'B');
5508       L  := New_Occurrence_Of (F1, Loc);
5509       R  := New_Occurrence_Of (F2, Loc);
5510 
5511       Func := Make_Defining_Identifier (Loc, Chars (Formal_Subp));
5512       Set_Ekind (Func, E_Function);
5513       Set_Is_Generic_Actual_Subprogram (Func);
5514 
5515       Spec :=
5516         Make_Function_Specification (Loc,
5517           Defining_Unit_Name       => Func,
5518           Parameter_Specifications => New_List (
5519             Make_Parameter_Specification (Loc,
5520                Defining_Identifier => F1,
5521                Parameter_Type      => New_Occurrence_Of (Op_Type, Loc))),
5522           Result_Definition        =>  New_Occurrence_Of (Ret_Type, Loc));
5523 
5524       if Is_Binary then
5525          Append_To (Parameter_Specifications (Spec),
5526             Make_Parameter_Specification (Loc,
5527               Defining_Identifier => F2,
5528               Parameter_Type      => New_Occurrence_Of (Op_Type, Loc)));
5529       end if;
5530 
5531       --  Build expression as a function call, or as an operator node
5532       --  that corresponds to the name of the actual, starting with
5533       --  binary operators.
5534 
5535       if Op_Name not in Any_Operator_Name then
5536          Expr :=
5537            Make_Function_Call (Loc,
5538              Name                   =>
5539                New_Occurrence_Of (Actual_Subp, Loc),
5540              Parameter_Associations => New_List (L));
5541 
5542          if Is_Binary then
5543             Append_To (Parameter_Associations (Expr), R);
5544          end if;
5545 
5546       --  Binary operators
5547 
5548       elsif Is_Binary then
5549          if Op_Name = Name_Op_And then
5550             Expr := Make_Op_And      (Loc, Left_Opnd => L, Right_Opnd => R);
5551          elsif Op_Name = Name_Op_Or then
5552             Expr := Make_Op_Or       (Loc, Left_Opnd => L, Right_Opnd => R);
5553          elsif Op_Name = Name_Op_Xor then
5554             Expr := Make_Op_Xor      (Loc, Left_Opnd => L, Right_Opnd => R);
5555          elsif Op_Name = Name_Op_Eq then
5556             Expr := Make_Op_Eq       (Loc, Left_Opnd => L, Right_Opnd => R);
5557          elsif Op_Name = Name_Op_Ne then
5558             Expr := Make_Op_Ne       (Loc, Left_Opnd => L, Right_Opnd => R);
5559          elsif Op_Name = Name_Op_Le then
5560             Expr := Make_Op_Le       (Loc, Left_Opnd => L, Right_Opnd => R);
5561          elsif Op_Name = Name_Op_Gt then
5562             Expr := Make_Op_Gt       (Loc, Left_Opnd => L, Right_Opnd => R);
5563          elsif Op_Name = Name_Op_Ge then
5564             Expr := Make_Op_Ge       (Loc, Left_Opnd => L, Right_Opnd => R);
5565          elsif Op_Name = Name_Op_Lt then
5566             Expr := Make_Op_Lt       (Loc, Left_Opnd => L, Right_Opnd => R);
5567          elsif Op_Name = Name_Op_Add then
5568             Expr := Make_Op_Add      (Loc, Left_Opnd => L, Right_Opnd => R);
5569          elsif Op_Name = Name_Op_Subtract then
5570             Expr := Make_Op_Subtract (Loc, Left_Opnd => L, Right_Opnd => R);
5571          elsif Op_Name = Name_Op_Concat then
5572             Expr := Make_Op_Concat   (Loc, Left_Opnd => L, Right_Opnd => R);
5573          elsif Op_Name = Name_Op_Multiply then
5574             Expr := Make_Op_Multiply (Loc, Left_Opnd => L, Right_Opnd => R);
5575          elsif Op_Name = Name_Op_Divide then
5576             Expr := Make_Op_Divide   (Loc, Left_Opnd => L, Right_Opnd => R);
5577          elsif Op_Name = Name_Op_Mod then
5578             Expr := Make_Op_Mod      (Loc, Left_Opnd => L, Right_Opnd => R);
5579          elsif Op_Name = Name_Op_Rem then
5580             Expr := Make_Op_Rem      (Loc, Left_Opnd => L, Right_Opnd => R);
5581          elsif Op_Name = Name_Op_Expon then
5582             Expr := Make_Op_Expon    (Loc, Left_Opnd => L, Right_Opnd => R);
5583          end if;
5584 
5585       --  Unary operators
5586 
5587       else
5588          if Op_Name = Name_Op_Add then
5589             Expr := Make_Op_Plus  (Loc, Right_Opnd => L);
5590          elsif Op_Name = Name_Op_Subtract then
5591             Expr := Make_Op_Minus (Loc, Right_Opnd => L);
5592          elsif Op_Name = Name_Op_Abs then
5593             Expr := Make_Op_Abs   (Loc, Right_Opnd => L);
5594          elsif Op_Name = Name_Op_Not then
5595             Expr := Make_Op_Not   (Loc, Right_Opnd => L);
5596          end if;
5597       end if;
5598 
5599       Decl :=
5600         Make_Expression_Function (Loc,
5601           Specification => Spec,
5602           Expression    => Expr);
5603 
5604       return Decl;
5605    end Build_Operator_Wrapper;
5606 
5607    -------------------------------------------
5608    -- Build_Instance_Compilation_Unit_Nodes --
5609    -------------------------------------------
5610 
5611    procedure Build_Instance_Compilation_Unit_Nodes
5612      (N        : Node_Id;
5613       Act_Body : Node_Id;
5614       Act_Decl : Node_Id)
5615    is
5616       Decl_Cunit : Node_Id;
5617       Body_Cunit : Node_Id;
5618       Citem      : Node_Id;
5619       New_Main   : constant Entity_Id := Defining_Entity (Act_Decl);
5620       Old_Main   : constant Entity_Id := Cunit_Entity (Main_Unit);
5621 
5622    begin
5623       --  A new compilation unit node is built for the instance declaration
5624 
5625       Decl_Cunit :=
5626         Make_Compilation_Unit (Sloc (N),
5627           Context_Items  => Empty_List,
5628           Unit           => Act_Decl,
5629           Aux_Decls_Node => Make_Compilation_Unit_Aux (Sloc (N)));
5630 
5631       Set_Parent_Spec (Act_Decl, Parent_Spec (N));
5632 
5633       --  The new compilation unit is linked to its body, but both share the
5634       --  same file, so we do not set Body_Required on the new unit so as not
5635       --  to create a spurious dependency on a non-existent body in the ali.
5636       --  This simplifies CodePeer unit traversal.
5637 
5638       --  We use the original instantiation compilation unit as the resulting
5639       --  compilation unit of the instance, since this is the main unit.
5640 
5641       Rewrite (N, Act_Body);
5642 
5643       --  Propagate the aspect specifications from the package body template to
5644       --  the instantiated version of the package body.
5645 
5646       if Has_Aspects (Act_Body) then
5647          Set_Aspect_Specifications
5648            (N, New_Copy_List_Tree (Aspect_Specifications (Act_Body)));
5649       end if;
5650 
5651       Body_Cunit := Parent (N);
5652 
5653       --  The two compilation unit nodes are linked by the Library_Unit field
5654 
5655       Set_Library_Unit (Decl_Cunit, Body_Cunit);
5656       Set_Library_Unit (Body_Cunit, Decl_Cunit);
5657 
5658       --  Preserve the private nature of the package if needed
5659 
5660       Set_Private_Present (Decl_Cunit, Private_Present (Body_Cunit));
5661 
5662       --  If the instance is not the main unit, its context, categorization
5663       --  and elaboration entity are not relevant to the compilation.
5664 
5665       if Body_Cunit /= Cunit (Main_Unit) then
5666          Make_Instance_Unit (Body_Cunit, In_Main => False);
5667          return;
5668       end if;
5669 
5670       --  The context clause items on the instantiation, which are now attached
5671       --  to the body compilation unit (since the body overwrote the original
5672       --  instantiation node), semantically belong on the spec, so copy them
5673       --  there. It's harmless to leave them on the body as well. In fact one
5674       --  could argue that they belong in both places.
5675 
5676       Citem := First (Context_Items (Body_Cunit));
5677       while Present (Citem) loop
5678          Append (New_Copy (Citem), Context_Items (Decl_Cunit));
5679          Next (Citem);
5680       end loop;
5681 
5682       --  Propagate categorization flags on packages, so that they appear in
5683       --  the ali file for the spec of the unit.
5684 
5685       if Ekind (New_Main) = E_Package then
5686          Set_Is_Pure           (Old_Main, Is_Pure (New_Main));
5687          Set_Is_Preelaborated  (Old_Main, Is_Preelaborated (New_Main));
5688          Set_Is_Remote_Types   (Old_Main, Is_Remote_Types (New_Main));
5689          Set_Is_Shared_Passive (Old_Main, Is_Shared_Passive (New_Main));
5690          Set_Is_Remote_Call_Interface
5691            (Old_Main, Is_Remote_Call_Interface (New_Main));
5692       end if;
5693 
5694       --  Make entry in Units table, so that binder can generate call to
5695       --  elaboration procedure for body, if any.
5696 
5697       Make_Instance_Unit (Body_Cunit, In_Main => True);
5698       Main_Unit_Entity := New_Main;
5699       Set_Cunit_Entity (Main_Unit, Main_Unit_Entity);
5700 
5701       --  Build elaboration entity, since the instance may certainly generate
5702       --  elaboration code requiring a flag for protection.
5703 
5704       Build_Elaboration_Entity (Decl_Cunit, New_Main);
5705    end Build_Instance_Compilation_Unit_Nodes;
5706 
5707    -----------------------------
5708    -- Check_Access_Definition --
5709    -----------------------------
5710 
5711    procedure Check_Access_Definition (N : Node_Id) is
5712    begin
5713       pragma Assert
5714         (Ada_Version >= Ada_2005 and then Present (Access_Definition (N)));
5715       null;
5716    end Check_Access_Definition;
5717 
5718    -----------------------------------
5719    -- Check_Formal_Package_Instance --
5720    -----------------------------------
5721 
5722    --  If the formal has specific parameters, they must match those of the
5723    --  actual. Both of them are instances, and the renaming declarations for
5724    --  their formal parameters appear in the same order in both. The analyzed
5725    --  formal has been analyzed in the context of the current instance.
5726 
5727    procedure Check_Formal_Package_Instance
5728      (Formal_Pack : Entity_Id;
5729       Actual_Pack : Entity_Id)
5730    is
5731       E1 : Entity_Id := First_Entity (Actual_Pack);
5732       E2 : Entity_Id := First_Entity (Formal_Pack);
5733 
5734       Expr1 : Node_Id;
5735       Expr2 : Node_Id;
5736 
5737       procedure Check_Mismatch (B : Boolean);
5738       --  Common error routine for mismatch between the parameters of the
5739       --  actual instance and those of the formal package.
5740 
5741       function Same_Instantiated_Constant (E1, E2 : Entity_Id) return Boolean;
5742       --  The formal may come from a nested formal package, and the actual may
5743       --  have been constant-folded. To determine whether the two denote the
5744       --  same entity we may have to traverse several definitions to recover
5745       --  the ultimate entity that they refer to.
5746 
5747       function Same_Instantiated_Function (E1, E2 : Entity_Id) return Boolean;
5748       --  The formal and the actual must be identical, but if both are
5749       --  given by attributes they end up renaming different generated bodies,
5750       --  and we must verify that the attributes themselves match.
5751 
5752       function Same_Instantiated_Variable (E1, E2 : Entity_Id) return Boolean;
5753       --  Similarly, if the formal comes from a nested formal package, the
5754       --  actual may designate the formal through multiple renamings, which
5755       --  have to be followed to determine the original variable in question.
5756 
5757       --------------------
5758       -- Check_Mismatch --
5759       --------------------
5760 
5761       procedure Check_Mismatch (B : Boolean) is
5762          --  A Formal_Type_Declaration for a derived private type is rewritten
5763          --  as a private extension decl. (see Analyze_Formal_Derived_Type),
5764          --  which is why we examine the original node.
5765 
5766          Kind : constant Node_Kind := Nkind (Original_Node (Parent (E2)));
5767 
5768       begin
5769          if Kind = N_Formal_Type_Declaration then
5770             return;
5771 
5772          elsif Nkind_In (Kind, N_Formal_Object_Declaration,
5773                                N_Formal_Package_Declaration)
5774            or else Kind in N_Formal_Subprogram_Declaration
5775          then
5776             null;
5777 
5778          --  Ada 2012: If both formal and actual are incomplete types they
5779          --  are conformant.
5780 
5781          elsif Is_Incomplete_Type (E1) and then Is_Incomplete_Type (E2) then
5782             null;
5783 
5784          elsif B then
5785             Error_Msg_NE
5786               ("actual for & in actual instance does not match formal",
5787                Parent (Actual_Pack), E1);
5788          end if;
5789       end Check_Mismatch;
5790 
5791       --------------------------------
5792       -- Same_Instantiated_Constant --
5793       --------------------------------
5794 
5795       function Same_Instantiated_Constant
5796         (E1, E2 : Entity_Id) return Boolean
5797       is
5798          Ent : Entity_Id;
5799 
5800       begin
5801          Ent := E2;
5802          while Present (Ent) loop
5803             if E1 = Ent then
5804                return True;
5805 
5806             elsif Ekind (Ent) /= E_Constant then
5807                return False;
5808 
5809             elsif Is_Entity_Name (Constant_Value (Ent)) then
5810                if Entity (Constant_Value (Ent)) = E1 then
5811                   return True;
5812                else
5813                   Ent := Entity (Constant_Value (Ent));
5814                end if;
5815 
5816             --  The actual may be a constant that has been folded. Recover
5817             --  original name.
5818 
5819             elsif Is_Entity_Name (Original_Node (Constant_Value (Ent))) then
5820                Ent := Entity (Original_Node (Constant_Value (Ent)));
5821 
5822             else
5823                return False;
5824             end if;
5825          end loop;
5826 
5827          return False;
5828       end Same_Instantiated_Constant;
5829 
5830       --------------------------------
5831       -- Same_Instantiated_Function --
5832       --------------------------------
5833 
5834       function Same_Instantiated_Function
5835         (E1, E2 : Entity_Id) return Boolean
5836       is
5837          U1, U2 : Node_Id;
5838       begin
5839          if Alias (E1) = Alias (E2) then
5840             return True;
5841 
5842          elsif Present (Alias (E2)) then
5843             U1 := Original_Node (Unit_Declaration_Node (E1));
5844             U2 := Original_Node (Unit_Declaration_Node (Alias (E2)));
5845 
5846             return Nkind (U1) = N_Subprogram_Renaming_Declaration
5847               and then Nkind (Name (U1)) = N_Attribute_Reference
5848 
5849               and then Nkind (U2) = N_Subprogram_Renaming_Declaration
5850               and then Nkind (Name (U2)) = N_Attribute_Reference
5851 
5852               and then
5853                 Attribute_Name (Name (U1)) = Attribute_Name (Name (U2));
5854          else
5855             return False;
5856          end if;
5857       end Same_Instantiated_Function;
5858 
5859       --------------------------------
5860       -- Same_Instantiated_Variable --
5861       --------------------------------
5862 
5863       function Same_Instantiated_Variable
5864         (E1, E2 : Entity_Id) return Boolean
5865       is
5866          function Original_Entity (E : Entity_Id) return Entity_Id;
5867          --  Follow chain of renamings to the ultimate ancestor
5868 
5869          ---------------------
5870          -- Original_Entity --
5871          ---------------------
5872 
5873          function Original_Entity (E : Entity_Id) return Entity_Id is
5874             Orig : Entity_Id;
5875 
5876          begin
5877             Orig := E;
5878             while Nkind (Parent (Orig)) = N_Object_Renaming_Declaration
5879               and then Present (Renamed_Object (Orig))
5880               and then Is_Entity_Name (Renamed_Object (Orig))
5881             loop
5882                Orig := Entity (Renamed_Object (Orig));
5883             end loop;
5884 
5885             return Orig;
5886          end Original_Entity;
5887 
5888       --  Start of processing for Same_Instantiated_Variable
5889 
5890       begin
5891          return Ekind (E1) = Ekind (E2)
5892            and then Original_Entity (E1) = Original_Entity (E2);
5893       end Same_Instantiated_Variable;
5894 
5895    --  Start of processing for Check_Formal_Package_Instance
5896 
5897    begin
5898       while Present (E1) and then Present (E2) loop
5899          exit when Ekind (E1) = E_Package
5900            and then Renamed_Entity (E1) = Renamed_Entity (Actual_Pack);
5901 
5902          --  If the formal is the renaming of the formal package, this
5903          --  is the end of its formal part, which may occur before the
5904          --  end of the formal part in the actual in the presence of
5905          --  defaulted parameters in the formal package.
5906 
5907          exit when Nkind (Parent (E2)) = N_Package_Renaming_Declaration
5908            and then Renamed_Entity (E2) = Scope (E2);
5909 
5910          --  The analysis of the actual may generate additional internal
5911          --  entities. If the formal is defaulted, there is no corresponding
5912          --  analysis and the internal entities must be skipped, until we
5913          --  find corresponding entities again.
5914 
5915          if Comes_From_Source (E2)
5916            and then not Comes_From_Source (E1)
5917            and then Chars (E1) /= Chars (E2)
5918          then
5919             while Present (E1) and then Chars (E1) /= Chars (E2) loop
5920                Next_Entity (E1);
5921             end loop;
5922          end if;
5923 
5924          if No (E1) then
5925             return;
5926 
5927          --  If the formal entity comes from a formal declaration, it was
5928          --  defaulted in the formal package, and no check is needed on it.
5929 
5930          elsif Nkind_In (Original_Node (Parent (E2)),
5931                          N_Formal_Object_Declaration,
5932                          N_Formal_Type_Declaration)
5933          then
5934             goto Next_E;
5935 
5936          --  Ditto for defaulted formal subprograms.
5937 
5938          elsif Is_Overloadable (E1)
5939            and then Nkind (Unit_Declaration_Node (E2)) in
5940                       N_Formal_Subprogram_Declaration
5941          then
5942             goto Next_E;
5943 
5944          elsif Is_Type (E1) then
5945 
5946             --  Subtypes must statically match. E1, E2 are the local entities
5947             --  that are subtypes of the actuals. Itypes generated for other
5948             --  parameters need not be checked, the check will be performed
5949             --  on the parameters themselves.
5950 
5951             --  If E2 is a formal type declaration, it is a defaulted parameter
5952             --  and needs no checking.
5953 
5954             if not Is_Itype (E1) and then not Is_Itype (E2) then
5955                Check_Mismatch
5956                  (not Is_Type (E2)
5957                    or else Etype (E1) /= Etype (E2)
5958                    or else not Subtypes_Statically_Match (E1, E2));
5959             end if;
5960 
5961          elsif Ekind (E1) = E_Constant then
5962 
5963             --  IN parameters must denote the same static value, or the same
5964             --  constant, or the literal null.
5965 
5966             Expr1 := Expression (Parent (E1));
5967 
5968             if Ekind (E2) /= E_Constant then
5969                Check_Mismatch (True);
5970                goto Next_E;
5971             else
5972                Expr2 := Expression (Parent (E2));
5973             end if;
5974 
5975             if Is_OK_Static_Expression (Expr1) then
5976                if not Is_OK_Static_Expression (Expr2) then
5977                   Check_Mismatch (True);
5978 
5979                elsif Is_Discrete_Type (Etype (E1)) then
5980                   declare
5981                      V1 : constant Uint := Expr_Value (Expr1);
5982                      V2 : constant Uint := Expr_Value (Expr2);
5983                   begin
5984                      Check_Mismatch (V1 /= V2);
5985                   end;
5986 
5987                elsif Is_Real_Type (Etype (E1)) then
5988                   declare
5989                      V1 : constant Ureal := Expr_Value_R (Expr1);
5990                      V2 : constant Ureal := Expr_Value_R (Expr2);
5991                   begin
5992                      Check_Mismatch (V1 /= V2);
5993                   end;
5994 
5995                elsif Is_String_Type (Etype (E1))
5996                  and then Nkind (Expr1) = N_String_Literal
5997                then
5998                   if Nkind (Expr2) /= N_String_Literal then
5999                      Check_Mismatch (True);
6000                   else
6001                      Check_Mismatch
6002                        (not String_Equal (Strval (Expr1), Strval (Expr2)));
6003                   end if;
6004                end if;
6005 
6006             elsif Is_Entity_Name (Expr1) then
6007                if Is_Entity_Name (Expr2) then
6008                   if Entity (Expr1) = Entity (Expr2) then
6009                      null;
6010                   else
6011                      Check_Mismatch
6012                        (not Same_Instantiated_Constant
6013                          (Entity (Expr1), Entity (Expr2)));
6014                   end if;
6015 
6016                else
6017                   Check_Mismatch (True);
6018                end if;
6019 
6020             elsif Is_Entity_Name (Original_Node (Expr1))
6021               and then Is_Entity_Name (Expr2)
6022               and then Same_Instantiated_Constant
6023                          (Entity (Original_Node (Expr1)), Entity (Expr2))
6024             then
6025                null;
6026 
6027             elsif Nkind (Expr1) = N_Null then
6028                Check_Mismatch (Nkind (Expr1) /= N_Null);
6029 
6030             else
6031                Check_Mismatch (True);
6032             end if;
6033 
6034          elsif Ekind (E1) = E_Variable then
6035             Check_Mismatch (not Same_Instantiated_Variable (E1, E2));
6036 
6037          elsif Ekind (E1) = E_Package then
6038             Check_Mismatch
6039               (Ekind (E1) /= Ekind (E2)
6040                 or else Renamed_Object (E1) /= Renamed_Object (E2));
6041 
6042          elsif Is_Overloadable (E1) then
6043 
6044             --  Verify that the actual subprograms match. Note that actuals
6045             --  that are attributes are rewritten as subprograms. If the
6046             --  subprogram in the formal package is defaulted, no check is
6047             --  needed. Note that this can only happen in Ada 2005 when the
6048             --  formal package can be partially parameterized.
6049 
6050             if Nkind (Unit_Declaration_Node (E1)) =
6051                                            N_Subprogram_Renaming_Declaration
6052               and then From_Default (Unit_Declaration_Node (E1))
6053             then
6054                null;
6055 
6056             --  If the formal package has an "others"  box association that
6057             --  covers this formal, there is no need for a check either.
6058 
6059             elsif Nkind (Unit_Declaration_Node (E2)) in
6060                     N_Formal_Subprogram_Declaration
6061               and then Box_Present (Unit_Declaration_Node (E2))
6062             then
6063                null;
6064 
6065             --  No check needed if subprogram is a defaulted null procedure
6066 
6067             elsif No (Alias (E2))
6068               and then Ekind (E2) = E_Procedure
6069               and then
6070                 Null_Present (Specification (Unit_Declaration_Node (E2)))
6071             then
6072                null;
6073 
6074             --  Otherwise the actual in the formal and the actual in the
6075             --  instantiation of the formal must match, up to renamings.
6076 
6077             else
6078                Check_Mismatch
6079                  (Ekind (E2) /= Ekind (E1)
6080                     or else not Same_Instantiated_Function (E1, E2));
6081             end if;
6082 
6083          else
6084             raise Program_Error;
6085          end if;
6086 
6087          <<Next_E>>
6088             Next_Entity (E1);
6089             Next_Entity (E2);
6090       end loop;
6091    end Check_Formal_Package_Instance;
6092 
6093    ---------------------------
6094    -- Check_Formal_Packages --
6095    ---------------------------
6096 
6097    procedure Check_Formal_Packages (P_Id : Entity_Id) is
6098       E           : Entity_Id;
6099       Formal_P    : Entity_Id;
6100       Formal_Decl : Node_Id;
6101 
6102    begin
6103       --  Iterate through the declarations in the instance, looking for package
6104       --  renaming declarations that denote instances of formal packages. Stop
6105       --  when we find the renaming of the current package itself. The
6106       --  declaration for a formal package without a box is followed by an
6107       --  internal entity that repeats the instantiation.
6108 
6109       E := First_Entity (P_Id);
6110       while Present (E) loop
6111          if Ekind (E) = E_Package then
6112             if Renamed_Object (E) = P_Id then
6113                exit;
6114 
6115             elsif Nkind (Parent (E)) /= N_Package_Renaming_Declaration then
6116                null;
6117 
6118             else
6119                Formal_Decl := Parent (Associated_Formal_Package (E));
6120 
6121                --  Nothing to check if the formal has a box or an others_clause
6122                --  (necessarily with a box).
6123 
6124                if Box_Present (Formal_Decl) then
6125                   null;
6126 
6127                elsif Nkind (First (Generic_Associations (Formal_Decl))) =
6128                        N_Others_Choice
6129                then
6130                   --  The internal validating package was generated but formal
6131                   --  and instance are known to be compatible.
6132 
6133                   Formal_P := Next_Entity (E);
6134                   Remove (Unit_Declaration_Node (Formal_P));
6135 
6136                else
6137                   Formal_P := Next_Entity (E);
6138                   Check_Formal_Package_Instance (Formal_P, E);
6139 
6140                   --  After checking, remove the internal validating package.
6141                   --  It is only needed for semantic checks, and as it may
6142                   --  contain generic formal declarations it should not reach
6143                   --  gigi.
6144 
6145                   Remove (Unit_Declaration_Node (Formal_P));
6146                end if;
6147             end if;
6148          end if;
6149 
6150          Next_Entity (E);
6151       end loop;
6152    end Check_Formal_Packages;
6153 
6154    ---------------------------------
6155    -- Check_Forward_Instantiation --
6156    ---------------------------------
6157 
6158    procedure Check_Forward_Instantiation (Decl : Node_Id) is
6159       S        : Entity_Id;
6160       Gen_Comp : Entity_Id := Cunit_Entity (Get_Source_Unit (Decl));
6161 
6162    begin
6163       --  The instantiation appears before the generic body if we are in the
6164       --  scope of the unit containing the generic, either in its spec or in
6165       --  the package body, and before the generic body.
6166 
6167       if Ekind (Gen_Comp) = E_Package_Body then
6168          Gen_Comp := Spec_Entity (Gen_Comp);
6169       end if;
6170 
6171       if In_Open_Scopes (Gen_Comp)
6172         and then No (Corresponding_Body (Decl))
6173       then
6174          S := Current_Scope;
6175 
6176          while Present (S)
6177            and then not Is_Compilation_Unit (S)
6178            and then not Is_Child_Unit (S)
6179          loop
6180             if Ekind (S) = E_Package then
6181                Set_Has_Forward_Instantiation (S);
6182             end if;
6183 
6184             S := Scope (S);
6185          end loop;
6186       end if;
6187    end Check_Forward_Instantiation;
6188 
6189    ---------------------------
6190    -- Check_Generic_Actuals --
6191    ---------------------------
6192 
6193    --  The visibility of the actuals may be different between the point of
6194    --  generic instantiation and the instantiation of the body.
6195 
6196    procedure Check_Generic_Actuals
6197      (Instance      : Entity_Id;
6198       Is_Formal_Box : Boolean)
6199    is
6200       E      : Entity_Id;
6201       Astype : Entity_Id;
6202 
6203       function Denotes_Previous_Actual (Typ : Entity_Id) return Boolean;
6204       --  For a formal that is an array type, the component type is often a
6205       --  previous formal in the same unit. The privacy status of the component
6206       --  type will have been examined earlier in the traversal of the
6207       --  corresponding actuals, and this status should not be modified for
6208       --  the array (sub)type itself. However, if the base type of the array
6209       --  (sub)type is private, its full view must be restored in the body to
6210       --  be consistent with subsequent index subtypes, etc.
6211       --
6212       --  To detect this case we have to rescan the list of formals, which is
6213       --  usually short enough to ignore the resulting inefficiency.
6214 
6215       -----------------------------
6216       -- Denotes_Previous_Actual --
6217       -----------------------------
6218 
6219       function Denotes_Previous_Actual (Typ : Entity_Id) return Boolean is
6220          Prev : Entity_Id;
6221 
6222       begin
6223          Prev := First_Entity (Instance);
6224          while Present (Prev) loop
6225             if Is_Type (Prev)
6226               and then Nkind (Parent (Prev)) = N_Subtype_Declaration
6227               and then Is_Entity_Name (Subtype_Indication (Parent (Prev)))
6228               and then Entity (Subtype_Indication (Parent (Prev))) = Typ
6229             then
6230                return True;
6231 
6232             elsif Prev = E then
6233                return False;
6234 
6235             else
6236                Next_Entity (Prev);
6237             end if;
6238          end loop;
6239 
6240          return False;
6241       end Denotes_Previous_Actual;
6242 
6243    --  Start of processing for Check_Generic_Actuals
6244 
6245    begin
6246       E := First_Entity (Instance);
6247       while Present (E) loop
6248          if Is_Type (E)
6249            and then Nkind (Parent (E)) = N_Subtype_Declaration
6250            and then Scope (Etype (E)) /= Instance
6251            and then Is_Entity_Name (Subtype_Indication (Parent (E)))
6252          then
6253             if Is_Array_Type (E)
6254               and then not Is_Private_Type (Etype (E))
6255               and then Denotes_Previous_Actual (Component_Type (E))
6256             then
6257                null;
6258             else
6259                Check_Private_View (Subtype_Indication (Parent (E)));
6260             end if;
6261 
6262             Set_Is_Generic_Actual_Type (E, True);
6263             Set_Is_Hidden (E, False);
6264             Set_Is_Potentially_Use_Visible (E,
6265               In_Use (Instance));
6266 
6267             --  We constructed the generic actual type as a subtype of the
6268             --  supplied type. This means that it normally would not inherit
6269             --  subtype specific attributes of the actual, which is wrong for
6270             --  the generic case.
6271 
6272             Astype := Ancestor_Subtype (E);
6273 
6274             if No (Astype) then
6275 
6276                --  This can happen when E is an itype that is the full view of
6277                --  a private type completed, e.g. with a constrained array. In
6278                --  that case, use the first subtype, which will carry size
6279                --  information. The base type itself is unconstrained and will
6280                --  not carry it.
6281 
6282                Astype := First_Subtype (E);
6283             end if;
6284 
6285             Set_Size_Info      (E,                (Astype));
6286             Set_RM_Size        (E, RM_Size        (Astype));
6287             Set_First_Rep_Item (E, First_Rep_Item (Astype));
6288 
6289             if Is_Discrete_Or_Fixed_Point_Type (E) then
6290                Set_RM_Size (E, RM_Size (Astype));
6291 
6292             --  In nested instances, the base type of an access actual may
6293             --  itself be private, and need to be exchanged.
6294 
6295             elsif Is_Access_Type (E)
6296               and then Is_Private_Type (Etype (E))
6297             then
6298                Check_Private_View
6299                  (New_Occurrence_Of (Etype (E), Sloc (Instance)));
6300             end if;
6301 
6302          elsif Ekind (E) = E_Package then
6303 
6304             --  If this is the renaming for the current instance, we're done.
6305             --  Otherwise it is a formal package. If the corresponding formal
6306             --  was declared with a box, the (instantiations of the) generic
6307             --  formal part are also visible. Otherwise, ignore the entity
6308             --  created to validate the actuals.
6309 
6310             if Renamed_Object (E) = Instance then
6311                exit;
6312 
6313             elsif Nkind (Parent (E)) /= N_Package_Renaming_Declaration then
6314                null;
6315 
6316             --  The visibility of a formal of an enclosing generic is already
6317             --  correct.
6318 
6319             elsif Denotes_Formal_Package (E) then
6320                null;
6321 
6322             elsif Present (Associated_Formal_Package (E))
6323               and then not Is_Generic_Formal (E)
6324             then
6325                if Box_Present (Parent (Associated_Formal_Package (E))) then
6326                   Check_Generic_Actuals (Renamed_Object (E), True);
6327 
6328                else
6329                   Check_Generic_Actuals (Renamed_Object (E), False);
6330                end if;
6331 
6332                Set_Is_Hidden (E, False);
6333             end if;
6334 
6335          --  If this is a subprogram instance (in a wrapper package) the
6336          --  actual is fully visible.
6337 
6338          elsif Is_Wrapper_Package (Instance) then
6339             Set_Is_Hidden (E, False);
6340 
6341          --  If the formal package is declared with a box, or if the formal
6342          --  parameter is defaulted, it is visible in the body.
6343 
6344          elsif Is_Formal_Box or else Is_Visible_Formal (E) then
6345             Set_Is_Hidden (E, False);
6346          end if;
6347 
6348          if Ekind (E) = E_Constant then
6349 
6350             --  If the type of the actual is a private type declared in the
6351             --  enclosing scope of the generic unit, the body of the generic
6352             --  sees the full view of the type (because it has to appear in
6353             --  the corresponding package body). If the type is private now,
6354             --  exchange views to restore the proper visiblity in the instance.
6355 
6356             declare
6357                Typ : constant Entity_Id := Base_Type (Etype (E));
6358                --  The type of the actual
6359 
6360                Gen_Id : Entity_Id;
6361                --  The generic unit
6362 
6363                Parent_Scope : Entity_Id;
6364                --  The enclosing scope of the generic unit
6365 
6366             begin
6367                if Is_Wrapper_Package (Instance) then
6368                   Gen_Id :=
6369                     Generic_Parent
6370                       (Specification
6371                         (Unit_Declaration_Node
6372                           (Related_Instance (Instance))));
6373                else
6374                   Gen_Id :=
6375                     Generic_Parent (Package_Specification (Instance));
6376                end if;
6377 
6378                Parent_Scope := Scope (Gen_Id);
6379 
6380                --  The exchange is only needed if the generic is defined
6381                --  within a package which is not a common ancestor of the
6382                --  scope of the instance, and is not already in scope.
6383 
6384                if Is_Private_Type (Typ)
6385                  and then Scope (Typ) = Parent_Scope
6386                  and then Scope (Instance) /= Parent_Scope
6387                  and then Ekind (Parent_Scope) = E_Package
6388                  and then not Is_Child_Unit (Gen_Id)
6389                then
6390                   Switch_View (Typ);
6391 
6392                   --  If the type of the entity is a subtype, it may also have
6393                   --  to be made visible, together with the base type of its
6394                   --  full view, after exchange.
6395 
6396                   if Is_Private_Type (Etype (E)) then
6397                      Switch_View (Etype (E));
6398                      Switch_View (Base_Type (Etype (E)));
6399                   end if;
6400                end if;
6401             end;
6402          end if;
6403 
6404          Next_Entity (E);
6405       end loop;
6406    end Check_Generic_Actuals;
6407 
6408    ------------------------------
6409    -- Check_Generic_Child_Unit --
6410    ------------------------------
6411 
6412    procedure Check_Generic_Child_Unit
6413      (Gen_Id           : Node_Id;
6414       Parent_Installed : in out Boolean)
6415    is
6416       Loc      : constant Source_Ptr := Sloc (Gen_Id);
6417       Gen_Par  : Entity_Id := Empty;
6418       E        : Entity_Id;
6419       Inst_Par : Entity_Id;
6420       S        : Node_Id;
6421 
6422       function Find_Generic_Child
6423         (Scop : Entity_Id;
6424          Id   : Node_Id) return Entity_Id;
6425       --  Search generic parent for possible child unit with the given name
6426 
6427       function In_Enclosing_Instance return Boolean;
6428       --  Within an instance of the parent, the child unit may be denoted by
6429       --  a simple name, or an abbreviated expanded name. Examine enclosing
6430       --  scopes to locate a possible parent instantiation.
6431 
6432       ------------------------
6433       -- Find_Generic_Child --
6434       ------------------------
6435 
6436       function Find_Generic_Child
6437         (Scop : Entity_Id;
6438          Id   : Node_Id) return Entity_Id
6439       is
6440          E : Entity_Id;
6441 
6442       begin
6443          --  If entity of name is already set, instance has already been
6444          --  resolved, e.g. in an enclosing instantiation.
6445 
6446          if Present (Entity (Id)) then
6447             if Scope (Entity (Id)) = Scop then
6448                return Entity (Id);
6449             else
6450                return Empty;
6451             end if;
6452 
6453          else
6454             E := First_Entity (Scop);
6455             while Present (E) loop
6456                if Chars (E) = Chars (Id)
6457                  and then Is_Child_Unit (E)
6458                then
6459                   if Is_Child_Unit (E)
6460                     and then not Is_Visible_Lib_Unit (E)
6461                   then
6462                      Error_Msg_NE
6463                        ("generic child unit& is not visible", Gen_Id, E);
6464                   end if;
6465 
6466                   Set_Entity (Id, E);
6467                   return E;
6468                end if;
6469 
6470                Next_Entity (E);
6471             end loop;
6472 
6473             return Empty;
6474          end if;
6475       end Find_Generic_Child;
6476 
6477       ---------------------------
6478       -- In_Enclosing_Instance --
6479       ---------------------------
6480 
6481       function In_Enclosing_Instance return Boolean is
6482          Enclosing_Instance : Node_Id;
6483          Instance_Decl      : Node_Id;
6484 
6485       begin
6486          --  We do not inline any call that contains instantiations, except
6487          --  for instantiations of Unchecked_Conversion, so if we are within
6488          --  an inlined body the current instance does not require parents.
6489 
6490          if In_Inlined_Body then
6491             pragma Assert (Chars (Gen_Id) = Name_Unchecked_Conversion);
6492             return False;
6493          end if;
6494 
6495          --  Loop to check enclosing scopes
6496 
6497          Enclosing_Instance := Current_Scope;
6498          while Present (Enclosing_Instance) loop
6499             Instance_Decl := Unit_Declaration_Node (Enclosing_Instance);
6500 
6501             if Ekind (Enclosing_Instance) = E_Package
6502               and then Is_Generic_Instance (Enclosing_Instance)
6503               and then Present
6504                 (Generic_Parent (Specification (Instance_Decl)))
6505             then
6506                --  Check whether the generic we are looking for is a child of
6507                --  this instance.
6508 
6509                E := Find_Generic_Child
6510                       (Generic_Parent (Specification (Instance_Decl)), Gen_Id);
6511                exit when Present (E);
6512 
6513             else
6514                E := Empty;
6515             end if;
6516 
6517             Enclosing_Instance := Scope (Enclosing_Instance);
6518          end loop;
6519 
6520          if No (E) then
6521 
6522             --  Not a child unit
6523 
6524             Analyze (Gen_Id);
6525             return False;
6526 
6527          else
6528             Rewrite (Gen_Id,
6529               Make_Expanded_Name (Loc,
6530                 Chars         => Chars (E),
6531                 Prefix        => New_Occurrence_Of (Enclosing_Instance, Loc),
6532                 Selector_Name => New_Occurrence_Of (E, Loc)));
6533 
6534             Set_Entity (Gen_Id, E);
6535             Set_Etype  (Gen_Id, Etype (E));
6536             Parent_Installed := False;      -- Already in scope.
6537             return True;
6538          end if;
6539       end In_Enclosing_Instance;
6540 
6541    --  Start of processing for Check_Generic_Child_Unit
6542 
6543    begin
6544       --  If the name of the generic is given by a selected component, it may
6545       --  be the name of a generic child unit, and the prefix is the name of an
6546       --  instance of the parent, in which case the child unit must be visible.
6547       --  If this instance is not in scope, it must be placed there and removed
6548       --  after instantiation, because what is being instantiated is not the
6549       --  original child, but the corresponding child present in the instance
6550       --  of the parent.
6551 
6552       --  If the child is instantiated within the parent, it can be given by
6553       --  a simple name. In this case the instance is already in scope, but
6554       --  the child generic must be recovered from the generic parent as well.
6555 
6556       if Nkind (Gen_Id) = N_Selected_Component then
6557          S := Selector_Name (Gen_Id);
6558          Analyze (Prefix (Gen_Id));
6559          Inst_Par := Entity (Prefix (Gen_Id));
6560 
6561          if Ekind (Inst_Par) = E_Package
6562            and then Present (Renamed_Object (Inst_Par))
6563          then
6564             Inst_Par := Renamed_Object (Inst_Par);
6565          end if;
6566 
6567          if Ekind (Inst_Par) = E_Package then
6568             if Nkind (Parent (Inst_Par)) = N_Package_Specification then
6569                Gen_Par := Generic_Parent (Parent (Inst_Par));
6570 
6571             elsif Nkind (Parent (Inst_Par)) = N_Defining_Program_Unit_Name
6572               and then
6573                 Nkind (Parent (Parent (Inst_Par))) = N_Package_Specification
6574             then
6575                Gen_Par := Generic_Parent (Parent (Parent (Inst_Par)));
6576             end if;
6577 
6578          elsif Ekind (Inst_Par) = E_Generic_Package
6579            and then Nkind (Parent (Gen_Id)) = N_Formal_Package_Declaration
6580          then
6581             --  A formal package may be a real child package, and not the
6582             --  implicit instance within a parent. In this case the child is
6583             --  not visible and has to be retrieved explicitly as well.
6584 
6585             Gen_Par := Inst_Par;
6586          end if;
6587 
6588          if Present (Gen_Par) then
6589 
6590             --  The prefix denotes an instantiation. The entity itself may be a
6591             --  nested generic, or a child unit.
6592 
6593             E := Find_Generic_Child (Gen_Par, S);
6594 
6595             if Present (E) then
6596                Change_Selected_Component_To_Expanded_Name (Gen_Id);
6597                Set_Entity (Gen_Id, E);
6598                Set_Etype (Gen_Id, Etype (E));
6599                Set_Entity (S, E);
6600                Set_Etype (S, Etype (E));
6601 
6602                --  Indicate that this is a reference to the parent
6603 
6604                if In_Extended_Main_Source_Unit (Gen_Id) then
6605                   Set_Is_Instantiated (Inst_Par);
6606                end if;
6607 
6608                --  A common mistake is to replicate the naming scheme of a
6609                --  hierarchy by instantiating a generic child directly, rather
6610                --  than the implicit child in a parent instance:
6611 
6612                --  generic .. package Gpar is ..
6613                --  generic .. package Gpar.Child is ..
6614                --  package Par is new Gpar ();
6615 
6616                --  with Gpar.Child;
6617                --  package Par.Child is new Gpar.Child ();
6618                --                           rather than Par.Child
6619 
6620                --  In this case the instantiation is within Par, which is an
6621                --  instance, but Gpar does not denote Par because we are not IN
6622                --  the instance of Gpar, so this is illegal. The test below
6623                --  recognizes this particular case.
6624 
6625                if Is_Child_Unit (E)
6626                  and then not Comes_From_Source (Entity (Prefix (Gen_Id)))
6627                  and then (not In_Instance
6628                             or else Nkind (Parent (Parent (Gen_Id))) =
6629                                                          N_Compilation_Unit)
6630                then
6631                   Error_Msg_N
6632                     ("prefix of generic child unit must be instance of parent",
6633                       Gen_Id);
6634                end if;
6635 
6636                if not In_Open_Scopes (Inst_Par)
6637                  and then Nkind (Parent (Gen_Id)) not in
6638                                            N_Generic_Renaming_Declaration
6639                then
6640                   Install_Parent (Inst_Par);
6641                   Parent_Installed := True;
6642 
6643                elsif In_Open_Scopes (Inst_Par) then
6644 
6645                   --  If the parent is already installed, install the actuals
6646                   --  for its formal packages. This is necessary when the child
6647                   --  instance is a child of the parent instance: in this case,
6648                   --  the parent is placed on the scope stack but the formal
6649                   --  packages are not made visible.
6650 
6651                   Install_Formal_Packages (Inst_Par);
6652                end if;
6653 
6654             else
6655                --  If the generic parent does not contain an entity that
6656                --  corresponds to the selector, the instance doesn't either.
6657                --  Analyzing the node will yield the appropriate error message.
6658                --  If the entity is not a child unit, then it is an inner
6659                --  generic in the parent.
6660 
6661                Analyze (Gen_Id);
6662             end if;
6663 
6664          else
6665             Analyze (Gen_Id);
6666 
6667             if Is_Child_Unit (Entity (Gen_Id))
6668               and then
6669                 Nkind (Parent (Gen_Id)) not in N_Generic_Renaming_Declaration
6670               and then not In_Open_Scopes (Inst_Par)
6671             then
6672                Install_Parent (Inst_Par);
6673                Parent_Installed := True;
6674 
6675             --  The generic unit may be the renaming of the implicit child
6676             --  present in an instance. In that case the parent instance is
6677             --  obtained from the name of the renamed entity.
6678 
6679             elsif Ekind (Entity (Gen_Id)) = E_Generic_Package
6680               and then Present (Renamed_Entity (Entity (Gen_Id)))
6681               and then Is_Child_Unit (Renamed_Entity (Entity (Gen_Id)))
6682             then
6683                declare
6684                   Renamed_Package : constant Node_Id :=
6685                                       Name (Parent (Entity (Gen_Id)));
6686                begin
6687                   if Nkind (Renamed_Package) = N_Expanded_Name then
6688                      Inst_Par := Entity (Prefix (Renamed_Package));
6689                      Install_Parent (Inst_Par);
6690                      Parent_Installed := True;
6691                   end if;
6692                end;
6693             end if;
6694          end if;
6695 
6696       elsif Nkind (Gen_Id) = N_Expanded_Name then
6697 
6698          --  Entity already present, analyze prefix, whose meaning may be an
6699          --  instance in the current context. If it is an instance of a
6700          --  relative within another, the proper parent may still have to be
6701          --  installed, if they are not of the same generation.
6702 
6703          Analyze (Prefix (Gen_Id));
6704 
6705          --  Prevent cascaded errors
6706 
6707          if Etype (Prefix (Gen_Id)) = Any_Type then
6708             return;
6709          end if;
6710 
6711          --  In the unlikely case that a local declaration hides the name of
6712          --  the parent package, locate it on the homonym chain. If the context
6713          --  is an instance of the parent, the renaming entity is flagged as
6714          --  such.
