gcc/ada/sem_util.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             S E M _ U T I L                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2004, 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 2,  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 COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 with Atree;    use Atree;
  28 with Casing;   use Casing;
  29 with Checks;   use Checks;
  30 with Debug;    use Debug;
  31 with Errout;   use Errout;
  32 with Elists;   use Elists;
  33 with Exp_Tss;  use Exp_Tss;
  34 with Exp_Util; use Exp_Util;
  35 with Fname;    use Fname;
  36 with Freeze;   use Freeze;
  37 with Lib;      use Lib;
  38 with Lib.Xref; use Lib.Xref;
  39 with Namet;    use Namet;
  40 with Nlists;   use Nlists;
  41 with Nmake;    use Nmake;
  42 with Output;   use Output;
  43 with Opt;      use Opt;
  44 with Rtsfind;  use Rtsfind;
  45 with Scans;    use Scans;
  46 with Scn;      use Scn;
  47 with Sem;      use Sem;
  48 with Sem_Ch8;  use Sem_Ch8;
  49 with Sem_Eval; use Sem_Eval;
  50 with Sem_Res;  use Sem_Res;
  51 with Sem_Type; use Sem_Type;
  52 with Sinfo;    use Sinfo;
  53 with Sinput;   use Sinput;
  54 with Snames;   use Snames;
  55 with Stand;    use Stand;
  56 with Style;
  57 with Stringt;  use Stringt;
  58 with Targparm; use Targparm;
  59 with Tbuild;   use Tbuild;
  60 with Ttypes;   use Ttypes;
  61 with Uname;    use Uname;
  62
  63 package body Sem_Util is
  64
  65    -----------------------
  66    -- Local Subprograms --
  67    -----------------------
  68
  69    function Build_Component_Subtype
  70      (C   : List_Id;
  71       Loc : Source_Ptr;
  72       T   : Entity_Id) return Node_Id;
  73    --  This function builds the subtype for Build_Actual_Subtype_Of_Component
  74    --  and Build_Discriminal_Subtype_Of_Component. C is a list of constraints,
  75    --  Loc is the source location, T is the original subtype.
  76
  77    function Is_Fully_Initialized_Variant (Typ : Entity_Id) return Boolean;
  78    --  Subsidiary to Is_Fully_Initialized_Type. For an unconstrained type
  79    --  with discriminants whose default values are static, examine only the
  80    --  components in the selected variant to determine whether all of them
  81    --  have a default.
  82
  83    function Has_Null_Extension (T : Entity_Id) return Boolean;
  84    --  T is a derived tagged type. Check whether the type extension is null.
  85    --  If the parent type is fully initialized, T can be treated as such.
  86
  87    --------------------------------
  88    -- Add_Access_Type_To_Process --
  89    --------------------------------
  90
  91    procedure Add_Access_Type_To_Process (E : Entity_Id; A : Entity_Id) is
  92       L : Elist_Id;
  93
  94    begin
  95       Ensure_Freeze_Node (E);
  96       L := Access_Types_To_Process (Freeze_Node (E));
  97
  98       if No (L) then
  99          L := New_Elmt_List;
 100          Set_Access_Types_To_Process (Freeze_Node (E), L);
 101       end if;
 102
 103       Append_Elmt (A, L);
 104    end Add_Access_Type_To_Process;
 105
 106    -----------------------
 107    -- Alignment_In_Bits --
 108    -----------------------
 109
 110    function Alignment_In_Bits (E : Entity_Id) return Uint is
 111    begin
 112       return Alignment (E) * System_Storage_Unit;
 113    end Alignment_In_Bits;
 114
 115    -----------------------------------------
 116    -- Apply_Compile_Time_Constraint_Error --
 117    -----------------------------------------
 118
 119    procedure Apply_Compile_Time_Constraint_Error
 120      (N      : Node_Id;
 121       Msg    : String;
 122       Reason : RT_Exception_Code;
 123       Ent    : Entity_Id  := Empty;
 124       Typ    : Entity_Id  := Empty;
 125       Loc    : Source_Ptr := No_Location;
 126       Rep    : Boolean    := True;
 127       Warn   : Boolean    := False)
 128    is
 129       Stat : constant Boolean := Is_Static_Expression (N);
 130       Rtyp : Entity_Id;
 131
 132    begin
 133       if No (Typ) then
 134          Rtyp := Etype (N);
 135       else
 136          Rtyp := Typ;
 137       end if;
 138
 139       Discard_Node (
 140         Compile_Time_Constraint_Error (N, Msg, Ent, Loc, Warn => Warn));
 141
 142       if not Rep then
 143          return;
 144       end if;
 145
 146       --  Now we replace the node by an N_Raise_Constraint_Error node
 147       --  This does not need reanalyzing, so set it as analyzed now.
 148
 149       Rewrite (N,
 150         Make_Raise_Constraint_Error (Sloc (N),
 151           Reason => Reason));
 152       Set_Analyzed (N, True);
 153       Set_Etype (N, Rtyp);
 154       Set_Raises_Constraint_Error (N);
 155
 156       --  If the original expression was marked as static, the result is
 157       --  still marked as static, but the Raises_Constraint_Error flag is
 158       --  always set so that further static evaluation is not attempted.
 159
 160       if Stat then
 161          Set_Is_Static_Expression (N);
 162       end if;
 163    end Apply_Compile_Time_Constraint_Error;
 164
 165    --------------------------
 166    -- Build_Actual_Subtype --
 167    --------------------------
 168
 169    function Build_Actual_Subtype
 170      (T : Entity_Id;
 171       N : Node_Or_Entity_Id) return Node_Id
 172    is
 173       Obj : Node_Id;
 174
 175       Loc         : constant Source_Ptr := Sloc (N);
 176       Constraints : List_Id;
 177       Decl        : Node_Id;
 178       Discr       : Entity_Id;
 179       Hi          : Node_Id;
 180       Lo          : Node_Id;
 181       Subt        : Entity_Id;
 182       Disc_Type   : Entity_Id;
 183
 184    begin
 185       if Nkind (N) = N_Defining_Identifier then
 186          Obj := New_Reference_To (N, Loc);
 187       else
 188          Obj := N;
 189       end if;
 190
 191       if Is_Array_Type (T) then
 192          Constraints := New_List;
 193
 194          for J in 1 .. Number_Dimensions (T) loop
 195
 196             --  Build an array subtype declaration with the nominal
 197             --  subtype and the bounds of the actual. Add the declaration
 198             --  in front of the local declarations for the subprogram, for
 199             --  analysis before any reference to the formal in the body.
 200
 201             Lo :=
 202               Make_Attribute_Reference (Loc,
 203                 Prefix         =>
 204                   Duplicate_Subexpr_No_Checks (Obj, Name_Req => True),
 205                 Attribute_Name => Name_First,
 206                 Expressions    => New_List (
 207                   Make_Integer_Literal (Loc, J)));
 208
 209             Hi :=
 210               Make_Attribute_Reference (Loc,
 211                 Prefix         =>
 212                   Duplicate_Subexpr_No_Checks (Obj, Name_Req => True),
 213                 Attribute_Name => Name_Last,
 214                 Expressions    => New_List (
 215                   Make_Integer_Literal (Loc, J)));
 216
 217             Append (Make_Range (Loc, Lo, Hi), Constraints);
 218          end loop;
 219
 220       --  If the type has unknown discriminants there is no constrained
 221       --  subtype to build. This is never called for a formal or for a
 222       --  lhs, so returning the type is ok ???
 223
 224       elsif Has_Unknown_Discriminants (T) then
 225          return T;
 226
 227       else
 228          Constraints := New_List;
 229
 230          if Is_Private_Type (T) and then No (Full_View (T)) then
 231
 232             --  Type is a generic derived type. Inherit discriminants from
 233             --  Parent type.