6715 
6716          Inst_Par := Entity (Prefix (Gen_Id));
6717          while Present (Inst_Par)
6718            and then not Is_Package_Or_Generic_Package (Inst_Par)
6719          loop
6720             Inst_Par := Homonym (Inst_Par);
6721          end loop;
6722 
6723          pragma Assert (Present (Inst_Par));
6724          Set_Entity (Prefix (Gen_Id), Inst_Par);
6725 
6726          if In_Enclosing_Instance then
6727             null;
6728 
6729          elsif Present (Entity (Gen_Id))
6730            and then Is_Child_Unit (Entity (Gen_Id))
6731            and then not In_Open_Scopes (Inst_Par)
6732          then
6733             Install_Parent (Inst_Par);
6734             Parent_Installed := True;
6735          end if;
6736 
6737       elsif In_Enclosing_Instance then
6738 
6739          --  The child unit is found in some enclosing scope
6740 
6741          null;
6742 
6743       else
6744          Analyze (Gen_Id);
6745 
6746          --  If this is the renaming of the implicit child in a parent
6747          --  instance, recover the parent name and install it.
6748 
6749          if Is_Entity_Name (Gen_Id) then
6750             E := Entity (Gen_Id);
6751 
6752             if Is_Generic_Unit (E)
6753               and then Nkind (Parent (E)) in N_Generic_Renaming_Declaration
6754               and then Is_Child_Unit (Renamed_Object (E))
6755               and then Is_Generic_Unit (Scope (Renamed_Object (E)))
6756               and then Nkind (Name (Parent (E))) = N_Expanded_Name
6757             then
6758                Rewrite (Gen_Id, New_Copy_Tree (Name (Parent (E))));
6759                Inst_Par := Entity (Prefix (Gen_Id));
6760 
6761                if not In_Open_Scopes (Inst_Par) then
6762                   Install_Parent (Inst_Par);
6763                   Parent_Installed := True;
6764                end if;
6765 
6766             --  If it is a child unit of a non-generic parent, it may be
6767             --  use-visible and given by a direct name. Install parent as
6768             --  for other cases.
6769 
6770             elsif Is_Generic_Unit (E)
6771               and then Is_Child_Unit (E)
6772               and then
6773                 Nkind (Parent (Gen_Id)) not in N_Generic_Renaming_Declaration
6774               and then not Is_Generic_Unit (Scope (E))
6775             then
6776                if not In_Open_Scopes (Scope (E)) then
6777                   Install_Parent (Scope (E));
6778                   Parent_Installed := True;
6779                end if;
6780             end if;
6781          end if;
6782       end if;
6783    end Check_Generic_Child_Unit;
6784 
6785    -----------------------------
6786    -- Check_Hidden_Child_Unit --
6787    -----------------------------
6788 
6789    procedure Check_Hidden_Child_Unit
6790      (N           : Node_Id;
6791       Gen_Unit    : Entity_Id;
6792       Act_Decl_Id : Entity_Id)
6793    is
6794       Gen_Id : constant Node_Id := Name (N);
6795 
6796    begin
6797       if Is_Child_Unit (Gen_Unit)
6798         and then Is_Child_Unit (Act_Decl_Id)
6799         and then Nkind (Gen_Id) = N_Expanded_Name
6800         and then Entity (Prefix (Gen_Id)) = Scope (Act_Decl_Id)
6801         and then Chars (Gen_Unit) = Chars (Act_Decl_Id)
6802       then
6803          Error_Msg_Node_2 := Scope (Act_Decl_Id);
6804          Error_Msg_NE
6805            ("generic unit & is implicitly declared in &",
6806             Defining_Unit_Name (N), Gen_Unit);
6807          Error_Msg_N ("\instance must have different name",
6808            Defining_Unit_Name (N));
6809       end if;
6810    end Check_Hidden_Child_Unit;
6811 
6812    ------------------------
6813    -- Check_Private_View --
6814    ------------------------
6815 
6816    procedure Check_Private_View (N : Node_Id) is
6817       T : constant Entity_Id := Etype (N);
6818       BT : Entity_Id;
6819 
6820    begin
6821       --  Exchange views if the type was not private in the generic but is
6822       --  private at the point of instantiation. Do not exchange views if
6823       --  the scope of the type is in scope. This can happen if both generic
6824       --  and instance are sibling units, or if type is defined in a parent.
6825       --  In this case the visibility of the type will be correct for all
6826       --  semantic checks.
6827 
6828       if Present (T) then
6829          BT := Base_Type (T);
6830 
6831          if Is_Private_Type (T)
6832            and then not Has_Private_View (N)
6833            and then Present (Full_View (T))
6834            and then not In_Open_Scopes (Scope (T))
6835          then
6836             --  In the generic, the full type was visible. Save the private
6837             --  entity, for subsequent exchange.
6838 
6839             Switch_View (T);
6840 
6841          elsif Has_Private_View (N)
6842            and then not Is_Private_Type (T)
6843            and then not Has_Been_Exchanged (T)
6844            and then Etype (Get_Associated_Node (N)) /= T
6845          then
6846             --  Only the private declaration was visible in the generic. If
6847             --  the type appears in a subtype declaration, the subtype in the
6848             --  instance must have a view compatible with that of its parent,
6849             --  which must be exchanged (see corresponding code in Restore_
6850             --  Private_Views). Otherwise, if the type is defined in a parent
6851             --  unit, leave full visibility within instance, which is safe.
6852 
6853             if In_Open_Scopes (Scope (Base_Type (T)))
6854               and then not Is_Private_Type (Base_Type (T))
6855               and then Comes_From_Source (Base_Type (T))
6856             then
6857                null;
6858 
6859             elsif Nkind (Parent (N)) = N_Subtype_Declaration
6860               or else not In_Private_Part (Scope (Base_Type (T)))
6861             then
6862                Prepend_Elmt (T, Exchanged_Views);
6863                Exchange_Declarations (Etype (Get_Associated_Node (N)));
6864             end if;
6865 
6866          --  For composite types with inconsistent representation exchange
6867          --  component types accordingly.
6868 
6869          elsif Is_Access_Type (T)
6870            and then Is_Private_Type (Designated_Type (T))
6871            and then not Has_Private_View (N)
6872            and then Present (Full_View (Designated_Type (T)))
6873          then
6874             Switch_View (Designated_Type (T));
6875 
6876          elsif Is_Array_Type (T) then
6877             if Is_Private_Type (Component_Type (T))
6878               and then not Has_Private_View (N)
6879               and then Present (Full_View (Component_Type (T)))
6880             then
6881                Switch_View (Component_Type (T));
6882             end if;
6883 
6884             --  The normal exchange mechanism relies on the setting of a
6885             --  flag on the reference in the generic. However, an additional
6886             --  mechanism is needed for types that are not explicitly
6887             --  mentioned in the generic, but may be needed in expanded code
6888             --  in the instance. This includes component types of arrays and
6889             --  designated types of access types. This processing must also
6890             --  include the index types of arrays which we take care of here.
6891 
6892             declare
6893                Indx : Node_Id;
6894                Typ  : Entity_Id;
6895 
6896             begin
6897                Indx := First_Index (T);
6898                while Present (Indx) loop
6899                   Typ := Base_Type (Etype (Indx));
6900 
6901                   if Is_Private_Type (Typ)
6902                     and then Present (Full_View (Typ))
6903                   then
6904                      Switch_View (Typ);
6905                   end if;
6906 
6907                   Next_Index (Indx);
6908                end loop;
6909             end;
6910 
6911          elsif Is_Private_Type (T)
6912            and then Present (Full_View (T))
6913            and then Is_Array_Type (Full_View (T))
6914            and then Is_Private_Type (Component_Type (Full_View (T)))
6915          then
6916             Switch_View (T);
6917 
6918          --  Finally, a non-private subtype may have a private base type, which
6919          --  must be exchanged for consistency. This can happen when a package
6920          --  body is instantiated, when the scope stack is empty but in fact
6921          --  the subtype and the base type are declared in an enclosing scope.
6922 
6923          --  Note that in this case we introduce an inconsistency in the view
6924          --  set, because we switch the base type BT, but there could be some
6925          --  private dependent subtypes of BT which remain unswitched. Such
6926          --  subtypes might need to be switched at a later point (see specific
6927          --  provision for that case in Switch_View).
6928 
6929          elsif not Is_Private_Type (T)
6930            and then not Has_Private_View (N)
6931            and then Is_Private_Type (BT)
6932            and then Present (Full_View (BT))
6933            and then not Is_Generic_Type (BT)
6934            and then not In_Open_Scopes (BT)
6935          then
6936             Prepend_Elmt (Full_View (BT), Exchanged_Views);
6937             Exchange_Declarations (BT);
6938          end if;
6939       end if;
6940    end Check_Private_View;
6941 
6942    -----------------------------
6943    -- Check_Hidden_Primitives --
6944    -----------------------------
6945 
6946    function Check_Hidden_Primitives (Assoc_List : List_Id) return Elist_Id is
6947       Actual : Node_Id;
6948       Gen_T  : Entity_Id;
6949       Result : Elist_Id := No_Elist;
6950 
6951    begin
6952       if No (Assoc_List) then
6953          return No_Elist;
6954       end if;
6955 
6956       --  Traverse the list of associations between formals and actuals
6957       --  searching for renamings of tagged types
6958 
6959       Actual := First (Assoc_List);
6960       while Present (Actual) loop
6961          if Nkind (Actual) = N_Subtype_Declaration then
6962             Gen_T := Generic_Parent_Type (Actual);
6963 
6964             if Present (Gen_T) and then Is_Tagged_Type (Gen_T) then
6965 
6966                --  Traverse the list of primitives of the actual types
6967                --  searching for hidden primitives that are visible in the
6968                --  corresponding generic formal; leave them visible and
6969                --  append them to Result to restore their decoration later.
6970 
6971                Install_Hidden_Primitives
6972                  (Prims_List => Result,
6973                   Gen_T      => Gen_T,
6974                   Act_T      => Entity (Subtype_Indication (Actual)));
6975             end if;
6976          end if;
6977 
6978          Next (Actual);
6979       end loop;
6980 
6981       return Result;
6982    end Check_Hidden_Primitives;
6983 
6984    --------------------------
6985    -- Contains_Instance_Of --
6986    --------------------------
6987 
6988    function Contains_Instance_Of
6989      (Inner : Entity_Id;
6990       Outer : Entity_Id;
6991       N     : Node_Id) return Boolean
6992    is
6993       Elmt : Elmt_Id;
6994       Scop : Entity_Id;
6995 
6996    begin
6997       Scop := Outer;
6998 
6999       --  Verify that there are no circular instantiations. We check whether
7000       --  the unit contains an instance of the current scope or some enclosing
7001       --  scope (in case one of the instances appears in a subunit). Longer
7002       --  circularities involving subunits might seem too pathological to
7003       --  consider, but they were not too pathological for the authors of
7004       --  DEC bc30vsq, so we loop over all enclosing scopes, and mark all
7005       --  enclosing generic scopes as containing an instance.
7006 
7007       loop
7008          --  Within a generic subprogram body, the scope is not generic, to
7009          --  allow for recursive subprograms. Use the declaration to determine
7010          --  whether this is a generic unit.
7011 
7012          if Ekind (Scop) = E_Generic_Package
7013            or else (Is_Subprogram (Scop)
7014                      and then Nkind (Unit_Declaration_Node (Scop)) =
7015                                         N_Generic_Subprogram_Declaration)
7016          then
7017             Elmt := First_Elmt (Inner_Instances (Inner));
7018 
7019             while Present (Elmt) loop
7020                if Node (Elmt) = Scop then
7021                   Error_Msg_Node_2 := Inner;
7022                   Error_Msg_NE
7023                     ("circular Instantiation: & instantiated within &!",
7024                      N, Scop);
7025                   return True;
7026 
7027                elsif Node (Elmt) = Inner then
7028                   return True;
7029 
7030                elsif Contains_Instance_Of (Node (Elmt), Scop, N) then
7031                   Error_Msg_Node_2 := Inner;
7032                   Error_Msg_NE
7033                     ("circular Instantiation: & instantiated within &!",
7034                      N, Node (Elmt));
7035                   return True;
7036                end if;
7037 
7038                Next_Elmt (Elmt);
7039             end loop;
7040 
7041             --  Indicate that Inner is being instantiated within Scop
7042 
7043             Append_Elmt (Inner, Inner_Instances (Scop));
7044          end if;
7045 
7046          if Scop = Standard_Standard then
7047             exit;
7048          else
7049             Scop := Scope (Scop);
7050          end if;
7051       end loop;
7052 
7053       return False;
7054    end Contains_Instance_Of;
7055 
7056    -----------------------
7057    -- Copy_Generic_Node --
7058    -----------------------
7059 
7060    function Copy_Generic_Node
7061      (N             : Node_Id;
7062       Parent_Id     : Node_Id;
7063       Instantiating : Boolean) return Node_Id
7064    is
7065       Ent   : Entity_Id;
7066       New_N : Node_Id;
7067 
7068       function Copy_Generic_Descendant (D : Union_Id) return Union_Id;
7069       --  Check the given value of one of the Fields referenced by the current
7070       --  node to determine whether to copy it recursively. The field may hold
7071       --  a Node_Id, a List_Id, or an Elist_Id, or a plain value (Sloc, Uint,
7072       --  Char) in which case it need not be copied.
7073 
7074       procedure Copy_Descendants;
7075       --  Common utility for various nodes
7076 
7077       function Copy_Generic_Elist (E : Elist_Id) return Elist_Id;
7078       --  Make copy of element list
7079 
7080       function Copy_Generic_List
7081         (L         : List_Id;
7082          Parent_Id : Node_Id) return List_Id;
7083       --  Apply Copy_Node recursively to the members of a node list
7084 
7085       function In_Defining_Unit_Name (Nam : Node_Id) return Boolean;
7086       --  True if an identifier is part of the defining program unit name of
7087       --  a child unit. The entity of such an identifier must be kept (for
7088       --  ASIS use) even though as the name of an enclosing generic it would
7089       --  otherwise not be preserved in the generic tree.
7090 
7091       ----------------------
7092       -- Copy_Descendants --
7093       ----------------------
7094 
7095       procedure Copy_Descendants is
7096          use Atree.Unchecked_Access;
7097          --  This code section is part of the implementation of an untyped
7098          --  tree traversal, so it needs direct access to node fields.
7099 
7100       begin
7101          Set_Field1 (New_N, Copy_Generic_Descendant (Field1 (N)));
7102          Set_Field2 (New_N, Copy_Generic_Descendant (Field2 (N)));
7103          Set_Field3 (New_N, Copy_Generic_Descendant (Field3 (N)));
7104          Set_Field4 (New_N, Copy_Generic_Descendant (Field4 (N)));
7105          Set_Field5 (New_N, Copy_Generic_Descendant (Field5 (N)));
7106       end Copy_Descendants;
7107 
7108       -----------------------------
7109       -- Copy_Generic_Descendant --
7110       -----------------------------
7111 
7112       function Copy_Generic_Descendant (D : Union_Id) return Union_Id is
7113       begin
7114          if D = Union_Id (Empty) then
7115             return D;
7116 
7117          elsif D in Node_Range then
7118             return Union_Id
7119               (Copy_Generic_Node (Node_Id (D), New_N, Instantiating));
7120 
7121          elsif D in List_Range then
7122             return Union_Id (Copy_Generic_List (List_Id (D), New_N));
7123 
7124          elsif D in Elist_Range then
7125             return Union_Id (Copy_Generic_Elist (Elist_Id (D)));
7126 
7127          --  Nothing else is copyable (e.g. Uint values), return as is
7128 
7129          else
7130             return D;
7131          end if;
7132       end Copy_Generic_Descendant;
7133 
7134       ------------------------
7135       -- Copy_Generic_Elist --
7136       ------------------------
7137 
7138       function Copy_Generic_Elist (E : Elist_Id) return Elist_Id is
7139          M : Elmt_Id;
7140          L : Elist_Id;
7141 
7142       begin
7143          if Present (E) then
7144             L := New_Elmt_List;
7145             M := First_Elmt (E);
7146             while Present (M) loop
7147                Append_Elmt
7148                  (Copy_Generic_Node (Node (M), Empty, Instantiating), L);
7149                Next_Elmt (M);
7150             end loop;
7151 
7152             return L;
7153 
7154          else
7155             return No_Elist;
7156          end if;
7157       end Copy_Generic_Elist;
7158 
7159       -----------------------
7160       -- Copy_Generic_List --
7161       -----------------------
7162 
7163       function Copy_Generic_List
7164         (L         : List_Id;
7165          Parent_Id : Node_Id) return List_Id
7166       is
7167          N     : Node_Id;
7168          New_L : List_Id;
7169 
7170       begin
7171          if Present (L) then
7172             New_L := New_List;
7173             Set_Parent (New_L, Parent_Id);
7174 
7175             N := First (L);
7176             while Present (N) loop
7177                Append (Copy_Generic_Node (N, Empty, Instantiating), New_L);
7178                Next (N);
7179             end loop;
7180 
7181             return New_L;
7182 
7183          else
7184             return No_List;
7185          end if;
7186       end Copy_Generic_List;
7187 
7188       ---------------------------
7189       -- In_Defining_Unit_Name --
7190       ---------------------------
7191 
7192       function In_Defining_Unit_Name (Nam : Node_Id) return Boolean is
7193       begin
7194          return
7195            Present (Parent (Nam))
7196              and then (Nkind (Parent (Nam)) = N_Defining_Program_Unit_Name
7197                         or else
7198                           (Nkind (Parent (Nam)) = N_Expanded_Name
7199                             and then In_Defining_Unit_Name (Parent (Nam))));
7200       end In_Defining_Unit_Name;
7201 
7202    --  Start of processing for Copy_Generic_Node
7203 
7204    begin
7205       if N = Empty then
7206          return N;
7207       end if;
7208 
7209       New_N := New_Copy (N);
7210 
7211       --  Copy aspects if present
7212 
7213       if Has_Aspects (N) then
7214          Set_Has_Aspects (New_N, False);
7215          Set_Aspect_Specifications
7216            (New_N, Copy_Generic_List (Aspect_Specifications (N), Parent_Id));
7217       end if;
7218 
7219       if Instantiating then
7220          Adjust_Instantiation_Sloc (New_N, S_Adjustment);
7221       end if;
7222 
7223       if not Is_List_Member (N) then
7224          Set_Parent (New_N, Parent_Id);
7225       end if;
7226 
7227       --  Special casing for identifiers and other entity names and operators
7228 
7229       if Nkind_In (New_N, N_Character_Literal,
7230                           N_Expanded_Name,
7231                           N_Identifier,
7232                           N_Operator_Symbol)
7233         or else Nkind (New_N) in N_Op
7234       then
7235          if not Instantiating then
7236 
7237             --  Link both nodes in order to assign subsequently the entity of
7238             --  the copy to the original node, in case this is a global
7239             --  reference.
7240 
7241             Set_Associated_Node (N, New_N);
7242 
7243             --  If we are within an instantiation, this is a nested generic
7244             --  that has already been analyzed at the point of definition.
7245             --  We must preserve references that were global to the enclosing
7246             --  parent at that point. Other occurrences, whether global or
7247             --  local to the current generic, must be resolved anew, so we
7248             --  reset the entity in the generic copy. A global reference has a
7249             --  smaller depth than the parent, or else the same depth in case
7250             --  both are distinct compilation units.
7251 
7252             --  A child unit is implicitly declared within the enclosing parent
7253             --  but is in fact global to it, and must be preserved.
7254 
7255             --  It is also possible for Current_Instantiated_Parent to be
7256             --  defined, and for this not to be a nested generic, namely if
7257             --  the unit is loaded through Rtsfind. In that case, the entity of
7258             --  New_N is only a link to the associated node, and not a defining
7259             --  occurrence.
7260 
7261             --  The entities for parent units in the defining_program_unit of a
7262             --  generic child unit are established when the context of the unit
7263             --  is first analyzed, before the generic copy is made. They are
7264             --  preserved in the copy for use in ASIS queries.
7265 
7266             Ent := Entity (New_N);
7267 
7268             if No (Current_Instantiated_Parent.Gen_Id) then
7269                if No (Ent)
7270                  or else Nkind (Ent) /= N_Defining_Identifier
7271                  or else not In_Defining_Unit_Name (N)
7272                then
7273                   Set_Associated_Node (New_N, Empty);
7274                end if;
7275 
7276             elsif No (Ent)
7277               or else
7278                 not Nkind_In (Ent, N_Defining_Identifier,
7279                                    N_Defining_Character_Literal,
7280                                    N_Defining_Operator_Symbol)
7281               or else No (Scope (Ent))
7282               or else
7283                 (Scope (Ent) = Current_Instantiated_Parent.Gen_Id
7284                   and then not Is_Child_Unit (Ent))
7285               or else
7286                 (Scope_Depth (Scope (Ent)) >
7287                              Scope_Depth (Current_Instantiated_Parent.Gen_Id)
7288                   and then
7289                     Get_Source_Unit (Ent) =
7290                     Get_Source_Unit (Current_Instantiated_Parent.Gen_Id))
7291             then
7292                Set_Associated_Node (New_N, Empty);
7293             end if;
7294 
7295          --  Case of instantiating identifier or some other name or operator
7296 
7297          else
7298             --  If the associated node is still defined, the entity in it
7299             --  is global, and must be copied to the instance. If this copy
7300             --  is being made for a body to inline, it is applied to an
7301             --  instantiated tree, and the entity is already present and
7302             --  must be also preserved.
7303 
7304             declare
7305                Assoc : constant Node_Id := Get_Associated_Node (N);
7306 
7307             begin
7308                if Present (Assoc) then
7309                   if Nkind (Assoc) = Nkind (N) then
7310                      Set_Entity (New_N, Entity (Assoc));
7311                      Check_Private_View (N);
7312 
7313                   --  The node is a reference to a global type and acts as the
7314                   --  subtype mark of a qualified expression created in order
7315                   --  to aid resolution of accidental overloading in instances.
7316                   --  Since N is a reference to a type, the Associated_Node of
7317                   --  N denotes an entity rather than another identifier. See
7318                   --  Qualify_Universal_Operands for details.
7319 
7320                   elsif Nkind (N) = N_Identifier
7321                     and then Nkind (Parent (N)) = N_Qualified_Expression
7322                     and then Subtype_Mark (Parent (N)) = N
7323                     and then Is_Qualified_Universal_Literal (Parent (N))
7324                   then
7325                      Set_Entity (New_N, Assoc);
7326 
7327                   --  The name in the call may be a selected component if the
7328                   --  call has not been analyzed yet, as may be the case for
7329                   --  pre/post conditions in a generic unit.
7330 
7331                   elsif Nkind (Assoc) = N_Function_Call
7332                     and then Is_Entity_Name (Name (Assoc))
7333                   then
7334                      Set_Entity (New_N, Entity (Name (Assoc)));
7335 
7336                   elsif Nkind_In (Assoc, N_Defining_Identifier,
7337                                          N_Defining_Character_Literal,
7338                                          N_Defining_Operator_Symbol)
7339                     and then Expander_Active
7340                   then
7341                      --  Inlining case: we are copying a tree that contains
7342                      --  global entities, which are preserved in the copy to be
7343                      --  used for subsequent inlining.
7344 
7345                      null;
7346 
7347                   else
7348                      Set_Entity (New_N, Empty);
7349                   end if;
7350                end if;
7351             end;
7352          end if;
7353 
7354          --  For expanded name, we must copy the Prefix and Selector_Name
7355 
7356          if Nkind (N) = N_Expanded_Name then
7357             Set_Prefix
7358               (New_N, Copy_Generic_Node (Prefix (N), New_N, Instantiating));
7359 
7360             Set_Selector_Name (New_N,
7361               Copy_Generic_Node (Selector_Name (N), New_N, Instantiating));
7362 
7363          --  For operators, we must copy the right operand
7364 
7365          elsif Nkind (N) in N_Op then
7366             Set_Right_Opnd (New_N,
7367               Copy_Generic_Node (Right_Opnd (N), New_N, Instantiating));
7368 
7369             --  And for binary operators, the left operand as well
7370 
7371             if Nkind (N) in N_Binary_Op then
7372                Set_Left_Opnd (New_N,
7373                  Copy_Generic_Node (Left_Opnd (N), New_N, Instantiating));
7374             end if;
7375          end if;
7376 
7377       --  Establish a link between an entity from the generic template and the
7378       --  corresponding entity in the generic copy to be analyzed.
7379 
7380       elsif Nkind (N) in N_Entity then
7381          if not Instantiating then
7382             Set_Associated_Entity (N, New_N);
7383          end if;
7384 
7385          --  Clear any existing link the copy may inherit from the replicated
7386          --  generic template entity.
7387 
7388          Set_Associated_Entity (New_N, Empty);
7389 
7390       --  Special casing for stubs
7391 
7392       elsif Nkind (N) in N_Body_Stub then
7393 
7394          --  In any case, we must copy the specification or defining
7395          --  identifier as appropriate.
7396 
7397          if Nkind (N) = N_Subprogram_Body_Stub then
7398             Set_Specification (New_N,
7399               Copy_Generic_Node (Specification (N), New_N, Instantiating));
7400 
7401          else
7402             Set_Defining_Identifier (New_N,
7403               Copy_Generic_Node
7404                 (Defining_Identifier (N), New_N, Instantiating));
7405          end if;
7406 
7407          --  If we are not instantiating, then this is where we load and
7408          --  analyze subunits, i.e. at the point where the stub occurs. A
7409          --  more permissive system might defer this analysis to the point
7410          --  of instantiation, but this seems too complicated for now.
7411 
7412          if not Instantiating then
7413             declare
7414                Subunit_Name : constant Unit_Name_Type := Get_Unit_Name (N);
7415                Subunit      : Node_Id;
7416                Unum         : Unit_Number_Type;
7417                New_Body     : Node_Id;
7418 
7419             begin
7420                --  Make sure that, if it is a subunit of the main unit that is
7421                --  preprocessed and if -gnateG is specified, the preprocessed
7422                --  file will be written.
7423 
7424                Lib.Analysing_Subunit_Of_Main :=
7425                  Lib.In_Extended_Main_Source_Unit (N);
7426                Unum :=
7427                  Load_Unit
7428                    (Load_Name  => Subunit_Name,
7429                     Required   => False,
7430                     Subunit    => True,
7431                     Error_Node => N);
7432                Lib.Analysing_Subunit_Of_Main := False;
7433 
7434                --  If the proper body is not found, a warning message will be
7435                --  emitted when analyzing the stub, or later at the point of
7436                --  instantiation. Here we just leave the stub as is.
7437 
7438                if Unum = No_Unit then
7439                   Subunits_Missing := True;
7440                   goto Subunit_Not_Found;
7441                end if;
7442 
7443                Subunit := Cunit (Unum);
7444 
7445                if Nkind (Unit (Subunit)) /= N_Subunit then
7446                   Error_Msg_N
7447                     ("found child unit instead of expected SEPARATE subunit",
7448                      Subunit);
7449                   Error_Msg_Sloc := Sloc (N);
7450                   Error_Msg_N ("\to complete stub #", Subunit);
7451                   goto Subunit_Not_Found;
7452                end if;
7453 
7454                --  We must create a generic copy of the subunit, in order to
7455                --  perform semantic analysis on it, and we must replace the
7456                --  stub in the original generic unit with the subunit, in order
7457                --  to preserve non-local references within.
7458 
7459                --  Only the proper body needs to be copied. Library_Unit and
7460                --  context clause are simply inherited by the generic copy.
7461                --  Note that the copy (which may be recursive if there are
7462                --  nested subunits) must be done first, before attaching it to
7463                --  the enclosing generic.
7464 
7465                New_Body :=
7466                  Copy_Generic_Node
7467                    (Proper_Body (Unit (Subunit)),
7468                     Empty, Instantiating => False);
7469 
7470                --  Now place the original proper body in the original generic
7471                --  unit. This is a body, not a compilation unit.
7472 
7473                Rewrite (N, Proper_Body (Unit (Subunit)));
7474                Set_Is_Compilation_Unit (Defining_Entity (N), False);
7475                Set_Was_Originally_Stub (N);
7476 
7477                --  Finally replace the body of the subunit with its copy, and
7478                --  make this new subunit into the library unit of the generic
7479                --  copy, which does not have stubs any longer.
7480 
7481                Set_Proper_Body (Unit (Subunit), New_Body);
7482                Set_Library_Unit (New_N, Subunit);
7483                Inherit_Context (Unit (Subunit), N);
7484             end;
7485 
7486          --  If we are instantiating, this must be an error case, since
7487          --  otherwise we would have replaced the stub node by the proper body
7488          --  that corresponds. So just ignore it in the copy (i.e. we have
7489          --  copied it, and that is good enough).
7490 
7491          else
7492             null;
7493          end if;
7494 
7495          <<Subunit_Not_Found>> null;
7496 
7497       --  If the node is a compilation unit, it is the subunit of a stub, which
7498       --  has been loaded already (see code below). In this case, the library
7499       --  unit field of N points to the parent unit (which is a compilation
7500       --  unit) and need not (and cannot) be copied.
7501 
7502       --  When the proper body of the stub is analyzed, the library_unit link
7503       --  is used to establish the proper context (see sem_ch10).
7504 
7505       --  The other fields of a compilation unit are copied as usual
7506 
7507       elsif Nkind (N) = N_Compilation_Unit then
7508 
7509          --  This code can only be executed when not instantiating, because in
7510          --  the copy made for an instantiation, the compilation unit node has
7511          --  disappeared at the point that a stub is replaced by its proper
7512          --  body.
7513 
7514          pragma Assert (not Instantiating);
7515 
7516          Set_Context_Items (New_N,
7517            Copy_Generic_List (Context_Items (N), New_N));
7518 
7519          Set_Unit (New_N,
7520            Copy_Generic_Node (Unit (N), New_N, False));
7521 
7522          Set_First_Inlined_Subprogram (New_N,
7523            Copy_Generic_Node
7524              (First_Inlined_Subprogram (N), New_N, False));
7525 
7526          Set_Aux_Decls_Node (New_N,
7527            Copy_Generic_Node (Aux_Decls_Node (N), New_N, False));
7528 
7529       --  For an assignment node, the assignment is known to be semantically
7530       --  legal if we are instantiating the template. This avoids incorrect
7531       --  diagnostics in generated code.
7532 
7533       elsif Nkind (N) = N_Assignment_Statement then
7534 
7535          --  Copy name and expression fields in usual manner
7536 
7537          Set_Name (New_N,
7538            Copy_Generic_Node (Name (N), New_N, Instantiating));
7539 
7540          Set_Expression (New_N,
7541            Copy_Generic_Node (Expression (N), New_N, Instantiating));
7542 
7543          if Instantiating then
7544             Set_Assignment_OK (Name (New_N), True);
7545          end if;
7546 
7547       elsif Nkind_In (N, N_Aggregate, N_Extension_Aggregate) then
7548          if not Instantiating then
7549             Set_Associated_Node (N, New_N);
7550 
7551          else
7552             if Present (Get_Associated_Node (N))
7553               and then Nkind (Get_Associated_Node (N)) = Nkind (N)
7554             then
7555                --  In the generic the aggregate has some composite type. If at
7556                --  the point of instantiation the type has a private view,
7557                --  install the full view (and that of its ancestors, if any).
7558 
7559                declare
7560                   T   : Entity_Id := (Etype (Get_Associated_Node (New_N)));
7561                   Rt  : Entity_Id;
7562 
7563                begin
7564                   if Present (T) and then Is_Private_Type (T) then
7565                      Switch_View (T);
7566                   end if;
7567 
7568                   if Present (T)
7569                     and then Is_Tagged_Type (T)
7570                     and then Is_Derived_Type (T)
7571                   then
7572                      Rt := Root_Type (T);
7573 
7574                      loop
7575                         T := Etype (T);
7576 
7577                         if Is_Private_Type (T) then
7578                            Switch_View (T);
7579                         end if;
7580 
7581                         exit when T = Rt;
7582                      end loop;
7583                   end if;
7584                end;
7585             end if;
7586          end if;
7587 
7588          --  Do not copy the associated node, which points to the generic copy
7589          --  of the aggregate.
7590 
7591          declare
7592             use Atree.Unchecked_Access;
7593             --  This code section is part of the implementation of an untyped
7594             --  tree traversal, so it needs direct access to node fields.
7595 
7596          begin
7597             Set_Field1 (New_N, Copy_Generic_Descendant (Field1 (N)));
7598             Set_Field2 (New_N, Copy_Generic_Descendant (Field2 (N)));
7599             Set_Field3 (New_N, Copy_Generic_Descendant (Field3 (N)));
7600             Set_Field5 (New_N, Copy_Generic_Descendant (Field5 (N)));
7601          end;
7602 
7603       --  Allocators do not have an identifier denoting the access type, so we
7604       --  must locate it through the expression to check whether the views are
7605       --  consistent.
7606 
7607       elsif Nkind (N) = N_Allocator
7608         and then Nkind (Expression (N)) = N_Qualified_Expression
7609         and then Is_Entity_Name (Subtype_Mark (Expression (N)))
7610         and then Instantiating
7611       then
7612          declare
7613             T     : constant Node_Id :=
7614                       Get_Associated_Node (Subtype_Mark (Expression (N)));
7615             Acc_T : Entity_Id;
7616 
7617          begin
7618             if Present (T) then
7619 
7620                --  Retrieve the allocator node in the generic copy
7621 
7622                Acc_T := Etype (Parent (Parent (T)));
7623 
7624                if Present (Acc_T) and then Is_Private_Type (Acc_T) then
7625                   Switch_View (Acc_T);
7626                end if;
7627             end if;
7628 
7629             Copy_Descendants;
7630          end;
7631 
7632       --  For a proper body, we must catch the case of a proper body that
7633       --  replaces a stub. This represents the point at which a separate
7634       --  compilation unit, and hence template file, may be referenced, so we
7635       --  must make a new source instantiation entry for the template of the
7636       --  subunit, and ensure that all nodes in the subunit are adjusted using
7637       --  this new source instantiation entry.
7638 
7639       elsif Nkind (N) in N_Proper_Body then
7640          declare
7641             Save_Adjustment : constant Sloc_Adjustment := S_Adjustment;
7642 
7643          begin
7644             if Instantiating and then Was_Originally_Stub (N) then
7645                Create_Instantiation_Source
7646                  (Instantiation_Node,
7647                   Defining_Entity (N),
7648                   S_Adjustment);
7649             end if;
7650 
7651             --  Now copy the fields of the proper body, using the new
7652             --  adjustment factor if one was needed as per test above.
7653 
7654             Copy_Descendants;
7655 
7656             --  Restore the original adjustment factor in case changed
7657 
7658             S_Adjustment := Save_Adjustment;
7659          end;
7660 
7661       elsif Nkind (N) = N_Pragma and then Instantiating then
7662 
7663          --  Do not copy Comment or Ident pragmas their content is relevant to
7664          --  the generic unit, not to the instantiating unit.
7665 
7666          if Nam_In (Pragma_Name (N), Name_Comment, Name_Ident) then
7667             New_N := Make_Null_Statement (Sloc (N));
7668 
7669          --  Do not copy pragmas generated from aspects because the pragmas do
7670          --  not carry any semantic information, plus they will be regenerated
7671          --  in the instance.
7672 
7673          --  However, generating C we need to copy them since postconditions
7674          --  are inlined by the front end, and the front-end inlining machinery
7675          --  relies on this routine to perform inlining.
7676 
7677          elsif From_Aspect_Specification (N)
7678            and then not Modify_Tree_For_C
7679          then
7680             New_N := Make_Null_Statement (Sloc (N));
7681 
7682          else
7683             Copy_Descendants;
7684          end if;
7685 
7686       elsif Nkind_In (N, N_Integer_Literal, N_Real_Literal) then
7687 
7688          --  No descendant fields need traversing
7689 
7690          null;
7691 
7692       elsif Nkind (N) = N_String_Literal
7693         and then Present (Etype (N))
7694         and then Instantiating
7695       then
7696          --  If the string is declared in an outer scope, the string_literal
7697          --  subtype created for it may have the wrong scope. Force reanalysis
7698          --  of the constant to generate a new itype in the proper context.
7699 
7700          Set_Etype (New_N, Empty);
7701          Set_Analyzed (New_N, False);
7702 
7703       --  For the remaining nodes, copy their descendants recursively
7704 
7705       else
7706          Copy_Descendants;
7707 
7708          if Instantiating and then Nkind (N) = N_Subprogram_Body then
7709             Set_Generic_Parent (Specification (New_N), N);
7710 
7711             --  Should preserve Corresponding_Spec??? (12.3(14))
7712          end if;
7713       end if;
7714 
7715       --  Propagate dimensions if present, so that they are reflected in the
7716       --  instance.
7717 
7718       if Nkind (N) in N_Has_Etype
7719         and then (Nkind (N) in N_Op or else Is_Entity_Name (N))
7720         and then Present (Etype (N))
7721         and then Is_Floating_Point_Type (Etype (N))
7722         and then Has_Dimension_System (Etype (N))
7723       then
7724          Copy_Dimensions (N, New_N);
7725       end if;
7726 
7727       return New_N;
7728    end Copy_Generic_Node;
7729 
7730    ----------------------------
7731    -- Denotes_Formal_Package --
7732    ----------------------------
7733 
7734    function Denotes_Formal_Package
7735      (Pack     : Entity_Id;
7736       On_Exit  : Boolean := False;
7737       Instance : Entity_Id := Empty) return Boolean
7738    is
7739       Par  : Entity_Id;
7740       Scop : constant Entity_Id := Scope (Pack);
7741       E    : Entity_Id;
7742 
7743       function Is_Actual_Of_Previous_Formal (P : Entity_Id) return Boolean;
7744       --  The package in question may be an actual for a previous formal
7745       --  package P of the current instance, so examine its actuals as well.
7746       --  This must be recursive over other formal packages.
7747 
7748       ----------------------------------
7749       -- Is_Actual_Of_Previous_Formal --
7750       ----------------------------------
7751 
7752       function Is_Actual_Of_Previous_Formal (P : Entity_Id) return Boolean is
7753          E1 : Entity_Id;
7754 
7755       begin
7756          E1 := First_Entity (P);
7757          while Present (E1) and then E1 /= Instance loop
7758             if Ekind (E1) = E_Package
7759               and then Nkind (Parent (E1)) = N_Package_Renaming_Declaration
7760             then
7761                if Renamed_Object (E1) = Pack then
7762                   return True;
7763 
7764                elsif E1 = P or else Renamed_Object (E1) = P then
7765                   return False;
7766 
7767                elsif Is_Actual_Of_Previous_Formal (E1) then
7768                   return True;
7769                end if;
7770             end if;
7771 
7772             Next_Entity (E1);
7773          end loop;
7774 
7775          return False;
7776       end Is_Actual_Of_Previous_Formal;
7777 
7778    --  Start of processing for Denotes_Formal_Package
7779 
7780    begin
7781       if On_Exit then
7782          Par :=
7783            Instance_Envs.Table
7784              (Instance_Envs.Last).Instantiated_Parent.Act_Id;
7785       else
7786          Par := Current_Instantiated_Parent.Act_Id;
7787       end if;
7788 
7789       if Ekind (Scop) = E_Generic_Package
7790         or else Nkind (Unit_Declaration_Node (Scop)) =
7791                                          N_Generic_Subprogram_Declaration
7792       then
7793          return True;
7794 
7795       elsif Nkind (Original_Node (Unit_Declaration_Node (Pack))) =
7796         N_Formal_Package_Declaration
7797       then
7798          return True;
7799 
7800       elsif No (Par) then
7801          return False;
7802 
7803       else
7804          --  Check whether this package is associated with a formal package of
7805          --  the enclosing instantiation. Iterate over the list of renamings.
7806 
7807          E := First_Entity (Par);
7808          while Present (E) loop
7809             if Ekind (E) /= E_Package
7810               or else Nkind (Parent (E)) /= N_Package_Renaming_Declaration
7811             then
7812                null;
7813 
7814             elsif Renamed_Object (E) = Par then
7815                return False;
7816 
7817             elsif Renamed_Object (E) = Pack then
7818                return True;
7819 
7820             elsif Is_Actual_Of_Previous_Formal (E) then
7821                return True;
7822 
7823             end if;
7824 
7825             Next_Entity (E);
7826          end loop;
7827 
7828          return False;
7829       end if;
7830    end Denotes_Formal_Package;
7831 
7832    -----------------
7833    -- End_Generic --
7834    -----------------
7835 
7836    procedure End_Generic is
7837    begin
7838       --  ??? More things could be factored out in this routine. Should
7839       --  probably be done at a later stage.
7840 
7841       Inside_A_Generic := Generic_Flags.Table (Generic_Flags.Last);
7842       Generic_Flags.Decrement_Last;
7843 
7844       Expander_Mode_Restore;
7845    end End_Generic;
7846 
7847    -------------
7848    -- Earlier --
7849    -------------
7850 
7851    function Earlier (N1, N2 : Node_Id) return Boolean is
7852       procedure Find_Depth (P : in out Node_Id; D : in out Integer);
7853       --  Find distance from given node to enclosing compilation unit
7854 
7855       ----------------
7856       -- Find_Depth --
7857       ----------------
7858 
7859       procedure Find_Depth (P : in out Node_Id; D : in out Integer) is
7860       begin
7861          while Present (P)
7862            and then Nkind (P) /= N_Compilation_Unit
7863          loop
7864             P := True_Parent (P);
7865             D := D + 1;
7866          end loop;
7867       end Find_Depth;
7868 
7869       --  Local declarations
7870 
7871       D1 : Integer := 0;
7872       D2 : Integer := 0;
7873       P1 : Node_Id := N1;
7874       P2 : Node_Id := N2;
7875       T1 : Source_Ptr;
7876       T2 : Source_Ptr;
7877 
7878    --  Start of processing for Earlier
7879 
7880    begin
7881       Find_Depth (P1, D1);
7882       Find_Depth (P2, D2);
7883 
7884       if P1 /= P2 then
7885          return False;
7886       else
7887          P1 := N1;
7888          P2 := N2;
7889       end if;
7890 
7891       while D1 > D2 loop
7892          P1 := True_Parent (P1);
7893          D1 := D1 - 1;
7894       end loop;
7895 
7896       while D2 > D1 loop
7897          P2 := True_Parent (P2);
7898          D2 := D2 - 1;
7899       end loop;
7900 
7901       --  At this point P1 and P2 are at the same distance from the root.
7902       --  We examine their parents until we find a common declarative list.
7903       --  If we reach the root, N1 and N2 do not descend from the same
7904       --  declarative list (e.g. one is nested in the declarative part and
7905       --  the other is in a block in the statement part) and the earlier
7906       --  one is already frozen.
7907 
7908       while not Is_List_Member (P1)
7909         or else not Is_List_Member (P2)
7910         or else List_Containing (P1) /= List_Containing (P2)
7911       loop
7912          P1 := True_Parent (P1);
7913          P2 := True_Parent (P2);
7914 
7915          if Nkind (Parent (P1)) = N_Subunit then
7916             P1 := Corresponding_Stub (Parent (P1));
7917          end if;
7918 
7919          if Nkind (Parent (P2)) = N_Subunit then
7920             P2 := Corresponding_Stub (Parent (P2));
7921          end if;
7922 
7923          if P1 = P2 then
7924             return False;
7925          end if;
7926       end loop;
7927 
7928       --  Expanded code usually shares the source location of the original
7929       --  construct it was generated for. This however may not necessarily
7930       --  reflect the true location of the code within the tree.
7931 
7932       --  Before comparing the slocs of the two nodes, make sure that we are
7933       --  working with correct source locations. Assume that P1 is to the left
7934       --  of P2. If either one does not come from source, traverse the common
7935       --  list heading towards the other node and locate the first source
7936       --  statement.
7937 
7938       --             P1                     P2
7939       --     ----+===+===+--------------+===+===+----
7940       --          expanded code          expanded code
7941 
7942       if not Comes_From_Source (P1) then
7943          while Present (P1) loop
7944 
7945             --  Neither P2 nor a source statement were located during the
7946             --  search. If we reach the end of the list, then P1 does not
7947             --  occur earlier than P2.
7948 
7949             --                     ---->
7950             --   start --- P2 ----- P1 --- end
7951 
7952             if No (Next (P1)) then
7953                return False;
7954 
7955             --  We encounter P2 while going to the right of the list. This
7956             --  means that P1 does indeed appear earlier.
7957 
7958             --             ---->
7959             --    start --- P1 ===== P2 --- end
7960             --                 expanded code in between
7961 
7962             elsif P1 = P2 then
7963                return True;
7964 
7965             --  No need to look any further since we have located a source
7966             --  statement.
7967 
7968             elsif Comes_From_Source (P1) then
7969                exit;
7970             end if;
7971 
7972             --  Keep going right
7973 
7974             Next (P1);
7975          end loop;
7976       end if;
7977 
7978       if not Comes_From_Source (P2) then
7979          while Present (P2) loop
7980 
7981             --  Neither P1 nor a source statement were located during the
7982             --  search. If we reach the start of the list, then P1 does not
7983             --  occur earlier than P2.
7984 
7985             --            <----
7986             --    start --- P2 --- P1 --- end
7987 
7988             if No (Prev (P2)) then
7989                return False;
7990 
7991             --  We encounter P1 while going to the left of the list. This
7992             --  means that P1 does indeed appear earlier.
7993 
7994             --                     <----
7995             --    start --- P1 ===== P2 --- end
7996             --                 expanded code in between
7997 
7998             elsif P2 = P1 then
7999                return True;
8000 
8001             --  No need to look any further since we have located a source
8002             --  statement.
8003 
8004             elsif Comes_From_Source (P2) then
8005                exit;
8006             end if;
8007 
8008             --  Keep going left
8009 
8010             Prev (P2);
8011          end loop;
8012       end if;
8013 
8014       --  At this point either both nodes came from source or we approximated
8015       --  their source locations through neighbouring source statements.
8016 
8017       T1 := Top_Level_Location (Sloc (P1));
8018       T2 := Top_Level_Location (Sloc (P2));
8019 
8020       --  When two nodes come from the same instance, they have identical top
8021       --  level locations. To determine proper relation within the tree, check
8022       --  their locations within the template.
8023 
8024       if T1 = T2 then
8025          return Sloc (P1) < Sloc (P2);
8026 
8027       --  The two nodes either come from unrelated instances or do not come
8028       --  from instantiated code at all.
8029 
8030       else
8031          return T1 < T2;
8032       end if;
8033    end Earlier;
8034 
8035    ----------------------
8036    -- Find_Actual_Type --
8037    ----------------------
8038 
8039    function Find_Actual_Type
8040      (Typ      : Entity_Id;
8041       Gen_Type : Entity_Id) return Entity_Id
8042    is
8043       Gen_Scope : constant Entity_Id := Scope (Gen_Type);
8044       T         : Entity_Id;
8045 
8046    begin
8047       --  Special processing only applies to child units
8048 
8049       if not Is_Child_Unit (Gen_Scope) then
8050          return Get_Instance_Of (Typ);
8051 
8052       --  If designated or component type is itself a formal of the child unit,
8053       --  its instance is available.
8054 
8055       elsif Scope (Typ) = Gen_Scope then
8056          return Get_Instance_Of (Typ);
8057 
8058       --  If the array or access type is not declared in the parent unit,
8059       --  no special processing needed.
8060 
8061       elsif not Is_Generic_Type (Typ)
8062         and then Scope (Gen_Scope) /= Scope (Typ)
8063       then
8064          return Get_Instance_Of (Typ);
8065 
8066       --  Otherwise, retrieve designated or component type by visibility
8067 
8068       else
8069          T := Current_Entity (Typ);
8070          while Present (T) loop
8071             if In_Open_Scopes (Scope (T)) then
8072                return T;
8073             elsif Is_Generic_Actual_Type (T) then
8074                return T;
8075             end if;
8076 
8077             T := Homonym (T);
8078          end loop;
8079 
8080          return Typ;
8081       end if;
8082    end Find_Actual_Type;
8083 
8084    ----------------------------
8085    -- Freeze_Subprogram_Body --
8086    ----------------------------
8087 
8088    procedure Freeze_Subprogram_Body
8089      (Inst_Node : Node_Id;
8090       Gen_Body  : Node_Id;
8091       Pack_Id   : Entity_Id)
8092   is
8093       Gen_Unit : constant Entity_Id := Get_Generic_Entity (Inst_Node);
8094       Par      : constant Entity_Id := Scope (Gen_Unit);
8095       E_G_Id   : Entity_Id;
8096       Enc_G    : Entity_Id;
8097       Enc_I    : Node_Id;
8098       F_Node   : Node_Id;
8099 
8100       function Enclosing_Package_Body (N : Node_Id) return Node_Id;
8101       --  Find innermost package body that encloses the given node, and which
8102       --  is not a compilation unit. Freeze nodes for the instance, or for its
8103       --  enclosing body, may be inserted after the enclosing_body of the
8104       --  generic unit. Used to determine proper placement of freeze node for
8105       --  both package and subprogram instances.
8106 
8107       function Package_Freeze_Node (B : Node_Id) return Node_Id;
8108       --  Find entity for given package body, and locate or create a freeze
8109       --  node for it.
8110 
8111       ----------------------------
8112       -- Enclosing_Package_Body --
8113       ----------------------------
8114 
8115       function Enclosing_Package_Body (N : Node_Id) return Node_Id is
8116          P : Node_Id;
8117 
8118       begin
8119          P := Parent (N);
8120          while Present (P)
8121            and then Nkind (Parent (P)) /= N_Compilation_Unit
8122          loop
8123             if Nkind (P) = N_Package_Body then
8124                if Nkind (Parent (P)) = N_Subunit then
8125                   return Corresponding_Stub (Parent (P));
8126                else
8127                   return P;
8128                end if;
8129             end if;
8130 
8131             P := True_Parent (P);
8132          end loop;
8133 
8134          return Empty;
8135       end Enclosing_Package_Body;
8136 
8137       -------------------------
8138       -- Package_Freeze_Node --
8139       -------------------------
8140 
8141       function Package_Freeze_Node (B : Node_Id) return Node_Id is
8142          Id : Entity_Id;
8143 
8144       begin
8145          if Nkind (B) = N_Package_Body then
8146             Id := Corresponding_Spec (B);
8147          else pragma Assert (Nkind (B) = N_Package_Body_Stub);
8148             Id := Corresponding_Spec (Proper_Body (Unit (Library_Unit (B))));
8149          end if;
8150 
8151          Ensure_Freeze_Node (Id);
8152          return Freeze_Node (Id);
8153       end Package_Freeze_Node;
8154 
8155    --  Start of processing for Freeze_Subprogram_Body
8156 
8157    begin
8158       --  If the instance and the generic body appear within the same unit, and
8159       --  the instance precedes the generic, the freeze node for the instance
8160       --  must appear after that of the generic. If the generic is nested
8161       --  within another instance I2, then current instance must be frozen
8162       --  after I2. In both cases, the freeze nodes are those of enclosing
8163       --  packages. Otherwise, the freeze node is placed at the end of the
8164       --  current declarative part.
8165 
8166       Enc_G  := Enclosing_Package_Body (Gen_Body);
8167       Enc_I  := Enclosing_Package_Body (Inst_Node);
8168       Ensure_Freeze_Node (Pack_Id);
8169       F_Node := Freeze_Node (Pack_Id);
8170 
8171       if Is_Generic_Instance (Par)
8172         and then Present (Freeze_Node (Par))
8173         and then In_Same_Declarative_Part (Freeze_Node (Par), Inst_Node)
8174       then
8175          --  The parent was a premature instantiation. Insert freeze node at
8176          --  the end the current declarative part.
8177 
8178          if ABE_Is_Certain (Get_Package_Instantiation_Node (Par)) then
8179             Insert_Freeze_Node_For_Instance (Inst_Node, F_Node);
8180 
8181          --  Handle the following case:
8182          --
8183          --    package Parent_Inst is new ...
8184          --    Parent_Inst []
8185          --
8186          --    procedure P ...  --  this body freezes Parent_Inst
8187          --
8188          --    package Inst is new ...
8189          --
8190          --  In this particular scenario, the freeze node for Inst must be
8191          --  inserted in the same manner as that of Parent_Inst - before the
8192          --  next source body or at the end of the declarative list (body not
8193          --  available). If body P did not exist and Parent_Inst was frozen
8194          --  after Inst, either by a body following Inst or at the end of the
8195          --  declarative region, the freeze node for Inst must be inserted
8196          --  after that of Parent_Inst. This relation is established by
8197          --  comparing the Slocs of Parent_Inst freeze node and Inst.
8198 
8199          elsif List_Containing (Get_Package_Instantiation_Node (Par)) =
8200                List_Containing (Inst_Node)
8201            and then Sloc (Freeze_Node (Par)) < Sloc (Inst_Node)
8202          then
8203             Insert_Freeze_Node_For_Instance (Inst_Node, F_Node);
8204 
8205          else
8206             Insert_After (Freeze_Node (Par), F_Node);
8207          end if;
8208 
8209       --  The body enclosing the instance should be frozen after the body that
8210       --  includes the generic, because the body of the instance may make
8211       --  references to entities therein. If the two are not in the same
8212       --  declarative part, or if the one enclosing the instance is frozen
8213       --  already, freeze the instance at the end of the current declarative
8214       --  part.
8215 
8216       elsif Is_Generic_Instance (Par)
8217         and then Present (Freeze_Node (Par))
8218         and then Present (Enc_I)
8219       then
8220          if In_Same_Declarative_Part (Freeze_Node (Par), Enc_I)
8221            or else
8222              (Nkind (Enc_I) = N_Package_Body
8223                and then
8224                  In_Same_Declarative_Part (Freeze_Node (Par), Parent (Enc_I)))
8225          then
8226             --  The enclosing package may contain several instances. Rather
8227             --  than computing the earliest point at which to insert its freeze
8228             --  node, we place it at the end of the declarative part of the
8229             --  parent of the generic.
8230 
8231             Insert_Freeze_Node_For_Instance
8232               (Freeze_Node (Par), Package_Freeze_Node (Enc_I));
8233          end if;
8234 
8235          Insert_Freeze_Node_For_Instance (Inst_Node, F_Node);
8236 
8237       elsif Present (Enc_G)
8238         and then Present (Enc_I)
8239         and then Enc_G /= Enc_I
8240         and then Earlier (Inst_Node, Gen_Body)
8241       then
8242          if Nkind (Enc_G) = N_Package_Body then
8243             E_G_Id :=
8244               Corresponding_Spec (Enc_G);
8245          else pragma Assert (Nkind (Enc_G) = N_Package_Body_Stub);
8246             E_G_Id :=
8247               Corresponding_Spec (Proper_Body (Unit (Library_Unit (Enc_G))));
8248          end if;
8249 
8250          --  Freeze package that encloses instance, and place node after the
8251          --  package that encloses generic. If enclosing package is already
8252          --  frozen we have to assume it is at the proper place. This may be a
8253          --  potential ABE that requires dynamic checking. Do not add a freeze
8254          --  node if the package that encloses the generic is inside the body
8255          --  that encloses the instance, because the freeze node would be in
8256          --  the wrong scope. Additional contortions needed if the bodies are
8257          --  within a subunit.
8258 
8259          declare
8260             Enclosing_Body : Node_Id;
8261 
8262          begin
8263             if Nkind (Enc_I) = N_Package_Body_Stub then
8264                Enclosing_Body := Proper_Body (Unit (Library_Unit (Enc_I)));
8265             else
8266                Enclosing_Body := Enc_I;
8267             end if;
8268 
8269             if Parent (List_Containing (Enc_G)) /= Enclosing_Body then
8270                Insert_Freeze_Node_For_Instance
8271                  (Enc_G, Package_Freeze_Node (Enc_I));
8272             end if;
8273          end;
8274 
8275          --  Freeze enclosing subunit before instance
8276 
8277          Ensure_Freeze_Node (E_G_Id);
8278 
8279          if not Is_List_Member (Freeze_Node (E_G_Id)) then
8280             Insert_After (Enc_G, Freeze_Node (E_G_Id));
8281          end if;
8282 
8283          Insert_Freeze_Node_For_Instance (Inst_Node, F_Node);
8284 
8285       else
8286          --  If none of the above, insert freeze node at the end of the current
8287          --  declarative part.
8288 
8289          Insert_Freeze_Node_For_Instance (Inst_Node, F_Node);
8290       end if;
8291    end Freeze_Subprogram_Body;
8292 
8293    ----------------
8294    -- Get_Gen_Id --
8295    ----------------
8296 
8297    function Get_Gen_Id (E : Assoc_Ptr) return Entity_Id is
8298    begin
8299       return Generic_Renamings.Table (E).Gen_Id;
8300    end Get_Gen_Id;
8301 
8302    ---------------------
8303    -- Get_Instance_Of --
8304    ---------------------
8305 
8306    function Get_Instance_Of (A : Entity_Id) return Entity_Id is
8307       Res : constant Assoc_Ptr := Generic_Renamings_HTable.Get (A);
8308 
8309    begin
8310       if Res /= Assoc_Null then
8311          return Generic_Renamings.Table (Res).Act_Id;
8312 
8313       else
8314          --  On exit, entity is not instantiated: not a generic parameter, or
8315          --  else parameter of an inner generic unit.
8316 
8317          return A;
8318       end if;
8319    end Get_Instance_Of;
8320 
8321    ------------------------------------
8322    -- Get_Package_Instantiation_Node --
8323    ------------------------------------
8324 
8325    function Get_Package_Instantiation_Node (A : Entity_Id) return Node_Id is
8326       Decl : Node_Id := Unit_Declaration_Node (A);
8327       Inst : Node_Id;
8328 
8329    begin
8330       --  If the Package_Instantiation attribute has been set on the package
8331       --  entity, then use it directly when it (or its Original_Node) refers
8332       --  to an N_Package_Instantiation node. In principle it should be
8333       --  possible to have this field set in all cases, which should be
8334       --  investigated, and would allow this function to be significantly
8335       --  simplified. ???
8336 
8337       Inst := Package_Instantiation (A);
8338 
8339       if Present (Inst) then
8340          if Nkind (Inst) = N_Package_Instantiation then
8341             return Inst;
8342 
8343          elsif Nkind (Original_Node (Inst)) = N_Package_Instantiation then
8344             return Original_Node (Inst);
8345          end if;
8346       end if;
8347 
8348       --  If the instantiation is a compilation unit that does not need body
8349       --  then the instantiation node has been rewritten as a package
8350       --  declaration for the instance, and we return the original node.
8351 
8352       --  If it is a compilation unit and the instance node has not been
8353       --  rewritten, then it is still the unit of the compilation. Finally, if
8354       --  a body is present, this is a parent of the main unit whose body has
8355       --  been compiled for inlining purposes, and the instantiation node has
8356       --  been rewritten with the instance body.
8357 
8358       --  Otherwise the instantiation node appears after the declaration. If
8359       --  the entity is a formal package, the declaration may have been
8360       --  rewritten as a generic declaration (in the case of a formal with box)
8361       --  or left as a formal package declaration if it has actuals, and is
8362       --  found with a forward search.
8363 
8364       if Nkind (Parent (Decl)) = N_Compilation_Unit then
8365          if Nkind (Decl) = N_Package_Declaration
8366            and then Present (Corresponding_Body (Decl))
8367          then
8368             Decl := Unit_Declaration_Node (Corresponding_Body (Decl));
8369          end if;
8370 
8371          if Nkind (Original_Node (Decl)) = N_Package_Instantiation then
8372             return Original_Node (Decl);
8373          else
8374             return Unit (Parent (Decl));
8375          end if;
8376 
8377       elsif Nkind (Decl) = N_Package_Declaration
8378         and then Nkind (Original_Node (Decl)) = N_Formal_Package_Declaration
8379       then
8380          return Original_Node (Decl);
8381 
8382       else
8383          Inst := Next (Decl);
8384          while not Nkind_In (Inst, N_Package_Instantiation,
8385                                    N_Formal_Package_Declaration)
8386          loop
8387             Next (Inst);
8388          end loop;
8389 
8390          return Inst;
8391       end if;
8392    end Get_Package_Instantiation_Node;
8393 
8394    ------------------------
8395    -- Has_Been_Exchanged --
8396    ------------------------
8397 
8398    function Has_Been_Exchanged (E : Entity_Id) return Boolean is
8399       Next : Elmt_Id;
8400 
8401    begin
8402       Next := First_Elmt (Exchanged_Views);
8403       while Present (Next) loop
8404          if Full_View (Node (Next)) = E then
8405             return True;
8406          end if;
8407 
8408          Next_Elmt (Next);
8409       end loop;
8410 
8411       return False;
8412    end Has_Been_Exchanged;
8413 
8414    ----------
8415    -- Hash --
8416    ----------
8417 
8418    function Hash (F : Entity_Id) return HTable_Range is
8419    begin
8420       return HTable_Range (F mod HTable_Size);
8421    end Hash;
8422 
8423    ------------------------
8424    -- Hide_Current_Scope --
8425    ------------------------
8426 
8427    procedure Hide_Current_Scope is
8428       C : constant Entity_Id := Current_Scope;
8429       E : Entity_Id;
8430 
8431    begin
8432       Set_Is_Hidden_Open_Scope (C);
8433 
8434       E := First_Entity (C);
8435       while Present (E) loop
8436          if Is_Immediately_Visible (E) then
8437             Set_Is_Immediately_Visible (E, False);
8438             Append_Elmt (E, Hidden_Entities);
8439          end if;
8440 
8441          Next_Entity (E);
8442       end loop;
8443 
8444       --  Make the scope name invisible as well. This is necessary, but might
8445       --  conflict with calls to Rtsfind later on, in case the scope is a
8446       --  predefined one. There is no clean solution to this problem, so for
8447       --  now we depend on the user not redefining Standard itself in one of
8448       --  the parent units.
8449 
8450       if Is_Immediately_Visible (C) and then C /= Standard_Standard then
8451          Set_Is_Immediately_Visible (C, False);
8452          Append_Elmt (C, Hidden_Entities);
8453       end if;
8454 
8455    end Hide_Current_Scope;
8456 
8457    --------------
8458    -- Init_Env --
8459    --------------
8460 
8461    procedure Init_Env is
8462       Saved : Instance_Env;
8463 
8464    begin
8465       Saved.Instantiated_Parent  := Current_Instantiated_Parent;
8466       Saved.Exchanged_Views      := Exchanged_Views;
8467       Saved.Hidden_Entities      := Hidden_Entities;
8468       Saved.Current_Sem_Unit     := Current_Sem_Unit;
8469       Saved.Parent_Unit_Visible  := Parent_Unit_Visible;
8470       Saved.Instance_Parent_Unit := Instance_Parent_Unit;
8471 
8472       --  Save configuration switches. These may be reset if the unit is a
8473       --  predefined unit, and the current mode is not Ada 2005.
8474 
8475       Save_Opt_Config_Switches (Saved.Switches);
8476 
8477       Instance_Envs.Append (Saved);
8478 
8479       Exchanged_Views := New_Elmt_List;
8480       Hidden_Entities := New_Elmt_List;
8481 
8482       --  Make dummy entry for Instantiated parent. If generic unit is legal,
8483       --  this is set properly in Set_Instance_Env.
8484 
8485       Current_Instantiated_Parent :=
8486         (Current_Scope, Current_Scope, Assoc_Null);
8487    end Init_Env;
8488 
8489    ------------------------------
8490    -- In_Same_Declarative_Part --
8491    ------------------------------
8492 
8493    function In_Same_Declarative_Part
8494      (F_Node : Node_Id;
8495       Inst   : Node_Id) return Boolean
8496    is
8497       Decls : constant Node_Id := Parent (F_Node);
8498       Nod   : Node_Id;
8499 
8500    begin
8501       Nod := Parent (Inst);
8502       while Present (Nod) loop
8503          if Nod = Decls then
8504             return True;
8505 
8506          elsif Nkind_In (Nod, N_Subprogram_Body,
8507                               N_Package_Body,
8508                               N_Package_Declaration,
8509                               N_Task_Body,
8510                               N_Protected_Body,
8511                               N_Block_Statement)
8512          then
8513             return False;
8514 
8515          elsif Nkind (Nod) = N_Subunit then
8516             Nod := Corresponding_Stub (Nod);
8517 
8518          elsif Nkind (Nod) = N_Compilation_Unit then
8519             return False;
8520 
8521          else
8522             Nod := Parent (Nod);
8523          end if;
8524       end loop;
8525 
8526       return False;
8527    end In_Same_Declarative_Part;
8528 
8529    ---------------------
8530    -- In_Main_Context --
8531    ---------------------
8532 
8533    function In_Main_Context (E : Entity_Id) return Boolean is
8534       Context : List_Id;
8535       Clause  : Node_Id;
8536       Nam     : Node_Id;
8537 
8538    begin
8539       if not Is_Compilation_Unit (E)
8540         or else Ekind (E) /= E_Package
8541         or else In_Private_Part (E)
8542       then
8543          return False;
8544       end if;
8545 
8546       Context := Context_Items (Cunit (Main_Unit));
8547 
8548       Clause  := First (Context);
8549       while Present (Clause) loop
8550          if Nkind (Clause) = N_With_Clause then
8551             Nam := Name (Clause);
8552 
8553             --  If the current scope is part of the context of the main unit,
8554             --  analysis of the corresponding with_clause is not complete, and
8555             --  the entity is not set. We use the Chars field directly, which
8556             --  might produce false positives in rare cases, but guarantees
8557             --  that we produce all the instance bodies we will need.
8558 
8559             if (Is_Entity_Name (Nam) and then Chars (Nam) = Chars (E))
8560                  or else (Nkind (Nam) = N_Selected_Component
8561                            and then Chars (Selector_Name (Nam)) = Chars (E))
8562             then
8563                return True;
8564             end if;
8565          end if;
8566 
8567          Next (Clause);
8568       end loop;
8569 
8570       return False;
8571    end In_Main_Context;
8572 
8573    ---------------------
8574    -- Inherit_Context --
8575    ---------------------
8576 
8577    procedure Inherit_Context (Gen_Decl : Node_Id; Inst : Node_Id) is
8578       Current_Context : List_Id;
8579       Current_Unit    : Node_Id;
8580       Item            : Node_Id;
8581       New_I           : Node_Id;
8582 
8583       Clause   : Node_Id;
8584       OK       : Boolean;
8585       Lib_Unit : Node_Id;
8586 
8587    begin
8588       if Nkind (Parent (Gen_Decl)) = N_Compilation_Unit then
8589 
8590          --  The inherited context is attached to the enclosing compilation
8591          --  unit. This is either the main unit, or the declaration for the
8592          --  main unit (in case the instantiation appears within the package
8593          --  declaration and the main unit is its body).
8594 
8595          Current_Unit := Parent (Inst);
8596          while Present (Current_Unit)
8597            and then Nkind (Current_Unit) /= N_Compilation_Unit
8598          loop
8599             Current_Unit := Parent (Current_Unit);
8600          end loop;
8601 
8602          Current_Context := Context_Items (Current_Unit);
8603 
8604          Item := First (Context_Items (Parent (Gen_Decl)));
8605          while Present (Item) loop
8606             if Nkind (Item) = N_With_Clause then
8607                Lib_Unit := Library_Unit (Item);
8608 
8609                --  Take care to prevent direct cyclic with's
8610 
8611                if Lib_Unit /= Current_Unit then
8612 
8613                   --  Do not add a unit if it is already in the context
8614 
8615                   Clause := First (Current_Context);
8616                   OK := True;
8617                   while Present (Clause) loop
8618                      if Nkind (Clause) = N_With_Clause and then
8619                        Library_Unit (Clause) = Lib_Unit
8620                      then
8621                         OK := False;
8622                         exit;
8623                      end if;
8624 
8625                      Next (Clause);
8626                   end loop;
8627 
8628                   if OK then
8629                      New_I := New_Copy (Item);
8630                      Set_Implicit_With (New_I, True);
8631                      Set_Implicit_With_From_Instantiation (New_I, True);
8632                      Append (New_I, Current_Context);
8633                   end if;
8634                end if;
8635             end if;
8636 
8637             Next (Item);
8638          end loop;
8639       end if;
8640    end Inherit_Context;
8641 
8642    ----------------
8643    -- Initialize --
8644    ----------------
8645 
8646    procedure Initialize is
8647    begin
8648       Generic_Renamings.Init;
8649       Instance_Envs.Init;
8650       Generic_Flags.Init;
8651       Generic_Renamings_HTable.Reset;
8652       Circularity_Detected := False;
8653       Exchanged_Views      := No_Elist;
8654       Hidden_Entities      := No_Elist;
8655    end Initialize;
8656 
8657    -------------------------------------
8658    -- Insert_Freeze_Node_For_Instance --
8659    -------------------------------------
8660 
8661    procedure Insert_Freeze_Node_For_Instance
8662      (N      : Node_Id;
8663       F_Node : Node_Id)
8664    is
8665       Decl  : Node_Id;
8666       Decls : List_Id;
8667       Inst  : Entity_Id;
8668       Par_N : Node_Id;
8669 
8670       function Enclosing_Body (N : Node_Id) return Node_Id;
8671       --  Find enclosing package or subprogram body, if any. Freeze node may
8672       --  be placed at end of current declarative list if previous instance
8673       --  and current one have different enclosing bodies.
8674 
8675       function Previous_Instance (Gen : Entity_Id) return Entity_Id;
8676       --  Find the local instance, if any, that declares the generic that is
8677       --  being instantiated. If present, the freeze node for this instance
8678       --  must follow the freeze node for the previous instance.
8679 
8680       --------------------
8681       -- Enclosing_Body --
8682       --------------------
8683 
8684       function Enclosing_Body (N : Node_Id) return Node_Id is
8685          P : Node_Id;
8686 
8687       begin
8688          P := Parent (N);
8689          while Present (P)
8690            and then Nkind (Parent (P)) /= N_Compilation_Unit
8691          loop
8692             if Nkind_In (P, N_Package_Body, N_Subprogram_Body) then
8693                if Nkind (Parent (P)) = N_Subunit then
8694                   return Corresponding_Stub (Parent (P));
8695                else
8696                   return P;
8697                end if;
8698             end if;
8699 
8700             P := True_Parent (P);
8701          end loop;
8702 
8703          return Empty;
8704       end Enclosing_Body;
8705 
8706       -----------------------
8707       -- Previous_Instance --
8708       -----------------------
8709 
8710       function Previous_Instance (Gen : Entity_Id) return Entity_Id is
8711          S : Entity_Id;
8712 
8713       begin
8714          S := Scope (Gen);
8715          while Present (S) and then S /= Standard_Standard loop
8716             if Is_Generic_Instance (S)
8717               and then In_Same_Source_Unit (S, N)
8718             then
8719                return S;
8720             end if;
8721 
8722             S := Scope (S);
8723          end loop;
8724 
8725          return Empty;
8726       end Previous_Instance;
8727 
8728    --  Start of processing for Insert_Freeze_Node_For_Instance
8729 
8730    begin
8731       if not Is_List_Member (F_Node) then
8732          Decl  := N;
8733          Decls := List_Containing (N);
8734          Inst  := Entity (F_Node);
8735          Par_N := Parent (Decls);
8736 
8737          --  When processing a subprogram instantiation, utilize the actual
8738          --  subprogram instantiation rather than its package wrapper as it
8739          --  carries all the context information.
8740 
8741          if Is_Wrapper_Package (Inst) then
8742             Inst := Related_Instance (Inst);
8743          end if;
8744 
8745          --  If this is a package instance, check whether the generic is
8746          --  declared in a previous instance and the current instance is
8747          --  not within the previous one.
8748 
8749          if Present (Generic_Parent (Parent (Inst)))
8750            and then Is_In_Main_Unit (N)
8751          then
8752             declare
8753                Enclosing_N : constant Node_Id := Enclosing_Body (N);
8754                Par_I       : constant Entity_Id :=
8755                                Previous_Instance
8756                                  (Generic_Parent (Parent (Inst)));
8757                Scop        : Entity_Id;
8758 
8759             begin
8760                if Present (Par_I)
8761                  and then Earlier (N, Freeze_Node (Par_I))
8762                then
8763                   Scop := Scope (Inst);
8764 
8765                   --  If the current instance is within the one that contains
8766                   --  the generic, the freeze node for the current one must
8767                   --  appear in the current declarative part. Ditto, if the
8768                   --  current instance is within another package instance or
8769                   --  within a body that does not enclose the current instance.
8770                   --  In these three cases the freeze node of the previous
8771                   --  instance is not relevant.
8772 
8773                   while Present (Scop) and then Scop /= Standard_Standard loop
8774                      exit when Scop = Par_I
8775                        or else
8776                          (Is_Generic_Instance (Scop)
8777                            and then Scope_Depth (Scop) > Scope_Depth (Par_I));
8778                      Scop := Scope (Scop);
8779                   end loop;
8780 
8781                   --  Previous instance encloses current instance
8782 
8783                   if Scop = Par_I then
8784                      null;
8785 
8786                   --  If the next node is a source body we must freeze in
8787                   --  the current scope as well.
8788 
8789                   elsif Present (Next (N))
8790                     and then Nkind_In (Next (N), N_Subprogram_Body,
8791                                                  N_Package_Body)
8792                     and then Comes_From_Source (Next (N))
8793                   then
8794                      null;
8795 
8796                   --  Current instance is within an unrelated instance
8797 
8798                   elsif Is_Generic_Instance (Scop) then
8799                      null;
8800 
8801                   --  Current instance is within an unrelated body
8802 
8803                   elsif Present (Enclosing_N)
8804                     and then Enclosing_N /= Enclosing_Body (Par_I)
8805                   then
8806                      null;
8807 
8808                   else
8809                      Insert_After (Freeze_Node (Par_I), F_Node);
8810                      return;
8811                   end if;
8812                end if;
8813             end;
8814          end if;
8815 
8816          --  When the instantiation occurs in a package declaration, append the
8817          --  freeze node to the private declarations (if any).
8818 
8819          if Nkind (Par_N) = N_Package_Specification
8820            and then Decls = Visible_Declarations (Par_N)
8821            and then Present (Private_Declarations (Par_N))
8822            and then not Is_Empty_List (Private_Declarations (Par_N))
8823          then
8824             Decls := Private_Declarations (Par_N);
8825             Decl  := First (Decls);
8826          end if;
8827 
8828          --  Determine the proper freeze point of a package instantiation. We
8829          --  adhere to the general rule of a package or subprogram body causing
8830          --  freezing of anything before it in the same declarative region. In
8831          --  this case, the proper freeze point of a package instantiation is
8832          --  before the first source body which follows, or before a stub. This
8833          --  ensures that entities coming from the instance are already frozen
8834          --  and usable in source bodies.
8835 
8836          if Nkind (Par_N) /= N_Package_Declaration
8837            and then Ekind (Inst) = E_Package
8838            and then Is_Generic_Instance (Inst)
8839            and then
8840              not In_Same_Source_Unit (Generic_Parent (Parent (Inst)), Inst)
8841          then
8842             while Present (Decl) loop
8843                if (Nkind (Decl) in N_Unit_Body
8844                      or else
8845                    Nkind (Decl) in N_Body_Stub)
8846                  and then Comes_From_Source (Decl)
8847                then
8848                   Insert_Before (Decl, F_Node);
8849                   return;
8850                end if;
8851 
8852                Next (Decl);
8853             end loop;
8854          end if;
8855 
8856          --  In a package declaration, or if no previous body, insert at end
8857          --  of list.
8858 
8859          Set_Sloc (F_Node, Sloc (Last (Decls)));
8860          Insert_After (Last (Decls), F_Node);
8861       end if;
8862    end Insert_Freeze_Node_For_Instance;
8863 
8864    ------------------
8865    -- Install_Body --
8866    ------------------
8867 
8868    procedure Install_Body
8869      (Act_Body : Node_Id;
8870       N        : Node_Id;
8871       Gen_Body : Node_Id;
8872       Gen_Decl : Node_Id)
8873    is
8874       Act_Id    : constant Entity_Id := Corresponding_Spec (Act_Body);
8875       Act_Unit  : constant Node_Id   := Unit (Cunit (Get_Source_Unit (N)));
8876       Gen_Id    : constant Entity_Id := Corresponding_Spec (Gen_Body);
8877       Par       : constant Entity_Id := Scope (Gen_Id);
8878       Gen_Unit  : constant Node_Id   :=
8879                     Unit (Cunit (Get_Source_Unit (Gen_Decl)));
8880       Orig_Body : Node_Id := Gen_Body;
8881       F_Node    : Node_Id;
8882       Body_Unit : Node_Id;
8883 
8884       Must_Delay : Boolean;
8885 
8886       function In_Same_Enclosing_Subp return Boolean;
8887       --  Check whether instance and generic body are within same subprogram.
8888 
8889       function True_Sloc (N : Node_Id) return Source_Ptr;
8890       --  If the instance is nested inside a generic unit, the Sloc of the
8891       --  instance indicates the place of the original definition, not the
8892       --  point of the current enclosing instance. Pending a better usage of
8893       --  Slocs to indicate instantiation places, we determine the place of
8894       --  origin of a node by finding the maximum sloc of any ancestor node.
8895       --  Why is this not equivalent to Top_Level_Location ???
8896 
8897       ----------------------------
8898       -- In_Same_Enclosing_Subp --
8899       ----------------------------
8900 
8901       function In_Same_Enclosing_Subp return Boolean is
8902          Scop : Entity_Id;
8903          Subp : Entity_Id;
8904 
8905       begin
8906          Scop := Scope (Act_Id);
8907          while Scop /= Standard_Standard
8908            and then not Is_Overloadable (Scop)
8909          loop
8910             Scop := Scope (Scop);
8911          end loop;
8912 
8913          if Scop = Standard_Standard then
8914             return False;
8915          else
8916             Subp := Scop;
8917          end if;
8918 
8919          Scop := Scope (Gen_Id);
8920          while Scop /= Standard_Standard loop
8921             if Scop = Subp then
8922                return True;
8923             else
8924                Scop := Scope (Scop);
8925             end if;
8926          end loop;
8927 
8928          return False;
8929       end In_Same_Enclosing_Subp;
8930 
8931       ---------------
8932       -- True_Sloc --
8933       ---------------
8934 
8935       function True_Sloc (N : Node_Id) return Source_Ptr is
8936          Res : Source_Ptr;
8937          N1  : Node_Id;
8938 
8939       begin
8940          Res := Sloc (N);
8941          N1 := N;
8942          while Present (N1) and then N1 /= Act_Unit loop
8943             if Sloc (N1) > Res then
8944                Res := Sloc (N1);
8945             end if;
8946 
8947             N1 := Parent (N1);
8948          end loop;
8949 
8950          return Res;
8951       end True_Sloc;
8952 
8953    --  Start of processing for Install_Body
8954 
8955    begin
8956       --  Handle first the case of an instance with incomplete actual types.
8957       --  The instance body cannot be placed after the declaration because
8958       --  full views have not been seen yet. Any use of the non-limited views
8959       --  in the instance body requires the presence of a regular with_clause
8960       --  in the enclosing unit, and will fail if this with_clause is missing.
8961       --  We place the instance body at the beginning of the enclosing body,
8962       --  which is the unit being compiled. The freeze node for the instance
8963       --  is then placed after the instance body.
8964 
8965       if not Is_Empty_Elmt_List (Incomplete_Actuals (Act_Id))
8966         and then Expander_Active
8967         and then Ekind (Scope (Act_Id)) = E_Package
8968       then
8969          declare
8970             Scop    : constant Entity_Id := Scope (Act_Id);
8971             Body_Id : constant Node_Id :=
8972                          Corresponding_Body (Unit_Declaration_Node (Scop));
8973 
8974          begin
8975             Ensure_Freeze_Node (Act_Id);
8976             F_Node := Freeze_Node (Act_Id);
8977             if Present (Body_Id) then
8978                Set_Is_Frozen (Act_Id, False);
8979                Prepend (Act_Body, Declarations (Parent (Body_Id)));
8980                if Is_List_Member (F_Node) then
8981                   Remove (F_Node);
8982                end if;
8983 
8984                Insert_After (Act_Body, F_Node);
8985             end if;
8986          end;
8987          return;
8988       end if;
8989 
8990       --  If the body is a subunit, the freeze point is the corresponding stub
8991       --  in the current compilation, not the subunit itself.
8992 
8993       if Nkind (Parent (Gen_Body)) = N_Subunit then
8994          Orig_Body := Corresponding_Stub (Parent (Gen_Body));
8995       else
8996          Orig_Body := Gen_Body;
8997       end if;
8998 
8999       Body_Unit := Unit (Cunit (Get_Source_Unit (Orig_Body)));
9000 
9001       --  If the instantiation and the generic definition appear in the same
9002       --  package declaration, this is an early instantiation. If they appear
9003       --  in the same declarative part, it is an early instantiation only if
9004       --  the generic body appears textually later, and the generic body is
9005       --  also in the main unit.
9006 
9007       --  If instance is nested within a subprogram, and the generic body
9008       --  is not, the instance is delayed because the enclosing body is. If
9009       --  instance and body are within the same scope, or the same subprogram
9010       --  body, indicate explicitly that the instance is delayed.
9011 
9012       Must_Delay :=
9013         (Gen_Unit = Act_Unit
9014           and then (Nkind_In (Gen_Unit, N_Package_Declaration,
9015                                         N_Generic_Package_Declaration)
9016                      or else (Gen_Unit = Body_Unit
9017                                and then True_Sloc (N) < Sloc (Orig_Body)))
9018           and then Is_In_Main_Unit (Gen_Unit)
9019           and then (Scope (Act_Id) = Scope (Gen_Id)
9020                      or else In_Same_Enclosing_Subp));
9021 
9022       --  If this is an early instantiation, the freeze node is placed after
9023       --  the generic body. Otherwise, if the generic appears in an instance,
9024       --  we cannot freeze the current instance until the outer one is frozen.
9025       --  This is only relevant if the current instance is nested within some
9026       --  inner scope not itself within the outer instance. If this scope is
9027       --  a package body in the same declarative part as the outer instance,
9028       --  then that body needs to be frozen after the outer instance. Finally,
9029       --  if no delay is needed, we place the freeze node at the end of the
9030       --  current declarative part.
9031 
9032       if Expander_Active then
9033          Ensure_Freeze_Node (Act_Id);
9034          F_Node := Freeze_Node (Act_Id);
9035 
9036          if Must_Delay then
9037             Insert_After (Orig_Body, F_Node);
9038 
9039          elsif Is_Generic_Instance (Par)
9040            and then Present (Freeze_Node (Par))
9041            and then Scope (Act_Id) /= Par
9042          then
9043             --  Freeze instance of inner generic after instance of enclosing
9044             --  generic.
9045 
9046             if In_Same_Declarative_Part (Freeze_Node (Par), N) then
9047 
9048                --  Handle the following case:
9049 
9050                --    package Parent_Inst is new ...
9051                --    Parent_Inst []
9052 
9053                --    procedure P ...  --  this body freezes Parent_Inst
9054 
9055                --    package Inst is new ...
9056 
9057                --  In this particular scenario, the freeze node for Inst must
9058                --  be inserted in the same manner as that of Parent_Inst,
9059                --  before the next source body or at the end of the declarative
9060                --  list (body not available). If body P did not exist and
9061                --  Parent_Inst was frozen after Inst, either by a body
9062                --  following Inst or at the end of the declarative region,
9063                --  the freeze node for Inst must be inserted after that of
9064                --  Parent_Inst. This relation is established by comparing
9065                --  the Slocs of Parent_Inst freeze node and Inst.
9066 
9067                if List_Containing (Get_Package_Instantiation_Node (Par)) =
9068                   List_Containing (N)
9069                  and then Sloc (Freeze_Node (Par)) < Sloc (N)
9070                then
9071                   Insert_Freeze_Node_For_Instance (N, F_Node);
9072                else
9073                   Insert_After (Freeze_Node (Par), F_Node);
9074                end if;
9075 
9076             --  Freeze package enclosing instance of inner generic after
9077             --  instance of enclosing generic.
9078 
9079             elsif Nkind_In (Parent (N), N_Package_Body, N_Subprogram_Body)
9080               and then In_Same_Declarative_Part (Freeze_Node (Par), Parent (N))
9081             then
9082                declare
9083                   Enclosing :  Entity_Id;
9084 
9085                begin
9086                   Enclosing := Corresponding_Spec (Parent (N));
9087 
9088                   if No (Enclosing) then
9089                      Enclosing := Defining_Entity (Parent (N));
9090                   end if;
9091 
9092                   Insert_Freeze_Node_For_Instance (N, F_Node);
9093                   Ensure_Freeze_Node (Enclosing);
9094 
9095                   if not Is_List_Member (Freeze_Node (Enclosing)) then
9096 
9097                      --  The enclosing context is a subunit, insert the freeze
9098                      --  node after the stub.
9099 
9100                      if Nkind (Parent (Parent (N))) = N_Subunit then
9101                         Insert_Freeze_Node_For_Instance
9102                           (Corresponding_Stub (Parent (Parent (N))),
9103                            Freeze_Node (Enclosing));
9104 
9105                      --  The enclosing context is a package with a stub body
9106                      --  which has already been replaced by the real body.
9107                      --  Insert the freeze node after the actual body.
9108 
9109                      elsif Ekind (Enclosing) = E_Package
9110                        and then Present (Body_Entity (Enclosing))
9111                        and then Was_Originally_Stub
9112                                   (Parent (Body_Entity (Enclosing)))
9113                      then
9114                         Insert_Freeze_Node_For_Instance
9115                           (Parent (Body_Entity (Enclosing)),
9116                            Freeze_Node (Enclosing));
9117 
9118                      --  The parent instance has been frozen before the body of
9119                      --  the enclosing package, insert the freeze node after
9120                      --  the body.
9121 
9122                      elsif List_Containing (Freeze_Node (Par)) =
9123                            List_Containing (Parent (N))
9124                        and then Sloc (Freeze_Node (Par)) < Sloc (Parent (N))
9125                      then
9126                         Insert_Freeze_Node_For_Instance
9127                           (Parent (N), Freeze_Node (Enclosing));
9128 
9129                      else
9130                         Insert_After
9131                           (Freeze_Node (Par), Freeze_Node (Enclosing));
9132                      end if;
9133                   end if;
9134                end;
9135 
9136             else
9137                Insert_Freeze_Node_For_Instance (N, F_Node);
9138             end if;
9139 
9140          else
9141             Insert_Freeze_Node_For_Instance (N, F_Node);
9142          end if;
9143       end if;
9144 
9145       Set_Is_Frozen (Act_Id);
9146       Insert_Before (N, Act_Body);
9147       Mark_Rewrite_Insertion (Act_Body);
9148    end Install_Body;
9149 
9150    -----------------------------
9151    -- Install_Formal_Packages --
9152    -----------------------------
9153 
9154    procedure Install_Formal_Packages (Par : Entity_Id) is
9155       E     : Entity_Id;
9156       Gen   : Entity_Id;
9157       Gen_E : Entity_Id := Empty;
9158 
9159    begin
9160       E := First_Entity (Par);
9161 
9162       --  If we are installing an instance parent, locate the formal packages
9163       --  of its generic parent.
9164 
9165       if Is_Generic_Instance (Par) then
9166          Gen   := Generic_Parent (Package_Specification (Par));
9167          Gen_E := First_Entity (Gen);
9168       end if;
9169 
9170       while Present (E) loop
9171          if Ekind (E) = E_Package
9172            and then Nkind (Parent (E)) = N_Package_Renaming_Declaration
9173          then
9174             --  If this is the renaming for the parent instance, done
9175 
9176             if Renamed_Object (E) = Par then
9177                exit;
9178 
9179             --  The visibility of a formal of an enclosing generic is already
9180             --  correct.
9181 
9182             elsif Denotes_Formal_Package (E) then
9183                null;
9184 
9185             elsif Present (Associated_Formal_Package (E)) then
9186                Check_Generic_Actuals (Renamed_Object (E), True);
9187                Set_Is_Hidden (E, False);
9188 
9189                --  Find formal package in generic unit that corresponds to
9190                --  (instance of) formal package in instance.
9191 
9192                while Present (Gen_E) and then Chars (Gen_E) /= Chars (E) loop
9193                   Next_Entity (Gen_E);
9194                end loop;
9195 
9196                if Present (Gen_E) then
9197                   Map_Formal_Package_Entities (Gen_E, E);
9198                end if;
9199             end if;
9200          end if;
9201 
9202          Next_Entity (E);
9203 
9204          if Present (Gen_E) then
9205             Next_Entity (Gen_E);
9206          end if;
9207       end loop;
9208    end Install_Formal_Packages;
9209 
9210    --------------------
9211    -- Install_Parent --
9212    --------------------
9213 
9214    procedure Install_Parent (P : Entity_Id; In_Body : Boolean := False) is
9215       Ancestors : constant Elist_Id  := New_Elmt_List;
9216       S         : constant Entity_Id := Current_Scope;
9217       Inst_Par  : Entity_Id;
9218       First_Par : Entity_Id;
9219       Inst_Node : Node_Id;
9220       Gen_Par   : Entity_Id;
9221       First_Gen : Entity_Id;
9222       Elmt      : Elmt_Id;
9223 
9224       procedure Install_Noninstance_Specs (Par : Entity_Id);
9225       --  Install the scopes of noninstance parent units ending with Par
9226 
9227       procedure Install_Spec (Par : Entity_Id);
9228       --  The child unit is within the declarative part of the parent, so the
9229       --  declarations within the parent are immediately visible.
9230 
9231       -------------------------------
9232       -- Install_Noninstance_Specs --
9233       -------------------------------
9234 
9235       procedure Install_Noninstance_Specs (Par : Entity_Id) is
9236       begin
9237          if Present (Par)
9238            and then Par /= Standard_Standard
9239            and then not In_Open_Scopes (Par)
9240          then
9241             Install_Noninstance_Specs (Scope (Par));
9242             Install_Spec (Par);
9243          end if;
9244       end Install_Noninstance_Specs;
9245 
9246       ------------------
9247       -- Install_Spec --
9248       ------------------
9249 
9250       procedure Install_Spec (Par : Entity_Id) is
9251          Spec : constant Node_Id := Package_Specification (Par);
9252 
9253       begin
9254          --  If this parent of the child instance is a top-level unit,
9255          --  then record the unit and its visibility for later resetting in
9256          --  Remove_Parent. We exclude units that are generic instances, as we
9257          --  only want to record this information for the ultimate top-level
9258          --  noninstance parent (is that always correct???).
9259 
9260          if Scope (Par) = Standard_Standard
9261            and then not Is_Generic_Instance (Par)
9262          then
9263             Parent_Unit_Visible := Is_Immediately_Visible (Par);
9264             Instance_Parent_Unit := Par;
9265          end if;
9266 
9267          --  Open the parent scope and make it and its declarations visible.
9268          --  If this point is not within a body, then only the visible
9269          --  declarations should be made visible, and installation of the
9270          --  private declarations is deferred until the appropriate point
9271          --  within analysis of the spec being instantiated (see the handling
9272          --  of parent visibility in Analyze_Package_Specification). This is
9273          --  relaxed in the case where the parent unit is Ada.Tags, to avoid
9274          --  private view problems that occur when compiling instantiations of
9275          --  a generic child of that package (Generic_Dispatching_Constructor).
9276          --  If the instance freezes a tagged type, inlinings of operations
9277          --  from Ada.Tags may need the full view of type Tag. If inlining took
9278          --  proper account of establishing visibility of inlined subprograms'
9279          --  parents then it should be possible to remove this
9280          --  special check. ???
9281 
9282          Push_Scope (Par);
9283          Set_Is_Immediately_Visible   (Par);
9284          Install_Visible_Declarations (Par);
9285          Set_Use (Visible_Declarations (Spec));
9286 
9287          if In_Body or else Is_RTU (Par, Ada_Tags) then
9288             Install_Private_Declarations (Par);
9289             Set_Use (Private_Declarations (Spec));
9290          end if;
9291       end Install_Spec;
9292 
9293    --  Start of processing for Install_Parent
9294 
9295    begin
9296       --  We need to install the parent instance to compile the instantiation
9297       --  of the child, but the child instance must appear in the current
9298       --  scope. Given that we cannot place the parent above the current scope
9299       --  in the scope stack, we duplicate the current scope and unstack both
9300       --  after the instantiation is complete.
9301 
9302       --  If the parent is itself the instantiation of a child unit, we must
9303       --  also stack the instantiation of its parent, and so on. Each such
9304       --  ancestor is the prefix of the name in a prior instantiation.
9305 
9306       --  If this is a nested instance, the parent unit itself resolves to
9307       --  a renaming of the parent instance, whose declaration we need.
9308 
9309       --  Finally, the parent may be a generic (not an instance) when the
9310       --  child unit appears as a formal package.