 234
 235             Disc_Type := Etype (Base_Type (T));
 236          else
 237             Disc_Type := T;
 238          end if;
 239
 240          Discr := First_Discriminant (Disc_Type);
 241
 242          while Present (Discr) loop
 243             Append_To (Constraints,
 244               Make_Selected_Component (Loc,
 245                 Prefix =>
 246                   Duplicate_Subexpr_No_Checks (Obj),
 247                 Selector_Name => New_Occurrence_Of (Discr, Loc)));
 248             Next_Discriminant (Discr);
 249          end loop;
 250       end if;
 251
 252       Subt :=
 253         Make_Defining_Identifier (Loc,
 254           Chars => New_Internal_Name ('S'));
 255       Set_Is_Internal (Subt);
 256
 257       Decl :=
 258         Make_Subtype_Declaration (Loc,
 259           Defining_Identifier => Subt,
 260           Subtype_Indication =>
 261             Make_Subtype_Indication (Loc,
 262               Subtype_Mark => New_Reference_To (T,  Loc),
 263               Constraint  =>
 264                 Make_Index_Or_Discriminant_Constraint (Loc,
 265                   Constraints => Constraints)));
 266
 267       Mark_Rewrite_Insertion (Decl);
 268       return Decl;
 269    end Build_Actual_Subtype;
 270
 271    ---------------------------------------
 272    -- Build_Actual_Subtype_Of_Component --
 273    ---------------------------------------
 274
 275    function Build_Actual_Subtype_Of_Component
 276      (T : Entity_Id;
 277       N : Node_Id) return Node_Id
 278    is
 279       Loc       : constant Source_Ptr := Sloc (N);
 280       P         : constant Node_Id    := Prefix (N);
 281       D         : Elmt_Id;
 282       Id        : Node_Id;
 283       Indx_Type : Entity_Id;
 284
 285       Deaccessed_T : Entity_Id;
 286       --  This is either a copy of T, or if T is an access type, then it is
 287       --  the directly designated type of this access type.
 288
 289       function Build_Actual_Array_Constraint return List_Id;
 290       --  If one or more of the bounds of the component depends on
 291       --  discriminants, build  actual constraint using the discriminants
 292       --  of the prefix.
 293
 294       function Build_Actual_Record_Constraint return List_Id;
 295       --  Similar to previous one, for discriminated components constrained
 296       --  by the discriminant of the enclosing object.
 297
 298       -----------------------------------
 299       -- Build_Actual_Array_Constraint --
 300       -----------------------------------
 301
 302       function Build_Actual_Array_Constraint return List_Id is
 303          Constraints : constant List_Id := New_List;
 304          Indx        : Node_Id;
 305          Hi          : Node_Id;
 306          Lo          : Node_Id;
 307          Old_Hi      : Node_Id;
 308          Old_Lo      : Node_Id;
 309
 310       begin
 311          Indx := First_Index (Deaccessed_T);
 312          while Present (Indx) loop
 313             Old_Lo := Type_Low_Bound  (Etype (Indx));
 314             Old_Hi := Type_High_Bound (Etype (Indx));
 315
 316             if Denotes_Discriminant (Old_Lo) then
 317                Lo :=
 318                  Make_Selected_Component (Loc,
 319                    Prefix => New_Copy_Tree (P),
 320                    Selector_Name => New_Occurrence_Of (Entity (Old_Lo), Loc));
 321
 322             else
 323                Lo := New_Copy_Tree (Old_Lo);
 324
 325                --  The new bound will be reanalyzed in the enclosing
 326                --  declaration. For literal bounds that come from a type
 327                --  declaration, the type of the context must be imposed, so
 328                --  insure that analysis will take place. For non-universal
 329                --  types this is not strictly necessary.
 330
 331                Set_Analyzed (Lo, False);
 332             end if;
 333
 334             if Denotes_Discriminant (Old_Hi) then
 335                Hi :=
 336                  Make_Selected_Component (Loc,
 337                    Prefix => New_Copy_Tree (P),
 338                    Selector_Name => New_Occurrence_Of (Entity (Old_Hi), Loc));
 339
 340             else
 341                Hi := New_Copy_Tree (Old_Hi);
 342                Set_Analyzed (Hi, False);
 343             end if;
 344
 345             Append (Make_Range (Loc, Lo, Hi), Constraints);
 346             Next_Index (Indx);
 347          end loop;
 348
 349          return Constraints;
 350       end Build_Actual_Array_Constraint;
 351
 352       ------------------------------------
 353       -- Build_Actual_Record_Constraint --
 354       ------------------------------------
 355
 356       function Build_Actual_Record_Constraint return List_Id is
 357          Constraints : constant List_Id := New_List;
 358          D           : Elmt_Id;
 359          D_Val       : Node_Id;
 360
 361       begin
 362          D := First_Elmt (Discriminant_Constraint (Deaccessed_T));
 363          while Present (D) loop
 364
 365             if Denotes_Discriminant (Node (D)) then
 366                D_Val :=  Make_Selected_Component (Loc,
 367                  Prefix => New_Copy_Tree (P),
 368                 Selector_Name => New_Occurrence_Of (Entity (Node (D)), Loc));
 369
 370             else
 371                D_Val := New_Copy_Tree (Node (D));
 372             end if;
 373
 374             Append (D_Val, Constraints);
 375             Next_Elmt (D);
 376          end loop;
 377
 378          return Constraints;
 379       end Build_Actual_Record_Constraint;
 380
 381    --  Start of processing for Build_Actual_Subtype_Of_Component
 382
 383    begin
 384       if In_Default_Expression then
 385          return Empty;
 386
 387       elsif Nkind (N) = N_Explicit_Dereference then
 388          if Is_Composite_Type (T)
 389            and then not Is_Constrained (T)
 390            and then not (Is_Class_Wide_Type (T)
 391                           and then Is_Constrained (Root_Type (T)))
 392            and then not Has_Unknown_Discriminants (T)
 393          then
 394             --  If the type of the dereference is already constrained, it
 395             --  is an actual subtype.
 396
 397             if Is_Array_Type (Etype (N))
 398               and then Is_Constrained (Etype (N))
 399             then
 400                return Empty;
 401             else
 402                Remove_Side_Effects (P);
 403                return Build_Actual_Subtype (T, N);
 404             end if;
 405          else
 406             return Empty;
 407          end if;
 408       end if;
 409
 410       if Ekind (T) = E_Access_Subtype then
 411          Deaccessed_T := Designated_Type (T);
 412       else
 413          Deaccessed_T := T;
 414       end if;
 415
 416       if Ekind (Deaccessed_T) = E_Array_Subtype then
 417          Id := First_Index (Deaccessed_T);
 418          Indx_Type := Underlying_Type (Etype (Id));
 419
 420          while Present (Id) loop
 421
 422             if Denotes_Discriminant (Type_Low_Bound  (Indx_Type)) or else
 423                Denotes_Discriminant (Type_High_Bound (Indx_Type))
 424             then
 425                Remove_Side_Effects (P);
 426                return
 427                  Build_Component_Subtype (
 428                    Build_Actual_Array_Constraint, Loc, Base_Type (T));
 429             end if;
 430
 431             Next_Index (Id);
 432          end loop;
 433
 434       elsif Is_Composite_Type (Deaccessed_T)
 435         and then Has_Discriminants (Deaccessed_T)
 436         and then not Has_Unknown_Discriminants (Deaccessed_T)
 437       then
 438          D := First_Elmt (Discriminant_Constraint (Deaccessed_T));
 439          while Present (D) loop
 440
 441             if Denotes_Discriminant (Node (D)) then
 442                Remove_Side_Effects (P);
 443                return
 444                  Build_Component_Subtype (
 445                    Build_Actual_Record_Constraint, Loc, Base_Type (T));
 446             end if;
 447
 448             Next_Elmt (D);
 449          end loop;
 450       end if;
 451
 452       --  If none of the above, the actual and nominal subtypes are the same
 453
 454       return Empty;
 455    end Build_Actual_Subtype_Of_Component;
 456
 457    -----------------------------
 458    -- Build_Component_Subtype --
 459    -----------------------------
 460
 461    function Build_Component_Subtype
 462      (C   : List_Id;
 463       Loc : Source_Ptr;
 464       T   : Entity_Id) return Node_Id
 465    is
 466       Subt : Entity_Id;
 467       Decl : Node_Id;
 468
 469    begin
 470       --  Unchecked_Union components do not require component subtypes
 471
 472       if Is_Unchecked_Union (T) then
 473          return Empty;
 474       end if;
 475
 476       Subt :=
 477         Make_Defining_Identifier (Loc,
 478           Chars => New_Internal_Name ('S'));
 479       Set_Is_Internal (Subt);
 480
 481       Decl :=
 482         Make_Subtype_Declaration (Loc,
 483           Defining_Identifier => Subt,
 484           Subtype_Indication =>
 485             Make_Subtype_Indication (Loc,
 486               Subtype_Mark => New_Reference_To (Base_Type (T),  Loc),
 487               Constraint  =>
 488                 Make_Index_Or_Discriminant_Constraint (Loc,
 489                   Constraints => C)));
 490
 491       Mark_Rewrite_Insertion (Decl);
 492       return Decl;
 493    end Build_Component_Subtype;
 494
 495    --------------------------------------------
 496    -- Build_Discriminal_Subtype_Of_Component --
 497    --------------------------------------------
 498
 499    function Build_Discriminal_Subtype_Of_Component
 500      (T : Entity_Id) return Node_Id
 501    is
 502       Loc : constant Source_Ptr := Sloc (T);
 503       D   : Elmt_Id;
 504       Id  : Node_Id;
 505
 506       function Build_Discriminal_Array_Constraint return List_Id;
 507       --  If one or more of the bounds of the component depends on
 508       --  discriminants, build  actual constraint using the discriminants
 509       --  of the prefix.