9311 
9312       Inst_Par := P;
9313 
9314       if Present (Renamed_Entity (Inst_Par)) then
9315          Inst_Par := Renamed_Entity (Inst_Par);
9316       end if;
9317 
9318       First_Par := Inst_Par;
9319 
9320       Gen_Par := Generic_Parent (Package_Specification (Inst_Par));
9321 
9322       First_Gen := Gen_Par;
9323 
9324       while Present (Gen_Par) and then Is_Child_Unit (Gen_Par) loop
9325 
9326          --  Load grandparent instance as well
9327 
9328          Inst_Node := Get_Package_Instantiation_Node (Inst_Par);
9329 
9330          if Nkind (Name (Inst_Node)) = N_Expanded_Name then
9331             Inst_Par := Entity (Prefix (Name (Inst_Node)));
9332 
9333             if Present (Renamed_Entity (Inst_Par)) then
9334                Inst_Par := Renamed_Entity (Inst_Par);
9335             end if;
9336 
9337             Gen_Par := Generic_Parent (Package_Specification (Inst_Par));
9338 
9339             if Present (Gen_Par) then
9340                Prepend_Elmt (Inst_Par, Ancestors);
9341 
9342             else
9343                --  Parent is not the name of an instantiation
9344 
9345                Install_Noninstance_Specs (Inst_Par);
9346                exit;
9347             end if;
9348 
9349          else
9350             --  Previous error
9351 
9352             exit;
9353          end if;
9354       end loop;
9355 
9356       if Present (First_Gen) then
9357          Append_Elmt (First_Par, Ancestors);
9358       else
9359          Install_Noninstance_Specs (First_Par);
9360       end if;
9361 
9362       if not Is_Empty_Elmt_List (Ancestors) then
9363          Elmt := First_Elmt (Ancestors);
9364          while Present (Elmt) loop
9365             Install_Spec (Node (Elmt));
9366             Install_Formal_Packages (Node (Elmt));
9367             Next_Elmt (Elmt);
9368          end loop;
9369       end if;
9370 
9371       if not In_Body then
9372          Push_Scope (S);
9373       end if;
9374    end Install_Parent;
9375 
9376    -------------------------------
9377    -- Install_Hidden_Primitives --
9378    -------------------------------
9379 
9380    procedure Install_Hidden_Primitives
9381      (Prims_List : in out Elist_Id;
9382       Gen_T      : Entity_Id;
9383       Act_T      : Entity_Id)
9384    is
9385       Elmt        : Elmt_Id;
9386       List        : Elist_Id := No_Elist;
9387       Prim_G_Elmt : Elmt_Id;
9388       Prim_A_Elmt : Elmt_Id;
9389       Prim_G      : Node_Id;
9390       Prim_A      : Node_Id;
9391 
9392    begin
9393       --  No action needed in case of serious errors because we cannot trust
9394       --  in the order of primitives
9395 
9396       if Serious_Errors_Detected > 0 then
9397          return;
9398 
9399       --  No action possible if we don't have available the list of primitive
9400       --  operations
9401 
9402       elsif No (Gen_T)
9403         or else not Is_Record_Type (Gen_T)
9404         or else not Is_Tagged_Type (Gen_T)
9405         or else not Is_Record_Type (Act_T)
9406         or else not Is_Tagged_Type (Act_T)
9407       then
9408          return;
9409 
9410       --  There is no need to handle interface types since their primitives
9411       --  cannot be hidden
9412 
9413       elsif Is_Interface (Gen_T) then
9414          return;
9415       end if;
9416 
9417       Prim_G_Elmt := First_Elmt (Primitive_Operations (Gen_T));
9418 
9419       if not Is_Class_Wide_Type (Act_T) then
9420          Prim_A_Elmt := First_Elmt (Primitive_Operations (Act_T));
9421       else
9422          Prim_A_Elmt := First_Elmt (Primitive_Operations (Root_Type (Act_T)));
9423       end if;
9424 
9425       loop
9426          --  Skip predefined primitives in the generic formal
9427 
9428          while Present (Prim_G_Elmt)
9429            and then Is_Predefined_Dispatching_Operation (Node (Prim_G_Elmt))
9430          loop
9431             Next_Elmt (Prim_G_Elmt);
9432          end loop;
9433 
9434          --  Skip predefined primitives in the generic actual
9435 
9436          while Present (Prim_A_Elmt)
9437            and then Is_Predefined_Dispatching_Operation (Node (Prim_A_Elmt))
9438          loop
9439             Next_Elmt (Prim_A_Elmt);
9440          end loop;
9441 
9442          exit when No (Prim_G_Elmt) or else No (Prim_A_Elmt);
9443 
9444          Prim_G := Node (Prim_G_Elmt);
9445          Prim_A := Node (Prim_A_Elmt);
9446 
9447          --  There is no need to handle interface primitives because their
9448          --  primitives are not hidden
9449 
9450          exit when Present (Interface_Alias (Prim_G));
9451 
9452          --  Here we install one hidden primitive
9453 
9454          if Chars (Prim_G) /= Chars (Prim_A)
9455            and then Has_Suffix (Prim_A, 'P')
9456            and then Remove_Suffix (Prim_A, 'P') = Chars (Prim_G)
9457          then
9458             Set_Chars (Prim_A, Chars (Prim_G));
9459             Append_New_Elmt (Prim_A, To => List);
9460          end if;
9461 
9462          Next_Elmt (Prim_A_Elmt);
9463          Next_Elmt (Prim_G_Elmt);
9464       end loop;
9465 
9466       --  Append the elements to the list of temporarily visible primitives
9467       --  avoiding duplicates.
9468 
9469       if Present (List) then
9470          if No (Prims_List) then
9471             Prims_List := New_Elmt_List;
9472          end if;
9473 
9474          Elmt := First_Elmt (List);
9475          while Present (Elmt) loop
9476             Append_Unique_Elmt (Node (Elmt), Prims_List);
9477             Next_Elmt (Elmt);
9478          end loop;
9479       end if;
9480    end Install_Hidden_Primitives;
9481 
9482    -------------------------------
9483    -- Restore_Hidden_Primitives --
9484    -------------------------------
9485 
9486    procedure Restore_Hidden_Primitives (Prims_List : in out Elist_Id) is
9487       Prim_Elmt : Elmt_Id;
9488       Prim      : Node_Id;
9489 
9490    begin
9491       if Prims_List /= No_Elist then
9492          Prim_Elmt := First_Elmt (Prims_List);
9493          while Present (Prim_Elmt) loop
9494             Prim := Node (Prim_Elmt);
9495             Set_Chars (Prim, Add_Suffix (Prim, 'P'));
9496             Next_Elmt (Prim_Elmt);
9497          end loop;
9498 
9499          Prims_List := No_Elist;
9500       end if;
9501    end Restore_Hidden_Primitives;
9502 
9503    --------------------------------
9504    -- Instantiate_Formal_Package --
9505    --------------------------------
9506 
9507    function Instantiate_Formal_Package
9508      (Formal          : Node_Id;
9509       Actual          : Node_Id;
9510       Analyzed_Formal : Node_Id) return List_Id
9511    is
9512       Loc         : constant Source_Ptr := Sloc (Actual);
9513       Actual_Pack : Entity_Id;
9514       Formal_Pack : Entity_Id;
9515       Gen_Parent  : Entity_Id;
9516       Decls       : List_Id;
9517       Nod         : Node_Id;
9518       Parent_Spec : Node_Id;
9519 
9520       procedure Find_Matching_Actual
9521        (F    : Node_Id;
9522         Act  : in out Entity_Id);
9523       --  We need to associate each formal entity in the formal package with
9524       --  the corresponding entity in the actual package. The actual package
9525       --  has been analyzed and possibly expanded, and as a result there is
9526       --  no one-to-one correspondence between the two lists (for example,
9527       --  the actual may include subtypes, itypes, and inherited primitive
9528       --  operations, interspersed among the renaming declarations for the
9529       --  actuals). We retrieve the corresponding actual by name because each
9530       --  actual has the same name as the formal, and they do appear in the
9531       --  same order.
9532 
9533       function Get_Formal_Entity (N : Node_Id) return Entity_Id;
9534       --  Retrieve entity of defining entity of generic formal parameter.
9535       --  Only the declarations of formals need to be considered when
9536       --  linking them to actuals, but the declarative list may include
9537       --  internal entities generated during analysis, and those are ignored.
9538 
9539       procedure Match_Formal_Entity
9540         (Formal_Node : Node_Id;
9541          Formal_Ent  : Entity_Id;
9542          Actual_Ent  : Entity_Id);
9543       --  Associates the formal entity with the actual. In the case where
9544       --  Formal_Ent is a formal package, this procedure iterates through all
9545       --  of its formals and enters associations between the actuals occurring
9546       --  in the formal package's corresponding actual package (given by
9547       --  Actual_Ent) and the formal package's formal parameters. This
9548       --  procedure recurses if any of the parameters is itself a package.
9549 
9550       function Is_Instance_Of
9551         (Act_Spec : Entity_Id;
9552          Gen_Anc  : Entity_Id) return Boolean;
9553       --  The actual can be an instantiation of a generic within another
9554       --  instance, in which case there is no direct link from it to the
9555       --  original generic ancestor. In that case, we recognize that the
9556       --  ultimate ancestor is the same by examining names and scopes.
9557 
9558       procedure Process_Nested_Formal (Formal : Entity_Id);
9559       --  If the current formal is declared with a box, its own formals are
9560       --  visible in the instance, as they were in the generic, and their
9561       --  Hidden flag must be reset. If some of these formals are themselves
9562       --  packages declared with a box, the processing must be recursive.
9563 
9564       --------------------------
9565       -- Find_Matching_Actual --
9566       --------------------------
9567 
9568       procedure Find_Matching_Actual
9569         (F   : Node_Id;
9570          Act : in out Entity_Id)
9571      is
9572          Formal_Ent : Entity_Id;
9573 
9574       begin
9575          case Nkind (Original_Node (F)) is
9576             when N_Formal_Object_Declaration |
9577                  N_Formal_Type_Declaration   =>
9578                Formal_Ent := Defining_Identifier (F);
9579 
9580                while Chars (Act) /= Chars (Formal_Ent) loop
9581                   Next_Entity (Act);
9582                end loop;
9583 
9584             when N_Formal_Subprogram_Declaration |
9585                  N_Formal_Package_Declaration    |
9586                  N_Package_Declaration           |
9587                  N_Generic_Package_Declaration   =>
9588                Formal_Ent := Defining_Entity (F);
9589 
9590                while Chars (Act) /= Chars (Formal_Ent) loop
9591                   Next_Entity (Act);
9592                end loop;
9593 
9594             when others =>
9595                raise Program_Error;
9596          end case;
9597       end Find_Matching_Actual;
9598 
9599       -------------------------
9600       -- Match_Formal_Entity --
9601       -------------------------
9602 
9603       procedure Match_Formal_Entity
9604         (Formal_Node : Node_Id;
9605          Formal_Ent  : Entity_Id;
9606          Actual_Ent  : Entity_Id)
9607       is
9608          Act_Pkg   : Entity_Id;
9609 
9610       begin
9611          Set_Instance_Of (Formal_Ent, Actual_Ent);
9612 
9613          if Ekind (Actual_Ent) = E_Package then
9614 
9615             --  Record associations for each parameter
9616 
9617             Act_Pkg := Actual_Ent;
9618 
9619             declare
9620                A_Ent  : Entity_Id := First_Entity (Act_Pkg);
9621                F_Ent  : Entity_Id;
9622                F_Node : Node_Id;
9623 
9624                Gen_Decl : Node_Id;
9625                Formals  : List_Id;
9626                Actual   : Entity_Id;
9627 
9628             begin
9629                --  Retrieve the actual given in the formal package declaration
9630 
9631                Actual := Entity (Name (Original_Node (Formal_Node)));
9632 
9633                --  The actual in the formal package declaration may be a
9634                --  renamed generic package, in which case we want to retrieve
9635                --  the original generic in order to traverse its formal part.
9636 
9637                if Present (Renamed_Entity (Actual)) then
9638                   Gen_Decl := Unit_Declaration_Node (Renamed_Entity (Actual));
9639                else
9640                   Gen_Decl := Unit_Declaration_Node (Actual);
9641                end if;
9642 
9643                Formals := Generic_Formal_Declarations (Gen_Decl);
9644 
9645                if Present (Formals) then
9646                   F_Node := First_Non_Pragma (Formals);
9647                else
9648                   F_Node := Empty;
9649                end if;
9650 
9651                while Present (A_Ent)
9652                  and then Present (F_Node)
9653                  and then A_Ent /= First_Private_Entity (Act_Pkg)
9654                loop
9655                   F_Ent := Get_Formal_Entity (F_Node);
9656 
9657                   if Present (F_Ent) then
9658 
9659                      --  This is a formal of the original package. Record
9660                      --  association and recurse.
9661 
9662                      Find_Matching_Actual (F_Node, A_Ent);
9663                      Match_Formal_Entity (F_Node, F_Ent, A_Ent);
9664                      Next_Entity (A_Ent);
9665                   end if;
9666 
9667                   Next_Non_Pragma (F_Node);
9668                end loop;
9669             end;
9670          end if;
9671       end Match_Formal_Entity;
9672 
9673       -----------------------
9674       -- Get_Formal_Entity --
9675       -----------------------
9676 
9677       function Get_Formal_Entity (N : Node_Id) return Entity_Id is
9678          Kind : constant Node_Kind := Nkind (Original_Node (N));
9679       begin
9680          case Kind is
9681             when N_Formal_Object_Declaration     =>
9682                return Defining_Identifier (N);
9683 
9684             when N_Formal_Type_Declaration       =>
9685                return Defining_Identifier (N);
9686 
9687             when N_Formal_Subprogram_Declaration =>
9688                return Defining_Unit_Name (Specification (N));
9689 
9690             when N_Formal_Package_Declaration    =>
9691                return Defining_Identifier (Original_Node (N));
9692 
9693             when N_Generic_Package_Declaration   =>
9694                return Defining_Identifier (Original_Node (N));
9695 
9696             --  All other declarations are introduced by semantic analysis and
9697             --  have no match in the actual.
9698 
9699             when others =>
9700                return Empty;
9701          end case;
9702       end Get_Formal_Entity;
9703 
9704       --------------------
9705       -- Is_Instance_Of --
9706       --------------------
9707 
9708       function Is_Instance_Of
9709         (Act_Spec : Entity_Id;
9710          Gen_Anc  : Entity_Id) return Boolean
9711       is
9712          Gen_Par : constant Entity_Id := Generic_Parent (Act_Spec);
9713 
9714       begin
9715          if No (Gen_Par) then
9716             return False;
9717 
9718          --  Simplest case: the generic parent of the actual is the formal
9719 
9720          elsif Gen_Par = Gen_Anc then
9721             return True;
9722 
9723          elsif Chars (Gen_Par) /= Chars (Gen_Anc) then
9724             return False;
9725 
9726          --  The actual may be obtained through several instantiations. Its
9727          --  scope must itself be an instance of a generic declared in the
9728          --  same scope as the formal. Any other case is detected above.
9729 
9730          elsif not Is_Generic_Instance (Scope (Gen_Par)) then
9731             return False;
9732 
9733          else
9734             return Generic_Parent (Parent (Scope (Gen_Par))) = Scope (Gen_Anc);
9735          end if;
9736       end Is_Instance_Of;
9737 
9738       ---------------------------
9739       -- Process_Nested_Formal --
9740       ---------------------------
9741 
9742       procedure Process_Nested_Formal (Formal : Entity_Id) is
9743          Ent : Entity_Id;
9744 
9745       begin
9746          if Present (Associated_Formal_Package (Formal))
9747            and then Box_Present (Parent (Associated_Formal_Package (Formal)))
9748          then
9749             Ent := First_Entity (Formal);
9750             while Present (Ent) loop
9751                Set_Is_Hidden (Ent, False);
9752                Set_Is_Visible_Formal (Ent);
9753                Set_Is_Potentially_Use_Visible
9754                  (Ent, Is_Potentially_Use_Visible (Formal));
9755 
9756                if Ekind (Ent) = E_Package then
9757                   exit when Renamed_Entity (Ent) = Renamed_Entity (Formal);
9758                   Process_Nested_Formal (Ent);
9759                end if;
9760 
9761                Next_Entity (Ent);
9762             end loop;
9763          end if;
9764       end Process_Nested_Formal;
9765 
9766    --  Start of processing for Instantiate_Formal_Package
9767 
9768    begin
9769       Analyze (Actual);
9770 
9771       if not Is_Entity_Name (Actual)
9772         or else Ekind (Entity (Actual)) /= E_Package
9773       then
9774          Error_Msg_N
9775            ("expect package instance to instantiate formal", Actual);
9776          Abandon_Instantiation (Actual);
9777          raise Program_Error;
9778 
9779       else
9780          Actual_Pack := Entity (Actual);
9781          Set_Is_Instantiated (Actual_Pack);
9782 
9783          --  The actual may be a renamed package, or an outer generic formal
9784          --  package whose instantiation is converted into a renaming.
9785 
9786          if Present (Renamed_Object (Actual_Pack)) then
9787             Actual_Pack := Renamed_Object (Actual_Pack);
9788          end if;
9789 
9790          if Nkind (Analyzed_Formal) = N_Formal_Package_Declaration then
9791             Gen_Parent  := Get_Instance_Of (Entity (Name (Analyzed_Formal)));
9792             Formal_Pack := Defining_Identifier (Analyzed_Formal);
9793          else
9794             Gen_Parent :=
9795               Generic_Parent (Specification (Analyzed_Formal));
9796             Formal_Pack :=
9797               Defining_Unit_Name (Specification (Analyzed_Formal));
9798          end if;
9799 
9800          if Nkind (Parent (Actual_Pack)) = N_Defining_Program_Unit_Name then
9801             Parent_Spec := Package_Specification (Actual_Pack);
9802          else
9803             Parent_Spec := Parent (Actual_Pack);
9804          end if;
9805 
9806          if Gen_Parent = Any_Id then
9807             Error_Msg_N
9808               ("previous error in declaration of formal package", Actual);
9809             Abandon_Instantiation (Actual);
9810 
9811          elsif
9812            Is_Instance_Of (Parent_Spec, Get_Instance_Of (Gen_Parent))
9813          then
9814             null;
9815 
9816          else
9817             Error_Msg_NE
9818               ("actual parameter must be instance of&", Actual, Gen_Parent);
9819             Abandon_Instantiation (Actual);
9820          end if;
9821 
9822          Set_Instance_Of (Defining_Identifier (Formal), Actual_Pack);
9823          Map_Formal_Package_Entities (Formal_Pack, Actual_Pack);
9824 
9825          Nod :=
9826            Make_Package_Renaming_Declaration (Loc,
9827              Defining_Unit_Name => New_Copy (Defining_Identifier (Formal)),
9828              Name               => New_Occurrence_Of (Actual_Pack, Loc));
9829 
9830          Set_Associated_Formal_Package
9831            (Defining_Unit_Name (Nod), Defining_Identifier (Formal));
9832          Decls := New_List (Nod);
9833 
9834          --  If the formal F has a box, then the generic declarations are
9835          --  visible in the generic G. In an instance of G, the corresponding
9836          --  entities in the actual for F (which are the actuals for the
9837          --  instantiation of the generic that F denotes) must also be made
9838          --  visible for analysis of the current instance. On exit from the
9839          --  current instance, those entities are made private again. If the
9840          --  actual is currently in use, these entities are also use-visible.
9841 
9842          --  The loop through the actual entities also steps through the formal
9843          --  entities and enters associations from formals to actuals into the
9844          --  renaming map. This is necessary to properly handle checking of
9845          --  actual parameter associations for later formals that depend on
9846          --  actuals declared in the formal package.
9847 
9848          --  In Ada 2005, partial parameterization requires that we make
9849          --  visible the actuals corresponding to formals that were defaulted
9850          --  in the formal package. There formals are identified because they
9851          --  remain formal generics within the formal package, rather than
9852          --  being renamings of the actuals supplied.
9853 
9854          declare
9855             Gen_Decl : constant Node_Id :=
9856                          Unit_Declaration_Node (Gen_Parent);
9857             Formals  : constant List_Id :=
9858                          Generic_Formal_Declarations (Gen_Decl);
9859 
9860             Actual_Ent       : Entity_Id;
9861             Actual_Of_Formal : Node_Id;
9862             Formal_Node      : Node_Id;
9863             Formal_Ent       : Entity_Id;
9864 
9865          begin
9866             if Present (Formals) then
9867                Formal_Node := First_Non_Pragma (Formals);
9868             else
9869                Formal_Node := Empty;
9870             end if;
9871 
9872             Actual_Ent := First_Entity (Actual_Pack);
9873             Actual_Of_Formal :=
9874                First (Visible_Declarations (Specification (Analyzed_Formal)));
9875             while Present (Actual_Ent)
9876               and then Actual_Ent /= First_Private_Entity (Actual_Pack)
9877             loop
9878                if Present (Formal_Node) then
9879                   Formal_Ent := Get_Formal_Entity (Formal_Node);
9880 
9881                   if Present (Formal_Ent) then
9882                      Find_Matching_Actual (Formal_Node, Actual_Ent);
9883                      Match_Formal_Entity (Formal_Node, Formal_Ent, Actual_Ent);
9884 
9885                      --  We iterate at the same time over the actuals of the
9886                      --  local package created for the formal, to determine
9887                      --  which one of the formals of the original generic were
9888                      --  defaulted in the formal. The corresponding actual
9889                      --  entities are visible in the enclosing instance.
9890 
9891                      if Box_Present (Formal)
9892                        or else
9893                          (Present (Actual_Of_Formal)
9894                            and then
9895                              Is_Generic_Formal
9896                                (Get_Formal_Entity (Actual_Of_Formal)))
9897                      then
9898                         Set_Is_Hidden (Actual_Ent, False);
9899                         Set_Is_Visible_Formal (Actual_Ent);
9900                         Set_Is_Potentially_Use_Visible
9901                           (Actual_Ent, In_Use (Actual_Pack));
9902 
9903                         if Ekind (Actual_Ent) = E_Package then
9904                            Process_Nested_Formal (Actual_Ent);
9905                         end if;
9906 
9907                      else
9908                         Set_Is_Hidden (Actual_Ent);
9909                         Set_Is_Potentially_Use_Visible (Actual_Ent, False);
9910                      end if;
9911                   end if;
9912 
9913                   Next_Non_Pragma (Formal_Node);
9914                   Next (Actual_Of_Formal);
9915 
9916                else
9917                   --  No further formals to match, but the generic part may
9918                   --  contain inherited operation that are not hidden in the
9919                   --  enclosing instance.
9920 
9921                   Next_Entity (Actual_Ent);
9922                end if;
9923             end loop;
9924 
9925             --  Inherited subprograms generated by formal derived types are
9926             --  also visible if the types are.
9927 
9928             Actual_Ent := First_Entity (Actual_Pack);
9929             while Present (Actual_Ent)
9930               and then Actual_Ent /= First_Private_Entity (Actual_Pack)
9931             loop
9932                if Is_Overloadable (Actual_Ent)
9933                  and then
9934                    Nkind (Parent (Actual_Ent)) = N_Subtype_Declaration
9935                  and then
9936                    not Is_Hidden (Defining_Identifier (Parent (Actual_Ent)))
9937                then
9938                   Set_Is_Hidden (Actual_Ent, False);
9939                   Set_Is_Potentially_Use_Visible
9940                     (Actual_Ent, In_Use (Actual_Pack));
9941                end if;
9942 
9943                Next_Entity (Actual_Ent);
9944             end loop;
9945          end;
9946 
9947          --  If the formal is not declared with a box, reanalyze it as an
9948          --  abbreviated instantiation, to verify the matching rules of 12.7.
9949          --  The actual checks are performed after the generic associations
9950          --  have been analyzed, to guarantee the same visibility for this
9951          --  instantiation and for the actuals.
9952 
9953          --  In Ada 2005, the generic associations for the formal can include
9954          --  defaulted parameters. These are ignored during check. This
9955          --  internal instantiation is removed from the tree after conformance
9956          --  checking, because it contains formal declarations for those
9957          --  defaulted parameters, and those should not reach the back-end.
9958 
9959          if not Box_Present (Formal) then
9960             declare
9961                I_Pack : constant Entity_Id :=
9962                           Make_Temporary (Sloc (Actual), 'P');
9963 
9964             begin
9965                Set_Is_Internal (I_Pack);
9966 
9967                Append_To (Decls,
9968                  Make_Package_Instantiation (Sloc (Actual),
9969                    Defining_Unit_Name   => I_Pack,
9970                    Name                 =>
9971                      New_Occurrence_Of
9972                        (Get_Instance_Of (Gen_Parent), Sloc (Actual)),
9973                    Generic_Associations => Generic_Associations (Formal)));
9974             end;
9975          end if;
9976 
9977          return Decls;
9978       end if;
9979    end Instantiate_Formal_Package;
9980 
9981    -----------------------------------
9982    -- Instantiate_Formal_Subprogram --
9983    -----------------------------------
9984 
9985    function Instantiate_Formal_Subprogram
9986      (Formal          : Node_Id;
9987       Actual          : Node_Id;
9988       Analyzed_Formal : Node_Id) return Node_Id
9989    is
9990       Analyzed_S : constant Entity_Id :=
9991                      Defining_Unit_Name (Specification (Analyzed_Formal));
9992       Formal_Sub : constant Entity_Id :=
9993                      Defining_Unit_Name (Specification (Formal));
9994 
9995       function From_Parent_Scope (Subp : Entity_Id) return Boolean;
9996       --  If the generic is a child unit, the parent has been installed on the
9997       --  scope stack, but a default subprogram cannot resolve to something
9998       --  on the parent because that parent is not really part of the visible
9999       --  context (it is there to resolve explicit local entities). If the
10000       --  default has resolved in this way, we remove the entity from immediate
10001       --  visibility and analyze the node again to emit an error message or
10002       --  find another visible candidate.
10003 
10004       procedure Valid_Actual_Subprogram (Act : Node_Id);
10005       --  Perform legality check and raise exception on failure
10006 
10007       -----------------------
10008       -- From_Parent_Scope --
10009       -----------------------
10010 
10011       function From_Parent_Scope (Subp : Entity_Id) return Boolean is
10012          Gen_Scope : Node_Id;
10013 
10014       begin
10015          Gen_Scope := Scope (Analyzed_S);
10016          while Present (Gen_Scope) and then Is_Child_Unit (Gen_Scope) loop
10017             if Scope (Subp) = Scope (Gen_Scope) then
10018                return True;
10019             end if;
10020 
10021             Gen_Scope := Scope (Gen_Scope);
10022          end loop;
10023 
10024          return False;
10025       end From_Parent_Scope;
10026 
10027       -----------------------------
10028       -- Valid_Actual_Subprogram --
10029       -----------------------------
10030 
10031       procedure Valid_Actual_Subprogram (Act : Node_Id) is
10032          Act_E : Entity_Id;
10033 
10034       begin
10035          if Is_Entity_Name (Act) then
10036             Act_E := Entity (Act);
10037 
10038          elsif Nkind (Act) = N_Selected_Component
10039            and then Is_Entity_Name (Selector_Name (Act))
10040          then
10041             Act_E := Entity (Selector_Name (Act));
10042 
10043          else
10044             Act_E := Empty;
10045          end if;
10046 
10047          if (Present (Act_E) and then Is_Overloadable (Act_E))
10048            or else Nkind_In (Act, N_Attribute_Reference,
10049                                   N_Indexed_Component,
10050                                   N_Character_Literal,
10051                                   N_Explicit_Dereference)
10052          then
10053             return;
10054          end if;
10055 
10056          Error_Msg_NE
10057            ("expect subprogram or entry name in instantiation of &",
10058             Instantiation_Node, Formal_Sub);
10059          Abandon_Instantiation (Instantiation_Node);
10060       end Valid_Actual_Subprogram;
10061 
10062       --  Local variables
10063 
10064       Decl_Node  : Node_Id;
10065       Loc        : Source_Ptr;
10066       Nam        : Node_Id;
10067       New_Spec   : Node_Id;
10068       New_Subp   : Entity_Id;
10069 
10070    --  Start of processing for Instantiate_Formal_Subprogram
10071 
10072    begin
10073       New_Spec := New_Copy_Tree (Specification (Formal));
10074 
10075       --  The tree copy has created the proper instantiation sloc for the
10076       --  new specification. Use this location for all other constructed
10077       --  declarations.
10078 
10079       Loc := Sloc (Defining_Unit_Name (New_Spec));
10080 
10081       --  Create new entity for the actual (New_Copy_Tree does not), and
10082       --  indicate that it is an actual.
10083 
10084       New_Subp := Make_Defining_Identifier (Loc, Chars (Formal_Sub));
10085       Set_Ekind (New_Subp, Ekind (Analyzed_S));
10086       Set_Is_Generic_Actual_Subprogram (New_Subp);
10087       Set_Defining_Unit_Name (New_Spec, New_Subp);
10088 
10089       --  Create new entities for the each of the formals in the specification
10090       --  of the renaming declaration built for the actual.
10091 
10092       if Present (Parameter_Specifications (New_Spec)) then
10093          declare
10094             F    : Node_Id;
10095             F_Id : Entity_Id;
10096 
10097          begin
10098             F := First (Parameter_Specifications (New_Spec));
10099             while Present (F) loop
10100                F_Id := Defining_Identifier (F);
10101 
10102                Set_Defining_Identifier (F,
10103                   Make_Defining_Identifier (Sloc (F_Id), Chars (F_Id)));
10104                Next (F);
10105             end loop;
10106          end;
10107       end if;
10108 
10109       --  Find entity of actual. If the actual is an attribute reference, it
10110       --  cannot be resolved here (its formal is missing) but is handled
10111       --  instead in Attribute_Renaming. If the actual is overloaded, it is
10112       --  fully resolved subsequently, when the renaming declaration for the
10113       --  formal is analyzed. If it is an explicit dereference, resolve the
10114       --  prefix but not the actual itself, to prevent interpretation as call.
10115 
10116       if Present (Actual) then
10117          Loc := Sloc (Actual);
10118          Set_Sloc (New_Spec, Loc);
10119 
10120          if Nkind (Actual) = N_Operator_Symbol then
10121             Find_Direct_Name (Actual);
10122 
10123          elsif Nkind (Actual) = N_Explicit_Dereference then
10124             Analyze (Prefix (Actual));
10125 
10126          elsif Nkind (Actual) /= N_Attribute_Reference then
10127             Analyze (Actual);
10128          end if;
10129 
10130          Valid_Actual_Subprogram (Actual);
10131          Nam := Actual;
10132 
10133       elsif Present (Default_Name (Formal)) then
10134          if not Nkind_In (Default_Name (Formal), N_Attribute_Reference,
10135                                                  N_Selected_Component,
10136                                                  N_Indexed_Component,
10137                                                  N_Character_Literal)
10138            and then Present (Entity (Default_Name (Formal)))
10139          then
10140             Nam := New_Occurrence_Of (Entity (Default_Name (Formal)), Loc);
10141          else
10142             Nam := New_Copy (Default_Name (Formal));
10143             Set_Sloc (Nam, Loc);
10144          end if;
10145 
10146       elsif Box_Present (Formal) then
10147 
10148          --  Actual is resolved at the point of instantiation. Create an
10149          --  identifier or operator with the same name as the formal.
10150 
10151          if Nkind (Formal_Sub) = N_Defining_Operator_Symbol then
10152             Nam :=
10153               Make_Operator_Symbol (Loc,
10154                 Chars  => Chars (Formal_Sub),
10155                 Strval => No_String);
10156          else
10157             Nam := Make_Identifier (Loc, Chars (Formal_Sub));
10158          end if;
10159 
10160       elsif Nkind (Specification (Formal)) = N_Procedure_Specification
10161         and then Null_Present (Specification (Formal))
10162       then
10163          --  Generate null body for procedure, for use in the instance
10164 
10165          Decl_Node :=
10166            Make_Subprogram_Body (Loc,
10167              Specification              => New_Spec,
10168              Declarations               => New_List,
10169              Handled_Statement_Sequence =>
10170                Make_Handled_Sequence_Of_Statements (Loc,
10171                  Statements => New_List (Make_Null_Statement (Loc))));
10172 
10173          Set_Is_Intrinsic_Subprogram (Defining_Unit_Name (New_Spec));
10174          return Decl_Node;
10175 
10176       else
10177          Error_Msg_Sloc := Sloc (Scope (Analyzed_S));
10178          Error_Msg_NE
10179            ("missing actual&", Instantiation_Node, Formal_Sub);
10180          Error_Msg_NE
10181            ("\in instantiation of & declared#",
10182               Instantiation_Node, Scope (Analyzed_S));
10183          Abandon_Instantiation (Instantiation_Node);
10184       end if;
10185 
10186       Decl_Node :=
10187         Make_Subprogram_Renaming_Declaration (Loc,
10188           Specification => New_Spec,
10189           Name          => Nam);
10190 
10191       --  If we do not have an actual and the formal specified <> then set to
10192       --  get proper default.
10193 
10194       if No (Actual) and then Box_Present (Formal) then
10195          Set_From_Default (Decl_Node);
10196       end if;
10197 
10198       --  Gather possible interpretations for the actual before analyzing the
10199       --  instance. If overloaded, it will be resolved when analyzing the
10200       --  renaming declaration.
10201 
10202       if Box_Present (Formal) and then No (Actual) then
10203          Analyze (Nam);
10204 
10205          if Is_Child_Unit (Scope (Analyzed_S))
10206            and then Present (Entity (Nam))
10207          then
10208             if not Is_Overloaded (Nam) then
10209                if From_Parent_Scope (Entity (Nam)) then
10210                   Set_Is_Immediately_Visible (Entity (Nam), False);
10211                   Set_Entity (Nam, Empty);
10212                   Set_Etype (Nam, Empty);
10213 
10214                   Analyze (Nam);
10215                   Set_Is_Immediately_Visible (Entity (Nam));
10216                end if;
10217 
10218             else
10219                declare
10220                   I  : Interp_Index;
10221                   It : Interp;
10222 
10223                begin
10224                   Get_First_Interp (Nam, I, It);
10225                   while Present (It.Nam) loop
10226                      if From_Parent_Scope (It.Nam) then
10227                         Remove_Interp (I);
10228                      end if;
10229 
10230                      Get_Next_Interp (I, It);
10231                   end loop;
10232                end;
10233             end if;
10234          end if;
10235       end if;
10236 
10237       --  The generic instantiation freezes the actual. This can only be done
10238       --  once the actual is resolved, in the analysis of the renaming
10239       --  declaration. To make the formal subprogram entity available, we set
10240       --  Corresponding_Formal_Spec to point to the formal subprogram entity.
10241       --  This is also needed in Analyze_Subprogram_Renaming for the processing
10242       --  of formal abstract subprograms.
10243 
10244       Set_Corresponding_Formal_Spec (Decl_Node, Analyzed_S);
10245 
10246       --  We cannot analyze the renaming declaration, and thus find the actual,
10247       --  until all the actuals are assembled in the instance. For subsequent
10248       --  checks of other actuals, indicate the node that will hold the
10249       --  instance of this formal.
10250 
10251       Set_Instance_Of (Analyzed_S, Nam);
10252 
10253       if Nkind (Actual) = N_Selected_Component
10254         and then Is_Task_Type (Etype (Prefix (Actual)))
10255         and then not Is_Frozen (Etype (Prefix (Actual)))
10256       then
10257          --  The renaming declaration will create a body, which must appear
10258          --  outside of the instantiation, We move the renaming declaration
10259          --  out of the instance, and create an additional renaming inside,
10260          --  to prevent freezing anomalies.
10261 
10262          declare
10263             Anon_Id : constant Entity_Id := Make_Temporary (Loc, 'E');
10264 
10265          begin
10266             Set_Defining_Unit_Name (New_Spec, Anon_Id);
10267             Insert_Before (Instantiation_Node, Decl_Node);
10268             Analyze (Decl_Node);
10269 
10270             --  Now create renaming within the instance
10271 
10272             Decl_Node :=
10273               Make_Subprogram_Renaming_Declaration (Loc,
10274                 Specification => New_Copy_Tree (New_Spec),
10275                 Name => New_Occurrence_Of (Anon_Id, Loc));
10276 
10277             Set_Defining_Unit_Name (Specification (Decl_Node),
10278               Make_Defining_Identifier (Loc, Chars (Formal_Sub)));
10279          end;
10280       end if;
10281 
10282       return Decl_Node;
10283    end Instantiate_Formal_Subprogram;
10284 
10285    ------------------------
10286    -- Instantiate_Object --
10287    ------------------------
10288 
10289    function Instantiate_Object
10290      (Formal          : Node_Id;
10291       Actual          : Node_Id;
10292       Analyzed_Formal : Node_Id) return List_Id
10293    is
10294       Gen_Obj     : constant Entity_Id  := Defining_Identifier (Formal);
10295       A_Gen_Obj   : constant Entity_Id  :=
10296                       Defining_Identifier (Analyzed_Formal);
10297       Acc_Def     : Node_Id             := Empty;
10298       Act_Assoc   : constant Node_Id    := Parent (Actual);
10299       Actual_Decl : Node_Id             := Empty;
10300       Decl_Node   : Node_Id;
10301       Def         : Node_Id;
10302       Ftyp        : Entity_Id;
10303       List        : constant List_Id    := New_List;
10304       Loc         : constant Source_Ptr := Sloc (Actual);
10305       Orig_Ftyp   : constant Entity_Id  := Etype (A_Gen_Obj);
10306       Subt_Decl   : Node_Id             := Empty;
10307       Subt_Mark   : Node_Id             := Empty;
10308 
10309       function Copy_Access_Def return Node_Id;
10310       --  If formal is an anonymous access, copy access definition of formal
10311       --  for generated object declaration.
10312 
10313       ---------------------
10314       -- Copy_Access_Def --
10315       ---------------------
10316 
10317       function Copy_Access_Def return Node_Id is
10318       begin
10319          Def := New_Copy_Tree (Acc_Def);
10320 
10321          --  In addition, if formal is an access to subprogram we need to
10322          --  generate new formals for the signature of the default, so that
10323          --  the tree is properly formatted for ASIS use.
10324 
10325          if Present (Access_To_Subprogram_Definition (Acc_Def)) then
10326             declare
10327                Par_Spec : Node_Id;
10328             begin
10329                Par_Spec :=
10330                  First (Parameter_Specifications
10331                           (Access_To_Subprogram_Definition (Def)));
10332                while Present (Par_Spec) loop
10333                   Set_Defining_Identifier (Par_Spec,
10334                     Make_Defining_Identifier (Sloc (Acc_Def),
10335                       Chars => Chars (Defining_Identifier (Par_Spec))));
10336                   Next (Par_Spec);
10337                end loop;
10338             end;
10339          end if;
10340 
10341          return Def;
10342       end Copy_Access_Def;
10343 
10344    --  Start of processing for Instantiate_Object
10345 
10346    begin
10347       --  Formal may be an anonymous access
10348 
10349       if Present (Subtype_Mark (Formal)) then
10350          Subt_Mark := Subtype_Mark (Formal);
10351       else
10352          Check_Access_Definition (Formal);
10353          Acc_Def := Access_Definition (Formal);
10354       end if;
10355 
10356       --  Sloc for error message on missing actual
10357 
10358       Error_Msg_Sloc := Sloc (Scope (A_Gen_Obj));
10359 
10360       if Get_Instance_Of (Gen_Obj) /= Gen_Obj then
10361          Error_Msg_N ("duplicate instantiation of generic parameter", Actual);
10362       end if;
10363 
10364       Set_Parent (List, Parent (Actual));
10365 
10366       --  OUT present
10367 
10368       if Out_Present (Formal) then
10369 
10370          --  An IN OUT generic actual must be a name. The instantiation is a
10371          --  renaming declaration. The actual is the name being renamed. We
10372          --  use the actual directly, rather than a copy, because it is not
10373          --  used further in the list of actuals, and because a copy or a use
10374          --  of relocate_node is incorrect if the instance is nested within a
10375          --  generic. In order to simplify ASIS searches, the Generic_Parent
10376          --  field links the declaration to the generic association.
10377 
10378          if No (Actual) then
10379             Error_Msg_NE
10380               ("missing actual &",
10381                Instantiation_Node, Gen_Obj);
10382             Error_Msg_NE
10383               ("\in instantiation of & declared#",
10384                Instantiation_Node, Scope (A_Gen_Obj));
10385             Abandon_Instantiation (Instantiation_Node);
10386          end if;
10387 
10388          if Present (Subt_Mark) then
10389             Decl_Node :=
10390               Make_Object_Renaming_Declaration (Loc,
10391                 Defining_Identifier => New_Copy (Gen_Obj),
10392                 Subtype_Mark        => New_Copy_Tree (Subt_Mark),
10393                 Name                => Actual);
10394 
10395          else pragma Assert (Present (Acc_Def));
10396             Decl_Node :=
10397               Make_Object_Renaming_Declaration (Loc,
10398                 Defining_Identifier => New_Copy (Gen_Obj),
10399                 Access_Definition   => New_Copy_Tree (Acc_Def),
10400                 Name                => Actual);
10401          end if;
10402 
10403          Set_Corresponding_Generic_Association (Decl_Node, Act_Assoc);
10404 
10405          --  The analysis of the actual may produce Insert_Action nodes, so
10406          --  the declaration must have a context in which to attach them.
10407 
10408          Append (Decl_Node, List);
10409          Analyze (Actual);
10410 
10411          --  Return if the analysis of the actual reported some error
10412 
10413          if Etype (Actual) = Any_Type then
10414             return List;
10415          end if;
10416 
10417          --  This check is performed here because Analyze_Object_Renaming will
10418          --  not check it when Comes_From_Source is False. Note though that the
10419          --  check for the actual being the name of an object will be performed
10420          --  in Analyze_Object_Renaming.
10421 
10422          if Is_Object_Reference (Actual)
10423            and then Is_Dependent_Component_Of_Mutable_Object (Actual)
10424          then
10425             Error_Msg_N
10426               ("illegal discriminant-dependent component for in out parameter",
10427                Actual);
10428          end if;
10429 
10430          --  The actual has to be resolved in order to check that it is a
10431          --  variable (due to cases such as F (1), where F returns access to
10432          --  an array, and for overloaded prefixes).
10433 
10434          Ftyp := Get_Instance_Of (Etype (A_Gen_Obj));
10435 
10436          --  If the type of the formal is not itself a formal, and the current
10437          --  unit is a child unit, the formal type must be declared in a
10438          --  parent, and must be retrieved by visibility.
10439 
10440          if Ftyp = Orig_Ftyp
10441            and then Is_Generic_Unit (Scope (Ftyp))
10442            and then Is_Child_Unit (Scope (A_Gen_Obj))
10443          then
10444             declare
10445                Temp : constant Node_Id :=
10446                         New_Copy_Tree (Subtype_Mark (Analyzed_Formal));
10447             begin
10448                Set_Entity (Temp, Empty);
10449                Find_Type (Temp);
10450                Ftyp := Entity (Temp);
10451             end;
10452          end if;
10453 
10454          if Is_Private_Type (Ftyp)
10455            and then not Is_Private_Type (Etype (Actual))
10456            and then (Base_Type (Full_View (Ftyp)) = Base_Type (Etype (Actual))
10457                       or else Base_Type (Etype (Actual)) = Ftyp)
10458          then
10459             --  If the actual has the type of the full view of the formal, or
10460             --  else a non-private subtype of the formal, then the visibility
10461             --  of the formal type has changed. Add to the actuals a subtype
10462             --  declaration that will force the exchange of views in the body
10463             --  of the instance as well.
10464 
10465             Subt_Decl :=
10466               Make_Subtype_Declaration (Loc,
10467                  Defining_Identifier => Make_Temporary (Loc, 'P'),
10468                  Subtype_Indication  => New_Occurrence_Of (Ftyp, Loc));
10469 
10470             Prepend (Subt_Decl, List);
10471 
10472             Prepend_Elmt (Full_View (Ftyp), Exchanged_Views);
10473             Exchange_Declarations (Ftyp);
10474          end if;
10475 
10476          Resolve (Actual, Ftyp);
10477 
10478          if not Denotes_Variable (Actual) then
10479             Error_Msg_NE ("actual for& must be a variable", Actual, Gen_Obj);
10480 
10481          elsif Base_Type (Ftyp) /= Base_Type (Etype (Actual)) then
10482 
10483             --  Ada 2005 (AI-423): For a generic formal object of mode in out,
10484             --  the type of the actual shall resolve to a specific anonymous
10485             --  access type.
10486 
10487             if Ada_Version < Ada_2005
10488               or else Ekind (Base_Type (Ftyp))           /=
10489                                                   E_Anonymous_Access_Type
10490               or else Ekind (Base_Type (Etype (Actual))) /=
10491                                                   E_Anonymous_Access_Type
10492             then
10493                Error_Msg_NE
10494                  ("type of actual does not match type of&", Actual, Gen_Obj);
10495             end if;
10496          end if;
10497 
10498          Note_Possible_Modification (Actual, Sure => True);
10499 
10500          --  Check for instantiation of atomic/volatile actual for
10501          --  non-atomic/volatile formal (RM C.6 (12)).
10502 
10503          if Is_Atomic_Object (Actual) and then not Is_Atomic (Orig_Ftyp) then
10504             Error_Msg_N
10505               ("cannot instantiate non-atomic formal object "
10506                & "with atomic actual", Actual);
10507 
10508          elsif Is_Volatile_Object (Actual) and then not Is_Volatile (Orig_Ftyp)
10509          then
10510             Error_Msg_N
10511               ("cannot instantiate non-volatile formal object "
10512                & "with volatile actual", Actual);
10513          end if;
10514 
10515       --  Formal in-parameter
10516 
10517       else
10518          --  The instantiation of a generic formal in-parameter is constant
10519          --  declaration. The actual is the expression for that declaration.
10520          --  Its type is a full copy of the type of the formal. This may be
10521          --  an access to subprogram, for which we need to generate entities
10522          --  for the formals in the new signature.
10523 
10524          if Present (Actual) then
10525             if Present (Subt_Mark) then
10526                Def := New_Copy_Tree (Subt_Mark);
10527             else pragma Assert (Present (Acc_Def));
10528                Def := Copy_Access_Def;
10529             end if;
10530 
10531             Decl_Node :=
10532               Make_Object_Declaration (Loc,
10533                 Defining_Identifier    => New_Copy (Gen_Obj),
10534                 Constant_Present       => True,
10535                 Null_Exclusion_Present => Null_Exclusion_Present (Formal),
10536                 Object_Definition      => Def,
10537                 Expression             => Actual);
10538 
10539             Set_Corresponding_Generic_Association (Decl_Node, Act_Assoc);
10540 
10541             --  A generic formal object of a tagged type is defined to be
10542             --  aliased so the new constant must also be treated as aliased.