 510
 511       function Build_Discriminal_Record_Constraint return List_Id;
 512       --  Similar to previous one, for discriminated components constrained
 513       --  by the discriminant of the enclosing object.
 514
 515       ----------------------------------------
 516       -- Build_Discriminal_Array_Constraint --
 517       ----------------------------------------
 518
 519       function Build_Discriminal_Array_Constraint return List_Id is
 520          Constraints : constant List_Id := New_List;
 521          Indx        : Node_Id;
 522          Hi          : Node_Id;
 523          Lo          : Node_Id;
 524          Old_Hi      : Node_Id;
 525          Old_Lo      : Node_Id;
 526
 527       begin
 528          Indx := First_Index (T);
 529          while Present (Indx) loop
 530             Old_Lo := Type_Low_Bound  (Etype (Indx));
 531             Old_Hi := Type_High_Bound (Etype (Indx));
 532
 533             if Denotes_Discriminant (Old_Lo) then
 534                Lo := New_Occurrence_Of (Discriminal (Entity (Old_Lo)), Loc);
 535
 536             else
 537                Lo := New_Copy_Tree (Old_Lo);
 538             end if;
 539
 540             if Denotes_Discriminant (Old_Hi) then
 541                Hi := New_Occurrence_Of (Discriminal (Entity (Old_Hi)), Loc);
 542
 543             else
 544                Hi := New_Copy_Tree (Old_Hi);
 545             end if;
 546
 547             Append (Make_Range (Loc, Lo, Hi), Constraints);
 548             Next_Index (Indx);
 549          end loop;
 550
 551          return Constraints;
 552       end Build_Discriminal_Array_Constraint;
 553
 554       -----------------------------------------
 555       -- Build_Discriminal_Record_Constraint --
 556       -----------------------------------------
 557
 558       function Build_Discriminal_Record_Constraint return List_Id is
 559          Constraints : constant List_Id := New_List;
 560          D           : Elmt_Id;
 561          D_Val       : Node_Id;
 562
 563       begin
 564          D := First_Elmt (Discriminant_Constraint (T));
 565          while Present (D) loop
 566             if Denotes_Discriminant (Node (D)) then
 567                D_Val :=
 568                  New_Occurrence_Of (Discriminal (Entity (Node (D))), Loc);
 569
 570             else
 571                D_Val := New_Copy_Tree (Node (D));
 572             end if;
 573
 574             Append (D_Val, Constraints);
 575             Next_Elmt (D);
 576          end loop;
 577
 578          return Constraints;
 579       end Build_Discriminal_Record_Constraint;
 580
 581    --  Start of processing for Build_Discriminal_Subtype_Of_Component
 582
 583    begin
 584       if Ekind (T) = E_Array_Subtype then
 585          Id := First_Index (T);
 586
 587          while Present (Id) loop
 588             if Denotes_Discriminant (Type_Low_Bound  (Etype (Id))) or else
 589                Denotes_Discriminant (Type_High_Bound (Etype (Id)))
 590             then
 591                return Build_Component_Subtype
 592                  (Build_Discriminal_Array_Constraint, Loc, T);
 593             end if;
 594
 595             Next_Index (Id);
 596          end loop;
 597
 598       elsif Ekind (T) = E_Record_Subtype
 599         and then Has_Discriminants (T)
 600         and then not Has_Unknown_Discriminants (T)
 601       then
 602          D := First_Elmt (Discriminant_Constraint (T));
 603          while Present (D) loop
 604             if Denotes_Discriminant (Node (D)) then
 605                return Build_Component_Subtype
 606                  (Build_Discriminal_Record_Constraint, Loc, T);
 607             end if;
 608
 609             Next_Elmt (D);
 610          end loop;
 611       end if;
 612
 613       --  If none of the above, the actual and nominal subtypes are the same
 614
 615       return Empty;
 616    end Build_Discriminal_Subtype_Of_Component;
 617
 618    ------------------------------
 619    -- Build_Elaboration_Entity --
 620    ------------------------------
 621
 622    procedure Build_Elaboration_Entity (N : Node_Id; Spec_Id : Entity_Id) is
 623       Loc       : constant Source_Ptr       := Sloc (N);
 624       Unum      : constant Unit_Number_Type := Get_Source_Unit (Loc);
 625       Decl      : Node_Id;
 626       P         : Natural;
 627       Elab_Ent  : Entity_Id;
 628
 629    begin
 630       --  Ignore if already constructed
 631
 632       if Present (Elaboration_Entity (Spec_Id)) then
 633          return;
 634       end if;
 635
 636       --  Construct name of elaboration entity as xxx_E, where xxx
 637       --  is the unit name with dots replaced by double underscore.
 638       --  We have to manually construct this name, since it will
 639       --  be elaborated in the outer scope, and thus will not have
 640       --  the unit name automatically prepended.
 641
 642       Get_Name_String (Unit_Name (Unum));
 643
 644       --  Replace the %s by _E
 645
 646       Name_Buffer (Name_Len - 1 .. Name_Len) := "_E";
 647
 648       --  Replace dots by double underscore
 649
 650       P := 2;
 651       while P < Name_Len - 2 loop
 652          if Name_Buffer (P) = '.' then
 653             Name_Buffer (P + 2 .. Name_Len + 1) :=
 654               Name_Buffer (P + 1 .. Name_Len);
 655             Name_Len := Name_Len + 1;
 656             Name_Buffer (P) := '_';
 657             Name_Buffer (P + 1) := '_';
 658             P := P + 3;
 659          else
 660             P := P + 1;
 661          end if;
 662       end loop;
 663
 664       --  Create elaboration flag
 665
 666       Elab_Ent :=
 667         Make_Defining_Identifier (Loc, Chars => Name_Find);
 668       Set_Elaboration_Entity (Spec_Id, Elab_Ent);
 669
 670       if No (Declarations (Aux_Decls_Node (N))) then
 671          Set_Declarations (Aux_Decls_Node (N), New_List);
 672       end if;
 673
 674       Decl :=
 675          Make_Object_Declaration (Loc,
 676            Defining_Identifier => Elab_Ent,
 677            Object_Definition   =>
 678              New_Occurrence_Of (Standard_Boolean, Loc),
 679            Expression          =>
 680              New_Occurrence_Of (Standard_False, Loc));
 681
 682       Append_To (Declarations (Aux_Decls_Node (N)), Decl);
 683       Analyze (Decl);
 684
 685       --  Reset True_Constant indication, since we will indeed
 686       --  assign a value to the variable in the binder main.
 687
 688       Set_Is_True_Constant (Elab_Ent, False);
 689       Set_Current_Value    (Elab_Ent, Empty);
 690
 691       --  We do not want any further qualification of the name (if we did
 692       --  not do this, we would pick up the name of the generic package
 693       --  in the case of a library level generic instantiation).
 694
 695       Set_Has_Qualified_Name       (Elab_Ent);
 696       Set_Has_Fully_Qualified_Name (Elab_Ent);
 697    end Build_Elaboration_Entity;
 698
 699    -----------------------------------
 700    -- Cannot_Raise_Constraint_Error --
 701    -----------------------------------
 702
 703    function Cannot_Raise_Constraint_Error (Expr : Node_Id) return Boolean is
 704    begin
 705       if Compile_Time_Known_Value (Expr) then
 706          return True;
 707
 708       elsif Do_Range_Check (Expr) then
 709          return False;
 710
 711       elsif Raises_Constraint_Error (Expr) then
 712          return False;
 713
 714       else
 715          case Nkind (Expr) is
 716             when N_Identifier =>
 717                return True;
 718
 719             when N_Expanded_Name =>
 720                return True;
 721
 722             when N_Selected_Component =>
 723                return not Do_Discriminant_Check (Expr);
 724
 725             when N_Attribute_Reference =>
 726                if Do_Overflow_Check (Expr) then
 727                   return False;
 728
 729                elsif No (Expressions (Expr)) then
 730                   return True;
 731
 732                else
 733                   declare
 734                      N : Node_Id := First (Expressions (Expr));
 735
 736                   begin
 737                      while Present (N) loop
 738                         if Cannot_Raise_Constraint_Error (N) then
 739                            Next (N);
 740                         else
 741                            return False;
 742                         end if;
 743                      end loop;
 744
 745                      return True;
 746                   end;
 747                end if;
 748
 749             when N_Type_Conversion =>
 750                if Do_Overflow_Check (Expr)
 751                  or else Do_Length_Check (Expr)
 752                  or else Do_Tag_Check (Expr)
 753                then
 754                   return False;
 755                else
 756                   return
 757                     Cannot_Raise_Constraint_Error (Expression (Expr));
 758                end if;
 759
 760             when N_Unchecked_Type_Conversion =>
 761                return Cannot_Raise_Constraint_Error (Expression (Expr));
 762
 763             when N_Unary_Op =>
 764                if Do_Overflow_Check (Expr) then
 765                   return False;
 766                else
 767                   return
 768                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
 769                end if;
 770
 771             when N_Op_Divide |
 772                  N_Op_Mod    |
 773                  N_Op_Rem
 774             =>
 775                if Do_Division_Check (Expr)
 776                  or else Do_Overflow_Check (Expr)
 777                then
 778                   return False;
 779                else
 780                   return
 781                     Cannot_Raise_Constraint_Error (Left_Opnd (Expr))
 782                       and then
 783                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
 784                end if;
 785
 786             when N_Op_Add                    |
 787                  N_Op_And                    |
 788                  N_Op_Concat                 |
 789                  N_Op_Eq                     |
 790                  N_Op_Expon                  |
 791                  N_Op_Ge                     |
 792                  N_Op_Gt                     |
 793                  N_Op_Le                     |
 794                  N_Op_Lt                     |
 795                  N_Op_Multiply               |
 796                  N_Op_Ne                     |
 797                  N_Op_Or                     |
 798                  N_Op_Rotate_Left            |
 799                  N_Op_Rotate_Right           |
 800                  N_Op_Shift_Left             |
 801                  N_Op_Shift_Right            |
 802                  N_Op_Shift_Right_Arithmetic |
 803                  N_Op_Subtract               |
 804                  N_Op_Xor
 805             =>
 806                if Do_Overflow_Check (Expr) then
 807                   return False;
 808                else
 809                   return
 810                     Cannot_Raise_Constraint_Error (Left_Opnd (Expr))
 811                       and then
 812                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
 813                end if;
 814
 815             when others =>
 816                return False;
 817          end case;
 818       end if;
 819    end Cannot_Raise_Constraint_Error;
 820
 821    --------------------------
 822    -- Check_Fully_Declared --
 823    --------------------------
 824
 825    procedure Check_Fully_Declared (T : Entity_Id; N : Node_Id) is
 826    begin
 827       if Ekind (T) = E_Incomplete_Type then
 828
 829          --  Ada 2005 (AI-50217): If the type is available through a limited
 830          --  with_clause, verify that its full view has been analyzed.
 831
 832          if From_With_Type (T)
 833            and then Present (Non_Limited_View (T))
 834            and then Ekind (Non_Limited_View (T)) /= E_Incomplete_Type
 835          then
 836             --  The non-limited view is fully declared
 837             null;
 838
 839          else
 840             Error_Msg_NE
 841               ("premature usage of incomplete}", N, First_Subtype (T));
 842          end if;
 843
 844       elsif Has_Private_Component (T)
 845         and then not Is_Generic_Type (Root_Type (T))
 846         and then not In_Default_Expression
 847       then
 848
 849          --  Special case: if T is the anonymous type created for a single
 850          --  task or protected object, use the name of the source object.
 851
 852          if Is_Concurrent_Type (T)
 853            and then not Comes_From_Source (T)
 854            and then Nkind (N) = N_Object_Declaration
 855          then
 856             Error_Msg_NE ("type of& has incomplete component", N,
 857               Defining_Identifier (N));
 858
 859          else
 860             Error_Msg_NE
 861               ("premature usage of incomplete}", N, First_Subtype (T));
 862          end if;
 863       end if;
 864    end Check_Fully_Declared;
 865
 866    ------------------------------------------
 867    -- Check_Potentially_Blocking_Operation --
 868    ------------------------------------------
 869
 870    procedure Check_Potentially_Blocking_Operation (N : Node_Id) is
 871       S   : Entity_Id;
 872
 873    begin
 874       --  N is one of the potentially blocking operations listed in 9.5.1(8).
 875       --  When pragma Detect_Blocking is active, the run time will raise
 876       --  Program_Error. Here we only issue a warning, since we generally
 877       --  support the use of potentially blocking operations in the absence
 878       --  of the pragma.
 879
 880       --  Indirect blocking through a subprogram call cannot be diagnosed
 881       --  statically without interprocedural analysis, so we do not attempt
 882       --  to do it here.
 883
 884       S := Scope (Current_Scope);
 885       while Present (S) and then S /= Standard_Standard loop
 886          if Is_Protected_Type (S) then
 887             Error_Msg_N
 888               ("potentially blocking operation in protected operation?", N);
 889
 890             return;
 891          end if;
 892
 893          S := Scope (S);
 894       end loop;
 895    end Check_Potentially_Blocking_Operation;
 896
 897    ---------------
 898    -- Check_VMS --
 899    ---------------
 900
 901    procedure Check_VMS (Construct : Node_Id) is
 902    begin
 903       if not OpenVMS_On_Target then
 904          Error_Msg_N
 905            ("this construct is allowed only in Open'V'M'S", Construct);
 906       end if;
 907    end Check_VMS;
 908
 909    ----------------------------------
 910    -- Collect_Primitive_Operations --
 911    ----------------------------------
 912
 913    function Collect_Primitive_Operations (T : Entity_Id) return Elist_Id is
 914       B_Type         : constant Entity_Id := Base_Type (T);
 915       B_Decl         : constant Node_Id   := Original_Node (Parent (B_Type));
 916       B_Scope        : Entity_Id          := Scope (B_Type);
 917       Op_List        : Elist_Id;
 918       Formal         : Entity_Id;
 919       Is_Prim        : Boolean;
 920       Formal_Derived : Boolean := False;
 921       Id             : Entity_Id;
 922
 923    begin
 924       --  For tagged types, the primitive operations are collected as they
 925       --  are declared, and held in an explicit list which is simply returned.