10543 
10544             if Is_Tagged_Type (Etype (A_Gen_Obj)) then
10545                Set_Aliased_Present (Decl_Node);
10546             end if;
10547 
10548             Append (Decl_Node, List);
10549 
10550             --  No need to repeat (pre-)analysis of some expression nodes
10551             --  already handled in Preanalyze_Actuals.
10552 
10553             if Nkind (Actual) /= N_Allocator then
10554                Analyze (Actual);
10555 
10556                --  Return if the analysis of the actual reported some error
10557 
10558                if Etype (Actual) = Any_Type then
10559                   return List;
10560                end if;
10561             end if;
10562 
10563             declare
10564                Formal_Type : constant Entity_Id := Etype (A_Gen_Obj);
10565                Typ         : Entity_Id;
10566 
10567             begin
10568                Typ := Get_Instance_Of (Formal_Type);
10569 
10570                --  If the actual appears in the current or an enclosing scope,
10571                --  use its type directly. This is relevant if it has an actual
10572                --  subtype that is distinct from its nominal one. This cannot
10573                --  be done in general because the type of the actual may
10574                --  depend on other actuals, and only be fully determined when
10575                --  the enclosing instance is analyzed.
10576 
10577                if Present (Etype (Actual))
10578                  and then Is_Constr_Subt_For_U_Nominal (Etype (Actual))
10579                then
10580                   Freeze_Before (Instantiation_Node, Etype (Actual));
10581                else
10582                   Freeze_Before (Instantiation_Node, Typ);
10583                end if;
10584 
10585                --  If the actual is an aggregate, perform name resolution on
10586                --  its components (the analysis of an aggregate does not do it)
10587                --  to capture local names that may be hidden if the generic is
10588                --  a child unit.
10589 
10590                if Nkind (Actual) = N_Aggregate then
10591                   Preanalyze_And_Resolve (Actual, Typ);
10592                end if;
10593 
10594                if Is_Limited_Type (Typ)
10595                  and then not OK_For_Limited_Init (Typ, Actual)
10596                then
10597                   Error_Msg_N
10598                     ("initialization not allowed for limited types", Actual);
10599                   Explain_Limited_Type (Typ, Actual);
10600                end if;
10601             end;
10602 
10603          elsif Present (Default_Expression (Formal)) then
10604 
10605             --  Use default to construct declaration
10606 
10607             if Present (Subt_Mark) then
10608                Def := New_Copy (Subt_Mark);
10609             else pragma Assert (Present (Acc_Def));
10610                Def := Copy_Access_Def;
10611             end if;
10612 
10613             Decl_Node :=
10614               Make_Object_Declaration (Sloc (Formal),
10615                 Defining_Identifier    => New_Copy (Gen_Obj),
10616                 Constant_Present       => True,
10617                 Null_Exclusion_Present => Null_Exclusion_Present (Formal),
10618                 Object_Definition      => Def,
10619                 Expression             => New_Copy_Tree
10620                                             (Default_Expression (Formal)));
10621 
10622             Append (Decl_Node, List);
10623             Set_Analyzed (Expression (Decl_Node), False);
10624 
10625          else
10626             Error_Msg_NE ("missing actual&", Instantiation_Node, Gen_Obj);
10627             Error_Msg_NE ("\in instantiation of & declared#",
10628                           Instantiation_Node, Scope (A_Gen_Obj));
10629 
10630             if Is_Scalar_Type (Etype (A_Gen_Obj)) then
10631 
10632                --  Create dummy constant declaration so that instance can be
10633                --  analyzed, to minimize cascaded visibility errors.
10634 
10635                if Present (Subt_Mark) then
10636                   Def := Subt_Mark;
10637                else pragma Assert (Present (Acc_Def));
10638                   Def := Acc_Def;
10639                end if;
10640 
10641                Decl_Node :=
10642                  Make_Object_Declaration (Loc,
10643                    Defining_Identifier    => New_Copy (Gen_Obj),
10644                    Constant_Present       => True,
10645                    Null_Exclusion_Present => Null_Exclusion_Present (Formal),
10646                    Object_Definition      => New_Copy (Def),
10647                    Expression             =>
10648                      Make_Attribute_Reference (Sloc (Gen_Obj),
10649                        Attribute_Name => Name_First,
10650                        Prefix         => New_Copy (Def)));
10651 
10652                Append (Decl_Node, List);
10653 
10654             else
10655                Abandon_Instantiation (Instantiation_Node);
10656             end if;
10657          end if;
10658       end if;
10659 
10660       if Nkind (Actual) in N_Has_Entity then
10661          Actual_Decl := Parent (Entity (Actual));
10662       end if;
10663 
10664       --  Ada 2005 (AI-423): For a formal object declaration with a null
10665       --  exclusion or an access definition that has a null exclusion: If the
10666       --  actual matching the formal object declaration denotes a generic
10667       --  formal object of another generic unit G, and the instantiation
10668       --  containing the actual occurs within the body of G or within the body
10669       --  of a generic unit declared within the declarative region of G, then
10670       --  the declaration of the formal object of G must have a null exclusion.
10671       --  Otherwise, the subtype of the actual matching the formal object
10672       --  declaration shall exclude null.
10673 
10674       if Ada_Version >= Ada_2005
10675         and then Present (Actual_Decl)
10676         and then Nkind_In (Actual_Decl, N_Formal_Object_Declaration,
10677                                         N_Object_Declaration)
10678         and then Nkind (Analyzed_Formal) = N_Formal_Object_Declaration
10679         and then not Has_Null_Exclusion (Actual_Decl)
10680         and then Has_Null_Exclusion (Analyzed_Formal)
10681       then
10682          Error_Msg_Sloc := Sloc (Analyzed_Formal);
10683          Error_Msg_N
10684            ("actual must exclude null to match generic formal#", Actual);
10685       end if;
10686 
10687       --  An effectively volatile object cannot be used as an actual in a
10688       --  generic instantiation (SPARK RM 7.1.3(7)). The following check is
10689       --  relevant only when SPARK_Mode is on as it is not a standard Ada
10690       --  legality rule, and also verifies that the actual is an object.
10691 
10692       if SPARK_Mode = On
10693         and then Present (Actual)
10694         and then Is_Object_Reference (Actual)
10695         and then Is_Effectively_Volatile_Object (Actual)
10696       then
10697          Error_Msg_N
10698            ("volatile object cannot act as actual in generic instantiation",
10699             Actual);
10700       end if;
10701 
10702       return List;
10703    end Instantiate_Object;
10704 
10705    ------------------------------
10706    -- Instantiate_Package_Body --
10707    ------------------------------
10708 
10709    procedure Instantiate_Package_Body
10710      (Body_Info     : Pending_Body_Info;
10711       Inlined_Body  : Boolean := False;
10712       Body_Optional : Boolean := False)
10713    is
10714       Act_Decl    : constant Node_Id    := Body_Info.Act_Decl;
10715       Inst_Node   : constant Node_Id    := Body_Info.Inst_Node;
10716       Loc         : constant Source_Ptr := Sloc (Inst_Node);
10717 
10718       Gen_Id      : constant Node_Id    := Name (Inst_Node);
10719       Gen_Unit    : constant Entity_Id  := Get_Generic_Entity (Inst_Node);
10720       Gen_Decl    : constant Node_Id    := Unit_Declaration_Node (Gen_Unit);
10721       Act_Spec    : constant Node_Id    := Specification (Act_Decl);
10722       Act_Decl_Id : constant Entity_Id  := Defining_Entity (Act_Spec);
10723 
10724       Save_IPSM        : constant Boolean := Ignore_Pragma_SPARK_Mode;
10725       Save_Style_Check : constant Boolean := Style_Check;
10726 
10727       Act_Body      : Node_Id;
10728       Act_Body_Id   : Entity_Id;
10729       Act_Body_Name : Node_Id;
10730       Gen_Body      : Node_Id;
10731       Gen_Body_Id   : Node_Id;
10732       Par_Ent       : Entity_Id := Empty;
10733       Par_Vis       : Boolean   := False;
10734 
10735       Parent_Installed : Boolean := False;
10736 
10737       Vis_Prims_List : Elist_Id := No_Elist;
10738       --  List of primitives made temporarily visible in the instantiation
10739       --  to match the visibility of the formal type
10740 
10741       procedure Check_Initialized_Types;
10742       --  In a generic package body, an entity of a generic private type may
10743       --  appear uninitialized. This is suspicious, unless the actual is a
10744       --  fully initialized type.
10745 
10746       -----------------------------
10747       -- Check_Initialized_Types --
10748       -----------------------------
10749 
10750       procedure Check_Initialized_Types is
10751          Decl       : Node_Id;
10752          Formal     : Entity_Id;
10753          Actual     : Entity_Id;
10754          Uninit_Var : Entity_Id;
10755 
10756       begin
10757          Decl := First (Generic_Formal_Declarations (Gen_Decl));
10758          while Present (Decl) loop
10759             Uninit_Var := Empty;
10760 
10761             if Nkind (Decl) = N_Private_Extension_Declaration then
10762                Uninit_Var := Uninitialized_Variable (Decl);
10763 
10764             elsif Nkind (Decl) = N_Formal_Type_Declaration
10765                     and then Nkind (Formal_Type_Definition (Decl)) =
10766                                           N_Formal_Private_Type_Definition
10767             then
10768                Uninit_Var :=
10769                  Uninitialized_Variable (Formal_Type_Definition (Decl));
10770             end if;
10771 
10772             if Present (Uninit_Var) then
10773                Formal := Defining_Identifier (Decl);
10774                Actual := First_Entity (Act_Decl_Id);
10775 
10776                --  For each formal there is a subtype declaration that renames
10777                --  the actual and has the same name as the formal. Locate the
10778                --  formal for warning message about uninitialized variables
10779                --  in the generic, for which the actual type should be a fully
10780                --  initialized type.
10781 
10782                while Present (Actual) loop
10783                   exit when Ekind (Actual) = E_Package
10784                     and then Present (Renamed_Object (Actual));
10785 
10786                   if Chars (Actual) = Chars (Formal)
10787                     and then not Is_Scalar_Type (Actual)
10788                     and then not Is_Fully_Initialized_Type (Actual)
10789                     and then Warn_On_No_Value_Assigned
10790                   then
10791                      Error_Msg_Node_2 := Formal;
10792                      Error_Msg_NE
10793                        ("generic unit has uninitialized variable& of "
10794                         & "formal private type &?v?", Actual, Uninit_Var);
10795                      Error_Msg_NE
10796                        ("actual type for& should be fully initialized type?v?",
10797                         Actual, Formal);
10798                      exit;
10799                   end if;
10800 
10801                   Next_Entity (Actual);
10802                end loop;
10803             end if;
10804 
10805             Next (Decl);
10806          end loop;
10807       end Check_Initialized_Types;
10808 
10809    --  Start of processing for Instantiate_Package_Body
10810 
10811    begin
10812       Gen_Body_Id := Corresponding_Body (Gen_Decl);
10813 
10814       --  The instance body may already have been processed, as the parent of
10815       --  another instance that is inlined (Load_Parent_Of_Generic).
10816 
10817       if Present (Corresponding_Body (Instance_Spec (Inst_Node))) then
10818          return;
10819       end if;
10820 
10821       Expander_Mode_Save_And_Set (Body_Info.Expander_Status);
10822 
10823       --  Re-establish the state of information on which checks are suppressed.
10824       --  This information was set in Body_Info at the point of instantiation,
10825       --  and now we restore it so that the instance is compiled using the
10826       --  check status at the instantiation (RM 11.5(7.2/2), AI95-00224-01).
10827 
10828       Local_Suppress_Stack_Top := Body_Info.Local_Suppress_Stack_Top;
10829       Scope_Suppress           := Body_Info.Scope_Suppress;
10830       Opt.Ada_Version          := Body_Info.Version;
10831       Opt.Ada_Version_Pragma   := Body_Info.Version_Pragma;
10832       Restore_Warnings (Body_Info.Warnings);
10833       Opt.SPARK_Mode           := Body_Info.SPARK_Mode;
10834       Opt.SPARK_Mode_Pragma    := Body_Info.SPARK_Mode_Pragma;
10835 
10836       if No (Gen_Body_Id) then
10837 
10838          --  Do not look for parent of generic body if none is required.
10839          --  This may happen when the routine is called as part of the
10840          --  Pending_Instantiations processing, when nested instances
10841          --  may precede the one generated from the main unit.
10842 
10843          if not Unit_Requires_Body (Defining_Entity (Gen_Decl))
10844            and then Body_Optional
10845          then
10846             return;
10847          else
10848             Load_Parent_Of_Generic
10849               (Inst_Node, Specification (Gen_Decl), Body_Optional);
10850             Gen_Body_Id := Corresponding_Body (Gen_Decl);
10851          end if;
10852       end if;
10853 
10854       --  Establish global variable for sloc adjustment and for error recovery
10855       --  In the case of an instance body for an instantiation with actuals
10856       --  from a limited view, the instance body is placed at the beginning
10857       --  of the enclosing package body: use the body entity as the source
10858       --  location for nodes of the instance body.
10859 
10860       if not Is_Empty_Elmt_List (Incomplete_Actuals (Act_Decl_Id)) then
10861          declare
10862             Scop    : constant Entity_Id := Scope (Act_Decl_Id);
10863             Body_Id : constant Node_Id :=
10864                          Corresponding_Body (Unit_Declaration_Node (Scop));
10865 
10866          begin
10867             Instantiation_Node := Body_Id;
10868          end;
10869       else
10870          Instantiation_Node := Inst_Node;
10871       end if;
10872 
10873       if Present (Gen_Body_Id) then
10874          Save_Env (Gen_Unit, Act_Decl_Id);
10875          Style_Check := False;
10876 
10877          --  If the context of the instance is subject to SPARK_Mode "off" or
10878          --  the annotation is altogether missing, set the global flag which
10879          --  signals Analyze_Pragma to ignore all SPARK_Mode pragmas within
10880          --  the instance.
10881 
10882          if SPARK_Mode /= On then
10883             Ignore_Pragma_SPARK_Mode := True;
10884          end if;
10885 
10886          Current_Sem_Unit := Body_Info.Current_Sem_Unit;
10887          Gen_Body := Unit_Declaration_Node (Gen_Body_Id);
10888 
10889          Create_Instantiation_Source
10890            (Inst_Node, Gen_Body_Id, S_Adjustment);
10891 
10892          Act_Body :=
10893            Copy_Generic_Node
10894              (Original_Node (Gen_Body), Empty, Instantiating => True);
10895 
10896          --  Create proper (possibly qualified) defining name for the body, to
10897          --  correspond to the one in the spec.
10898 
10899          Act_Body_Id :=
10900            Make_Defining_Identifier (Sloc (Act_Decl_Id), Chars (Act_Decl_Id));
10901          Set_Comes_From_Source (Act_Body_Id, Comes_From_Source (Act_Decl_Id));
10902 
10903          --  Some attributes of spec entity are not inherited by body entity
10904 
10905          Set_Handler_Records (Act_Body_Id, No_List);
10906 
10907          if Nkind (Defining_Unit_Name (Act_Spec)) =
10908                                            N_Defining_Program_Unit_Name
10909          then
10910             Act_Body_Name :=
10911               Make_Defining_Program_Unit_Name (Loc,
10912                 Name                =>
10913                   New_Copy_Tree (Name (Defining_Unit_Name (Act_Spec))),
10914                 Defining_Identifier => Act_Body_Id);
10915          else
10916             Act_Body_Name := Act_Body_Id;
10917          end if;
10918 
10919          Set_Defining_Unit_Name (Act_Body, Act_Body_Name);
10920 
10921          Set_Corresponding_Spec (Act_Body, Act_Decl_Id);
10922          Check_Generic_Actuals (Act_Decl_Id, False);
10923          Check_Initialized_Types;
10924 
10925          --  Install primitives hidden at the point of the instantiation but
10926          --  visible when processing the generic formals
10927 
10928          declare
10929             E : Entity_Id;
10930 
10931          begin
10932             E := First_Entity (Act_Decl_Id);
10933             while Present (E) loop
10934                if Is_Type (E)
10935                  and then not Is_Itype (E)
10936                  and then Is_Generic_Actual_Type (E)
10937                  and then Is_Tagged_Type (E)
10938                then
10939                   Install_Hidden_Primitives
10940                     (Prims_List => Vis_Prims_List,
10941                      Gen_T      => Generic_Parent_Type (Parent (E)),
10942                      Act_T      => E);
10943                end if;
10944 
10945                Next_Entity (E);
10946             end loop;
10947          end;
10948 
10949          --  If it is a child unit, make the parent instance (which is an
10950          --  instance of the parent of the generic) visible. The parent
10951          --  instance is the prefix of the name of the generic unit.
10952 
10953          if Ekind (Scope (Gen_Unit)) = E_Generic_Package
10954            and then Nkind (Gen_Id) = N_Expanded_Name
10955          then
10956             Par_Ent := Entity (Prefix (Gen_Id));
10957             Par_Vis := Is_Immediately_Visible (Par_Ent);
10958             Install_Parent (Par_Ent, In_Body => True);
10959             Parent_Installed := True;
10960 
10961          elsif Is_Child_Unit (Gen_Unit) then
10962             Par_Ent := Scope (Gen_Unit);
10963             Par_Vis := Is_Immediately_Visible (Par_Ent);
10964             Install_Parent (Par_Ent, In_Body => True);
10965             Parent_Installed := True;
10966          end if;
10967 
10968          --  If the instantiation is a library unit, and this is the main unit,
10969          --  then build the resulting compilation unit nodes for the instance.
10970          --  If this is a compilation unit but it is not the main unit, then it
10971          --  is the body of a unit in the context, that is being compiled
10972          --  because it is encloses some inlined unit or another generic unit
10973          --  being instantiated. In that case, this body is not part of the
10974          --  current compilation, and is not attached to the tree, but its
10975          --  parent must be set for analysis.
10976 
10977          if Nkind (Parent (Inst_Node)) = N_Compilation_Unit then
10978 
10979             --  Replace instance node with body of instance, and create new
10980             --  node for corresponding instance declaration.
10981 
10982             Build_Instance_Compilation_Unit_Nodes
10983               (Inst_Node, Act_Body, Act_Decl);
10984             Analyze (Inst_Node);
10985 
10986             if Parent (Inst_Node) = Cunit (Main_Unit) then
10987 
10988                --  If the instance is a child unit itself, then set the scope
10989                --  of the expanded body to be the parent of the instantiation
10990                --  (ensuring that the fully qualified name will be generated
10991                --  for the elaboration subprogram).
10992 
10993                if Nkind (Defining_Unit_Name (Act_Spec)) =
10994                                               N_Defining_Program_Unit_Name
10995                then
10996                   Set_Scope (Defining_Entity (Inst_Node), Scope (Act_Decl_Id));
10997                end if;
10998             end if;
10999 
11000          --  Case where instantiation is not a library unit
11001 
11002          else
11003             --  If this is an early instantiation, i.e. appears textually
11004             --  before the corresponding body and must be elaborated first,
11005             --  indicate that the body instance is to be delayed.
11006 
11007             Install_Body (Act_Body, Inst_Node, Gen_Body, Gen_Decl);
11008 
11009             --  Now analyze the body. We turn off all checks if this is an
11010             --  internal unit, since there is no reason to have checks on for
11011             --  any predefined run-time library code. All such code is designed
11012             --  to be compiled with checks off.
11013 
11014             --  Note that we do NOT apply this criterion to children of GNAT
11015             --  The latter units must suppress checks explicitly if needed.
11016 
11017             --  We also do not suppress checks in CodePeer mode where we are
11018             --  interested in finding possible runtime errors.
11019 
11020             if not CodePeer_Mode
11021               and then Is_Predefined_File_Name
11022                          (Unit_File_Name (Get_Source_Unit (Gen_Decl)))
11023             then
11024                Analyze (Act_Body, Suppress => All_Checks);
11025             else
11026                Analyze (Act_Body);
11027             end if;
11028          end if;
11029 
11030          Inherit_Context (Gen_Body, Inst_Node);
11031 
11032          --  Remove the parent instances if they have been placed on the scope
11033          --  stack to compile the body.
11034 
11035          if Parent_Installed then
11036             Remove_Parent (In_Body => True);
11037 
11038             --  Restore the previous visibility of the parent
11039 
11040             Set_Is_Immediately_Visible (Par_Ent, Par_Vis);
11041          end if;
11042 
11043          Restore_Hidden_Primitives (Vis_Prims_List);
11044          Restore_Private_Views (Act_Decl_Id);
11045 
11046          --  Remove the current unit from visibility if this is an instance
11047          --  that is not elaborated on the fly for inlining purposes.
11048 
11049          if not Inlined_Body then
11050             Set_Is_Immediately_Visible (Act_Decl_Id, False);
11051          end if;
11052 
11053          Restore_Env;
11054          Ignore_Pragma_SPARK_Mode := Save_IPSM;
11055          Style_Check := Save_Style_Check;
11056 
11057       --  If we have no body, and the unit requires a body, then complain. This
11058       --  complaint is suppressed if we have detected other errors (since a
11059       --  common reason for missing the body is that it had errors).
11060       --  In CodePeer mode, a warning has been emitted already, no need for
11061       --  further messages.
11062 
11063       elsif Unit_Requires_Body (Gen_Unit)
11064         and then not Body_Optional
11065       then
11066          if CodePeer_Mode then
11067             null;
11068 
11069          elsif Serious_Errors_Detected = 0 then
11070             Error_Msg_NE
11071               ("cannot find body of generic package &", Inst_Node, Gen_Unit);
11072 
11073          --  Don't attempt to perform any cleanup actions if some other error
11074          --  was already detected, since this can cause blowups.
11075 
11076          else
11077             return;
11078          end if;
11079 
11080       --  Case of package that does not need a body
11081 
11082       else
11083          --  If the instantiation of the declaration is a library unit, rewrite
11084          --  the original package instantiation as a package declaration in the
11085          --  compilation unit node.
11086 
11087          if Nkind (Parent (Inst_Node)) = N_Compilation_Unit then
11088             Set_Parent_Spec (Act_Decl, Parent_Spec (Inst_Node));
11089             Rewrite (Inst_Node, Act_Decl);
11090 
11091             --  Generate elaboration entity, in case spec has elaboration code.
11092             --  This cannot be done when the instance is analyzed, because it
11093             --  is not known yet whether the body exists.
11094 
11095             Set_Elaboration_Entity_Required (Act_Decl_Id, False);
11096             Build_Elaboration_Entity (Parent (Inst_Node), Act_Decl_Id);
11097 
11098          --  If the instantiation is not a library unit, then append the
11099          --  declaration to the list of implicitly generated entities, unless
11100          --  it is already a list member which means that it was already
11101          --  processed
11102 
11103          elsif not Is_List_Member (Act_Decl) then
11104             Mark_Rewrite_Insertion (Act_Decl);
11105             Insert_Before (Inst_Node, Act_Decl);
11106          end if;
11107       end if;
11108 
11109       Expander_Mode_Restore;
11110    end Instantiate_Package_Body;
11111 
11112    ---------------------------------
11113    -- Instantiate_Subprogram_Body --
11114    ---------------------------------
11115 
11116    procedure Instantiate_Subprogram_Body
11117      (Body_Info     : Pending_Body_Info;
11118       Body_Optional : Boolean := False)
11119    is
11120       Act_Decl    : constant Node_Id    := Body_Info.Act_Decl;
11121       Inst_Node   : constant Node_Id    := Body_Info.Inst_Node;
11122       Loc         : constant Source_Ptr := Sloc (Inst_Node);
11123       Gen_Id      : constant Node_Id    := Name (Inst_Node);
11124       Gen_Unit    : constant Entity_Id  := Get_Generic_Entity (Inst_Node);
11125       Gen_Decl    : constant Node_Id    := Unit_Declaration_Node (Gen_Unit);
11126       Act_Decl_Id : constant Entity_Id  :=
11127                       Defining_Unit_Name (Specification (Act_Decl));
11128       Pack_Id     : constant Entity_Id  :=
11129                       Defining_Unit_Name (Parent (Act_Decl));
11130 
11131       Saved_IPSM        : constant Boolean        := Ignore_Pragma_SPARK_Mode;
11132       Saved_Style_Check : constant Boolean        := Style_Check;
11133       Saved_Warnings    : constant Warning_Record := Save_Warnings;
11134 
11135       Act_Body    : Node_Id;
11136       Act_Body_Id : Entity_Id;
11137       Gen_Body    : Node_Id;
11138       Gen_Body_Id : Node_Id;
11139       Pack_Body   : Node_Id;
11140       Par_Ent     : Entity_Id := Empty;
11141       Par_Vis     : Boolean   := False;
11142       Ret_Expr    : Node_Id;
11143 
11144       Parent_Installed : Boolean := False;
11145 
11146    begin
11147       Gen_Body_Id := Corresponding_Body (Gen_Decl);
11148 
11149       --  Subprogram body may have been created already because of an inline
11150       --  pragma, or because of multiple elaborations of the enclosing package
11151       --  when several instances of the subprogram appear in the main unit.
11152 
11153       if Present (Corresponding_Body (Act_Decl)) then
11154          return;
11155       end if;
11156 
11157       Expander_Mode_Save_And_Set (Body_Info.Expander_Status);
11158 
11159       --  Re-establish the state of information on which checks are suppressed.
11160       --  This information was set in Body_Info at the point of instantiation,
11161       --  and now we restore it so that the instance is compiled using the
11162       --  check status at the instantiation (RM 11.5(7.2/2), AI95-00224-01).
11163 
11164       Local_Suppress_Stack_Top := Body_Info.Local_Suppress_Stack_Top;
11165       Scope_Suppress           := Body_Info.Scope_Suppress;
11166       Opt.Ada_Version          := Body_Info.Version;
11167       Opt.Ada_Version_Pragma   := Body_Info.Version_Pragma;
11168       Restore_Warnings (Body_Info.Warnings);
11169       Opt.SPARK_Mode           := Body_Info.SPARK_Mode;
11170       Opt.SPARK_Mode_Pragma    := Body_Info.SPARK_Mode_Pragma;
11171 
11172       if No (Gen_Body_Id) then
11173 
11174          --  For imported generic subprogram, no body to compile, complete
11175          --  the spec entity appropriately.
11176 
11177          if Is_Imported (Gen_Unit) then
11178             Set_Is_Imported (Act_Decl_Id);
11179             Set_First_Rep_Item (Act_Decl_Id, First_Rep_Item (Gen_Unit));
11180             Set_Interface_Name (Act_Decl_Id, Interface_Name (Gen_Unit));
11181             Set_Convention     (Act_Decl_Id, Convention     (Gen_Unit));
11182             Set_Has_Completion (Act_Decl_Id);
11183             return;
11184 
11185          --  For other cases, compile the body
11186 
11187          else
11188             Load_Parent_Of_Generic
11189               (Inst_Node, Specification (Gen_Decl), Body_Optional);
11190             Gen_Body_Id := Corresponding_Body (Gen_Decl);
11191          end if;
11192       end if;
11193 
11194       Instantiation_Node := Inst_Node;
11195 
11196       if Present (Gen_Body_Id) then
11197          Gen_Body := Unit_Declaration_Node (Gen_Body_Id);
11198 
11199          if Nkind (Gen_Body) = N_Subprogram_Body_Stub then
11200 
11201             --  Either body is not present, or context is non-expanding, as
11202             --  when compiling a subunit. Mark the instance as completed, and
11203             --  diagnose a missing body when needed.
11204 
11205             if Expander_Active
11206               and then Operating_Mode = Generate_Code
11207             then
11208                Error_Msg_N
11209                  ("missing proper body for instantiation", Gen_Body);
11210             end if;
11211 
11212             Set_Has_Completion (Act_Decl_Id);
11213             return;
11214          end if;
11215 
11216          Save_Env (Gen_Unit, Act_Decl_Id);
11217          Style_Check := False;
11218 
11219          --  If the context of the instance is subject to SPARK_Mode "off" or
11220          --  the annotation is altogether missing, set the global flag which
11221          --  signals Analyze_Pragma to ignore all SPARK_Mode pragmas within
11222          --  the instance.
11223 
11224          if SPARK_Mode /= On then
11225             Ignore_Pragma_SPARK_Mode := True;
11226          end if;
11227 
11228          Current_Sem_Unit := Body_Info.Current_Sem_Unit;
11229          Create_Instantiation_Source
11230            (Inst_Node,
11231             Gen_Body_Id,
11232             S_Adjustment);
11233 
11234          Act_Body :=
11235            Copy_Generic_Node
11236              (Original_Node (Gen_Body), Empty, Instantiating => True);
11237 
11238          --  Create proper defining name for the body, to correspond to the one
11239          --  in the spec.
11240 
11241          Act_Body_Id :=
11242            Make_Defining_Identifier (Sloc (Act_Decl_Id), Chars (Act_Decl_Id));
11243 
11244          Set_Comes_From_Source (Act_Body_Id, Comes_From_Source (Act_Decl_Id));
11245          Set_Defining_Unit_Name (Specification (Act_Body), Act_Body_Id);
11246 
11247          Set_Corresponding_Spec (Act_Body, Act_Decl_Id);
11248          Set_Has_Completion (Act_Decl_Id);
11249          Check_Generic_Actuals (Pack_Id, False);
11250 
11251          --  Generate a reference to link the visible subprogram instance to
11252          --  the generic body, which for navigation purposes is the only
11253          --  available source for the instance.
11254 
11255          Generate_Reference
11256            (Related_Instance (Pack_Id),
11257              Gen_Body_Id, 'b', Set_Ref => False, Force => True);
11258 
11259          --  If it is a child unit, make the parent instance (which is an
11260          --  instance of the parent of the generic) visible. The parent
11261          --  instance is the prefix of the name of the generic unit.
11262 
11263          if Ekind (Scope (Gen_Unit)) = E_Generic_Package
11264            and then Nkind (Gen_Id) = N_Expanded_Name
11265          then
11266             Par_Ent := Entity (Prefix (Gen_Id));
11267             Par_Vis := Is_Immediately_Visible (Par_Ent);
11268             Install_Parent (Par_Ent, In_Body => True);
11269             Parent_Installed := True;
11270 
11271          elsif Is_Child_Unit (Gen_Unit) then
11272             Par_Ent := Scope (Gen_Unit);
11273             Par_Vis := Is_Immediately_Visible (Par_Ent);
11274             Install_Parent (Par_Ent, In_Body => True);
11275             Parent_Installed := True;
11276          end if;
11277 
11278          --  Subprogram body is placed in the body of wrapper package,
11279          --  whose spec contains the subprogram declaration as well as
11280          --  the renaming declarations for the generic parameters.
11281 
11282          Pack_Body :=
11283            Make_Package_Body (Loc,
11284              Defining_Unit_Name => New_Copy (Pack_Id),
11285              Declarations       => New_List (Act_Body));
11286 
11287          Set_Corresponding_Spec (Pack_Body, Pack_Id);
11288 
11289          --  If the instantiation is a library unit, then build resulting
11290          --  compilation unit nodes for the instance. The declaration of
11291          --  the enclosing package is the grandparent of the subprogram
11292          --  declaration. First replace the instantiation node as the unit
11293          --  of the corresponding compilation.
11294 
11295          if Nkind (Parent (Inst_Node)) = N_Compilation_Unit then
11296             if Parent (Inst_Node) = Cunit (Main_Unit) then
11297                Set_Unit (Parent (Inst_Node), Inst_Node);
11298                Build_Instance_Compilation_Unit_Nodes
11299                  (Inst_Node, Pack_Body, Parent (Parent (Act_Decl)));
11300                Analyze (Inst_Node);
11301             else
11302                Set_Parent (Pack_Body, Parent (Inst_Node));
11303                Analyze (Pack_Body);
11304             end if;
11305 
11306          else
11307             Insert_Before (Inst_Node, Pack_Body);
11308             Mark_Rewrite_Insertion (Pack_Body);
11309             Analyze (Pack_Body);
11310 
11311             if Expander_Active then
11312                Freeze_Subprogram_Body (Inst_Node, Gen_Body, Pack_Id);
11313             end if;
11314          end if;
11315 
11316          Inherit_Context (Gen_Body, Inst_Node);
11317 
11318          Restore_Private_Views (Pack_Id, False);
11319 
11320          if Parent_Installed then
11321             Remove_Parent (In_Body => True);
11322 
11323             --  Restore the previous visibility of the parent
11324 
11325             Set_Is_Immediately_Visible (Par_Ent, Par_Vis);
11326          end if;
11327 
11328          Restore_Env;
11329          Ignore_Pragma_SPARK_Mode := Saved_IPSM;
11330          Style_Check := Saved_Style_Check;
11331          Restore_Warnings (Saved_Warnings);
11332 
11333       --  Body not found. Error was emitted already. If there were no previous
11334       --  errors, this may be an instance whose scope is a premature instance.
11335       --  In that case we must insure that the (legal) program does raise
11336       --  program error if executed. We generate a subprogram body for this
11337       --  purpose. See DEC ac30vso.
11338 
11339       --  Should not reference proprietary DEC tests in comments ???
11340 
11341       elsif Serious_Errors_Detected = 0
11342         and then Nkind (Parent (Inst_Node)) /= N_Compilation_Unit
11343       then
11344          if Body_Optional then
11345             return;
11346 
11347          elsif Ekind (Act_Decl_Id) = E_Procedure then
11348             Act_Body :=
11349               Make_Subprogram_Body (Loc,
11350                  Specification              =>
11351                    Make_Procedure_Specification (Loc,
11352                      Defining_Unit_Name         =>
11353                        Make_Defining_Identifier (Loc, Chars (Act_Decl_Id)),
11354                        Parameter_Specifications =>
11355                        New_Copy_List
11356                          (Parameter_Specifications (Parent (Act_Decl_Id)))),
11357 
11358                  Declarations               => Empty_List,
11359                  Handled_Statement_Sequence =>
11360                    Make_Handled_Sequence_Of_Statements (Loc,
11361                      Statements =>
11362                        New_List (
11363                          Make_Raise_Program_Error (Loc,
11364                            Reason =>
11365                              PE_Access_Before_Elaboration))));
11366 
11367          else
11368             Ret_Expr :=
11369               Make_Raise_Program_Error (Loc,
11370                 Reason => PE_Access_Before_Elaboration);
11371 
11372             Set_Etype (Ret_Expr, (Etype (Act_Decl_Id)));
11373             Set_Analyzed (Ret_Expr);
11374 
11375             Act_Body :=
11376               Make_Subprogram_Body (Loc,
11377                 Specification =>
11378                   Make_Function_Specification (Loc,
11379                      Defining_Unit_Name         =>
11380                        Make_Defining_Identifier (Loc, Chars (Act_Decl_Id)),
11381                        Parameter_Specifications =>
11382                        New_Copy_List
11383                          (Parameter_Specifications (Parent (Act_Decl_Id))),
11384                      Result_Definition =>
11385                        New_Occurrence_Of (Etype (Act_Decl_Id), Loc)),
11386 
11387                   Declarations               => Empty_List,
11388                   Handled_Statement_Sequence =>
11389                     Make_Handled_Sequence_Of_Statements (Loc,
11390                       Statements =>
11391                         New_List
11392                           (Make_Simple_Return_Statement (Loc, Ret_Expr))));
11393          end if;
11394 
11395          Pack_Body :=
11396            Make_Package_Body (Loc,
11397              Defining_Unit_Name => New_Copy (Pack_Id),
11398              Declarations       => New_List (Act_Body));
11399 
11400          Insert_After (Inst_Node, Pack_Body);
11401          Set_Corresponding_Spec (Pack_Body, Pack_Id);
11402          Analyze (Pack_Body);
11403       end if;
11404 
11405       Expander_Mode_Restore;
11406    end Instantiate_Subprogram_Body;
11407 
11408    ----------------------
11409    -- Instantiate_Type --
11410    ----------------------
11411 
11412    function Instantiate_Type
11413      (Formal          : Node_Id;
11414       Actual          : Node_Id;
11415       Analyzed_Formal : Node_Id;
11416       Actual_Decls    : List_Id) return List_Id
11417    is
11418       Gen_T      : constant Entity_Id  := Defining_Identifier (Formal);
11419       A_Gen_T    : constant Entity_Id  :=
11420                      Defining_Identifier (Analyzed_Formal);
11421       Ancestor   : Entity_Id := Empty;
11422       Def        : constant Node_Id    := Formal_Type_Definition (Formal);
11423       Act_T      : Entity_Id;
11424       Decl_Node  : Node_Id;
11425       Decl_Nodes : List_Id;
11426       Loc        : Source_Ptr;
11427       Subt       : Entity_Id;
11428 
11429       procedure Diagnose_Predicated_Actual;
11430       --  There are a number of constructs in which a discrete type with
11431       --  predicates is illegal, e.g. as an index in an array type declaration.
11432       --  If a generic type is used is such a construct in a generic package
11433       --  declaration, it carries the flag No_Predicate_On_Actual. it is part
11434       --  of the generic contract that the actual cannot have predicates.
11435 
11436       procedure Validate_Array_Type_Instance;
11437       procedure Validate_Access_Subprogram_Instance;
11438       procedure Validate_Access_Type_Instance;
11439       procedure Validate_Derived_Type_Instance;
11440       procedure Validate_Derived_Interface_Type_Instance;
11441       procedure Validate_Discriminated_Formal_Type;
11442       procedure Validate_Interface_Type_Instance;
11443       procedure Validate_Private_Type_Instance;
11444       procedure Validate_Incomplete_Type_Instance;
11445       --  These procedures perform validation tests for the named case.
11446       --  Validate_Discriminated_Formal_Type is shared by formal private
11447       --  types and Ada 2012 formal incomplete types.
11448 
11449       function Subtypes_Match (Gen_T, Act_T : Entity_Id) return Boolean;
11450       --  Check that base types are the same and that the subtypes match
11451       --  statically. Used in several of the above.
11452 
11453       ---------------------------------
11454       --  Diagnose_Predicated_Actual --
11455       ---------------------------------
11456 
11457       procedure Diagnose_Predicated_Actual is
11458       begin
11459          if No_Predicate_On_Actual (A_Gen_T)
11460            and then Has_Predicates (Act_T)
11461          then
11462             Error_Msg_NE
11463               ("actual for& cannot be a type with predicate",
11464                Instantiation_Node, A_Gen_T);
11465 
11466          elsif No_Dynamic_Predicate_On_Actual (A_Gen_T)
11467            and then Has_Predicates (Act_T)
11468            and then not Has_Static_Predicate_Aspect (Act_T)
11469          then
11470             Error_Msg_NE
11471               ("actual for& cannot be a type with a dynamic predicate",
11472                Instantiation_Node, A_Gen_T);
11473          end if;
11474       end Diagnose_Predicated_Actual;
11475 
11476       --------------------
11477       -- Subtypes_Match --
11478       --------------------
11479 
11480       function Subtypes_Match (Gen_T, Act_T : Entity_Id) return Boolean is
11481          T : constant Entity_Id := Get_Instance_Of (Gen_T);
11482 
11483       begin
11484          --  Some detailed comments would be useful here ???
11485 
11486          return ((Base_Type (T) = Act_T
11487                    or else Base_Type (T) = Base_Type (Act_T))
11488                   and then Subtypes_Statically_Match (T, Act_T))
11489 
11490            or else (Is_Class_Wide_Type (Gen_T)
11491                      and then Is_Class_Wide_Type (Act_T)
11492                      and then Subtypes_Match
11493                                 (Get_Instance_Of (Root_Type (Gen_T)),
11494                                  Root_Type (Act_T)))
11495 
11496            or else
11497              (Ekind_In (Gen_T, E_Anonymous_Access_Subprogram_Type,
11498                                E_Anonymous_Access_Type)
11499                and then Ekind (Act_T) = Ekind (Gen_T)
11500                and then Subtypes_Statically_Match
11501                           (Designated_Type (Gen_T), Designated_Type (Act_T)));
11502       end Subtypes_Match;
11503 
11504       -----------------------------------------
11505       -- Validate_Access_Subprogram_Instance --
11506       -----------------------------------------
11507 
11508       procedure Validate_Access_Subprogram_Instance is
11509       begin
11510          if not Is_Access_Type (Act_T)
11511            or else Ekind (Designated_Type (Act_T)) /= E_Subprogram_Type
11512          then
11513             Error_Msg_NE
11514               ("expect access type in instantiation of &", Actual, Gen_T);
11515             Abandon_Instantiation (Actual);
11516          end if;
11517 
11518          --  According to AI05-288, actuals for access_to_subprograms must be
11519          --  subtype conformant with the generic formal. Previous to AI05-288
11520          --  only mode conformance was required.
11521 
11522          --  This is a binding interpretation that applies to previous versions
11523          --  of the language, no need to maintain previous weaker checks.
11524 
11525          Check_Subtype_Conformant
11526            (Designated_Type (Act_T),
11527             Designated_Type (A_Gen_T),
11528             Actual,
11529             Get_Inst => True);
11530 
11531          if Ekind (Base_Type (Act_T)) = E_Access_Protected_Subprogram_Type then
11532             if Ekind (A_Gen_T) = E_Access_Subprogram_Type then
11533                Error_Msg_NE
11534                  ("protected access type not allowed for formal &",
11535                   Actual, Gen_T);
11536             end if;
11537 
11538          elsif Ekind (A_Gen_T) = E_Access_Protected_Subprogram_Type then
11539             Error_Msg_NE
11540               ("expect protected access type for formal &",
11541                Actual, Gen_T);
11542          end if;
11543 
11544          --  If the formal has a specified convention (which in most cases
11545          --  will be StdCall) verify that the actual has the same convention.
11546 
11547          if Has_Convention_Pragma (A_Gen_T)
11548            and then Convention (A_Gen_T) /= Convention (Act_T)
11549          then
11550             Error_Msg_Name_1 := Get_Convention_Name (Convention (A_Gen_T));
11551             Error_Msg_NE
11552               ("actual for formal & must have convention %", Actual, Gen_T);
11553          end if;
11554       end Validate_Access_Subprogram_Instance;
11555 
11556       -----------------------------------
11557       -- Validate_Access_Type_Instance --
11558       -----------------------------------
11559 
11560       procedure Validate_Access_Type_Instance is
11561          Desig_Type : constant Entity_Id :=
11562                         Find_Actual_Type (Designated_Type (A_Gen_T), A_Gen_T);
11563          Desig_Act  : Entity_Id;
11564 
11565       begin
11566          if not Is_Access_Type (Act_T) then
11567             Error_Msg_NE
11568               ("expect access type in instantiation of &", Actual, Gen_T);
11569             Abandon_Instantiation (Actual);
11570          end if;
11571 
11572          if Is_Access_Constant (A_Gen_T) then
11573             if not Is_Access_Constant (Act_T) then
11574                Error_Msg_N
11575                  ("actual type must be access-to-constant type", Actual);
11576                Abandon_Instantiation (Actual);
11577             end if;
11578          else
11579             if Is_Access_Constant (Act_T) then
11580                Error_Msg_N
11581                  ("actual type must be access-to-variable type", Actual);
11582                Abandon_Instantiation (Actual);
11583 
11584             elsif Ekind (A_Gen_T) = E_General_Access_Type
11585               and then Ekind (Base_Type (Act_T)) /= E_General_Access_Type
11586             then
11587                Error_Msg_N -- CODEFIX
11588                  ("actual must be general access type!", Actual);
11589                Error_Msg_NE -- CODEFIX
11590                  ("add ALL to }!", Actual, Act_T);
11591                Abandon_Instantiation (Actual);
11592             end if;
11593          end if;
11594 
11595          --  The designated subtypes, that is to say the subtypes introduced
11596          --  by an access type declaration (and not by a subtype declaration)
11597          --  must match.
11598 
11599          Desig_Act := Designated_Type (Base_Type (Act_T));
11600 
11601          --  The designated type may have been introduced through a limited_
11602          --  with clause, in which case retrieve the non-limited view. This
11603          --  applies to incomplete types as well as to class-wide types.
11604 
11605          if From_Limited_With (Desig_Act) then
11606             Desig_Act := Available_View (Desig_Act);
11607          end if;
11608 
11609          if not Subtypes_Match (Desig_Type, Desig_Act) then
11610             Error_Msg_NE
11611               ("designated type of actual does not match that of formal &",
11612                Actual, Gen_T);
11613 
11614             if not Predicates_Match (Desig_Type, Desig_Act) then
11615                Error_Msg_N ("\predicates do not match", Actual);
11616             end if;
11617 
11618             Abandon_Instantiation (Actual);
11619 
11620          elsif Is_Access_Type (Designated_Type (Act_T))
11621            and then Is_Constrained (Designated_Type (Designated_Type (Act_T)))
11622                       /=
11623                     Is_Constrained (Designated_Type (Desig_Type))
11624          then
11625             Error_Msg_NE
11626               ("designated type of actual does not match that of formal &",
11627                Actual, Gen_T);
11628 
11629             if not Predicates_Match (Desig_Type, Desig_Act) then
11630                Error_Msg_N ("\predicates do not match", Actual);
11631             end if;
11632 
11633             Abandon_Instantiation (Actual);
11634          end if;
11635 
11636          --  Ada 2005: null-exclusion indicators of the two types must agree
11637 
11638          if Can_Never_Be_Null (A_Gen_T) /= Can_Never_Be_Null (Act_T) then
11639             Error_Msg_NE
11640               ("non null exclusion of actual and formal & do not match",
11641                  Actual, Gen_T);
11642          end if;
11643       end Validate_Access_Type_Instance;
11644 
11645       ----------------------------------
11646       -- Validate_Array_Type_Instance --
11647       ----------------------------------
11648 
11649       procedure Validate_Array_Type_Instance is
11650          I1 : Node_Id;
11651          I2 : Node_Id;
11652          T2 : Entity_Id;
11653 
11654          function Formal_Dimensions return Nat;
11655          --  Count number of dimensions in array type formal
11656 
11657          -----------------------
11658          -- Formal_Dimensions --
11659          -----------------------
11660 
11661          function Formal_Dimensions return Nat is
11662             Num   : Nat := 0;
11663             Index : Node_Id;
11664 
11665          begin
11666             if Nkind (Def) = N_Constrained_Array_Definition then
11667                Index := First (Discrete_Subtype_Definitions (Def));
11668             else
11669                Index := First (Subtype_Marks (Def));
11670             end if;
11671 
11672             while Present (Index) loop
11673                Num := Num + 1;
11674                Next_Index (Index);
11675             end loop;
11676 
11677             return Num;
11678          end Formal_Dimensions;
11679 
11680       --  Start of processing for Validate_Array_Type_Instance
11681 
11682       begin
11683          if not Is_Array_Type (Act_T) then
11684             Error_Msg_NE
11685               ("expect array type in instantiation of &", Actual, Gen_T);
11686             Abandon_Instantiation (Actual);
11687 
11688          elsif Nkind (Def) = N_Constrained_Array_Definition then
11689             if not (Is_Constrained (Act_T)) then
11690                Error_Msg_NE
11691                  ("expect constrained array in instantiation of &",
11692                   Actual, Gen_T);
11693                Abandon_Instantiation (Actual);
11694             end if;
11695 
11696          else
11697             if Is_Constrained (Act_T) then
11698                Error_Msg_NE
11699                  ("expect unconstrained array in instantiation of &",
11700                   Actual, Gen_T);
11701                Abandon_Instantiation (Actual);
11702             end if;
11703          end if;
11704 
11705          if Formal_Dimensions /= Number_Dimensions (Act_T) then
11706             Error_Msg_NE
11707               ("dimensions of actual do not match formal &", Actual, Gen_T);
11708             Abandon_Instantiation (Actual);
11709          end if;
11710 
11711          I1 := First_Index (A_Gen_T);
11712          I2 := First_Index (Act_T);
11713          for J in 1 .. Formal_Dimensions loop
11714 
11715             --  If the indexes of the actual were given by a subtype_mark,
11716             --  the index was transformed into a range attribute. Retrieve
11717             --  the original type mark for checking.