 926
 927       if Is_Tagged_Type (B_Type) then
 928          return Primitive_Operations (B_Type);
 929
 930       --  An untagged generic type that is a derived type inherits the
 931       --  primitive operations of its parent type. Other formal types only
 932       --  have predefined operators, which are not explicitly represented.
 933
 934       elsif Is_Generic_Type (B_Type) then
 935          if Nkind (B_Decl) = N_Formal_Type_Declaration
 936            and then Nkind (Formal_Type_Definition (B_Decl))
 937              = N_Formal_Derived_Type_Definition
 938          then
 939             Formal_Derived := True;
 940          else
 941             return New_Elmt_List;
 942          end if;
 943       end if;
 944
 945       Op_List := New_Elmt_List;
 946
 947       if B_Scope = Standard_Standard then
 948          if B_Type = Standard_String then
 949             Append_Elmt (Standard_Op_Concat, Op_List);
 950
 951          elsif B_Type = Standard_Wide_String then
 952             Append_Elmt (Standard_Op_Concatw, Op_List);
 953
 954          else
 955             null;
 956          end if;
 957
 958       elsif (Is_Package (B_Scope)
 959                and then Nkind (
 960                  Parent (Declaration_Node (First_Subtype (T))))
 961                    /=  N_Package_Body)
 962
 963         or else Is_Derived_Type (B_Type)
 964       then
 965          --  The primitive operations appear after the base type, except
 966          --  if the derivation happens within the private part of B_Scope
 967          --  and the type is a private type, in which case both the type
 968          --  and some primitive operations may appear before the base
 969          --  type, and the list of candidates starts after the type.
 970
 971          if In_Open_Scopes (B_Scope)
 972            and then Scope (T) = B_Scope
 973            and then In_Private_Part (B_Scope)
 974          then
 975             Id := Next_Entity (T);
 976          else
 977             Id := Next_Entity (B_Type);
 978          end if;
 979
 980          while Present (Id) loop
 981
 982             --  Note that generic formal subprograms are not
 983             --  considered to be primitive operations and thus
 984             --  are never inherited.
 985
 986             if Is_Overloadable (Id)
 987               and then Nkind (Parent (Parent (Id)))
 988                          /= N_Formal_Subprogram_Declaration
 989             then
 990                Is_Prim := False;
 991
 992                if Base_Type (Etype (Id)) = B_Type then
 993                   Is_Prim := True;
 994                else
 995                   Formal := First_Formal (Id);
 996                   while Present (Formal) loop
 997                      if Base_Type (Etype (Formal)) = B_Type then
 998                         Is_Prim := True;
 999                         exit;
1000
1001                      elsif Ekind (Etype (Formal)) = E_Anonymous_Access_Type
1002                        and then Base_Type
1003                          (Designated_Type (Etype (Formal))) = B_Type
1004                      then
1005                         Is_Prim := True;
1006                         exit;
1007                      end if;
1008
1009                      Next_Formal (Formal);
1010                   end loop;
1011                end if;
1012
1013                --  For a formal derived type, the only primitives are the
1014                --  ones inherited from the parent type. Operations appearing
1015                --  in the package declaration are not primitive for it.
1016
1017                if Is_Prim
1018                  and then (not Formal_Derived
1019                             or else Present (Alias (Id)))
1020                then
1021                   Append_Elmt (Id, Op_List);
1022                end if;
1023             end if;
1024
1025             Next_Entity (Id);
1026
1027             --  For a type declared in System, some of its operations
1028             --  may appear in  the target-specific extension to System.
1029
1030             if No (Id)
1031               and then Chars (B_Scope) = Name_System
1032               and then Scope (B_Scope) = Standard_Standard
1033               and then Present_System_Aux
1034             then
1035                B_Scope := System_Aux_Id;
1036                Id := First_Entity (System_Aux_Id);
1037             end if;
1038          end loop;
1039       end if;
1040
1041       return Op_List;
1042    end Collect_Primitive_Operations;
1043
1044    -----------------------------------
1045    -- Compile_Time_Constraint_Error --
1046    -----------------------------------
1047
1048    function Compile_Time_Constraint_Error
1049      (N    : Node_Id;
1050       Msg  : String;
1051       Ent  : Entity_Id  := Empty;
1052       Loc  : Source_Ptr := No_Location;
1053       Warn : Boolean  := False) return Node_Id
1054    is
1055       Msgc : String (1 .. Msg'Length + 2);
1056       Msgl : Natural;
1057       Wmsg : Boolean;
1058       P    : Node_Id;
1059       Msgs : Boolean;
1060       Eloc : Source_Ptr;
1061
1062    begin
1063       --  A static constraint error in an instance body is not a fatal error.
1064       --  we choose to inhibit the message altogether, because there is no
1065       --  obvious node (for now) on which to post it. On the other hand the
1066       --  offending node must be replaced with a constraint_error in any case.
1067
1068       --  No messages are generated if we already posted an error on this node
1069
1070       if not Error_Posted (N) then
1071          if Loc /= No_Location then
1072             Eloc := Loc;
1073          else
1074             Eloc := Sloc (N);
1075          end if;
1076
1077          --  Make all such messages unconditional
1078
1079          Msgc (1 .. Msg'Length) := Msg;
1080          Msgc (Msg'Length + 1) := '!';
1081          Msgl := Msg'Length + 1;
1082
1083          --  Message is a warning, even in Ada 95 case
1084
1085          if Msg (Msg'Length) = '?' then
1086             Wmsg := True;
1087
1088          --  In Ada 83, all messages are warnings. In the private part and
1089          --  the body of an instance, constraint_checks are only warnings.
1090          --  We also make this a warning if the Warn parameter is set.
1091
1092          elsif Warn
1093            or else (Ada_Version = Ada_83 and then Comes_From_Source (N))
1094          then
1095             Msgl := Msgl + 1;
1096             Msgc (Msgl) := '?';
1097             Wmsg := True;
1098
1099          elsif In_Instance_Not_Visible then
1100             Msgl := Msgl + 1;
1101             Msgc (Msgl) := '?';
1102             Wmsg := True;
1103
1104          --  Otherwise we have a real error message (Ada 95 static case)
1105
1106          else
1107             Wmsg := False;
1108          end if;
1109
1110          --  Should we generate a warning? The answer is not quite yes. The
1111          --  very annoying exception occurs in the case of a short circuit
1112          --  operator where the left operand is static and decisive. Climb
1113          --  parents to see if that is the case we have here.
1114
1115          Msgs := True;
1116          P := N;
1117
1118          loop
1119             P := Parent (P);
1120
1121             if (Nkind (P) = N_And_Then
1122                 and then Compile_Time_Known_Value (Left_Opnd (P))
1123                 and then Is_False (Expr_Value (Left_Opnd (P))))
1124               or else (Nkind (P) = N_Or_Else
1125                 and then Compile_Time_Known_Value (Left_Opnd (P))
1126                 and then Is_True (Expr_Value (Left_Opnd (P))))
1127             then
1128                Msgs := False;
1129                exit;
1130
1131             elsif Nkind (P) = N_Component_Association
1132               and then Nkind (Parent (P)) = N_Aggregate
1133             then
1134                null;  --   Keep going.
1135
1136             else
1137                exit when Nkind (P) not in N_Subexpr;
1138             end if;
1139          end loop;
1140
1141          if Msgs then
1142             if Present (Ent) then
1143                Error_Msg_NEL (Msgc (1 .. Msgl), N, Ent, Eloc);
1144             else
1145                Error_Msg_NEL (Msgc (1 .. Msgl), N, Etype (N), Eloc);
1146             end if;
1147
1148             if Wmsg then
1149                if Inside_Init_Proc then
1150                   Error_Msg_NEL
1151                     ("\& will be raised for objects of this type!?",
1152                      N, Standard_Constraint_Error, Eloc);
1153                else
1154                   Error_Msg_NEL
1155                     ("\& will be raised at run time!?",
1156                      N, Standard_Constraint_Error, Eloc);
1157                end if;
1158             else
1159                Error_Msg_NEL
1160                  ("\static expression raises&!",
1161                   N, Standard_Constraint_Error, Eloc);
1162             end if;
1163          end if;
1164       end if;
1165
1166       return N;
1167    end Compile_Time_Constraint_Error;
1168
1169    -----------------------
1170    -- Conditional_Delay --
1171    -----------------------
1172
1173    procedure Conditional_Delay (New_Ent, Old_Ent : Entity_Id) is
1174    begin
1175       if Has_Delayed_Freeze (Old_Ent) and then not Is_Frozen (Old_Ent) then
1176          Set_Has_Delayed_Freeze (New_Ent);
1177       end if;
1178    end Conditional_Delay;
1179
1180    --------------------
1181    -- Current_Entity --
1182    --------------------
1183
1184    --  The currently visible definition for a given identifier is the
1185    --  one most chained at the start of the visibility chain, i.e. the
1186    --  one that is referenced by the Node_Id value of the name of the
1187    --  given identifier.
1188
1189    function Current_Entity (N : Node_Id) return Entity_Id is
1190    begin
1191       return Get_Name_Entity_Id (Chars (N));
1192    end Current_Entity;
1193
1194    -----------------------------
1195    -- Current_Entity_In_Scope --
1196    -----------------------------
1197
1198    function Current_Entity_In_Scope (N : Node_Id) return Entity_Id is
1199       E  : Entity_Id;
1200       CS : constant Entity_Id := Current_Scope;
1201
1202       Transient_Case : constant Boolean := Scope_Is_Transient;
1203
1204    begin
1205       E := Get_Name_Entity_Id (Chars (N));
1206
1207       while Present (E)
1208         and then Scope (E) /= CS
1209         and then (not Transient_Case or else Scope (E) /= Scope (CS))
1210       loop
1211          E := Homonym (E);
1212       end loop;
1213
1214       return E;
1215    end Current_Entity_In_Scope;
1216
1217    -------------------
1218    -- Current_Scope --
1219    -------------------
1220
1221    function Current_Scope return Entity_Id is
1222    begin
1223       if Scope_Stack.Last = -1 then
1224          return Standard_Standard;
1225       else
1226          declare
1227             C : constant Entity_Id :=
1228                   Scope_Stack.Table (Scope_Stack.Last).Entity;
1229          begin
1230             if Present (C) then
1231                return C;
1232             else
1233                return Standard_Standard;
1234             end if;
1235          end;
1236       end if;
1237    end Current_Scope;
1238
1239    ------------------------
1240    -- Current_Subprogram --
1241    ------------------------
1242
1243    function Current_Subprogram return Entity_Id is
1244       Scop : constant Entity_Id := Current_Scope;
1245
1246    begin
1247       if Is_Subprogram (Scop) or else Is_Generic_Subprogram (Scop) then
1248          return Scop;
1249       else
1250          return Enclosing_Subprogram (Scop);
1251       end if;
1252    end Current_Subprogram;
1253
1254    ---------------------
1255    -- Defining_Entity --
1256    ---------------------
1257
1258    function Defining_Entity (N : Node_Id) return Entity_Id is
1259       K   : constant Node_Kind := Nkind (N);
1260       Err : Entity_Id := Empty;
1261
1262    begin
1263       case K is
1264          when
1265            N_Subprogram_Declaration                 |
1266            N_Abstract_Subprogram_Declaration        |
1267            N_Subprogram_Body                        |
1268            N_Package_Declaration                    |
1269            N_Subprogram_Renaming_Declaration        |
1270            N_Subprogram_Body_Stub                   |
1271            N_Generic_Subprogram_Declaration         |
1272            N_Generic_Package_Declaration            |
1273            N_Formal_Subprogram_Declaration
1274          =>
1275             return Defining_Entity (Specification (N));
1276
1277          when
1278            N_Component_Declaration                  |
1279            N_Defining_Program_Unit_Name             |
1280            N_Discriminant_Specification             |
1281            N_Entry_Body                             |
1282            N_Entry_Declaration                      |
1283            N_Entry_Index_Specification              |
1284            N_Exception_Declaration                  |
1285            N_Exception_Renaming_Declaration         |
1286            N_Formal_Object_Declaration              |
1287            N_Formal_Package_Declaration             |
1288            N_Formal_Type_Declaration                |
1289            N_Full_Type_Declaration                  |
1290            N_Implicit_Label_Declaration             |
1291            N_Incomplete_Type_Declaration            |
1292            N_Loop_Parameter_Specification           |
1293            N_Number_Declaration                     |
1294            N_Object_Declaration                     |
1295            N_Object_Renaming_Declaration            |
1296            N_Package_Body_Stub                      |
1297            N_Parameter_Specification                |
1298            N_Private_Extension_Declaration          |
1299            N_Private_Type_Declaration               |
1300            N_Protected_Body                         |
1301            N_Protected_Body_Stub                    |
1302            N_Protected_Type_Declaration             |
1303            N_Single_Protected_Declaration           |
1304            N_Single_Task_Declaration                |
1305            N_Subtype_Declaration                    |
1306            N_Task_Body                              |
1307            N_Task_Body_Stub                         |
1308            N_Task_Type_Declaration
1309          =>
1310             return Defining_Identifier (N);
1311
1312          when N_Subunit =>
1313             return Defining_Entity (Proper_Body (N));
1314
1315          when
1316            N_Function_Instantiation                 |
1317            N_Function_Specification                 |
1318            N_Generic_Function_Renaming_Declaration  |
1319            N_Generic_Package_Renaming_Declaration   |
1320            N_Generic_Procedure_Renaming_Declaration |
1321            N_Package_Body                           |
1322            N_Package_Instantiation                  |
1323            N_Package_Renaming_Declaration           |
1324            N_Package_Specification                  |
1325            N_Procedure_Instantiation                |
1326            N_Procedure_Specification
1327          =>
1328             declare
1329                Nam : constant Node_Id := Defining_Unit_Name (N);
1330
1331             begin
1332                if Nkind (Nam) in N_Entity then
1333                   return Nam;
1334
1335                --  For Error, make up a name and attach to declaration
1336                --  so we can continue semantic analysis
1337
1338                elsif Nam = Error then
1339                   Err :=
1340                     Make_Defining_Identifier (Sloc (N),
1341                       Chars => New_Internal_Name ('T'));
1342                   Set_Defining_Unit_Name (N, Err);
1343
1344                   return Err;
1345                --  If not an entity, get defining identifier
1346
1347                else
1348                   return Defining_Identifier (Nam);
1349                end if;
1350             end;
1351
1352          when N_Block_Statement =>
1353             return Entity (Identifier (N));
1354
1355          when others =>
1356             raise Program_Error;
1357
1358       end case;
1359    end Defining_Entity;
1360
1361    --------------------------
1362    -- Denotes_Discriminant --
1363    --------------------------
1364
1365    function Denotes_Discriminant
1366      (N               : Node_Id;
1367       Check_Protected : Boolean := False) return Boolean
1368    is
1369       E : Entity_Id;
1370    begin
1371       if not Is_Entity_Name (N)
1372         or else No (Entity (N))
1373       then
1374          return False;
1375       else
1376          E := Entity (N);
1377       end if;
1378
1379       --  If we are checking for a protected type, the discriminant may have
1380       --  been rewritten as the corresponding discriminal of the original type
1381       --  or of the corresponding concurrent record, depending on whether we
1382       --  are in the spec or body of the protected type.