11718 
11719             if Is_Entity_Name (Original_Node (I2)) then
11720                T2 := Entity (Original_Node (I2));
11721             else
11722                T2 := Etype (I2);
11723             end if;
11724 
11725             if not Subtypes_Match
11726                      (Find_Actual_Type (Etype (I1), A_Gen_T), T2)
11727             then
11728                Error_Msg_NE
11729                  ("index types of actual do not match those of formal &",
11730                   Actual, Gen_T);
11731                Abandon_Instantiation (Actual);
11732             end if;
11733 
11734             Next_Index (I1);
11735             Next_Index (I2);
11736          end loop;
11737 
11738          --  Check matching subtypes. Note that there are complex visibility
11739          --  issues when the generic is a child unit and some aspect of the
11740          --  generic type is declared in a parent unit of the generic. We do
11741          --  the test to handle this special case only after a direct check
11742          --  for static matching has failed. The case where both the component
11743          --  type and the array type are separate formals, and the component
11744          --  type is a private view may also require special checking in
11745          --  Subtypes_Match.
11746 
11747          if Subtypes_Match
11748            (Component_Type (A_Gen_T), Component_Type (Act_T))
11749              or else
11750                Subtypes_Match
11751                  (Find_Actual_Type (Component_Type (A_Gen_T), A_Gen_T),
11752                   Component_Type (Act_T))
11753          then
11754             null;
11755          else
11756             Error_Msg_NE
11757               ("component subtype of actual does not match that of formal &",
11758                Actual, Gen_T);
11759             Abandon_Instantiation (Actual);
11760          end if;
11761 
11762          if Has_Aliased_Components (A_Gen_T)
11763            and then not Has_Aliased_Components (Act_T)
11764          then
11765             Error_Msg_NE
11766               ("actual must have aliased components to match formal type &",
11767                Actual, Gen_T);
11768          end if;
11769       end Validate_Array_Type_Instance;
11770 
11771       -----------------------------------------------
11772       --  Validate_Derived_Interface_Type_Instance --
11773       -----------------------------------------------
11774 
11775       procedure Validate_Derived_Interface_Type_Instance is
11776          Par  : constant Entity_Id := Entity (Subtype_Indication (Def));
11777          Elmt : Elmt_Id;
11778 
11779       begin
11780          --  First apply interface instance checks
11781 
11782          Validate_Interface_Type_Instance;
11783 
11784          --  Verify that immediate parent interface is an ancestor of
11785          --  the actual.
11786 
11787          if Present (Par)
11788            and then not Interface_Present_In_Ancestor (Act_T, Par)
11789          then
11790             Error_Msg_NE
11791               ("interface actual must include progenitor&", Actual, Par);
11792          end if;
11793 
11794          --  Now verify that the actual includes all other ancestors of
11795          --  the formal.
11796 
11797          Elmt := First_Elmt (Interfaces (A_Gen_T));
11798          while Present (Elmt) loop
11799             if not Interface_Present_In_Ancestor
11800                      (Act_T, Get_Instance_Of (Node (Elmt)))
11801             then
11802                Error_Msg_NE
11803                  ("interface actual must include progenitor&",
11804                     Actual, Node (Elmt));
11805             end if;
11806 
11807             Next_Elmt (Elmt);
11808          end loop;
11809       end Validate_Derived_Interface_Type_Instance;
11810 
11811       ------------------------------------
11812       -- Validate_Derived_Type_Instance --
11813       ------------------------------------
11814 
11815       procedure Validate_Derived_Type_Instance is
11816          Actual_Discr   : Entity_Id;
11817          Ancestor_Discr : Entity_Id;
11818 
11819       begin
11820          --  If the parent type in the generic declaration is itself a previous
11821          --  formal type, then it is local to the generic and absent from the
11822          --  analyzed generic definition. In that case the ancestor is the
11823          --  instance of the formal (which must have been instantiated
11824          --  previously), unless the ancestor is itself a formal derived type.
11825          --  In this latter case (which is the subject of Corrigendum 8652/0038
11826          --  (AI-202) the ancestor of the formals is the ancestor of its
11827          --  parent. Otherwise, the analyzed generic carries the parent type.
11828          --  If the parent type is defined in a previous formal package, then
11829          --  the scope of that formal package is that of the generic type
11830          --  itself, and it has already been mapped into the corresponding type
11831          --  in the actual package.
11832 
11833          --  Common case: parent type defined outside of the generic
11834 
11835          if Is_Entity_Name (Subtype_Mark (Def))
11836            and then Present (Entity (Subtype_Mark (Def)))
11837          then
11838             Ancestor := Get_Instance_Of (Entity (Subtype_Mark (Def)));
11839 
11840          --  Check whether parent is defined in a previous formal package
11841 
11842          elsif
11843            Scope (Scope (Base_Type (Etype (A_Gen_T)))) = Scope (A_Gen_T)
11844          then
11845             Ancestor :=
11846               Get_Instance_Of (Base_Type (Etype (A_Gen_T)));
11847 
11848          --  The type may be a local derivation, or a type extension of a
11849          --  previous formal, or of a formal of a parent package.
11850 
11851          elsif Is_Derived_Type (Get_Instance_Of (A_Gen_T))
11852           or else
11853             Ekind (Get_Instance_Of (A_Gen_T)) = E_Record_Type_With_Private
11854          then
11855             --  Check whether the parent is another derived formal type in the
11856             --  same generic unit.
11857 
11858             if Etype (A_Gen_T) /= A_Gen_T
11859               and then Is_Generic_Type (Etype (A_Gen_T))
11860               and then Scope (Etype (A_Gen_T)) = Scope (A_Gen_T)
11861               and then Etype (Etype (A_Gen_T)) /= Etype (A_Gen_T)
11862             then
11863                --  Locate ancestor of parent from the subtype declaration
11864                --  created for the actual.
11865 
11866                declare
11867                   Decl : Node_Id;
11868 
11869                begin
11870                   Decl := First (Actual_Decls);
11871                   while Present (Decl) loop
11872                      if Nkind (Decl) = N_Subtype_Declaration
11873                        and then Chars (Defining_Identifier (Decl)) =
11874                                                     Chars (Etype (A_Gen_T))
11875                      then
11876                         Ancestor := Generic_Parent_Type (Decl);
11877                         exit;
11878                      else
11879                         Next (Decl);
11880                      end if;
11881                   end loop;
11882                end;
11883 
11884                pragma Assert (Present (Ancestor));
11885 
11886                --  The ancestor itself may be a previous formal that has been
11887                --  instantiated.
11888 
11889                Ancestor := Get_Instance_Of (Ancestor);
11890 
11891             else
11892                Ancestor :=
11893                  Get_Instance_Of (Base_Type (Get_Instance_Of (A_Gen_T)));
11894             end if;
11895 
11896          --  Check whether parent is a previous formal of the current generic
11897 
11898          elsif Is_Derived_Type (A_Gen_T)
11899            and then Is_Generic_Type (Etype (A_Gen_T))
11900            and then Scope (A_Gen_T) = Scope (Etype (A_Gen_T))
11901          then
11902             Ancestor := Get_Instance_Of (First_Subtype (Etype (A_Gen_T)));
11903 
11904          --  An unusual case: the actual is a type declared in a parent unit,
11905          --  but is not a formal type so there is no instance_of for it.
11906          --  Retrieve it by analyzing the record extension.
11907 
11908          elsif Is_Child_Unit (Scope (A_Gen_T))
11909            and then In_Open_Scopes (Scope (Act_T))
11910            and then Is_Generic_Instance (Scope (Act_T))
11911          then
11912             Analyze (Subtype_Mark (Def));
11913             Ancestor := Entity (Subtype_Mark (Def));
11914 
11915          else
11916             Ancestor := Get_Instance_Of (Etype (Base_Type (A_Gen_T)));
11917          end if;
11918 
11919          --  If the formal derived type has pragma Preelaborable_Initialization
11920          --  then the actual type must have preelaborable initialization.
11921 
11922          if Known_To_Have_Preelab_Init (A_Gen_T)
11923            and then not Has_Preelaborable_Initialization (Act_T)
11924          then
11925             Error_Msg_NE
11926               ("actual for & must have preelaborable initialization",
11927                Actual, Gen_T);
11928          end if;
11929 
11930          --  Ada 2005 (AI-251)
11931 
11932          if Ada_Version >= Ada_2005 and then Is_Interface (Ancestor) then
11933             if not Interface_Present_In_Ancestor (Act_T, Ancestor) then
11934                Error_Msg_NE
11935                  ("(Ada 2005) expected type implementing & in instantiation",
11936                   Actual, Ancestor);
11937             end if;
11938 
11939          --  Finally verify that the (instance of) the ancestor is an ancestor
11940          --  of the actual.
11941 
11942          elsif not Is_Ancestor (Base_Type (Ancestor), Act_T) then
11943             Error_Msg_NE
11944               ("expect type derived from & in instantiation",
11945                Actual, First_Subtype (Ancestor));
11946             Abandon_Instantiation (Actual);
11947          end if;
11948 
11949          --  Ada 2005 (AI-443): Synchronized formal derived type checks. Note
11950          --  that the formal type declaration has been rewritten as a private
11951          --  extension.
11952 
11953          if Ada_Version >= Ada_2005
11954            and then Nkind (Parent (A_Gen_T)) = N_Private_Extension_Declaration
11955            and then Synchronized_Present (Parent (A_Gen_T))
11956          then
11957             --  The actual must be a synchronized tagged type
11958 
11959             if not Is_Tagged_Type (Act_T) then
11960                Error_Msg_N
11961                  ("actual of synchronized type must be tagged", Actual);
11962                Abandon_Instantiation (Actual);
11963 
11964             elsif Nkind (Parent (Act_T)) = N_Full_Type_Declaration
11965               and then Nkind (Type_Definition (Parent (Act_T))) =
11966                                                  N_Derived_Type_Definition
11967               and then not Synchronized_Present
11968                              (Type_Definition (Parent (Act_T)))
11969             then
11970                Error_Msg_N
11971                  ("actual of synchronized type must be synchronized", Actual);
11972                Abandon_Instantiation (Actual);
11973             end if;
11974          end if;
11975 
11976          --  Perform atomic/volatile checks (RM C.6(12)). Note that AI05-0218-1
11977          --  removes the second instance of the phrase "or allow pass by copy".
11978 
11979          if Is_Atomic (Act_T) and then not Is_Atomic (Ancestor) then
11980             Error_Msg_N
11981               ("cannot have atomic actual type for non-atomic formal type",
11982                Actual);
11983 
11984          elsif Is_Volatile (Act_T) and then not Is_Volatile (Ancestor) then
11985             Error_Msg_N
11986               ("cannot have volatile actual type for non-volatile formal type",
11987                Actual);
11988          end if;
11989 
11990          --  It should not be necessary to check for unknown discriminants on
11991          --  Formal, but for some reason Has_Unknown_Discriminants is false for
11992          --  A_Gen_T, so Is_Definite_Subtype incorrectly returns True. This
11993          --  needs fixing. ???
11994 
11995          if Is_Definite_Subtype (A_Gen_T)
11996            and then not Unknown_Discriminants_Present (Formal)
11997            and then not Is_Definite_Subtype (Act_T)
11998          then
11999             Error_Msg_N ("actual subtype must be constrained", Actual);
12000             Abandon_Instantiation (Actual);
12001          end if;
12002 
12003          if not Unknown_Discriminants_Present (Formal) then
12004             if Is_Constrained (Ancestor) then
12005                if not Is_Constrained (Act_T) then
12006                   Error_Msg_N ("actual subtype must be constrained", Actual);
12007                   Abandon_Instantiation (Actual);
12008                end if;
12009 
12010             --  Ancestor is unconstrained, Check if generic formal and actual
12011             --  agree on constrainedness. The check only applies to array types
12012             --  and discriminated types.
12013 
12014             elsif Is_Constrained (Act_T) then
12015                if Ekind (Ancestor) = E_Access_Type
12016                  or else (not Is_Constrained (A_Gen_T)
12017                            and then Is_Composite_Type (A_Gen_T))
12018                then
12019                   Error_Msg_N ("actual subtype must be unconstrained", Actual);
12020                   Abandon_Instantiation (Actual);
12021                end if;
12022 
12023             --  A class-wide type is only allowed if the formal has unknown
12024             --  discriminants.
12025 
12026             elsif Is_Class_Wide_Type (Act_T)
12027               and then not Has_Unknown_Discriminants (Ancestor)
12028             then
12029                Error_Msg_NE
12030                  ("actual for & cannot be a class-wide type", Actual, Gen_T);
12031                Abandon_Instantiation (Actual);
12032 
12033             --  Otherwise, the formal and actual must have the same number
12034             --  of discriminants and each discriminant of the actual must
12035             --  correspond to a discriminant of the formal.
12036 
12037             elsif Has_Discriminants (Act_T)
12038               and then not Has_Unknown_Discriminants (Act_T)
12039               and then Has_Discriminants (Ancestor)
12040             then
12041                Actual_Discr   := First_Discriminant (Act_T);
12042                Ancestor_Discr := First_Discriminant (Ancestor);
12043                while Present (Actual_Discr)
12044                  and then Present (Ancestor_Discr)
12045                loop
12046                   if Base_Type (Act_T) /= Base_Type (Ancestor) and then
12047                     No (Corresponding_Discriminant (Actual_Discr))
12048                   then
12049                      Error_Msg_NE
12050                        ("discriminant & does not correspond "
12051                         & "to ancestor discriminant", Actual, Actual_Discr);
12052                      Abandon_Instantiation (Actual);
12053                   end if;
12054 
12055                   Next_Discriminant (Actual_Discr);
12056                   Next_Discriminant (Ancestor_Discr);
12057                end loop;
12058 
12059                if Present (Actual_Discr) or else Present (Ancestor_Discr) then
12060                   Error_Msg_NE
12061                     ("actual for & must have same number of discriminants",
12062                      Actual, Gen_T);
12063                   Abandon_Instantiation (Actual);
12064                end if;
12065 
12066             --  This case should be caught by the earlier check for
12067             --  constrainedness, but the check here is added for completeness.
12068 
12069             elsif Has_Discriminants (Act_T)
12070               and then not Has_Unknown_Discriminants (Act_T)
12071             then
12072                Error_Msg_NE
12073                  ("actual for & must not have discriminants", Actual, Gen_T);
12074                Abandon_Instantiation (Actual);
12075 
12076             elsif Has_Discriminants (Ancestor) then
12077                Error_Msg_NE
12078                  ("actual for & must have known discriminants", Actual, Gen_T);
12079                Abandon_Instantiation (Actual);
12080             end if;
12081 
12082             if not Subtypes_Statically_Compatible
12083                      (Act_T, Ancestor, Formal_Derived_Matching => True)
12084             then
12085                Error_Msg_N
12086                  ("constraint on actual is incompatible with formal", Actual);
12087                Abandon_Instantiation (Actual);
12088             end if;
12089          end if;
12090 
12091          --  If the formal and actual types are abstract, check that there
12092          --  are no abstract primitives of the actual type that correspond to
12093          --  nonabstract primitives of the formal type (second sentence of
12094          --  RM95 3.9.3(9)).
12095 
12096          if Is_Abstract_Type (A_Gen_T) and then Is_Abstract_Type (Act_T) then
12097             Check_Abstract_Primitives : declare
12098                Gen_Prims  : constant Elist_Id :=
12099                              Primitive_Operations (A_Gen_T);
12100                Gen_Elmt   : Elmt_Id;
12101                Gen_Subp   : Entity_Id;
12102                Anc_Subp   : Entity_Id;
12103                Anc_Formal : Entity_Id;
12104                Anc_F_Type : Entity_Id;
12105 
12106                Act_Prims  : constant Elist_Id  := Primitive_Operations (Act_T);
12107                Act_Elmt   : Elmt_Id;
12108                Act_Subp   : Entity_Id;
12109                Act_Formal : Entity_Id;
12110                Act_F_Type : Entity_Id;
12111 
12112                Subprograms_Correspond : Boolean;
12113 
12114                function Is_Tagged_Ancestor (T1, T2 : Entity_Id) return Boolean;
12115                --  Returns true if T2 is derived directly or indirectly from
12116                --  T1, including derivations from interfaces. T1 and T2 are
12117                --  required to be specific tagged base types.
12118 
12119                ------------------------
12120                -- Is_Tagged_Ancestor --
12121                ------------------------
12122 
12123                function Is_Tagged_Ancestor (T1, T2 : Entity_Id) return Boolean
12124                is
12125                   Intfc_Elmt : Elmt_Id;
12126 
12127                begin
12128                   --  The predicate is satisfied if the types are the same
12129 
12130                   if T1 = T2 then
12131                      return True;
12132 
12133                   --  If we've reached the top of the derivation chain then
12134                   --  we know that T1 is not an ancestor of T2.
12135 
12136                   elsif Etype (T2) = T2 then
12137                      return False;
12138 
12139                   --  Proceed to check T2's immediate parent
12140 
12141                   elsif Is_Ancestor (T1, Base_Type (Etype (T2))) then
12142                      return True;
12143 
12144                   --  Finally, check to see if T1 is an ancestor of any of T2's
12145                   --  progenitors.
12146 
12147                   else
12148                      Intfc_Elmt := First_Elmt (Interfaces (T2));
12149                      while Present (Intfc_Elmt) loop
12150                         if Is_Ancestor (T1, Node (Intfc_Elmt)) then
12151                            return True;
12152                         end if;
12153 
12154                         Next_Elmt (Intfc_Elmt);
12155                      end loop;
12156                   end if;
12157 
12158                   return False;
12159                end Is_Tagged_Ancestor;
12160 
12161             --  Start of processing for Check_Abstract_Primitives
12162 
12163             begin
12164                --  Loop over all of the formal derived type's primitives
12165 
12166                Gen_Elmt := First_Elmt (Gen_Prims);
12167                while Present (Gen_Elmt) loop
12168                   Gen_Subp := Node (Gen_Elmt);
12169 
12170                   --  If the primitive of the formal is not abstract, then
12171                   --  determine whether there is a corresponding primitive of
12172                   --  the actual type that's abstract.
12173 
12174                   if not Is_Abstract_Subprogram (Gen_Subp) then
12175                      Act_Elmt := First_Elmt (Act_Prims);
12176                      while Present (Act_Elmt) loop
12177                         Act_Subp := Node (Act_Elmt);
12178 
12179                         --  If we find an abstract primitive of the actual,
12180                         --  then we need to test whether it corresponds to the
12181                         --  subprogram from which the generic formal primitive
12182                         --  is inherited.
12183 
12184                         if Is_Abstract_Subprogram (Act_Subp) then
12185                            Anc_Subp := Alias (Gen_Subp);
12186 
12187                            --  Test whether we have a corresponding primitive
12188                            --  by comparing names, kinds, formal types, and
12189                            --  result types.
12190 
12191                            if Chars (Anc_Subp) = Chars (Act_Subp)
12192                              and then Ekind (Anc_Subp) = Ekind (Act_Subp)
12193                            then
12194                               Anc_Formal := First_Formal (Anc_Subp);
12195                               Act_Formal := First_Formal (Act_Subp);
12196                               while Present (Anc_Formal)
12197                                 and then Present (Act_Formal)
12198                               loop
12199                                  Anc_F_Type := Etype (Anc_Formal);
12200                                  Act_F_Type := Etype (Act_Formal);
12201 
12202                                  if Ekind (Anc_F_Type) =
12203                                                         E_Anonymous_Access_Type
12204                                  then
12205                                     Anc_F_Type := Designated_Type (Anc_F_Type);
12206 
12207                                     if Ekind (Act_F_Type) =
12208                                                         E_Anonymous_Access_Type
12209                                     then
12210                                        Act_F_Type :=
12211                                          Designated_Type (Act_F_Type);
12212                                     else
12213                                        exit;
12214                                     end if;
12215 
12216                                  elsif
12217                                    Ekind (Act_F_Type) = E_Anonymous_Access_Type
12218                                  then
12219                                     exit;
12220                                  end if;
12221 
12222                                  Anc_F_Type := Base_Type (Anc_F_Type);
12223                                  Act_F_Type := Base_Type (Act_F_Type);
12224 
12225                                  --  If the formal is controlling, then the
12226                                  --  the type of the actual primitive's formal
12227                                  --  must be derived directly or indirectly
12228                                  --  from the type of the ancestor primitive's
12229                                  --  formal.
12230 
12231                                  if Is_Controlling_Formal (Anc_Formal) then
12232                                     if not Is_Tagged_Ancestor
12233                                              (Anc_F_Type, Act_F_Type)
12234                                     then
12235                                        exit;
12236                                     end if;
12237 
12238                                  --  Otherwise the types of the formals must
12239                                  --  be the same.
12240 
12241                                  elsif Anc_F_Type /= Act_F_Type then
12242                                     exit;
12243                                  end if;
12244 
12245                                  Next_Entity (Anc_Formal);
12246                                  Next_Entity (Act_Formal);
12247                               end loop;
12248 
12249                               --  If we traversed through all of the formals
12250                               --  then so far the subprograms correspond, so
12251                               --  now check that any result types correspond.
12252 
12253                               if No (Anc_Formal) and then No (Act_Formal) then
12254                                  Subprograms_Correspond := True;
12255 
12256                                  if Ekind (Act_Subp) = E_Function then
12257                                     Anc_F_Type := Etype (Anc_Subp);
12258                                     Act_F_Type := Etype (Act_Subp);
12259 
12260                                     if Ekind (Anc_F_Type) =
12261                                                         E_Anonymous_Access_Type
12262                                     then
12263                                        Anc_F_Type :=
12264                                          Designated_Type (Anc_F_Type);
12265 
12266                                        if Ekind (Act_F_Type) =
12267                                                         E_Anonymous_Access_Type
12268                                        then
12269                                           Act_F_Type :=
12270                                             Designated_Type (Act_F_Type);
12271                                        else
12272                                           Subprograms_Correspond := False;
12273                                        end if;
12274 
12275                                     elsif
12276                                       Ekind (Act_F_Type)
12277                                         = E_Anonymous_Access_Type
12278                                     then
12279                                        Subprograms_Correspond := False;
12280                                     end if;
12281 
12282                                     Anc_F_Type := Base_Type (Anc_F_Type);
12283                                     Act_F_Type := Base_Type (Act_F_Type);
12284 
12285                                     --  Now either the result types must be
12286                                     --  the same or, if the result type is
12287                                     --  controlling, the result type of the
12288                                     --  actual primitive must descend from the
12289                                     --  result type of the ancestor primitive.
12290 
12291                                     if Subprograms_Correspond
12292                                       and then Anc_F_Type /= Act_F_Type
12293                                       and then
12294                                         Has_Controlling_Result (Anc_Subp)
12295                                       and then not Is_Tagged_Ancestor
12296                                                      (Anc_F_Type, Act_F_Type)
12297                                     then
12298                                        Subprograms_Correspond := False;
12299                                     end if;
12300                                  end if;
12301 
12302                                  --  Found a matching subprogram belonging to
12303                                  --  formal ancestor type, so actual subprogram
12304                                  --  corresponds and this violates 3.9.3(9).
12305 
12306                                  if Subprograms_Correspond then
12307                                     Error_Msg_NE
12308                                       ("abstract subprogram & overrides "
12309                                        & "nonabstract subprogram of ancestor",
12310                                        Actual, Act_Subp);
12311                                  end if;
12312                               end if;
12313                            end if;
12314                         end if;
12315 
12316                         Next_Elmt (Act_Elmt);
12317                      end loop;
12318                   end if;
12319 
12320                   Next_Elmt (Gen_Elmt);
12321                end loop;
12322             end Check_Abstract_Primitives;
12323          end if;
12324 
12325          --  Verify that limitedness matches. If parent is a limited
12326          --  interface then the generic formal is not unless declared
12327          --  explicitly so. If not declared limited, the actual cannot be
12328          --  limited (see AI05-0087).
12329 
12330          --  Even though this AI is a binding interpretation, we enable the
12331          --  check only in Ada 2012 mode, because this improper construct
12332          --  shows up in user code and in existing B-tests.
12333 
12334          if Is_Limited_Type (Act_T)
12335            and then not Is_Limited_Type (A_Gen_T)
12336            and then Ada_Version >= Ada_2012
12337          then
12338             if In_Instance then
12339                null;
12340             else
12341                Error_Msg_NE
12342                  ("actual for non-limited & cannot be a limited type",
12343                   Actual, Gen_T);
12344                Explain_Limited_Type (Act_T, Actual);
12345                Abandon_Instantiation (Actual);
12346             end if;
12347          end if;
12348       end Validate_Derived_Type_Instance;
12349 
12350       ----------------------------------------
12351       -- Validate_Discriminated_Formal_Type --
12352       ----------------------------------------
12353 
12354       procedure Validate_Discriminated_Formal_Type is
12355          Formal_Discr : Entity_Id;
12356          Actual_Discr : Entity_Id;
12357          Formal_Subt  : Entity_Id;
12358 
12359       begin
12360          if Has_Discriminants (A_Gen_T) then
12361             if not Has_Discriminants (Act_T) then
12362                Error_Msg_NE
12363                  ("actual for & must have discriminants", Actual, Gen_T);
12364                Abandon_Instantiation (Actual);
12365 
12366             elsif Is_Constrained (Act_T) then
12367                Error_Msg_NE
12368                  ("actual for & must be unconstrained", Actual, Gen_T);
12369                Abandon_Instantiation (Actual);
12370 
12371             else
12372                Formal_Discr := First_Discriminant (A_Gen_T);
12373                Actual_Discr := First_Discriminant (Act_T);
12374                while Formal_Discr /= Empty loop
12375                   if Actual_Discr = Empty then
12376                      Error_Msg_NE
12377                        ("discriminants on actual do not match formal",
12378                         Actual, Gen_T);
12379                      Abandon_Instantiation (Actual);
12380                   end if;
12381 
12382                   Formal_Subt := Get_Instance_Of (Etype (Formal_Discr));
12383 
12384                   --  Access discriminants match if designated types do
12385 
12386                   if Ekind (Base_Type (Formal_Subt)) = E_Anonymous_Access_Type
12387                     and then (Ekind (Base_Type (Etype (Actual_Discr)))) =
12388                                 E_Anonymous_Access_Type
12389                     and then
12390                       Get_Instance_Of
12391                         (Designated_Type (Base_Type (Formal_Subt))) =
12392                            Designated_Type (Base_Type (Etype (Actual_Discr)))
12393                   then
12394                      null;
12395 
12396                   elsif Base_Type (Formal_Subt) /=
12397                           Base_Type (Etype (Actual_Discr))
12398                   then
12399                      Error_Msg_NE
12400                        ("types of actual discriminants must match formal",
12401                         Actual, Gen_T);
12402                      Abandon_Instantiation (Actual);
12403 
12404                   elsif not Subtypes_Statically_Match
12405                               (Formal_Subt, Etype (Actual_Discr))
12406                     and then Ada_Version >= Ada_95
12407                   then
12408                      Error_Msg_NE
12409                        ("subtypes of actual discriminants must match formal",
12410                         Actual, Gen_T);
12411                      Abandon_Instantiation (Actual);
12412                   end if;
12413 
12414                   Next_Discriminant (Formal_Discr);
12415                   Next_Discriminant (Actual_Discr);
12416                end loop;
12417 
12418                if Actual_Discr /= Empty then
12419                   Error_Msg_NE
12420                     ("discriminants on actual do not match formal",
12421                      Actual, Gen_T);
12422                   Abandon_Instantiation (Actual);
12423                end if;
12424             end if;
12425          end if;
12426       end Validate_Discriminated_Formal_Type;
12427 
12428       ---------------------------------------
12429       -- Validate_Incomplete_Type_Instance --
12430       ---------------------------------------
12431 
12432       procedure Validate_Incomplete_Type_Instance is
12433       begin
12434          if not Is_Tagged_Type (Act_T)
12435            and then Is_Tagged_Type (A_Gen_T)
12436          then
12437             Error_Msg_NE
12438               ("actual for & must be a tagged type", Actual, Gen_T);
12439          end if;
12440 
12441          Validate_Discriminated_Formal_Type;
12442       end Validate_Incomplete_Type_Instance;
12443 
12444       --------------------------------------
12445       -- Validate_Interface_Type_Instance --
12446       --------------------------------------
12447 
12448       procedure Validate_Interface_Type_Instance is
12449       begin
12450          if not Is_Interface (Act_T) then
12451             Error_Msg_NE
12452               ("actual for formal interface type must be an interface",
12453                Actual, Gen_T);
12454 
12455          elsif Is_Limited_Type (Act_T) /= Is_Limited_Type (A_Gen_T)
12456            or else Is_Task_Interface (A_Gen_T) /= Is_Task_Interface (Act_T)
12457            or else Is_Protected_Interface (A_Gen_T) /=
12458                    Is_Protected_Interface (Act_T)
12459            or else Is_Synchronized_Interface (A_Gen_T) /=
12460                    Is_Synchronized_Interface (Act_T)
12461          then
12462             Error_Msg_NE
12463               ("actual for interface& does not match (RM 12.5.5(4))",
12464                Actual, Gen_T);
12465          end if;
12466       end Validate_Interface_Type_Instance;
12467 
12468       ------------------------------------
12469       -- Validate_Private_Type_Instance --
12470       ------------------------------------
12471 
12472       procedure Validate_Private_Type_Instance is
12473       begin
12474          if Is_Limited_Type (Act_T)
12475            and then not Is_Limited_Type (A_Gen_T)
12476          then
12477             if In_Instance then
12478                null;
12479             else
12480                Error_Msg_NE
12481                  ("actual for non-limited & cannot be a limited type", Actual,
12482                   Gen_T);
12483                Explain_Limited_Type (Act_T, Actual);
12484                Abandon_Instantiation (Actual);
12485             end if;
12486 
12487          elsif Known_To_Have_Preelab_Init (A_Gen_T)
12488            and then not Has_Preelaborable_Initialization (Act_T)
12489          then
12490             Error_Msg_NE
12491               ("actual for & must have preelaborable initialization", Actual,
12492                Gen_T);
12493 
12494          elsif not Is_Definite_Subtype (Act_T)
12495             and then Is_Definite_Subtype (A_Gen_T)
12496             and then Ada_Version >= Ada_95
12497          then
12498             Error_Msg_NE
12499               ("actual for & must be a definite subtype", Actual, Gen_T);
12500 
12501          elsif not Is_Tagged_Type (Act_T)
12502            and then Is_Tagged_Type (A_Gen_T)
12503          then
12504             Error_Msg_NE
12505               ("actual for & must be a tagged type", Actual, Gen_T);
12506          end if;
12507 
12508          Validate_Discriminated_Formal_Type;
12509          Ancestor := Gen_T;
12510       end Validate_Private_Type_Instance;
12511 
12512    --  Start of processing for Instantiate_Type
12513 
12514    begin
12515       if Get_Instance_Of (A_Gen_T) /= A_Gen_T then
12516          Error_Msg_N ("duplicate instantiation of generic type", Actual);
12517          return New_List (Error);
12518 
12519       elsif not Is_Entity_Name (Actual)
12520         or else not Is_Type (Entity (Actual))
12521       then
12522          Error_Msg_NE
12523            ("expect valid subtype mark to instantiate &", Actual, Gen_T);
12524          Abandon_Instantiation (Actual);
12525 
12526       else
12527          Act_T := Entity (Actual);
12528 
12529          --  Ada 2005 (AI-216): An Unchecked_Union subtype shall only be passed
12530          --  as a generic actual parameter if the corresponding formal type
12531          --  does not have a known_discriminant_part, or is a formal derived
12532          --  type that is an Unchecked_Union type.
12533 
12534          if Is_Unchecked_Union (Base_Type (Act_T)) then
12535             if not Has_Discriminants (A_Gen_T)
12536               or else (Is_Derived_Type (A_Gen_T)
12537                         and then Is_Unchecked_Union (A_Gen_T))
12538             then
12539                null;
12540             else
12541                Error_Msg_N ("unchecked union cannot be the actual for a "
12542                             & "discriminated formal type", Act_T);
12543 
12544             end if;
12545          end if;
12546 
12547          --  Deal with fixed/floating restrictions
12548 
12549          if Is_Floating_Point_Type (Act_T) then
12550             Check_Restriction (No_Floating_Point, Actual);
12551          elsif Is_Fixed_Point_Type (Act_T) then
12552             Check_Restriction (No_Fixed_Point, Actual);
12553          end if;
12554 
12555          --  Deal with error of using incomplete type as generic actual.
12556          --  This includes limited views of a type, even if the non-limited
12557          --  view may be available.
12558 
12559          if Ekind (Act_T) = E_Incomplete_Type
12560            or else (Is_Class_Wide_Type (Act_T)
12561                      and then Ekind (Root_Type (Act_T)) = E_Incomplete_Type)
12562          then
12563             --  If the formal is an incomplete type, the actual can be
12564             --  incomplete as well.
12565 
12566             if Ekind (A_Gen_T) = E_Incomplete_Type then
12567                null;
12568 
12569             elsif Is_Class_Wide_Type (Act_T)
12570               or else No (Full_View (Act_T))
12571             then
12572                Error_Msg_N ("premature use of incomplete type", Actual);
12573                Abandon_Instantiation (Actual);
12574             else
12575                Act_T := Full_View (Act_T);
12576                Set_Entity (Actual, Act_T);
12577 
12578                if Has_Private_Component (Act_T) then
12579                   Error_Msg_N
12580                     ("premature use of type with private component", Actual);
12581                end if;
12582             end if;
12583 
12584          --  Deal with error of premature use of private type as generic actual
12585 
12586          elsif Is_Private_Type (Act_T)
12587            and then Is_Private_Type (Base_Type (Act_T))
12588            and then not Is_Generic_Type (Act_T)
12589            and then not Is_Derived_Type (Act_T)
12590            and then No (Full_View (Root_Type (Act_T)))
12591          then
12592             --  If the formal is an incomplete type, the actual can be
12593             --  private or incomplete as well.
12594 
12595             if Ekind (A_Gen_T) = E_Incomplete_Type then
12596                null;
12597             else
12598                Error_Msg_N ("premature use of private type", Actual);
12599             end if;
12600 
12601          elsif Has_Private_Component (Act_T) then
12602             Error_Msg_N
12603               ("premature use of type with private component", Actual);
12604          end if;
12605 
12606          Set_Instance_Of (A_Gen_T, Act_T);
12607 
12608          --  If the type is generic, the class-wide type may also be used
12609 
12610          if Is_Tagged_Type (A_Gen_T)
12611            and then Is_Tagged_Type (Act_T)
12612            and then not Is_Class_Wide_Type (A_Gen_T)
12613          then
12614             Set_Instance_Of (Class_Wide_Type (A_Gen_T),
12615               Class_Wide_Type (Act_T));
12616          end if;
12617 
12618          if not Is_Abstract_Type (A_Gen_T)
12619            and then Is_Abstract_Type (Act_T)
12620          then
12621             Error_Msg_N
12622               ("actual of non-abstract formal cannot be abstract", Actual);
12623          end if;
12624 
12625          --  A generic scalar type is a first subtype for which we generate
12626          --  an anonymous base type. Indicate that the instance of this base
12627          --  is the base type of the actual.
12628 
12629          if Is_Scalar_Type (A_Gen_T) then
12630             Set_Instance_Of (Etype (A_Gen_T), Etype (Act_T));
12631          end if;
12632       end if;
12633 
12634       if Error_Posted (Act_T) then
12635          null;
12636       else
12637          case Nkind (Def) is
12638             when N_Formal_Private_Type_Definition =>
12639                Validate_Private_Type_Instance;
12640 
12641             when N_Formal_Incomplete_Type_Definition =>
12642                Validate_Incomplete_Type_Instance;
12643 
12644             when N_Formal_Derived_Type_Definition =>
12645                Validate_Derived_Type_Instance;
12646 
12647             when N_Formal_Discrete_Type_Definition =>
12648                if not Is_Discrete_Type (Act_T) then
12649                   Error_Msg_NE
12650                     ("expect discrete type in instantiation of&",
12651                      Actual, Gen_T);
12652                   Abandon_Instantiation (Actual);
12653                end if;
12654 
12655                Diagnose_Predicated_Actual;
12656 
12657             when N_Formal_Signed_Integer_Type_Definition =>
12658                if not Is_Signed_Integer_Type (Act_T) then
12659                   Error_Msg_NE
12660                     ("expect signed integer type in instantiation of&",
12661                      Actual, Gen_T);
12662                   Abandon_Instantiation (Actual);
12663                end if;
12664 
12665                Diagnose_Predicated_Actual;
12666 
12667             when N_Formal_Modular_Type_Definition =>
12668                if not Is_Modular_Integer_Type (Act_T) then
12669                   Error_Msg_NE
12670                     ("expect modular type in instantiation of &",
12671                        Actual, Gen_T);
12672                   Abandon_Instantiation (Actual);
12673                end if;
12674 
12675                Diagnose_Predicated_Actual;
12676 
12677             when N_Formal_Floating_Point_Definition =>
12678                if not Is_Floating_Point_Type (Act_T) then
12679                   Error_Msg_NE
12680                     ("expect float type in instantiation of &", Actual, Gen_T);
12681                   Abandon_Instantiation (Actual);
12682                end if;
12683 
12684             when N_Formal_Ordinary_Fixed_Point_Definition =>
12685                if not Is_Ordinary_Fixed_Point_Type (Act_T) then
12686                   Error_Msg_NE
12687                     ("expect ordinary fixed point type in instantiation of &",
12688                      Actual, Gen_T);
12689                   Abandon_Instantiation (Actual);
12690                end if;
12691 
12692             when N_Formal_Decimal_Fixed_Point_Definition =>
12693                if not Is_Decimal_Fixed_Point_Type (Act_T) then
12694                   Error_Msg_NE
12695                     ("expect decimal type in instantiation of &",
12696                      Actual, Gen_T);
12697                   Abandon_Instantiation (Actual);
12698                end if;
12699 
12700             when N_Array_Type_Definition =>
12701                Validate_Array_Type_Instance;
12702 
12703             when N_Access_To_Object_Definition =>
12704                Validate_Access_Type_Instance;
12705 
12706             when N_Access_Function_Definition |
12707                  N_Access_Procedure_Definition =>
12708                Validate_Access_Subprogram_Instance;
12709 
12710             when N_Record_Definition           =>
12711                Validate_Interface_Type_Instance;
12712 
12713             when N_Derived_Type_Definition     =>
12714                Validate_Derived_Interface_Type_Instance;
12715 
12716             when others =>
12717                raise Program_Error;
12718 
12719          end case;
12720       end if;
12721 
12722       Subt := New_Copy (Gen_T);
12723 
12724       --  Use adjusted sloc of subtype name as the location for other nodes in
12725       --  the subtype declaration.
12726 
12727       Loc  := Sloc (Subt);
12728 
12729       Decl_Node :=
12730         Make_Subtype_Declaration (Loc,
12731           Defining_Identifier => Subt,
12732           Subtype_Indication  => New_Occurrence_Of (Act_T, Loc));
12733 
12734       if Is_Private_Type (Act_T) then
12735          Set_Has_Private_View (Subtype_Indication (Decl_Node));
12736 
12737       elsif Is_Access_Type (Act_T)
12738         and then Is_Private_Type (Designated_Type (Act_T))
12739       then
12740          Set_Has_Private_View (Subtype_Indication (Decl_Node));
12741       end if;
12742 
12743       --  In Ada 2012 the actual may be a limited view. Indicate that
12744       --  the local subtype must be treated as such.
12745 
12746       if From_Limited_With (Act_T) then
12747          Set_Ekind (Subt, E_Incomplete_Subtype);
12748          Set_From_Limited_With (Subt);
12749       end if;
12750 
12751       Decl_Nodes := New_List (Decl_Node);
12752 
12753       --  Flag actual derived types so their elaboration produces the
12754       --  appropriate renamings for the primitive operations of the ancestor.
12755       --  Flag actual for formal private types as well, to determine whether
12756       --  operations in the private part may override inherited operations.
12757       --  If the formal has an interface list, the ancestor is not the
12758       --  parent, but the analyzed formal that includes the interface
12759       --  operations of all its progenitors.
12760 
12761       --  Same treatment for formal private types, so we can check whether the
12762       --  type is tagged limited when validating derivations in the private
12763       --  part. (See AI05-096).
12764 
12765       if Nkind (Def) = N_Formal_Derived_Type_Definition then
12766          if Present (Interface_List (Def)) then
12767             Set_Generic_Parent_Type (Decl_Node, A_Gen_T);
12768          else
12769             Set_Generic_Parent_Type (Decl_Node, Ancestor);
12770          end if;
12771 
12772       elsif Nkind_In (Def, N_Formal_Private_Type_Definition,
12773                            N_Formal_Incomplete_Type_Definition)
12774       then
12775          Set_Generic_Parent_Type (Decl_Node, A_Gen_T);
12776       end if;
12777 
12778       --  If the actual is a synchronized type that implements an interface,
12779       --  the primitive operations are attached to the corresponding record,
12780       --  and we have to treat it as an additional generic actual, so that its
12781       --  primitive operations become visible in the instance. The task or
12782       --  protected type itself does not carry primitive operations.
12783 
12784       if Is_Concurrent_Type (Act_T)
12785         and then Is_Tagged_Type (Act_T)
12786         and then Present (Corresponding_Record_Type (Act_T))
12787         and then Present (Ancestor)
12788         and then Is_Interface (Ancestor)
12789       then
12790          declare
12791             Corr_Rec  : constant Entity_Id :=
12792                           Corresponding_Record_Type (Act_T);
12793             New_Corr  : Entity_Id;
12794             Corr_Decl : Node_Id;
12795 
12796          begin
12797             New_Corr := Make_Temporary (Loc, 'S');
12798             Corr_Decl :=
12799               Make_Subtype_Declaration (Loc,
12800                 Defining_Identifier => New_Corr,
12801                 Subtype_Indication  =>
12802                   New_Occurrence_Of (Corr_Rec, Loc));
12803             Append_To (Decl_Nodes, Corr_Decl);
12804 
12805             if Ekind (Act_T) = E_Task_Type then
12806                Set_Ekind (Subt, E_Task_Subtype);
12807             else
12808                Set_Ekind (Subt, E_Protected_Subtype);
12809             end if;
12810 
12811             Set_Corresponding_Record_Type (Subt, Corr_Rec);
12812             Set_Generic_Parent_Type (Corr_Decl, Ancestor);
12813             Set_Generic_Parent_Type (Decl_Node, Empty);
12814          end;
12815       end if;
12816 
12817       --  For a floating-point type, capture dimension info if any, because
12818       --  the generated subtype declaration does not come from source and
12819       --  will not process dimensions.
12820 
12821       if Is_Floating_Point_Type (Act_T) then
12822          Copy_Dimensions (Act_T, Subt);
12823       end if;
12824 
12825       return Decl_Nodes;
12826    end Instantiate_Type;
12827 
12828    ---------------------
12829    -- Is_In_Main_Unit --
12830    ---------------------
12831 
12832    function Is_In_Main_Unit (N : Node_Id) return Boolean is
12833       Unum         : constant Unit_Number_Type := Get_Source_Unit (N);
12834       Current_Unit : Node_Id;
12835 
12836    begin
12837       if Unum = Main_Unit then
12838          return True;
12839 
12840       --  If the current unit is a subunit then it is either the main unit or
12841       --  is being compiled as part of the main unit.
12842 
12843       elsif Nkind (N) = N_Compilation_Unit then
12844          return Nkind (Unit (N)) = N_Subunit;
12845       end if;
12846 
12847       Current_Unit := Parent (N);
12848       while Present (Current_Unit)
12849         and then Nkind (Current_Unit) /= N_Compilation_Unit
12850       loop
12851          Current_Unit := Parent (Current_Unit);
12852       end loop;
12853 
12854       --  The instantiation node is in the main unit, or else the current node
12855       --  (perhaps as the result of nested instantiations) is in the main unit,
12856       --  or in the declaration of the main unit, which in this last case must
12857       --  be a body.
12858 
12859       return
12860         Current_Unit = Cunit (Main_Unit)
12861           or else Current_Unit = Library_Unit (Cunit (Main_Unit))
12862           or else (Present (Library_Unit (Current_Unit))
12863                     and then Is_In_Main_Unit (Library_Unit (Current_Unit)));
12864    end Is_In_Main_Unit;
12865 
12866    ----------------------------
12867    -- Load_Parent_Of_Generic --
12868    ----------------------------
12869 
12870    procedure Load_Parent_Of_Generic
12871      (N             : Node_Id;
12872       Spec          : Node_Id;
12873       Body_Optional : Boolean := False)
12874    is
12875       Comp_Unit          : constant Node_Id := Cunit (Get_Source_Unit (Spec));
12876       Saved_Style_Check  : constant Boolean := Style_Check;
12877       Saved_Warnings     : constant Warning_Record := Save_Warnings;
12878       True_Parent        : Node_Id;
12879       Inst_Node          : Node_Id;
12880       OK                 : Boolean;
12881       Previous_Instances : constant Elist_Id := New_Elmt_List;
12882 
12883       procedure Collect_Previous_Instances (Decls : List_Id);
12884       --  Collect all instantiations in the given list of declarations, that
12885       --  precede the generic that we need to load. If the bodies of these
12886       --  instantiations are available, we must analyze them, to ensure that
12887       --  the public symbols generated are the same when the unit is compiled
12888       --  to generate code, and when it is compiled in the context of a unit
12889       --  that needs a particular nested instance. This process is applied to
12890       --  both package and subprogram instances.
12891 
12892       --------------------------------
12893       -- Collect_Previous_Instances --
12894       --------------------------------
12895 
12896       procedure Collect_Previous_Instances (Decls : List_Id) is
12897          Decl : Node_Id;
12898 
12899       begin
12900          Decl := First (Decls);
12901          while Present (Decl) loop
12902             if Sloc (Decl) >= Sloc (Inst_Node) then
12903                return;
12904 
12905             --  If Decl is an instantiation, then record it as requiring
12906             --  instantiation of the corresponding body, except if it is an
12907             --  abbreviated instantiation generated internally for conformance
12908             --  checking purposes only for the case of a formal package
12909             --  declared without a box (see Instantiate_Formal_Package). Such
12910             --  an instantiation does not generate any code (the actual code
12911             --  comes from actual) and thus does not need to be analyzed here.
12912             --  If the instantiation appears with a generic package body it is
12913             --  not analyzed here either.
12914 
12915             elsif Nkind (Decl) = N_Package_Instantiation
12916               and then not Is_Internal (Defining_Entity (Decl))
12917             then
12918                Append_Elmt (Decl, Previous_Instances);
12919 
12920             --  For a subprogram instantiation, omit instantiations intrinsic
12921             --  operations (Unchecked_Conversions, etc.) that have no bodies.
12922 
12923             elsif Nkind_In (Decl, N_Function_Instantiation,
12924                                   N_Procedure_Instantiation)
12925               and then not Is_Intrinsic_Subprogram (Entity (Name (Decl)))
12926             then
12927                Append_Elmt (Decl, Previous_Instances);
12928 
12929             elsif Nkind (Decl) = N_Package_Declaration then
12930                Collect_Previous_Instances
12931                  (Visible_Declarations (Specification (Decl)));
12932                Collect_Previous_Instances
12933                  (Private_Declarations (Specification (Decl)));
12934 
12935             --  Previous non-generic bodies may contain instances as well
12936 
12937             elsif Nkind (Decl) = N_Package_Body
12938               and then Ekind (Corresponding_Spec (Decl)) /= E_Generic_Package
12939             then
12940                Collect_Previous_Instances (Declarations (Decl));
12941 
12942             elsif Nkind (Decl) = N_Subprogram_Body
12943               and then not Acts_As_Spec (Decl)
12944               and then not Is_Generic_Subprogram (Corresponding_Spec (Decl))
12945             then
12946                Collect_Previous_Instances (Declarations (Decl));
12947             end if;
12948 
12949             Next (Decl);
12950          end loop;
12951       end Collect_Previous_Instances;
12952 
12953    --  Start of processing for Load_Parent_Of_Generic
12954 
12955    begin
12956       if not In_Same_Source_Unit (N, Spec)
12957         or else Nkind (Unit (Comp_Unit)) = N_Package_Declaration
12958         or else (Nkind (Unit (Comp_Unit)) = N_Package_Body
12959                   and then not Is_In_Main_Unit (Spec))
12960       then
12961          --  Find body of parent of spec, and analyze it. A special case arises
12962          --  when the parent is an instantiation, that is to say when we are
12963          --  currently instantiating a nested generic. In that case, there is
12964          --  no separate file for the body of the enclosing instance. Instead,
12965          --  the enclosing body must be instantiated as if it were a pending
12966          --  instantiation, in order to produce the body for the nested generic
12967          --  we require now. Note that in that case the generic may be defined
12968          --  in a package body, the instance defined in the same package body,
12969          --  and the original enclosing body may not be in the main unit.
12970 
12971          Inst_Node := Empty;
12972 
12973          True_Parent := Parent (Spec);
12974          while Present (True_Parent)
12975            and then Nkind (True_Parent) /= N_Compilation_Unit
12976          loop
12977             if Nkind (True_Parent) = N_Package_Declaration
12978               and then
12979                 Nkind (Original_Node (True_Parent)) = N_Package_Instantiation
12980             then
12981                --  Parent is a compilation unit that is an instantiation.
12982                --  Instantiation node has been replaced with package decl.
12983 
12984                Inst_Node := Original_Node (True_Parent);
12985                exit;
12986 
12987             elsif Nkind (True_Parent) = N_Package_Declaration
12988               and then Present (Generic_Parent (Specification (True_Parent)))
12989               and then Nkind (Parent (True_Parent)) /= N_Compilation_Unit
12990             then
12991                --  Parent is an instantiation within another specification.
12992                --  Declaration for instance has been inserted before original
12993                --  instantiation node. A direct link would be preferable?
12994 
12995                Inst_Node := Next (True_Parent);
12996                while Present (Inst_Node)
12997                  and then Nkind (Inst_Node) /= N_Package_Instantiation
12998                loop
12999                   Next (Inst_Node);
13000                end loop;
13001 
13002                --  If the instance appears within a generic, and the generic
13003                --  unit is defined within a formal package of the enclosing
13004                --  generic, there is no generic body available, and none
13005                --  needed. A more precise test should be used ???
13006 
13007                if No (Inst_Node) then
13008                   return;
13009                end if;
13010 
13011                exit;
13012 
13013             else
13014                True_Parent := Parent (True_Parent);
13015             end if;
13016          end loop;
13017 
13018          --  Case where we are currently instantiating a nested generic
13019 
13020          if Present (Inst_Node) then
13021             if Nkind (Parent (True_Parent)) = N_Compilation_Unit then
13022 
13023                --  Instantiation node and declaration of instantiated package
13024                --  were exchanged when only the declaration was needed.
13025                --  Restore instantiation node before proceeding with body.
13026 
13027                Set_Unit (Parent (True_Parent), Inst_Node);
13028             end if;
13029 
13030             --  Now complete instantiation of enclosing body, if it appears in
13031             --  some other unit. If it appears in the current unit, the body
13032             --  will have been instantiated already.
13033 
13034             if No (Corresponding_Body (Instance_Spec (Inst_Node))) then
13035 
13036                --  We need to determine the expander mode to instantiate the
13037                --  enclosing body. Because the generic body we need may use
13038                --  global entities declared in the enclosing package (including
13039                --  aggregates) it is in general necessary to compile this body
13040                --  with expansion enabled, except if we are within a generic
13041                --  package, in which case the usual generic rule applies.
13042 
13043                declare
13044                   Exp_Status         : Boolean := True;
13045                   Scop               : Entity_Id;
13046 
13047                begin
13048                   --  Loop through scopes looking for generic package
13049 
13050                   Scop := Scope (Defining_Entity (Instance_Spec (Inst_Node)));
13051                   while Present (Scop)
13052                     and then Scop /= Standard_Standard
13053                   loop
13054                      if Ekind (Scop) = E_Generic_Package then
13055                         Exp_Status := False;
13056                         exit;
13057                      end if;
13058 
13059                      Scop := Scope (Scop);
13060                   end loop;
13061 
13062                   --  Collect previous instantiations in the unit that contains
13063                   --  the desired generic.
13064 
13065                   if Nkind (Parent (True_Parent)) /= N_Compilation_Unit
13066                     and then not Body_Optional
13067                   then
13068                      declare
13069                         Decl : Elmt_Id;
13070                         Info : Pending_Body_Info;
13071                         Par  : Node_Id;
13072 
13073                      begin
13074                         Par := Parent (Inst_Node);
13075                         while Present (Par) loop
13076                            exit when Nkind (Parent (Par)) = N_Compilation_Unit;
13077                            Par := Parent (Par);
13078                         end loop;
13079 
13080                         pragma Assert (Present (Par));
13081 
13082                         if Nkind (Par) = N_Package_Body then
13083                            Collect_Previous_Instances (Declarations (Par));
13084 
13085                         elsif Nkind (Par) = N_Package_Declaration then
13086                            Collect_Previous_Instances
13087                              (Visible_Declarations (Specification (Par)));
13088                            Collect_Previous_Instances
13089                              (Private_Declarations (Specification (Par)));
13090 
13091                         else
13092                            --  Enclosing unit is a subprogram body. In this
13093                            --  case all instance bodies are processed in order
13094                            --  and there is no need to collect them separately.
13095 
13096                            null;
13097                         end if;
13098 
13099                         Decl := First_Elmt (Previous_Instances);
13100                         while Present (Decl) loop
13101                            Info :=
13102                              (Inst_Node                => Node (Decl),
13103                               Act_Decl                 =>
13104                                 Instance_Spec (Node (Decl)),
13105                               Expander_Status          => Exp_Status,
13106                               Current_Sem_Unit         =>
13107                                 Get_Code_Unit (Sloc (Node (Decl))),
13108                               Scope_Suppress           => Scope_Suppress,
13109                               Local_Suppress_Stack_Top =>
13110                                 Local_Suppress_Stack_Top,
13111                               Version                  => Ada_Version,
13112                               Version_Pragma           => Ada_Version_Pragma,
13113                               Warnings                 => Save_Warnings,
13114                               SPARK_Mode               => SPARK_Mode,
13115                               SPARK_Mode_Pragma        => SPARK_Mode_Pragma);
13116 
13117                            --  Package instance
13118 
13119                            if
13120                              Nkind (Node (Decl)) = N_Package_Instantiation
13121                            then
13122                               Instantiate_Package_Body
13123                                 (Info, Body_Optional => True);
13124 
13125                            --  Subprogram instance
13126 
13127                            else
13128                               --  The instance_spec is in the wrapper package,
13129                               --  usually followed by its local renaming
13130                               --  declaration. See Build_Subprogram_Renaming
13131                               --  for details. If the instance carries aspects,
13132                               --  these result in the corresponding pragmas,
13133                               --  inserted after the subprogram declaration.
13134                               --  They must be skipped as well when retrieving
13135                               --  the desired spec. A direct link would be
13136                               --  more robust ???
13137 
13138                               declare
13139                                  Decl : Node_Id :=
13140                                           (Last (Visible_Declarations
13141                                             (Specification (Info.Act_Decl))));
13142                               begin
13143                                  while Nkind_In (Decl,
13144                                    N_Subprogram_Renaming_Declaration, N_Pragma)
13145                                  loop
13146                                     Decl := Prev (Decl);
13147                                  end loop;
13148 
13149                                  Info.Act_Decl := Decl;
13150                               end;
13151 
13152                               Instantiate_Subprogram_Body
13153                                 (Info, Body_Optional => True);
13154                            end if;
13155 
13156                            Next_Elmt (Decl);
13157                         end loop;
13158                      end;
13159                   end if;
13160 
13161                   Instantiate_Package_Body
13162                     (Body_Info =>
13163                        ((Inst_Node                => Inst_Node,
13164                          Act_Decl                 => True_Parent,
13165                          Expander_Status          => Exp_Status,
13166                          Current_Sem_Unit         => Get_Code_Unit
13167                                                        (Sloc (Inst_Node)),
13168                          Scope_Suppress           => Scope_Suppress,
13169                          Local_Suppress_Stack_Top => Local_Suppress_Stack_Top,
13170                          Version                  => Ada_Version,
13171                          Version_Pragma           => Ada_Version_Pragma,
13172                          Warnings                 => Save_Warnings,
13173                          SPARK_Mode               => SPARK_Mode,
13174                          SPARK_Mode_Pragma        => SPARK_Mode_Pragma)),
13175                      Body_Optional => Body_Optional);
13176                end;
13177             end if;
13178 
13179          --  Case where we are not instantiating a nested generic
13180 
13181          else
13182             Opt.Style_Check := False;
13183             Expander_Mode_Save_And_Set (True);
13184             Load_Needed_Body (Comp_Unit, OK);
13185             Opt.Style_Check := Saved_Style_Check;
13186             Restore_Warnings (Saved_Warnings);
13187             Expander_Mode_Restore;
13188 
13189             if not OK
13190               and then Unit_Requires_Body (Defining_Entity (Spec))
13191               and then not Body_Optional
13192             then
13193                declare
13194                   Bname : constant Unit_Name_Type :=
13195                             Get_Body_Name (Get_Unit_Name (Unit (Comp_Unit)));
13196 
13197                begin
13198                   --  In CodePeer mode, the missing body may make the analysis
13199                   --  incomplete, but we do not treat it as fatal.
13200 
13201                   if CodePeer_Mode then
13202                      return;
13203 
13204                   else
13205                      Error_Msg_Unit_1 := Bname;
13206                      Error_Msg_N ("this instantiation requires$!", N);
13207                      Error_Msg_File_1 :=
13208                        Get_File_Name (Bname, Subunit => False);
13209                      Error_Msg_N ("\but file{ was not found!", N);
13210                      raise Unrecoverable_Error;
13211                   end if;
13212                end;
13213             end if;
13214          end if;
13215       end if;
13216 
13217       --  If loading parent of the generic caused an instantiation circularity,
13218       --  we abandon compilation at this point, because otherwise in some cases
13219       --  we get into trouble with infinite recursions after this point.
13220 
13221       if Circularity_Detected then
13222          raise Unrecoverable_Error;
13223       end if;
13224    end Load_Parent_Of_Generic;
13225 
13226    ---------------------------------
13227    -- Map_Formal_Package_Entities --
13228    ---------------------------------
13229 
13230    procedure Map_Formal_Package_Entities (Form : Entity_Id; Act : Entity_Id) is
13231       E1 : Entity_Id;
13232       E2 : Entity_Id;
13233 
13234    begin
13235       Set_Instance_Of (Form, Act);
13236 
13237       --  Traverse formal and actual package to map the corresponding entities.
13238       --  We skip over internal entities that may be generated during semantic
13239       --  analysis, and find the matching entities by name, given that they
13240       --  must appear in the same order.
13241 
13242       E1 := First_Entity (Form);
13243       E2 := First_Entity (Act);
13244       while Present (E1) and then E1 /= First_Private_Entity (Form) loop
13245          --  Could this test be a single condition??? Seems like it could, and
13246          --  isn't FPE (Form) a constant anyway???
13247 
13248          if not Is_Internal (E1)
13249            and then Present (Parent (E1))
13250            and then not Is_Class_Wide_Type (E1)
13251            and then not Is_Internal_Name (Chars (E1))
13252          then
13253             while Present (E2) and then Chars (E2) /= Chars (E1) loop
13254                Next_Entity (E2);
13255             end loop;
13256 
13257             if No (E2) then
13258                exit;
13259             else
13260                Set_Instance_Of (E1, E2);
13261 
13262                if Is_Type (E1) and then Is_Tagged_Type (E2) then
13263                   Set_Instance_Of (Class_Wide_Type (E1), Class_Wide_Type (E2));
13264                end if;
13265 
13266                if Is_Constrained (E1) then
13267                   Set_Instance_Of (Base_Type (E1), Base_Type (E2));
13268                end if;
13269 
13270                if Ekind (E1) = E_Package and then No (Renamed_Object (E1)) then
13271                   Map_Formal_Package_Entities (E1, E2);
13272                end if;
13273             end if;
13274          end if;
13275 
13276          Next_Entity (E1);
13277       end loop;
13278    end Map_Formal_Package_Entities;
13279 
13280    -----------------------
13281    -- Move_Freeze_Nodes --
13282    -----------------------
13283 
13284    procedure Move_Freeze_Nodes
13285      (Out_Of : Entity_Id;
13286       After  : Node_Id;
13287       L      : List_Id)
13288    is
13289       Decl      : Node_Id;
13290       Next_Decl : Node_Id;
13291       Next_Node : Node_Id := After;
13292       Spec      : Node_Id;
13293 
13294       function Is_Outer_Type (T : Entity_Id) return Boolean;
13295       --  Check whether entity is declared in a scope external to that of the
13296       --  generic unit.
13297 
13298       -------------------
13299       -- Is_Outer_Type --
13300       -------------------
13301 
13302       function Is_Outer_Type (T : Entity_Id) return Boolean is
13303          Scop : Entity_Id := Scope (T);
13304 
13305       begin
13306          if Scope_Depth (Scop) < Scope_Depth (Out_Of) then
13307             return True;
13308 
13309          else
13310             while Scop /= Standard_Standard loop
13311                if Scop = Out_Of then
13312                   return False;
13313                else
13314                   Scop := Scope (Scop);
13315                end if;
13316             end loop;
13317 
13318             return True;
13319          end if;
13320       end Is_Outer_Type;
13321 
13322    --  Start of processing for Move_Freeze_Nodes
13323 
13324    begin
13325       if No (L) then
13326          return;
13327       end if;
13328 
13329       --  First remove the freeze nodes that may appear before all other
13330       --  declarations.
13331 
13332       Decl := First (L);
13333       while Present (Decl)
13334         and then Nkind (Decl) = N_Freeze_Entity
13335         and then Is_Outer_Type (Entity (Decl))
13336       loop
13337          Decl := Remove_Head (L);
13338          Insert_After (Next_Node, Decl);
13339          Set_Analyzed (Decl, False);
13340          Next_Node := Decl;
13341          Decl := First (L);
13342       end loop;
13343 
13344       --  Next scan the list of declarations and remove each freeze node that
13345       --  appears ahead of the current node.
13346 
13347       while Present (Decl) loop
13348          while Present (Next (Decl))
13349            and then Nkind (Next (Decl)) = N_Freeze_Entity
13350            and then Is_Outer_Type (Entity (Next (Decl)))
13351          loop
13352             Next_Decl := Remove_Next (Decl);
13353             Insert_After (Next_Node, Next_Decl);
13354             Set_Analyzed (Next_Decl, False);
13355             Next_Node := Next_Decl;
13356          end loop;
13357 
13358          --  If the declaration is a nested package or concurrent type, then
13359          --  recurse. Nested generic packages will have been processed from the
13360          --  inside out.
13361 
13362          case Nkind (Decl) is
13363             when N_Package_Declaration =>
13364                Spec := Specification (Decl);
13365 
13366             when N_Task_Type_Declaration =>
13367                Spec := Task_Definition (Decl);
13368 
13369             when N_Protected_Type_Declaration =>
13370                Spec := Protected_Definition (Decl);
13371 
13372             when others =>
13373                Spec := Empty;
13374          end case;
13375 
13376          if Present (Spec) then
13377             Move_Freeze_Nodes (Out_Of, Next_Node, Visible_Declarations (Spec));
13378             Move_Freeze_Nodes (Out_Of, Next_Node, Private_Declarations (Spec));
13379          end if;
13380 
13381          Next (Decl);
13382       end loop;
13383    end Move_Freeze_Nodes;
13384 
13385    ----------------
13386    -- Next_Assoc --
13387    ----------------
13388 
13389    function Next_Assoc (E : Assoc_Ptr) return Assoc_Ptr is
13390    begin
13391       return Generic_Renamings.Table (E).Next_In_HTable;
13392    end Next_Assoc;
13393 
13394    ------------------------
13395    -- Preanalyze_Actuals --
13396    ------------------------
13397 
13398    procedure Preanalyze_Actuals (N : Node_Id; Inst : Entity_Id := Empty) is
13399       Assoc : Node_Id;
13400       Act   : Node_Id;
13401       Errs  : constant Nat := Serious_Errors_Detected;
13402 
13403       Cur : Entity_Id := Empty;
13404       --  Current homograph of the instance name
13405 
13406       Vis : Boolean;
13407       --  Saved visibility status of the current homograph
13408 
13409    begin
13410       Assoc := First (Generic_Associations (N));
13411 
13412       --  If the instance is a child unit, its name may hide an outer homonym,
13413       --  so make it invisible to perform name resolution on the actuals.
13414 
13415       if Nkind (Defining_Unit_Name (N)) = N_Defining_Program_Unit_Name
13416         and then Present
13417           (Current_Entity (Defining_Identifier (Defining_Unit_Name (N))))
13418       then
13419          Cur := Current_Entity (Defining_Identifier (Defining_Unit_Name (N)));
13420 
13421          if Is_Compilation_Unit (Cur) then
13422             Vis := Is_Immediately_Visible (Cur);
13423             Set_Is_Immediately_Visible (Cur, False);
13424          else
13425             Cur := Empty;
13426          end if;
13427       end if;
13428 
13429       while Present (Assoc) loop
13430          if Nkind (Assoc) /= N_Others_Choice then
13431             Act := Explicit_Generic_Actual_Parameter (Assoc);
13432 
13433             --  Within a nested instantiation, a defaulted actual is an empty
13434             --  association, so nothing to analyze. If the subprogram actual
13435             --  is an attribute, analyze prefix only, because actual is not a
13436             --  complete attribute reference.
13437 
13438             --  If actual is an allocator, analyze expression only. The full
13439             --  analysis can generate code, and if instance is a compilation
13440             --  unit we have to wait until the package instance is installed
13441             --  to have a proper place to insert this code.
13442 
13443             --  String literals may be operators, but at this point we do not
13444             --  know whether the actual is a formal subprogram or a string.
13445 
13446             if No (Act) then
13447                null;
13448 
13449             elsif Nkind (Act) = N_Attribute_Reference then
13450                Analyze (Prefix (Act));
13451 
13452             elsif Nkind (Act) = N_Explicit_Dereference then
13453                Analyze (Prefix (Act));
13454 
13455             elsif Nkind (Act) = N_Allocator then
13456                declare
13457                   Expr : constant Node_Id := Expression (Act);
13458 
13459                begin
13460                   if Nkind (Expr) = N_Subtype_Indication then
13461                      Analyze (Subtype_Mark (Expr));
13462 
13463                      --  Analyze separately each discriminant constraint, when
13464                      --  given with a named association.
13465 
13466                      declare
13467                         Constr : Node_Id;
13468 
13469                      begin
13470                         Constr := First (Constraints (Constraint (Expr)));
13471                         while Present (Constr) loop
13472                            if Nkind (Constr) = N_Discriminant_Association then
13473                               Analyze (Expression (Constr));
13474                            else
13475                               Analyze (Constr);
13476                            end if;
13477 
13478                            Next (Constr);
13479                         end loop;
13480                      end;
13481 
13482                   else
13483                      Analyze (Expr);
13484                   end if;
13485                end;
13486 
13487             elsif Nkind (Act) /= N_Operator_Symbol then
13488                Analyze (Act);
13489 
13490                --  Within a package instance, mark actuals that are limited
13491                --  views, so their use can be moved to the body of the
13492                --  enclosing unit.
13493 
13494                if Is_Entity_Name (Act)
13495                  and then Is_Type (Entity (Act))
13496                  and then From_Limited_With (Entity (Act))
13497                  and then Present (Inst)
13498                then
13499                   Append_Elmt (Entity (Act), Incomplete_Actuals (Inst));
13500                end if;
13501             end if;
13502 
13503             if Errs /= Serious_Errors_Detected then
13504 
13505                --  Do a minimal analysis of the generic, to prevent spurious
13506                --  warnings complaining about the generic being unreferenced,
13507                --  before abandoning the instantiation.
13508 
13509                Analyze (Name (N));
13510 
13511                if Is_Entity_Name (Name (N))
13512                  and then Etype (Name (N)) /= Any_Type
13513                then
13514                   Generate_Reference  (Entity (Name (N)), Name (N));
13515                   Set_Is_Instantiated (Entity (Name (N)));
13516                end if;
13517 
13518                if Present (Cur) then
13519 
13520                   --  For the case of a child instance hiding an outer homonym,
13521                   --  provide additional warning which might explain the error.
13522 
13523                   Set_Is_Immediately_Visible (Cur, Vis);
13524                   Error_Msg_NE
13525                     ("& hides outer unit with the same name??",
13526                      N, Defining_Unit_Name (N));
13527                end if;
13528 
13529                Abandon_Instantiation (Act);
13530             end if;
13531          end if;
13532 
13533          Next (Assoc);
13534       end loop;
13535 
13536       if Present (Cur) then
13537          Set_Is_Immediately_Visible (Cur, Vis);
13538       end if;
13539    end Preanalyze_Actuals;
13540 
13541    -------------------
13542    -- Remove_Parent --
13543    -------------------
13544 
13545    procedure Remove_Parent (In_Body : Boolean := False) is
13546       S : Entity_Id := Current_Scope;
13547       --  S is the scope containing the instantiation just completed. The scope
13548       --  stack contains the parent instances of the instantiation, followed by
13549       --  the original S.
13550 
13551       Cur_P  : Entity_Id;
13552       E      : Entity_Id;
13553       P      : Entity_Id;
13554       Hidden : Elmt_Id;
13555 
13556    begin
13557       --  After child instantiation is complete, remove from scope stack the
13558       --  extra copy of the current scope, and then remove parent instances.
13559 
13560       if not In_Body then
13561          Pop_Scope;
13562 
13563          while Current_Scope /= S loop
13564             P := Current_Scope;
13565             End_Package_Scope (Current_Scope);
13566 
13567             if In_Open_Scopes (P) then
13568                E := First_Entity (P);
13569                while Present (E) loop
13570                   Set_Is_Immediately_Visible (E, True);
13571                   Next_Entity (E);
13572                end loop;
13573 
13574                --  If instantiation is declared in a block, it is the enclosing
13575                --  scope that might be a parent instance. Note that only one
13576                --  block can be involved, because the parent instances have
13577                --  been installed within it.
13578 
13579                if Ekind (P) = E_Block then
13580                   Cur_P := Scope (P);
13581                else
13582                   Cur_P := P;
13583                end if;
13584 
13585                if Is_Generic_Instance (Cur_P) and then P /= Current_Scope then
13586                   --  We are within an instance of some sibling. Retain
13587                   --  visibility of parent, for proper subsequent cleanup, and
13588                   --  reinstall private declarations as well.
13589 
13590                   Set_In_Private_Part (P);
13591                   Install_Private_Declarations (P);
13592                end if;
13593 
13594             --  If the ultimate parent is a top-level unit recorded in
13595             --  Instance_Parent_Unit, then reset its visibility to what it was
13596             --  before instantiation. (It's not clear what the purpose is of
13597             --  testing whether Scope (P) is In_Open_Scopes, but that test was
13598             --  present before the ultimate parent test was added.???)
13599 
13600             elsif not In_Open_Scopes (Scope (P))
13601               or else (P = Instance_Parent_Unit
13602                         and then not Parent_Unit_Visible)
13603             then
13604                Set_Is_Immediately_Visible (P, False);
13605 
13606             --  If the current scope is itself an instantiation of a generic
13607             --  nested within P, and we are in the private part of body of this
13608             --  instantiation, restore the full views of P, that were removed
13609             --  in End_Package_Scope above. This obscure case can occur when a
13610             --  subunit of a generic contains an instance of a child unit of
13611             --  its generic parent unit.
13612 
13613             elsif S = Current_Scope and then Is_Generic_Instance (S) then
13614                declare
13615                   Par : constant Entity_Id :=
13616                           Generic_Parent (Package_Specification (S));
13617                begin
13618                   if Present (Par)
13619                     and then P = Scope (Par)
13620                     and then (In_Package_Body (S) or else In_Private_Part (S))
13621                   then
13622                      Set_In_Private_Part (P);
13623                      Install_Private_Declarations (P);
13624                   end if;
13625                end;
13626             end if;
13627          end loop;
13628 
13629          --  Reset visibility of entities in the enclosing scope
13630 
13631          Set_Is_Hidden_Open_Scope (Current_Scope, False);
13632 
13633          Hidden := First_Elmt (Hidden_Entities);
13634          while Present (Hidden) loop
13635             Set_Is_Immediately_Visible (Node (Hidden), True);
13636             Next_Elmt (Hidden);
13637          end loop;
13638 
13639       else
13640          --  Each body is analyzed separately, and there is no context that
13641          --  needs preserving from one body instance to the next, so remove all
13642          --  parent scopes that have been installed.
13643 
13644          while Present (S) loop
13645             End_Package_Scope (S);
13646             Set_Is_Immediately_Visible (S, False);
13647             S := Current_Scope;
13648             exit when S = Standard_Standard;
13649          end loop;
13650       end if;
13651    end Remove_Parent;
13652 
13653    -----------------
13654    -- Restore_Env --
13655    -----------------
13656 
13657    procedure Restore_Env is
13658       Saved : Instance_Env renames Instance_Envs.Table (Instance_Envs.Last);
13659 
13660    begin
13661       if No (Current_Instantiated_Parent.Act_Id) then
13662          --  Restore environment after subprogram inlining
13663 
13664          Restore_Private_Views (Empty);
13665       end if;
13666 
13667       Current_Instantiated_Parent := Saved.Instantiated_Parent;
13668       Exchanged_Views             := Saved.Exchanged_Views;
13669       Hidden_Entities             := Saved.Hidden_Entities;
13670       Current_Sem_Unit            := Saved.Current_Sem_Unit;
13671       Parent_Unit_Visible         := Saved.Parent_Unit_Visible;
13672       Instance_Parent_Unit        := Saved.Instance_Parent_Unit;
13673 
13674       Restore_Opt_Config_Switches (Saved.Switches);
13675 
13676       Instance_Envs.Decrement_Last;
13677    end Restore_Env;
13678 
13679    ---------------------------
13680    -- Restore_Private_Views --
13681    ---------------------------
13682 
13683    procedure Restore_Private_Views
13684      (Pack_Id    : Entity_Id;
13685       Is_Package : Boolean := True)
13686    is
13687       M        : Elmt_Id;
13688       E        : Entity_Id;
13689       Typ      : Entity_Id;
13690       Dep_Elmt : Elmt_Id;
13691       Dep_Typ  : Node_Id;
13692 
13693       procedure Restore_Nested_Formal (Formal : Entity_Id);
13694       --  Hide the generic formals of formal packages declared with box which
13695       --  were reachable in the current instantiation.
13696 
13697       ---------------------------
13698       -- Restore_Nested_Formal --
13699       ---------------------------
13700 
13701       procedure Restore_Nested_Formal (Formal : Entity_Id) is
13702          Ent : Entity_Id;
13703 
13704       begin
13705          if Present (Renamed_Object (Formal))
13706            and then Denotes_Formal_Package (Renamed_Object (Formal), True)
13707          then
13708             return;
13709 
13710          elsif Present (Associated_Formal_Package (Formal)) then
13711             Ent := First_Entity (Formal);
13712             while Present (Ent) loop
13713                exit when Ekind (Ent) = E_Package
13714                  and then Renamed_Entity (Ent) = Renamed_Entity (Formal);
13715 
13716                Set_Is_Hidden (Ent);
13717                Set_Is_Potentially_Use_Visible (Ent, False);
13718 
13719                --  If package, then recurse
13720 
13721                if Ekind (Ent) = E_Package then
13722                   Restore_Nested_Formal (Ent);
13723                end if;
13724 
13725                Next_Entity (Ent);
13726             end loop;
13727          end if;
13728       end Restore_Nested_Formal;
13729 
13730    --  Start of processing for Restore_Private_Views
13731 
13732    begin
13733       M := First_Elmt (Exchanged_Views);
13734       while Present (M) loop
13735          Typ := Node (M);
13736 
13737          --  Subtypes of types whose views have been exchanged, and that are
13738          --  defined within the instance, were not on the Private_Dependents
13739          --  list on entry to the instance, so they have to be exchanged
13740          --  explicitly now, in order to remain consistent with the view of the
13741          --  parent type.
13742 
13743          if Ekind_In (Typ, E_Private_Type,
13744                            E_Limited_Private_Type,
13745                            E_Record_Type_With_Private)
13746          then
13747             Dep_Elmt := First_Elmt (Private_Dependents (Typ));
13748             while Present (Dep_Elmt) loop
13749                Dep_Typ := Node (Dep_Elmt);
13750 
13751                if Scope (Dep_Typ) = Pack_Id
13752                  and then Present (Full_View (Dep_Typ))
13753                then
13754                   Replace_Elmt (Dep_Elmt, Full_View (Dep_Typ));
13755                   Exchange_Declarations (Dep_Typ);
13756                end if;
13757 
13758                Next_Elmt (Dep_Elmt);
13759             end loop;
13760          end if;
13761 
13762          Exchange_Declarations (Node (M));
13763          Next_Elmt (M);
13764       end loop;
13765 
13766       if No (Pack_Id) then
13767          return;
13768       end if;
13769 
13770       --  Make the generic formal parameters private, and make the formal types
13771       --  into subtypes of the actuals again.
13772 
13773       E := First_Entity (Pack_Id);
13774       while Present (E) loop
13775          Set_Is_Hidden (E, True);
13776 
13777          if Is_Type (E)
13778            and then Nkind (Parent (E)) = N_Subtype_Declaration
13779          then
13780             --  If the actual for E is itself a generic actual type from
13781             --  an enclosing instance, E is still a generic actual type
13782             --  outside of the current instance. This matter when resolving
13783             --  an overloaded call that may be ambiguous in the enclosing
13784             --  instance, when two of its actuals coincide.
13785 
13786             if Is_Entity_Name (Subtype_Indication (Parent (E)))
13787               and then Is_Generic_Actual_Type
13788                          (Entity (Subtype_Indication (Parent (E))))
13789             then
13790                null;
13791             else
13792                Set_Is_Generic_Actual_Type (E, False);
13793             end if;
13794 
13795             --  An unusual case of aliasing: the actual may also be directly
13796             --  visible in the generic, and be private there, while it is fully
13797             --  visible in the context of the instance. The internal subtype
13798             --  is private in the instance but has full visibility like its
13799             --  parent in the enclosing scope. This enforces the invariant that
13800             --  the privacy status of all private dependents of a type coincide
13801             --  with that of the parent type. This can only happen when a
13802             --  generic child unit is instantiated within a sibling.
13803 
13804             if Is_Private_Type (E)
13805               and then not Is_Private_Type (Etype (E))
13806             then
13807                Exchange_Declarations (E);
13808             end if;
13809 
13810          elsif Ekind (E) = E_Package then
13811 
13812             --  The end of the renaming list is the renaming of the generic
13813             --  package itself. If the instance is a subprogram, all entities
13814             --  in the corresponding package are renamings. If this entity is
13815             --  a formal package, make its own formals private as well. The
13816             --  actual in this case is itself the renaming of an instantiation.
13817             --  If the entity is not a package renaming, it is the entity
13818             --  created to validate formal package actuals: ignore it.
13819 
13820             --  If the actual is itself a formal package for the enclosing
13821             --  generic, or the actual for such a formal package, it remains
13822             --  visible on exit from the instance, and therefore nothing needs
13823             --  to be done either, except to keep it accessible.
13824 
13825             if Is_Package and then Renamed_Object (E) = Pack_Id then
13826                exit;
13827 
13828             elsif Nkind (Parent (E)) /= N_Package_Renaming_Declaration then
13829                null;
13830 
13831             elsif
13832               Denotes_Formal_Package (Renamed_Object (E), True, Pack_Id)
13833             then
13834                Set_Is_Hidden (E, False);
13835 
13836             else
13837                declare
13838                   Act_P : constant Entity_Id := Renamed_Object (E);
13839                   Id    : Entity_Id;
13840 
13841                begin
13842                   Id := First_Entity (Act_P);
13843                   while Present (Id)
13844                     and then Id /= First_Private_Entity (Act_P)
13845                   loop
13846                      exit when Ekind (Id) = E_Package
13847                                  and then Renamed_Object (Id) = Act_P;
13848 
13849                      Set_Is_Hidden (Id, True);
13850                      Set_Is_Potentially_Use_Visible (Id, In_Use (Act_P));
13851 
13852                      if Ekind (Id) = E_Package then
13853                         Restore_Nested_Formal (Id);
13854                      end if;
13855 
13856                      Next_Entity (Id);
13857                   end loop;
13858                end;
13859             end if;
13860          end if;
13861 
13862          Next_Entity (E);
13863       end loop;
13864    end Restore_Private_Views;
13865 
13866    --------------
13867    -- Save_Env --
13868    --------------
13869 
13870    procedure Save_Env
13871      (Gen_Unit : Entity_Id;
13872       Act_Unit : Entity_Id)
13873    is
13874    begin
13875       Init_Env;
13876       Set_Instance_Env (Gen_Unit, Act_Unit);
13877    end Save_Env;
13878 
13879    ----------------------------
13880    -- Save_Global_References --
13881    ----------------------------
13882 
13883    procedure Save_Global_References (Templ : Node_Id) is
13884 
13885       --  ??? it is horrible to use global variables in highly recursive code
13886 
13887       E : Entity_Id;
13888       --  The entity of the current associated node
13889 
13890       Gen_Scope : Entity_Id;
13891       --  The scope of the generic for which references are being saved
13892 
13893       N2 : Node_Id;
13894       --  The current associated node
13895 
13896       function Is_Global (E : Entity_Id) return Boolean;
13897       --  Check whether entity is defined outside of generic unit. Examine the
13898       --  scope of an entity, and the scope of the scope, etc, until we find
13899       --  either Standard, in which case the entity is global, or the generic
13900       --  unit itself, which indicates that the entity is local. If the entity
13901       --  is the generic unit itself, as in the case of a recursive call, or
13902       --  the enclosing generic unit, if different from the current scope, then
13903       --  it is local as well, because it will be replaced at the point of
13904       --  instantiation. On the other hand, if it is a reference to a child
13905       --  unit of a common ancestor, which appears in an instantiation, it is
13906       --  global because it is used to denote a specific compilation unit at
13907       --  the time the instantiations will be analyzed.
13908 
13909       procedure Qualify_Universal_Operands
13910         (Op        : Node_Id;
13911          Func_Call : Node_Id);
13912       --  Op denotes a binary or unary operator in generic template Templ. Node
13913       --  Func_Call is the function call alternative of the operator within the
13914       --  the analyzed copy of the template. Change each operand which yields a
13915       --  universal type by wrapping it into a qualified expression
13916       --
13917       --    Actual_Typ'(Operand)
13918       --
13919       --  where Actual_Typ is the type of corresponding actual parameter of
13920       --  Operand in Func_Call.
13921 
13922       procedure Reset_Entity (N : Node_Id);
13923       --  Save semantic information on global entity so that it is not resolved
13924       --  again at instantiation time.
13925 
13926       procedure Save_Entity_Descendants (N : Node_Id);
13927       --  Apply Save_Global_References to the two syntactic descendants of
13928       --  non-terminal nodes that carry an Associated_Node and are processed
13929       --  through Reset_Entity. Once the global entity (if any) has been
13930       --  captured together with its type, only two syntactic descendants need
13931       --  to be traversed to complete the processing of the tree rooted at N.
13932       --  This applies to Selected_Components, Expanded_Names, and to Operator
13933       --  nodes. N can also be a character literal, identifier, or operator
13934       --  symbol node, but the call has no effect in these cases.
13935 
13936       procedure Save_Global_Defaults (N1 : Node_Id; N2 : Node_Id);
13937       --  Default actuals in nested instances must be handled specially
13938       --  because there is no link to them from the original tree. When an
13939       --  actual subprogram is given by a default, we add an explicit generic
13940       --  association for it in the instantiation node. When we save the
13941       --  global references on the name of the instance, we recover the list
13942       --  of generic associations, and add an explicit one to the original
13943       --  generic tree, through which a global actual can be preserved.
13944       --  Similarly, if a child unit is instantiated within a sibling, in the
13945       --  context of the parent, we must preserve the identifier of the parent
13946       --  so that it can be properly resolved in a subsequent instantiation.
13947 
13948       procedure Save_Global_Descendant (D : Union_Id);
13949       --  Apply Save_References recursively to the descendants of node D
13950 
13951       procedure Save_References (N : Node_Id);
13952       --  This is the recursive procedure that does the work, once the
13953       --  enclosing generic scope has been established.
13954 
13955       ---------------
13956       -- Is_Global --
13957       ---------------
13958 
13959       function Is_Global (E : Entity_Id) return Boolean is
13960          Se : Entity_Id;
13961 
13962          function Is_Instance_Node (Decl : Node_Id) return Boolean;
13963          --  Determine whether the parent node of a reference to a child unit
13964          --  denotes an instantiation or a formal package, in which case the
13965          --  reference to the child unit is global, even if it appears within
13966          --  the current scope (e.g. when the instance appears within the body
13967          --  of an ancestor).
13968 
13969          ----------------------
13970          -- Is_Instance_Node --
13971          ----------------------
13972 
13973          function Is_Instance_Node (Decl : Node_Id) return Boolean is
13974          begin
13975             return Nkind (Decl) in N_Generic_Instantiation
13976                      or else
13977                    Nkind (Original_Node (Decl)) = N_Formal_Package_Declaration;
13978          end Is_Instance_Node;
13979 
13980       --  Start of processing for Is_Global
13981 
13982       begin
13983          if E = Gen_Scope then
13984             return False;
13985 
13986          elsif E = Standard_Standard then
13987             return True;
13988 
13989          elsif Is_Child_Unit (E)
13990            and then (Is_Instance_Node (Parent (N2))
13991                       or else (Nkind (Parent (N2)) = N_Expanded_Name
13992                                 and then N2 = Selector_Name (Parent (N2))
13993                                 and then
13994                                   Is_Instance_Node (Parent (Parent (N2)))))
13995          then
13996             return True;
13997 
13998          else
13999             Se := Scope (E);
14000             while Se /= Gen_Scope loop
14001                if Se = Standard_Standard then
14002                   return True;
14003                else
14004                   Se := Scope (Se);
14005                end if;
14006             end loop;
14007 
14008             return False;
14009          end if;
14010       end Is_Global;
14011 
14012       --------------------------------
14013       -- Qualify_Universal_Operands --
14014       --------------------------------
14015 
14016       procedure Qualify_Universal_Operands
14017         (Op        : Node_Id;
14018          Func_Call : Node_Id)
14019       is
14020          procedure Qualify_Operand (Opnd : Node_Id; Actual : Node_Id);
14021          --  Rewrite operand Opnd as a qualified expression of the form
14022          --
14023          --    Actual_Typ'(Opnd)
14024          --
14025          --  where Actual is the corresponding actual parameter of Opnd in
14026          --  function call Func_Call.
14027 
14028          function Qualify_Type
14029            (Loc : Source_Ptr;
14030             Typ : Entity_Id) return Node_Id;
14031          --  Qualify type Typ by creating a selected component of the form
14032          --
14033          --    Scope_Of_Typ.Typ
14034 
14035          ---------------------
14036          -- Qualify_Operand --
14037          ---------------------
14038 
14039          procedure Qualify_Operand (Opnd : Node_Id; Actual : Node_Id) is
14040             Loc  : constant Source_Ptr := Sloc (Opnd);
14041             Typ  : constant Entity_Id  := Etype (Actual);
14042             Mark : Node_Id;
14043             Qual : Node_Id;
14044 
14045          begin
14046             --  Qualify the operand when it is of a universal type. Note that
14047             --  the template is unanalyzed and it is not possible to directly
14048             --  query the type. This transformation is not done when the type
14049             --  of the actual is internally generated because the type will be
14050             --  regenerated in the instance.
14051 
14052             if Yields_Universal_Type (Opnd)
14053               and then Comes_From_Source (Typ)
14054               and then not Is_Hidden (Typ)
14055             then
14056                --  The type of the actual may be a global reference. Save this
14057                --  information by creating a reference to it.
14058 
14059                if Is_Global (Typ) then
14060                   Mark := New_Occurrence_Of (Typ, Loc);
14061 
14062                --  Otherwise rely on resolution to find the proper type within
14063                --  the instance.
14064 
14065                else
14066                   Mark := Qualify_Type (Loc, Typ);
14067                end if;
14068 
14069                Qual :=
14070                  Make_Qualified_Expression (Loc,
14071                    Subtype_Mark => Mark,
14072                    Expression   => Relocate_Node (Opnd));
14073 
14074                --  Mark the qualification to distinguish it from other source
14075                --  constructs and signal the instantiation mechanism that this
14076                --  node requires special processing. See Copy_Generic_Node for
14077                --  details.
14078 
14079                Set_Is_Qualified_Universal_Literal (Qual);
14080 
14081                Rewrite (Opnd, Qual);
14082             end if;
14083          end Qualify_Operand;
14084 
14085          ------------------
14086          -- Qualify_Type --
14087          ------------------
14088 
14089          function Qualify_Type
14090            (Loc : Source_Ptr;
14091             Typ : Entity_Id) return Node_Id
14092          is
14093             Scop   : constant Entity_Id := Scope (Typ);
14094             Result : Node_Id;
14095 
14096          begin
14097             Result := Make_Identifier (Loc, Chars (Typ));
14098 
14099             if Present (Scop) and then not Is_Generic_Unit (Scop) then
14100                Result :=
14101                  Make_Selected_Component (Loc,
14102                    Prefix        => Make_Identifier (Loc, Chars (Scop)),
14103                    Selector_Name => Result);
14104             end if;
14105 
14106             return Result;
14107          end Qualify_Type;
14108 
14109          --  Local variables
14110 
14111          Actuals : constant List_Id := Parameter_Associations (Func_Call);
14112 
14113       --  Start of processing for Qualify_Universal_Operands
14114 
14115       begin
14116          if Nkind (Op) in N_Binary_Op then
14117             Qualify_Operand (Left_Opnd  (Op), First (Actuals));
14118             Qualify_Operand (Right_Opnd (Op), Next (First (Actuals)));
14119 
14120          elsif Nkind (Op) in N_Unary_Op then
14121             Qualify_Operand (Right_Opnd (Op), First (Actuals));
14122          end if;
14123       end Qualify_Universal_Operands;
14124 
14125       ------------------
14126       -- Reset_Entity --
14127       ------------------
14128 
14129       procedure Reset_Entity (N : Node_Id) is
14130          procedure Set_Global_Type (N : Node_Id; N2 : Node_Id);
14131          --  If the type of N2 is global to the generic unit, save the type in
14132          --  the generic node. Just as we perform name capture for explicit
14133          --  references within the generic, we must capture the global types
14134          --  of local entities because they may participate in resolution in
14135          --  the instance.