1383
1384       return Ekind (E) = E_Discriminant
1385         or else
1386           (Check_Protected
1387             and then Ekind (E) = E_In_Parameter
1388             and then Present (Discriminal_Link (E))
1389             and then
1390               (Is_Protected_Type (Scope (Discriminal_Link (E)))
1391                 or else
1392                   Is_Concurrent_Record_Type (Scope (Discriminal_Link (E)))));
1393
1394    end Denotes_Discriminant;
1395
1396    -----------------------------
1397    -- Depends_On_Discriminant --
1398    -----------------------------
1399
1400    function Depends_On_Discriminant (N : Node_Id) return Boolean is
1401       L : Node_Id;
1402       H : Node_Id;
1403
1404    begin
1405       Get_Index_Bounds (N, L, H);
1406       return Denotes_Discriminant (L) or else Denotes_Discriminant (H);
1407    end Depends_On_Discriminant;
1408
1409    -------------------------
1410    -- Designate_Same_Unit --
1411    -------------------------
1412
1413    function Designate_Same_Unit
1414      (Name1 : Node_Id;
1415       Name2 : Node_Id) return Boolean
1416    is
1417       K1 : constant Node_Kind := Nkind (Name1);
1418       K2 : constant Node_Kind := Nkind (Name2);
1419
1420       function Prefix_Node (N : Node_Id) return Node_Id;
1421       --  Returns the parent unit name node of a defining program unit name
1422       --  or the prefix if N is a selected component or an expanded name.
1423
1424       function Select_Node (N : Node_Id) return Node_Id;
1425       --  Returns the defining identifier node of a defining program unit
1426       --  name or  the selector node if N is a selected component or an
1427       --  expanded name.
1428
1429       -----------------
1430       -- Prefix_Node --
1431       -----------------
1432
1433       function Prefix_Node (N : Node_Id) return Node_Id is
1434       begin
1435          if Nkind (N) = N_Defining_Program_Unit_Name then
1436             return Name (N);
1437
1438          else
1439             return Prefix (N);
1440          end if;
1441       end Prefix_Node;
1442
1443       -----------------
1444       -- Select_Node --
1445       -----------------
1446
1447       function Select_Node (N : Node_Id) return Node_Id is
1448       begin
1449          if Nkind (N) = N_Defining_Program_Unit_Name then
1450             return Defining_Identifier (N);
1451
1452          else
1453             return Selector_Name (N);
1454          end if;
1455       end Select_Node;
1456
1457    --  Start of processing for Designate_Next_Unit
1458
1459    begin
1460       if (K1 = N_Identifier or else
1461           K1 = N_Defining_Identifier)
1462         and then
1463          (K2 = N_Identifier or else
1464           K2 = N_Defining_Identifier)
1465       then
1466          return Chars (Name1) = Chars (Name2);
1467
1468       elsif
1469          (K1 = N_Expanded_Name      or else
1470           K1 = N_Selected_Component or else
1471           K1 = N_Defining_Program_Unit_Name)
1472         and then
1473          (K2 = N_Expanded_Name      or else
1474           K2 = N_Selected_Component or else
1475           K2 = N_Defining_Program_Unit_Name)
1476       then
1477          return
1478            (Chars (Select_Node (Name1)) = Chars (Select_Node (Name2)))
1479              and then
1480                Designate_Same_Unit (Prefix_Node (Name1), Prefix_Node (Name2));
1481
1482       else
1483          return False;
1484       end if;
1485    end Designate_Same_Unit;
1486
1487    ----------------------------
1488    -- Enclosing_Generic_Body --
1489    ----------------------------
1490
1491    function Enclosing_Generic_Body
1492      (E : Entity_Id) return Node_Id
1493    is
1494       P    : Node_Id;
1495       Decl : Node_Id;
1496       Spec : Node_Id;
1497
1498    begin
1499       P := Parent (E);
1500
1501       while Present (P) loop
1502          if Nkind (P) = N_Package_Body
1503            or else Nkind (P) = N_Subprogram_Body
1504          then
1505             Spec := Corresponding_Spec (P);
1506
1507             if Present (Spec) then
1508                Decl := Unit_Declaration_Node (Spec);
1509
1510                if Nkind (Decl) = N_Generic_Package_Declaration
1511                  or else Nkind (Decl) = N_Generic_Subprogram_Declaration
1512                then
1513                   return P;
1514                end if;
1515             end if;
1516          end if;
1517
1518          P := Parent (P);
1519       end loop;
1520
1521       return Empty;
1522    end Enclosing_Generic_Body;
1523
1524    -------------------------------
1525    -- Enclosing_Lib_Unit_Entity --
1526    -------------------------------
1527
1528    function Enclosing_Lib_Unit_Entity return Entity_Id is
1529       Unit_Entity : Entity_Id := Current_Scope;
1530
1531    begin
1532       --  Look for enclosing library unit entity by following scope links.
1533       --  Equivalent to, but faster than indexing through the scope stack.
1534
1535       while (Present (Scope (Unit_Entity))
1536         and then Scope (Unit_Entity) /= Standard_Standard)
1537         and not Is_Child_Unit (Unit_Entity)
1538       loop
1539          Unit_Entity := Scope (Unit_Entity);
1540       end loop;
1541
1542       return Unit_Entity;
1543    end Enclosing_Lib_Unit_Entity;
1544
1545    -----------------------------
1546    -- Enclosing_Lib_Unit_Node --
1547    -----------------------------
1548
1549    function Enclosing_Lib_Unit_Node (N : Node_Id) return Node_Id is
1550       Current_Node : Node_Id := N;
1551
1552    begin
1553       while Present (Current_Node)
1554         and then Nkind (Current_Node) /= N_Compilation_Unit
1555       loop
1556          Current_Node := Parent (Current_Node);
1557       end loop;
1558
1559       if Nkind (Current_Node) /= N_Compilation_Unit then
1560          return Empty;
1561       end if;
1562
1563       return Current_Node;
1564    end Enclosing_Lib_Unit_Node;
1565
1566    --------------------------
1567    -- Enclosing_Subprogram --
1568    --------------------------
1569
1570    function Enclosing_Subprogram (E : Entity_Id) return Entity_Id is
1571       Dynamic_Scope : constant Entity_Id := Enclosing_Dynamic_Scope (E);
1572
1573    begin
1574       if Dynamic_Scope = Standard_Standard then
1575          return Empty;
1576
1577       elsif Ekind (Dynamic_Scope) = E_Subprogram_Body then
1578          return Corresponding_Spec (Parent (Parent (Dynamic_Scope)));
1579
1580       elsif Ekind (Dynamic_Scope) = E_Block then
1581          return Enclosing_Subprogram (Dynamic_Scope);
1582
1583       elsif Ekind (Dynamic_Scope) = E_Task_Type then
1584          return Get_Task_Body_Procedure (Dynamic_Scope);
1585
1586       elsif Convention (Dynamic_Scope) = Convention_Protected then
1587          return Protected_Body_Subprogram (Dynamic_Scope);
1588
1589       else
1590          return Dynamic_Scope;
1591       end if;
1592    end Enclosing_Subprogram;
1593
1594    ------------------------
1595    -- Ensure_Freeze_Node --
1596    ------------------------
1597
1598    procedure Ensure_Freeze_Node (E : Entity_Id) is
1599       FN : Node_Id;
1600
1601    begin
1602       if No (Freeze_Node (E)) then
1603          FN := Make_Freeze_Entity (Sloc (E));
1604          Set_Has_Delayed_Freeze (E);
1605          Set_Freeze_Node (E, FN);
1606          Set_Access_Types_To_Process (FN, No_Elist);
1607          Set_TSS_Elist (FN, No_Elist);
1608          Set_Entity (FN, E);
1609       end if;
1610    end Ensure_Freeze_Node;
1611
1612    ----------------
1613    -- Enter_Name --
1614    ----------------
1615
1616    procedure Enter_Name (Def_Id : Node_Id) is
1617       C : constant Entity_Id := Current_Entity (Def_Id);
1618       E : constant Entity_Id := Current_Entity_In_Scope (Def_Id);
1619       S : constant Entity_Id := Current_Scope;
1620
1621    begin
1622       Generate_Definition (Def_Id);
1623
1624       --  Add new name to current scope declarations. Check for duplicate
1625       --  declaration, which may or may not be a genuine error.
1626
1627       if Present (E) then
1628
1629          --  Case of previous entity entered because of a missing declaration
1630          --  or else a bad subtype indication. Best is to use the new entity,
1631          --  and make the previous one invisible.
1632
1633          if Etype (E) = Any_Type then
1634             Set_Is_Immediately_Visible (E, False);
1635
1636          --  Case of renaming declaration constructed for package instances.