14136 
14137          function Top_Ancestor (E : Entity_Id) return Entity_Id;
14138          --  Find the ultimate ancestor of the current unit. If it is not a
14139          --  generic unit, then the name of the current unit in the prefix of
14140          --  an expanded name must be replaced with its generic homonym to
14141          --  ensure that it will be properly resolved in an instance.
14142 
14143          ---------------------
14144          -- Set_Global_Type --
14145          ---------------------
14146 
14147          procedure Set_Global_Type (N : Node_Id; N2 : Node_Id) is
14148             Typ : constant Entity_Id := Etype (N2);
14149 
14150          begin
14151             Set_Etype (N, Typ);
14152 
14153             --  If the entity of N is not the associated node, this is a
14154             --  nested generic and it has an associated node as well, whose
14155             --  type is already the full view (see below). Indicate that the
14156             --  original node has a private view.
14157 
14158             if Entity (N) /= N2 and then Has_Private_View (Entity (N)) then
14159                Set_Has_Private_View (N);
14160             end if;
14161 
14162             --  If not a private type, nothing else to do
14163 
14164             if not Is_Private_Type (Typ) then
14165                if Is_Array_Type (Typ)
14166                  and then Is_Private_Type (Component_Type (Typ))
14167                then
14168                   Set_Has_Private_View (N);
14169                end if;
14170 
14171             --  If it is a derivation of a private type in a context where no
14172             --  full view is needed, nothing to do either.
14173 
14174             elsif No (Full_View (Typ)) and then Typ /= Etype (Typ) then
14175                null;
14176 
14177             --  Otherwise mark the type for flipping and use the full view when
14178             --  available.
14179 
14180             else
14181                Set_Has_Private_View (N);
14182 
14183                if Present (Full_View (Typ)) then
14184                   Set_Etype (N2, Full_View (Typ));
14185                end if;
14186             end if;
14187 
14188             if Is_Floating_Point_Type (Typ)
14189               and then Has_Dimension_System (Typ)
14190             then
14191                Copy_Dimensions (N2, N);
14192             end if;
14193 
14194          end Set_Global_Type;
14195 
14196          ------------------
14197          -- Top_Ancestor --
14198          ------------------
14199 
14200          function Top_Ancestor (E : Entity_Id) return Entity_Id is
14201             Par : Entity_Id;
14202 
14203          begin
14204             Par := E;
14205             while Is_Child_Unit (Par) loop
14206                Par := Scope (Par);
14207             end loop;
14208 
14209             return Par;
14210          end Top_Ancestor;
14211 
14212       --  Start of processing for Reset_Entity
14213 
14214       begin
14215          N2 := Get_Associated_Node (N);
14216          E  := Entity (N2);
14217 
14218          if Present (E) then
14219 
14220             --  If the node is an entry call to an entry in an enclosing task,
14221             --  it is rewritten as a selected component. No global entity to
14222             --  preserve in this case, since the expansion will be redone in
14223             --  the instance.
14224 
14225             if not Nkind_In (E, N_Defining_Character_Literal,
14226                                 N_Defining_Identifier,
14227                                 N_Defining_Operator_Symbol)
14228             then
14229                Set_Associated_Node (N, Empty);
14230                Set_Etype (N, Empty);
14231                return;
14232             end if;
14233 
14234             --  If the entity is an itype created as a subtype of an access
14235             --  type with a null exclusion restore source entity for proper
14236             --  visibility. The itype will be created anew in the instance.
14237 
14238             if Is_Itype (E)
14239               and then Ekind (E) = E_Access_Subtype
14240               and then Is_Entity_Name (N)
14241               and then Chars (Etype (E)) = Chars (N)
14242             then
14243                E := Etype (E);
14244                Set_Entity (N2, E);
14245                Set_Etype  (N2, E);
14246             end if;
14247 
14248             if Is_Global (E) then
14249 
14250                --  If the entity is a package renaming that is the prefix of
14251                --  an expanded name, it has been rewritten as the renamed
14252                --  package, which is necessary semantically but complicates
14253                --  ASIS tree traversal, so we recover the original entity to
14254                --  expose the renaming. Take into account that the context may
14255                --  be a nested generic, that the original node may itself have
14256                --  an associated node that had better be an entity, and that
14257                --  the current node is still a selected component.
14258 
14259                if Ekind (E) = E_Package
14260                  and then Nkind (N) = N_Selected_Component
14261                  and then Nkind (Parent (N)) = N_Expanded_Name
14262                  and then Present (Original_Node (N2))
14263                  and then Is_Entity_Name (Original_Node (N2))
14264                  and then Present (Entity (Original_Node (N2)))
14265                then
14266                   if Is_Global (Entity (Original_Node (N2))) then
14267                      N2 := Original_Node (N2);
14268                      Set_Associated_Node (N, N2);
14269                      Set_Global_Type (N, N2);
14270 
14271                   --  Renaming is local, and will be resolved in instance
14272 
14273                   else
14274                      Set_Associated_Node (N, Empty);
14275                      Set_Etype (N, Empty);
14276                   end if;
14277 
14278                else
14279                   Set_Global_Type (N, N2);
14280                end if;
14281 
14282             elsif Nkind (N) = N_Op_Concat
14283               and then Is_Generic_Type (Etype (N2))
14284               and then (Base_Type (Etype (Right_Opnd (N2))) = Etype (N2)
14285                           or else
14286                         Base_Type (Etype (Left_Opnd  (N2))) = Etype (N2))
14287               and then Is_Intrinsic_Subprogram (E)
14288             then
14289                null;
14290 
14291             --  Entity is local. Mark generic node as unresolved. Note that now
14292             --  it does not have an entity.
14293 
14294             else
14295                Set_Associated_Node (N, Empty);
14296                Set_Etype (N, Empty);
14297             end if;
14298 
14299             if Nkind (Parent (N)) in N_Generic_Instantiation
14300               and then N = Name (Parent (N))
14301             then
14302                Save_Global_Defaults (Parent (N), Parent (N2));
14303             end if;
14304 
14305          elsif Nkind (Parent (N)) = N_Selected_Component
14306            and then Nkind (Parent (N2)) = N_Expanded_Name
14307          then
14308             if Is_Global (Entity (Parent (N2))) then
14309                Change_Selected_Component_To_Expanded_Name (Parent (N));
14310                Set_Associated_Node (Parent (N), Parent (N2));
14311                Set_Global_Type (Parent (N), Parent (N2));
14312                Save_Entity_Descendants (N);
14313 
14314             --  If this is a reference to the current generic entity, replace
14315             --  by the name of the generic homonym of the current package. This
14316             --  is because in an instantiation Par.P.Q will not resolve to the
14317             --  name of the instance, whose enclosing scope is not necessarily
14318             --  Par. We use the generic homonym rather that the name of the
14319             --  generic itself because it may be hidden by a local declaration.
14320 
14321             elsif In_Open_Scopes (Entity (Parent (N2)))
14322               and then not
14323                 Is_Generic_Unit (Top_Ancestor (Entity (Prefix (Parent (N2)))))
14324             then
14325                if Ekind (Entity (Parent (N2))) = E_Generic_Package then
14326                   Rewrite (Parent (N),
14327                     Make_Identifier (Sloc (N),
14328                       Chars =>
14329                         Chars (Generic_Homonym (Entity (Parent (N2))))));
14330                else
14331                   Rewrite (Parent (N),
14332                     Make_Identifier (Sloc (N),
14333                       Chars => Chars (Selector_Name (Parent (N2)))));
14334                end if;
14335             end if;
14336 
14337             if Nkind (Parent (Parent (N))) in N_Generic_Instantiation
14338               and then Parent (N) = Name (Parent (Parent (N)))
14339             then
14340                Save_Global_Defaults
14341                  (Parent (Parent (N)), Parent (Parent (N2)));
14342             end if;
14343 
14344          --  A selected component may denote a static constant that has been
14345          --  folded. If the static constant is global to the generic, capture
14346          --  its value. Otherwise the folding will happen in any instantiation.
14347 
14348          elsif Nkind (Parent (N)) = N_Selected_Component
14349            and then Nkind_In (Parent (N2), N_Integer_Literal, N_Real_Literal)
14350          then
14351             if Present (Entity (Original_Node (Parent (N2))))
14352               and then Is_Global (Entity (Original_Node (Parent (N2))))
14353             then
14354                Rewrite (Parent (N), New_Copy (Parent (N2)));
14355                Set_Analyzed (Parent (N), False);
14356             end if;
14357 
14358          --  A selected component may be transformed into a parameterless
14359          --  function call. If the called entity is global, rewrite the node
14360          --  appropriately, i.e. as an extended name for the global entity.
14361 
14362          elsif Nkind (Parent (N)) = N_Selected_Component
14363            and then Nkind (Parent (N2)) = N_Function_Call
14364            and then N = Selector_Name (Parent (N))
14365          then
14366             if No (Parameter_Associations (Parent (N2))) then
14367                if Is_Global (Entity (Name (Parent (N2)))) then
14368                   Change_Selected_Component_To_Expanded_Name (Parent (N));
14369                   Set_Associated_Node (Parent (N), Name (Parent (N2)));
14370                   Set_Global_Type (Parent (N), Name (Parent (N2)));
14371                   Save_Entity_Descendants (N);
14372 
14373                else
14374                   Set_Is_Prefixed_Call (Parent (N));
14375                   Set_Associated_Node (N, Empty);
14376                   Set_Etype (N, Empty);
14377                end if;
14378 
14379             --  In Ada 2005, X.F may be a call to a primitive operation,
14380             --  rewritten as F (X). This rewriting will be done again in an
14381             --  instance, so keep the original node. Global entities will be
14382             --  captured as for other constructs. Indicate that this must
14383             --  resolve as a call, to prevent accidental overloading in the
14384             --  instance, if both a component and a primitive operation appear
14385             --  as candidates.
14386 
14387             else
14388                Set_Is_Prefixed_Call (Parent (N));
14389             end if;
14390 
14391          --  Entity is local. Reset in generic unit, so that node is resolved
14392          --  anew at the point of instantiation.
14393 
14394          else
14395             Set_Associated_Node (N, Empty);
14396             Set_Etype (N, Empty);
14397          end if;
14398       end Reset_Entity;
14399 
14400       -----------------------------
14401       -- Save_Entity_Descendants --
14402       -----------------------------
14403 
14404       procedure Save_Entity_Descendants (N : Node_Id) is
14405       begin
14406          case Nkind (N) is
14407             when N_Binary_Op =>
14408                Save_Global_Descendant (Union_Id (Left_Opnd  (N)));
14409                Save_Global_Descendant (Union_Id (Right_Opnd (N)));
14410 
14411             when N_Unary_Op =>
14412                Save_Global_Descendant (Union_Id (Right_Opnd (N)));
14413 
14414             when N_Expanded_Name      |
14415                  N_Selected_Component =>
14416                Save_Global_Descendant (Union_Id (Prefix (N)));
14417                Save_Global_Descendant (Union_Id (Selector_Name (N)));
14418 
14419             when N_Identifier         |
14420                  N_Character_Literal  |
14421                  N_Operator_Symbol    =>
14422                null;
14423 
14424             when others =>
14425                raise Program_Error;
14426          end case;
14427       end Save_Entity_Descendants;
14428 
14429       --------------------------
14430       -- Save_Global_Defaults --
14431       --------------------------
14432 
14433       procedure Save_Global_Defaults (N1 : Node_Id; N2 : Node_Id) is
14434          Loc    : constant Source_Ptr := Sloc (N1);
14435          Assoc2 : constant List_Id    := Generic_Associations (N2);
14436          Gen_Id : constant Entity_Id  := Get_Generic_Entity (N2);
14437          Assoc1 : List_Id;
14438          Act1   : Node_Id;
14439          Act2   : Node_Id;
14440          Def    : Node_Id;
14441          Ndec   : Node_Id;
14442          Subp   : Entity_Id;
14443          Actual : Entity_Id;
14444 
14445       begin
14446          Assoc1 := Generic_Associations (N1);
14447 
14448          if Present (Assoc1) then
14449             Act1 := First (Assoc1);
14450          else
14451             Act1 := Empty;
14452             Set_Generic_Associations (N1, New_List);
14453             Assoc1 := Generic_Associations (N1);
14454          end if;
14455 
14456          if Present (Assoc2) then
14457             Act2 := First (Assoc2);
14458          else
14459             return;
14460          end if;
14461 
14462          while Present (Act1) and then Present (Act2) loop
14463             Next (Act1);
14464             Next (Act2);
14465          end loop;
14466 
14467          --  Find the associations added for default subprograms
14468 
14469          if Present (Act2) then
14470             while Nkind (Act2) /= N_Generic_Association
14471               or else No (Entity (Selector_Name (Act2)))
14472               or else not Is_Overloadable (Entity (Selector_Name (Act2)))
14473             loop
14474                Next (Act2);
14475             end loop;
14476 
14477             --  Add a similar association if the default is global. The
14478             --  renaming declaration for the actual has been analyzed, and
14479             --  its alias is the program it renames. Link the actual in the
14480             --  original generic tree with the node in the analyzed tree.
14481 
14482             while Present (Act2) loop
14483                Subp := Entity (Selector_Name (Act2));
14484                Def  := Explicit_Generic_Actual_Parameter (Act2);
14485 
14486                --  Following test is defence against rubbish errors
14487 
14488                if No (Alias (Subp)) then
14489                   return;
14490                end if;
14491 
14492                --  Retrieve the resolved actual from the renaming declaration
14493                --  created for the instantiated formal.
14494 
14495                Actual := Entity (Name (Parent (Parent (Subp))));
14496                Set_Entity (Def, Actual);
14497                Set_Etype (Def, Etype (Actual));
14498 
14499                if Is_Global (Actual) then
14500                   Ndec :=
14501                     Make_Generic_Association (Loc,
14502                       Selector_Name                     =>
14503                         New_Occurrence_Of (Subp, Loc),
14504                       Explicit_Generic_Actual_Parameter =>
14505                         New_Occurrence_Of (Actual, Loc));
14506 
14507                   Set_Associated_Node
14508                     (Explicit_Generic_Actual_Parameter (Ndec), Def);
14509 
14510                   Append (Ndec, Assoc1);
14511 
14512                --  If there are other defaults, add a dummy association in case
14513                --  there are other defaulted formals with the same name.
14514 
14515                elsif Present (Next (Act2)) then
14516                   Ndec :=
14517                     Make_Generic_Association (Loc,
14518                       Selector_Name                     =>
14519                         New_Occurrence_Of (Subp, Loc),
14520                       Explicit_Generic_Actual_Parameter => Empty);
14521 
14522                   Append (Ndec, Assoc1);
14523                end if;
14524 
14525                Next (Act2);
14526             end loop;
14527          end if;
14528 
14529          if Nkind (Name (N1)) = N_Identifier
14530            and then Is_Child_Unit (Gen_Id)
14531            and then Is_Global (Gen_Id)
14532            and then Is_Generic_Unit (Scope (Gen_Id))
14533            and then In_Open_Scopes (Scope (Gen_Id))
14534          then
14535             --  This is an instantiation of a child unit within a sibling, so
14536             --  that the generic parent is in scope. An eventual instance must
14537             --  occur within the scope of an instance of the parent. Make name
14538             --  in instance into an expanded name, to preserve the identifier
14539             --  of the parent, so it can be resolved subsequently.
14540 
14541             Rewrite (Name (N2),
14542               Make_Expanded_Name (Loc,
14543                 Chars         => Chars (Gen_Id),
14544                 Prefix        => New_Occurrence_Of (Scope (Gen_Id), Loc),
14545                 Selector_Name => New_Occurrence_Of (Gen_Id, Loc)));
14546             Set_Entity (Name (N2), Gen_Id);
14547 
14548             Rewrite (Name (N1),
14549                Make_Expanded_Name (Loc,
14550                 Chars         => Chars (Gen_Id),
14551                 Prefix        => New_Occurrence_Of (Scope (Gen_Id), Loc),
14552                 Selector_Name => New_Occurrence_Of (Gen_Id, Loc)));
14553 
14554             Set_Associated_Node (Name (N1), Name (N2));
14555             Set_Associated_Node (Prefix (Name (N1)), Empty);
14556             Set_Associated_Node
14557               (Selector_Name (Name (N1)), Selector_Name (Name (N2)));
14558             Set_Etype (Name (N1), Etype (Gen_Id));
14559          end if;
14560       end Save_Global_Defaults;
14561 
14562       ----------------------------
14563       -- Save_Global_Descendant --
14564       ----------------------------
14565 
14566       procedure Save_Global_Descendant (D : Union_Id) is
14567          N1 : Node_Id;
14568 
14569       begin
14570          if D in Node_Range then
14571             if D = Union_Id (Empty) then
14572                null;
14573 
14574             elsif Nkind (Node_Id (D)) /= N_Compilation_Unit then
14575                Save_References (Node_Id (D));
14576             end if;
14577 
14578          elsif D in List_Range then
14579             pragma Assert (D /= Union_Id (No_List));
14580             --  Because No_List = Empty, which is in Node_Range above
14581 
14582             if Is_Empty_List (List_Id (D)) then
14583                null;
14584 
14585             else
14586                N1 := First (List_Id (D));
14587                while Present (N1) loop
14588                   Save_References (N1);
14589                   Next (N1);
14590                end loop;
14591             end if;
14592 
14593          --  Element list or other non-node field, nothing to do
14594 
14595          else
14596             null;
14597          end if;
14598       end Save_Global_Descendant;
14599 
14600       ---------------------
14601       -- Save_References --
14602       ---------------------
14603 
14604       --  This is the recursive procedure that does the work once the enclosing
14605       --  generic scope has been established. We have to treat specially a
14606       --  number of node rewritings that are required by semantic processing
14607       --  and which change the kind of nodes in the generic copy: typically
14608       --  constant-folding, replacing an operator node by a string literal, or
14609       --  a selected component by an expanded name. In each of those cases, the
14610       --  transformation is propagated to the generic unit.
14611 
14612       procedure Save_References (N : Node_Id) is
14613          Loc : constant Source_Ptr := Sloc (N);
14614 
14615          function Requires_Delayed_Save (Nod : Node_Id) return Boolean;
14616          --  Determine whether arbitrary node Nod requires delayed capture of
14617          --  global references within its aspect specifications.
14618 
14619          procedure Save_References_In_Aggregate (N : Node_Id);
14620          --  Save all global references in [extension] aggregate node N
14621 
14622          procedure Save_References_In_Char_Lit_Or_Op_Symbol (N : Node_Id);
14623          --  Save all global references in a character literal or operator
14624          --  symbol denoted by N.
14625 
14626          procedure Save_References_In_Descendants (N : Node_Id);
14627          --  Save all global references in all descendants of node N
14628 
14629          procedure Save_References_In_Identifier (N : Node_Id);
14630          --  Save all global references in identifier node N
14631 
14632          procedure Save_References_In_Operator (N : Node_Id);
14633          --  Save all global references in operator node N
14634 
14635          procedure Save_References_In_Pragma (Prag : Node_Id);
14636          --  Save all global references found within the expression of pragma
14637          --  Prag.
14638 
14639          ---------------------------
14640          -- Requires_Delayed_Save --
14641          ---------------------------
14642 
14643          function Requires_Delayed_Save (Nod : Node_Id) return Boolean is
14644          begin
14645             --  Generic packages and subprograms require delayed capture of
14646             --  global references within their aspects due to the timing of
14647             --  annotation analysis.
14648 
14649             if Nkind_In (Nod, N_Generic_Package_Declaration,
14650                               N_Generic_Subprogram_Declaration,
14651                               N_Package_Body,
14652                               N_Package_Body_Stub,
14653                               N_Subprogram_Body,
14654                               N_Subprogram_Body_Stub)
14655             then
14656                --  Since the capture of global references is done on the
14657                --  unanalyzed generic template, there is no information around
14658                --  to infer the context. Use the Associated_Entity linkages to
14659                --  peek into the analyzed generic copy and determine what the
14660                --  template corresponds to.
14661 
14662                if Nod = Templ then
14663                   return
14664                     Is_Generic_Declaration_Or_Body
14665                       (Unit_Declaration_Node
14666                         (Associated_Entity (Defining_Entity (Nod))));
14667 
14668                --  Otherwise the generic unit being processed is not the top
14669                --  level template. It is safe to capture of global references
14670                --  within the generic unit because at this point the top level
14671                --  copy is fully analyzed.
14672 
14673                else
14674                   return False;
14675                end if;
14676 
14677             --  Otherwise capture the global references without interference
14678 
14679             else
14680                return False;
14681             end if;
14682          end Requires_Delayed_Save;
14683 
14684          ----------------------------------
14685          -- Save_References_In_Aggregate --
14686          ----------------------------------
14687 
14688          procedure Save_References_In_Aggregate (N : Node_Id) is
14689             Nam   : Node_Id;
14690             Qual  : Node_Id   := Empty;
14691             Typ   : Entity_Id := Empty;
14692 
14693             use Atree.Unchecked_Access;
14694             --  This code section is part of implementing an untyped tree
14695             --  traversal, so it needs direct access to node fields.
14696 
14697          begin
14698             N2 := Get_Associated_Node (N);
14699 
14700             if Present (N2) then
14701                Typ := Etype (N2);
14702 
14703                --  In an instance within a generic, use the name of the actual
14704                --  and not the original generic parameter. If the actual is
14705                --  global in the current generic it must be preserved for its
14706                --  instantiation.
14707 
14708                if Nkind (Parent (Typ)) = N_Subtype_Declaration
14709                  and then Present (Generic_Parent_Type (Parent (Typ)))
14710                then
14711                   Typ := Base_Type (Typ);
14712                   Set_Etype (N2, Typ);
14713                end if;
14714             end if;
14715 
14716             if No (N2) or else No (Typ) or else not Is_Global (Typ) then
14717                Set_Associated_Node (N, Empty);
14718 
14719                --  If the aggregate is an actual in a call, it has been
14720                --  resolved in the current context, to some local type. The
14721                --  enclosing call may have been disambiguated by the aggregate,
14722                --  and this disambiguation might fail at instantiation time
14723                --  because the type to which the aggregate did resolve is not
14724                --  preserved. In order to preserve some of this information,
14725                --  wrap the aggregate in a qualified expression, using the id
14726                --  of its type. For further disambiguation we qualify the type
14727                --  name with its scope (if visible) because both id's will have
14728                --  corresponding entities in an instance. This resolves most of
14729                --  the problems with missing type information on aggregates in
14730                --  instances.
14731 
14732                if Present (N2)
14733                  and then Nkind (N2) = Nkind (N)
14734                  and then Nkind (Parent (N2)) in N_Subprogram_Call
14735                  and then Present (Typ)
14736                  and then Comes_From_Source (Typ)
14737                then
14738                   Nam := Make_Identifier (Loc, Chars (Typ));
14739 
14740                   if Is_Immediately_Visible (Scope (Typ)) then
14741                      Nam :=
14742                        Make_Selected_Component (Loc,
14743                          Prefix        =>
14744                            Make_Identifier (Loc, Chars (Scope (Typ))),
14745                          Selector_Name => Nam);
14746                   end if;
14747 
14748                   Qual :=
14749                     Make_Qualified_Expression (Loc,
14750                       Subtype_Mark => Nam,
14751                       Expression   => Relocate_Node (N));
14752                end if;
14753             end if;
14754 
14755             Save_Global_Descendant (Field1 (N));
14756             Save_Global_Descendant (Field2 (N));
14757             Save_Global_Descendant (Field3 (N));
14758             Save_Global_Descendant (Field5 (N));
14759 
14760             if Present (Qual) then
14761                Rewrite (N, Qual);
14762             end if;
14763          end Save_References_In_Aggregate;
14764 
14765          ----------------------------------------------
14766          -- Save_References_In_Char_Lit_Or_Op_Symbol --
14767          ----------------------------------------------
14768 
14769          procedure Save_References_In_Char_Lit_Or_Op_Symbol (N : Node_Id) is
14770          begin
14771             if Nkind (N) = Nkind (Get_Associated_Node (N)) then
14772                Reset_Entity (N);
14773 
14774             elsif Nkind (N) = N_Operator_Symbol
14775               and then Nkind (Get_Associated_Node (N)) = N_String_Literal
14776             then
14777                Change_Operator_Symbol_To_String_Literal (N);
14778             end if;
14779          end Save_References_In_Char_Lit_Or_Op_Symbol;
14780 
14781          ------------------------------------
14782          -- Save_References_In_Descendants --
14783          ------------------------------------
14784 
14785          procedure Save_References_In_Descendants (N : Node_Id) is
14786             use Atree.Unchecked_Access;
14787             --  This code section is part of implementing an untyped tree
14788             --  traversal, so it needs direct access to node fields.
14789 
14790          begin
14791             Save_Global_Descendant (Field1 (N));
14792             Save_Global_Descendant (Field2 (N));
14793             Save_Global_Descendant (Field3 (N));
14794             Save_Global_Descendant (Field4 (N));
14795             Save_Global_Descendant (Field5 (N));
14796          end Save_References_In_Descendants;
14797 
14798          -----------------------------------
14799          -- Save_References_In_Identifier --
14800          -----------------------------------
14801 
14802          procedure Save_References_In_Identifier (N : Node_Id) is
14803          begin
14804             --  The node did not undergo a transformation
14805 
14806             if Nkind (N) = Nkind (Get_Associated_Node (N)) then
14807 
14808                --  If this is a discriminant reference, always save it. It is
14809                --  used in the instance to find the corresponding discriminant
14810                --  positionally rather than by name.
14811 
14812                Set_Original_Discriminant
14813                  (N, Original_Discriminant (Get_Associated_Node (N)));
14814                Reset_Entity (N);
14815 
14816             --  The analysis of the generic copy transformed the identifier
14817             --  into another construct. Propagate the changes to the template.
14818 
14819             else
14820                N2 := Get_Associated_Node (N);
14821 
14822                --  The identifier denotes a call to a parameterless function.
14823                --  Mark the node as resolved when the function is external.
14824 
14825                if Nkind (N2) = N_Function_Call then
14826                   E := Entity (Name (N2));
14827 
14828                   if Present (E) and then Is_Global (E) then
14829                      Set_Etype (N, Etype (N2));
14830                   else
14831                      Set_Associated_Node (N, Empty);
14832                      Set_Etype (N, Empty);
14833                   end if;
14834 
14835                --  The identifier denotes a named number that was constant
14836                --  folded. Preserve the original name for ASIS and undo the
14837                --  constant folding which will be repeated in the instance.
14838 
14839                elsif Nkind_In (N2, N_Integer_Literal, N_Real_Literal)
14840                  and then Is_Entity_Name (Original_Node (N2))
14841                then
14842                   Set_Associated_Node (N, Original_Node (N2));
14843                   Reset_Entity (N);
14844 
14845                --  The identifier resolved to a string literal. Propagate this
14846                --  information to the generic template.
14847 
14848                elsif Nkind (N2) = N_String_Literal then
14849                   Rewrite (N, New_Copy (N2));
14850 
14851                --  The identifier is rewritten as a dereference if it is the
14852                --  prefix of an implicit dereference. Preserve the original
14853                --  tree as the analysis of the instance will expand the node
14854                --  again, but preserve the resolved entity if it is global.
14855 
14856                elsif Nkind (N2) = N_Explicit_Dereference then
14857                   if Is_Entity_Name (Prefix (N2))
14858                     and then Present (Entity (Prefix (N2)))
14859                     and then Is_Global (Entity (Prefix (N2)))
14860                   then
14861                      Set_Associated_Node (N, Prefix (N2));
14862 
14863                   elsif Nkind (Prefix (N2)) = N_Function_Call
14864                     and then Present (Entity (Name (Prefix (N2))))
14865                     and then Is_Global (Entity (Name (Prefix (N2))))
14866                   then
14867                      Rewrite (N,
14868                        Make_Explicit_Dereference (Loc,
14869                          Prefix =>
14870                            Make_Function_Call (Loc,
14871                              Name =>
14872                                New_Occurrence_Of
14873                                  (Entity (Name (Prefix (N2))), Loc))));
14874 
14875                   else
14876                      Set_Associated_Node (N, Empty);
14877                      Set_Etype (N, Empty);
14878                   end if;
14879 
14880                --  The subtype mark of a nominally unconstrained object is
14881                --  rewritten as a subtype indication using the bounds of the
14882                --  expression. Recover the original subtype mark.
14883 
14884                elsif Nkind (N2) = N_Subtype_Indication
14885                  and then Is_Entity_Name (Original_Node (N2))
14886                then
14887                   Set_Associated_Node (N, Original_Node (N2));
14888                   Reset_Entity (N);
14889                end if;
14890             end if;
14891          end Save_References_In_Identifier;
14892 
14893          ---------------------------------
14894          -- Save_References_In_Operator --
14895          ---------------------------------
14896 
14897          procedure Save_References_In_Operator (N : Node_Id) is
14898          begin
14899             --  The node did not undergo a transformation
14900 
14901             if Nkind (N) = Nkind (Get_Associated_Node (N)) then
14902                if Nkind (N) = N_Op_Concat then
14903                   Set_Is_Component_Left_Opnd (N,
14904                     Is_Component_Left_Opnd (Get_Associated_Node (N)));
14905 
14906                   Set_Is_Component_Right_Opnd (N,
14907                     Is_Component_Right_Opnd (Get_Associated_Node (N)));
14908                end if;
14909 
14910                Reset_Entity (N);
14911 
14912             --  The analysis of the generic copy transformed the operator into
14913             --  some other construct. Propagate the changes to the template if
14914             --  applicable.
14915 
14916             else
14917                N2 := Get_Associated_Node (N);
14918 
14919                --  The operator resoved to a function call
14920 
14921                if Nkind (N2) = N_Function_Call then
14922 
14923                   --  Add explicit qualifications in the generic template for
14924                   --  all operands of universal type. This aids resolution by
14925                   --  preserving the actual type of a literal or an attribute
14926                   --  that yields a universal result.
14927 
14928                   Qualify_Universal_Operands (N, N2);
14929 
14930                   E := Entity (Name (N2));
14931 
14932                   if Present (E) and then Is_Global (E) then
14933                      Set_Etype (N, Etype (N2));
14934                   else
14935                      Set_Associated_Node (N, Empty);
14936                      Set_Etype           (N, Empty);
14937                   end if;
14938 
14939                --  The operator was folded into a literal
14940 
14941                elsif Nkind_In (N2, N_Integer_Literal,
14942                                    N_Real_Literal,
14943                                    N_String_Literal)
14944                then
14945                   if Present (Original_Node (N2))
14946                     and then Nkind (Original_Node (N2)) = Nkind (N)
14947                   then
14948                      --  Operation was constant-folded. Whenever possible,
14949                      --  recover semantic information from unfolded node,
14950                      --  for ASIS use.
14951 
14952                      Set_Associated_Node (N, Original_Node (N2));
14953 
14954                      if Nkind (N) = N_Op_Concat then
14955                         Set_Is_Component_Left_Opnd (N,
14956                           Is_Component_Left_Opnd  (Get_Associated_Node (N)));
14957                         Set_Is_Component_Right_Opnd (N,
14958                           Is_Component_Right_Opnd (Get_Associated_Node (N)));
14959                      end if;
14960 
14961                      Reset_Entity (N);
14962 
14963                   --  Propagate the constant folding back to the template
14964 
14965                   else
14966                      Rewrite (N, New_Copy (N2));
14967                      Set_Analyzed (N, False);
14968                   end if;
14969 
14970                --  The operator was folded into an enumeration literal. Retain
14971                --  the entity to avoid spurious ambiguities if it is overloaded
14972                --  at the point of instantiation or inlining.
14973 
14974                elsif Nkind (N2) = N_Identifier
14975                  and then Ekind (Entity (N2)) = E_Enumeration_Literal
14976                then
14977                   Rewrite (N, New_Copy (N2));
14978                   Set_Analyzed (N, False);
14979                end if;
14980             end if;
14981 
14982             --  Complete the operands check if node has not been constant
14983             --  folded.
14984 
14985             if Nkind (N) in N_Op then
14986                Save_Entity_Descendants (N);
14987             end if;
14988          end Save_References_In_Operator;
14989 
14990          -------------------------------
14991          -- Save_References_In_Pragma --
14992          -------------------------------
14993 
14994          procedure Save_References_In_Pragma (Prag : Node_Id) is
14995             Context : Node_Id;
14996             Do_Save : Boolean := True;
14997 
14998             use Atree.Unchecked_Access;
14999             --  This code section is part of implementing an untyped tree
15000             --  traversal, so it needs direct access to node fields.
15001 
15002          begin
15003             --  Do not save global references in pragmas generated from aspects
15004             --  because the pragmas will be regenerated at instantiation time.
15005 
15006             if From_Aspect_Specification (Prag) then
15007                Do_Save := False;
15008 
15009             --  The capture of global references within contract-related source
15010             --  pragmas associated with generic packages, subprograms or their
15011             --  respective bodies must be delayed due to timing of annotation
15012             --  analysis. Global references are still captured in routine
15013             --  Save_Global_References_In_Contract.
15014 
15015             elsif Is_Generic_Contract_Pragma (Prag) and then Prag /= Templ then
15016                if Is_Package_Contract_Annotation (Prag) then
15017                   Context := Find_Related_Package_Or_Body (Prag);
15018                else
15019                   pragma Assert (Is_Subprogram_Contract_Annotation (Prag));
15020                   Context := Find_Related_Declaration_Or_Body (Prag);
15021                end if;
15022 
15023                --  The use of Original_Node accounts for the case when the
15024                --  related context is generic template.
15025 
15026                if Requires_Delayed_Save (Original_Node (Context)) then
15027                   Do_Save := False;
15028                end if;
15029             end if;
15030 
15031             --  For all other cases, save all global references within the
15032             --  descendants, but skip the following semantic fields:
15033 
15034             --    Field1 - Next_Pragma
15035             --    Field3 - Corresponding_Aspect
15036             --    Field5 - Next_Rep_Item
15037 
15038             if Do_Save then
15039                Save_Global_Descendant (Field2 (Prag));
15040                Save_Global_Descendant (Field4 (Prag));
15041             end if;
15042          end Save_References_In_Pragma;
15043 
15044       --  Start of processing for Save_References
15045 
15046       begin
15047          if N = Empty then
15048             null;
15049 
15050          --  Aggregates
15051 
15052          elsif Nkind_In (N, N_Aggregate, N_Extension_Aggregate) then
15053             Save_References_In_Aggregate (N);
15054 
15055          --  Character literals, operator symbols
15056 
15057          elsif Nkind_In (N, N_Character_Literal, N_Operator_Symbol) then
15058             Save_References_In_Char_Lit_Or_Op_Symbol (N);
15059 
15060          --  Defining identifiers
15061 
15062          elsif Nkind (N) in N_Entity then
15063             null;
15064 
15065          --  Identifiers
15066 
15067          elsif Nkind (N) = N_Identifier then
15068             Save_References_In_Identifier (N);
15069 
15070          --  Operators
15071 
15072          elsif Nkind (N) in N_Op then
15073             Save_References_In_Operator (N);
15074 
15075          --  Pragmas
15076 
15077          elsif Nkind (N) = N_Pragma then
15078             Save_References_In_Pragma (N);
15079 
15080          else
15081             Save_References_In_Descendants (N);
15082          end if;
15083 
15084          --  Save all global references found within the aspect specifications
15085          --  of the related node.
15086 
15087          if Permits_Aspect_Specifications (N) and then Has_Aspects (N) then
15088 
15089             --  The capture of global references within aspects associated with
15090             --  generic packages, subprograms or their bodies must be delayed
15091             --  due to timing of annotation analysis. Global references are
15092             --  still captured in routine Save_Global_References_In_Contract.
15093 
15094             if Requires_Delayed_Save (N) then
15095                null;
15096 
15097             --  Otherwise save all global references within the aspects
15098 
15099             else
15100                Save_Global_References_In_Aspects (N);
15101             end if;
15102          end if;
15103       end Save_References;
15104 
15105    --  Start of processing for Save_Global_References
15106 
15107    begin
15108       Gen_Scope := Current_Scope;
15109 
15110       --  If the generic unit is a child unit, references to entities in the
15111       --  parent are treated as local, because they will be resolved anew in
15112       --  the context of the instance of the parent.
15113 
15114       while Is_Child_Unit (Gen_Scope)
15115         and then Ekind (Scope (Gen_Scope)) = E_Generic_Package
15116       loop
15117          Gen_Scope := Scope (Gen_Scope);
15118       end loop;
15119 
15120       Save_References (Templ);
15121    end Save_Global_References;
15122 
15123    ---------------------------------------
15124    -- Save_Global_References_In_Aspects --
15125    ---------------------------------------
15126 
15127    procedure Save_Global_References_In_Aspects (N : Node_Id) is
15128       Asp  : Node_Id;
15129       Expr : Node_Id;
15130 
15131    begin
15132       Asp := First (Aspect_Specifications (N));
15133       while Present (Asp) loop
15134          Expr := Expression (Asp);
15135 
15136          if Present (Expr) then
15137             Save_Global_References (Expr);
15138          end if;
15139 
15140          Next (Asp);
15141       end loop;
15142    end Save_Global_References_In_Aspects;
15143 
15144    ------------------------------------------
15145    -- Set_Copied_Sloc_For_Inherited_Pragma --
15146    ------------------------------------------
15147 
15148    procedure Set_Copied_Sloc_For_Inherited_Pragma
15149      (N : Node_Id;
15150       E : Entity_Id)
15151    is
15152    begin
15153       Create_Instantiation_Source (N, E,
15154         Inlined_Body     => False,
15155         Inherited_Pragma => True,
15156         Factor           => S_Adjustment);
15157    end Set_Copied_Sloc_For_Inherited_Pragma;
15158 
15159    --------------------------------------
15160    -- Set_Copied_Sloc_For_Inlined_Body --
15161    --------------------------------------
15162 
15163    procedure Set_Copied_Sloc_For_Inlined_Body (N : Node_Id; E : Entity_Id) is
15164    begin
15165       Create_Instantiation_Source (N, E,
15166         Inlined_Body     => True,
15167         Inherited_Pragma => False,
15168         Factor           => S_Adjustment);
15169    end Set_Copied_Sloc_For_Inlined_Body;
15170 
15171    ---------------------
15172    -- Set_Instance_Of --
15173    ---------------------
15174 
15175    procedure Set_Instance_Of (A : Entity_Id; B : Entity_Id) is
15176    begin
15177       Generic_Renamings.Table (Generic_Renamings.Last) := (A, B, Assoc_Null);
15178       Generic_Renamings_HTable.Set (Generic_Renamings.Last);
15179       Generic_Renamings.Increment_Last;
15180    end Set_Instance_Of;
15181 
15182    --------------------
15183    -- Set_Next_Assoc --
15184    --------------------
15185 
15186    procedure Set_Next_Assoc (E : Assoc_Ptr; Next : Assoc_Ptr) is
15187    begin
15188       Generic_Renamings.Table (E).Next_In_HTable := Next;
15189    end Set_Next_Assoc;
15190 
15191    -------------------
15192    -- Start_Generic --
15193    -------------------
15194 
15195    procedure Start_Generic is
15196    begin
15197       --  ??? More things could be factored out in this routine.
15198       --  Should probably be done at a later stage.
15199 
15200       Generic_Flags.Append (Inside_A_Generic);
15201       Inside_A_Generic := True;
15202 
15203       Expander_Mode_Save_And_Set (False);
15204    end Start_Generic;
15205 
15206    ----------------------
15207    -- Set_Instance_Env --
15208    ----------------------
15209 
15210    procedure Set_Instance_Env
15211      (Gen_Unit : Entity_Id;
15212       Act_Unit : Entity_Id)
15213    is
15214       Assertion_Status       : constant Boolean := Assertions_Enabled;
15215       Save_SPARK_Mode        : constant SPARK_Mode_Type := SPARK_Mode;
15216       Save_SPARK_Mode_Pragma : constant Node_Id := SPARK_Mode_Pragma;
15217 
15218    begin
15219       --  Regardless of the current mode, predefined units are analyzed in the
15220       --  most current Ada mode, and earlier version Ada checks do not apply
15221       --  to predefined units. Nothing needs to be done for non-internal units.
15222       --  These are always analyzed in the current mode.
15223 
15224       if Is_Internal_File_Name
15225            (Fname              => Unit_File_Name (Get_Source_Unit (Gen_Unit)),
15226             Renamings_Included => True)
15227       then
15228          Set_Opt_Config_Switches (True, Current_Sem_Unit = Main_Unit);
15229 
15230          --  In Ada2012 we may want to enable assertions in an instance of a
15231          --  predefined unit, in which case we need to preserve the current
15232          --  setting for the Assertions_Enabled flag. This will become more
15233          --  critical when pre/postconditions are added to predefined units,
15234          --  as is already the case for some numeric libraries.
15235 
15236          if Ada_Version >= Ada_2012 then
15237             Assertions_Enabled := Assertion_Status;
15238          end if;
15239 
15240          --  SPARK_Mode for an instance is the one applicable at the point of
15241          --  instantiation.
15242 
15243          SPARK_Mode := Save_SPARK_Mode;
15244          SPARK_Mode_Pragma := Save_SPARK_Mode_Pragma;
15245       end if;
15246 
15247       Current_Instantiated_Parent :=
15248         (Gen_Id         => Gen_Unit,
15249          Act_Id         => Act_Unit,
15250          Next_In_HTable => Assoc_Null);
15251    end Set_Instance_Env;
15252 
15253    -----------------
15254    -- Switch_View --
15255    -----------------
15256 
15257    procedure Switch_View (T : Entity_Id) is
15258       BT        : constant Entity_Id := Base_Type (T);
15259       Priv_Elmt : Elmt_Id := No_Elmt;
15260       Priv_Sub  : Entity_Id;
15261 
15262    begin
15263       --  T may be private but its base type may have been exchanged through
15264       --  some other occurrence, in which case there is nothing to switch
15265       --  besides T itself. Note that a private dependent subtype of a private
15266       --  type might not have been switched even if the base type has been,
15267       --  because of the last branch of Check_Private_View (see comment there).
15268 
15269       if not Is_Private_Type (BT) then
15270          Prepend_Elmt (Full_View (T), Exchanged_Views);
15271          Exchange_Declarations (T);
15272          return;
15273       end if;
15274 
15275       Priv_Elmt := First_Elmt (Private_Dependents (BT));
15276 
15277       if Present (Full_View (BT)) then
15278          Prepend_Elmt (Full_View (BT), Exchanged_Views);
15279          Exchange_Declarations (BT);
15280       end if;
15281 
15282       while Present (Priv_Elmt) loop
15283          Priv_Sub := (Node (Priv_Elmt));
15284 
15285          --  We avoid flipping the subtype if the Etype of its full view is
15286          --  private because this would result in a malformed subtype. This
15287          --  occurs when the Etype of the subtype full view is the full view of
15288          --  the base type (and since the base types were just switched, the
15289          --  subtype is pointing to the wrong view). This is currently the case
15290          --  for tagged record types, access types (maybe more?) and needs to
15291          --  be resolved. ???
15292 
15293          if Present (Full_View (Priv_Sub))
15294            and then not Is_Private_Type (Etype (Full_View (Priv_Sub)))
15295          then
15296             Prepend_Elmt (Full_View (Priv_Sub), Exchanged_Views);
15297             Exchange_Declarations (Priv_Sub);
15298          end if;
15299 
15300          Next_Elmt (Priv_Elmt);
15301       end loop;
15302    end Switch_View;
15303 
15304    -----------------
15305    -- True_Parent --
15306    -----------------
15307 
15308    function True_Parent (N : Node_Id) return Node_Id is
15309    begin
15310       if Nkind (Parent (N)) = N_Subunit then
15311          return Parent (Corresponding_Stub (Parent (N)));
15312       else
15313          return Parent (N);
15314       end if;
15315    end True_Parent;
15316 
15317    -----------------------------
15318    -- Valid_Default_Attribute --
15319    -----------------------------
15320 
15321    procedure Valid_Default_Attribute (Nam : Entity_Id; Def : Node_Id) is
15322       Attr_Id : constant Attribute_Id :=
15323                   Get_Attribute_Id (Attribute_Name (Def));
15324       T       : constant Entity_Id := Entity (Prefix (Def));
15325       Is_Fun  : constant Boolean := (Ekind (Nam) = E_Function);
15326       F       : Entity_Id;
15327       Num_F   : Nat;
15328       OK      : Boolean;
15329 
15330    begin
15331       if No (T) or else T = Any_Id then
15332          return;
15333       end if;
15334 
15335       Num_F := 0;
15336       F := First_Formal (Nam);
15337       while Present (F) loop
15338          Num_F := Num_F + 1;
15339          Next_Formal (F);
15340       end loop;
15341 
15342       case Attr_Id is
15343          when Attribute_Adjacent |  Attribute_Ceiling   | Attribute_Copy_Sign |
15344               Attribute_Floor    |  Attribute_Fraction  | Attribute_Machine   |
15345               Attribute_Model    |  Attribute_Remainder | Attribute_Rounding  |
15346               Attribute_Unbiased_Rounding  =>
15347             OK := Is_Fun
15348                     and then Num_F = 1
15349                     and then Is_Floating_Point_Type (T);
15350 
15351          when Attribute_Image    | Attribute_Pred       | Attribute_Succ |
15352               Attribute_Value    | Attribute_Wide_Image |
15353               Attribute_Wide_Value  =>
15354             OK := (Is_Fun and then Num_F = 1 and then Is_Scalar_Type (T));
15355 
15356          when Attribute_Max      |  Attribute_Min  =>
15357             OK := (Is_Fun and then Num_F = 2 and then Is_Scalar_Type (T));
15358 
15359          when Attribute_Input =>
15360             OK := (Is_Fun and then Num_F = 1);
15361 
15362          when Attribute_Output | Attribute_Read | Attribute_Write =>
15363             OK := (not Is_Fun and then Num_F = 2);
15364 
15365          when others =>
15366             OK := False;
15367       end case;
15368 
15369       if not OK then
15370          Error_Msg_N
15371            ("attribute reference has wrong profile for subprogram", Def);
15372       end if;
15373    end Valid_Default_Attribute;
15374 
15375 end Sem_Ch12;