1637          --  if there is an explicit declaration with the same identifier,
1638          --  the renaming is not immediately visible any longer, but remains
1639          --  visible through selected component notation.
1640
1641          elsif Nkind (Parent (E)) = N_Package_Renaming_Declaration
1642            and then not Comes_From_Source (E)
1643          then
1644             Set_Is_Immediately_Visible (E, False);
1645
1646          --  The new entity may be the package renaming, which has the same
1647          --  same name as a generic formal which has been seen already.
1648
1649          elsif Nkind (Parent (Def_Id)) = N_Package_Renaming_Declaration
1650             and then not Comes_From_Source (Def_Id)
1651          then
1652             Set_Is_Immediately_Visible (E, False);
1653
1654          --  For a fat pointer corresponding to a remote access to subprogram,
1655          --  we use the same identifier as the RAS type, so that the proper
1656          --  name appears in the stub. This type is only retrieved through
1657          --  the RAS type and never by visibility, and is not added to the
1658          --  visibility list (see below).
1659
1660          elsif Nkind (Parent (Def_Id)) = N_Full_Type_Declaration
1661            and then Present (Corresponding_Remote_Type (Def_Id))
1662          then
1663             null;
1664
1665          --  A controller component for a type extension overrides the
1666          --  inherited component.
1667
1668          elsif Chars (E) = Name_uController then
1669             null;
1670
1671          --  Case of an implicit operation or derived literal. The new entity
1672          --  hides the implicit one,  which is removed from all visibility,
1673          --  i.e. the entity list of its scope, and homonym chain of its name.
1674
1675          elsif (Is_Overloadable (E) and then Is_Inherited_Operation (E))
1676            or else Is_Internal (E)
1677          then
1678             declare
1679                Prev     : Entity_Id;
1680                Prev_Vis : Entity_Id;
1681                Decl     : constant Node_Id := Parent (E);
1682
1683             begin
1684                --  If E is an implicit declaration, it cannot be the first
1685                --  entity in the scope.
1686
1687                Prev := First_Entity (Current_Scope);
1688
1689                while Present (Prev)
1690                  and then Next_Entity (Prev) /= E
1691                loop
1692                   Next_Entity (Prev);
1693                end loop;
1694
1695                if No (Prev) then
1696
1697                   --  If E is not on the entity chain of the current scope,
1698                   --  it is an implicit declaration in the generic formal
1699                   --  part of a generic subprogram. When analyzing the body,
1700                   --  the generic formals are visible but not on the entity
1701                   --  chain of the subprogram. The new entity will become
1702                   --  the visible one in the body.
1703
1704                   pragma Assert
1705                     (Nkind (Parent (Decl)) = N_Generic_Subprogram_Declaration);
1706                   null;
1707
1708                else
1709                   Set_Next_Entity (Prev, Next_Entity (E));
1710
1711                   if No (Next_Entity (Prev)) then
1712                      Set_Last_Entity (Current_Scope, Prev);
1713                   end if;
1714
1715                   if E = Current_Entity (E) then
1716                      Prev_Vis := Empty;
1717
1718                   else
1719                      Prev_Vis := Current_Entity (E);
1720                      while Homonym (Prev_Vis) /= E loop
1721                         Prev_Vis := Homonym (Prev_Vis);
1722                      end loop;
1723                   end if;
1724
1725                   if Present (Prev_Vis)  then
1726
1727                      --  Skip E in the visibility chain
1728
1729                      Set_Homonym (Prev_Vis, Homonym (E));
1730
1731                   else
1732                      Set_Name_Entity_Id (Chars (E), Homonym (E));
1733                   end if;
1734                end if;
1735             end;
1736
1737          --  This section of code could use a comment ???
1738
1739          elsif Present (Etype (E))
1740            and then Is_Concurrent_Type (Etype (E))
1741            and then E = Def_Id
1742          then
1743             return;
1744
1745          --  In the body or private part of an instance, a type extension
1746          --  may introduce a component with the same name as that of an
1747          --  actual. The legality rule is not enforced, but the semantics
1748          --  of the full type with two components of the same name are not
1749          --  clear at this point ???
1750
1751          elsif In_Instance_Not_Visible  then
1752             null;
1753
1754          --  When compiling a package body, some child units may have become
1755          --  visible. They cannot conflict with local entities that hide them.
1756
1757          elsif Is_Child_Unit (E)
1758            and then In_Open_Scopes (Scope (E))
1759            and then not Is_Immediately_Visible (E)
1760          then
1761             null;
1762
1763          --  Conversely, with front-end inlining we may compile the parent
1764          --  body first, and a child unit subsequently. The context is now
1765          --  the parent spec, and body entities are not visible.
1766
1767          elsif Is_Child_Unit (Def_Id)
1768            and then Is_Package_Body_Entity (E)
1769            and then not In_Package_Body (Current_Scope)
1770          then
1771             null;
1772
1773          --  Case of genuine duplicate declaration
1774
1775          else
1776             Error_Msg_Sloc := Sloc (E);
1777
1778             --  If the previous declaration is an incomplete type declaration
1779             --  this may be an attempt to complete it with a private type.
1780             --  The following avoids confusing cascaded errors.
1781
1782             if Nkind (Parent (E)) = N_Incomplete_Type_Declaration
1783               and then Nkind (Parent (Def_Id)) = N_Private_Type_Declaration
1784             then
1785                Error_Msg_N
1786                  ("incomplete type cannot be completed" &
1787                         " with a private declaration",
1788                     Parent (Def_Id));
1789                Set_Is_Immediately_Visible (E, False);
1790                Set_Full_View (E, Def_Id);
1791
1792             elsif Ekind (E) = E_Discriminant
1793               and then Present (Scope (Def_Id))
1794               and then Scope (Def_Id) /= Current_Scope
1795             then
1796                --  An inherited component of a record conflicts with
1797                --  a new discriminant. The discriminant is inserted first
1798                --  in the scope, but the error should be posted on it, not
1799                --  on the component.
1800
1801                Error_Msg_Sloc := Sloc (Def_Id);
1802                Error_Msg_N ("& conflicts with declaration#", E);
1803                return;
1804
1805             --  If the name of the unit appears in its own context clause,
1806             --  a dummy package with the name has already been created, and
1807             --  the error emitted. Try to continue quietly.
1808
1809             elsif Error_Posted (E)
1810               and then Sloc (E) = No_Location
1811               and then Nkind (Parent (E)) = N_Package_Specification
1812               and then Current_Scope = Standard_Standard
1813             then
1814                Set_Scope (Def_Id, Current_Scope);
1815                return;
1816
1817             else
1818                Error_Msg_N ("& conflicts with declaration#", Def_Id);
1819
1820                --  Avoid cascaded messages with duplicate components in
1821                --  derived types.
1822
1823                if Ekind (E) = E_Component
1824                  or else Ekind (E) = E_Discriminant
1825                then
1826                   return;
1827                end if;
1828             end if;
1829
1830             if Nkind (Parent (Parent (Def_Id)))
1831                  = N_Generic_Subprogram_Declaration
1832               and then Def_Id =
1833                 Defining_Entity (Specification (Parent (Parent (Def_Id))))
1834             then
1835                Error_Msg_N ("\generic units cannot be overloaded", Def_Id);
1836             end if;
1837
1838             --  If entity is in standard, then we are in trouble, because
1839             --  it means that we have a library package with a duplicated
1840             --  name. That's hard to recover from, so abort!
1841
1842             if S = Standard_Standard then
1843                raise Unrecoverable_Error;
1844
1845             --  Otherwise we continue with the declaration. Having two
1846             --  identical declarations should not cause us too much trouble!
1847
1848             else
1849                null;
1850             end if;
1851          end if;
1852       end if;
1853
1854       --  If we fall through, declaration is OK , or OK enough to continue
1855
1856       --  If Def_Id is a discriminant or a record component we are in the
1857       --  midst of inheriting components in a derived record definition.
1858       --  Preserve their Ekind and Etype.
1859
1860       if Ekind (Def_Id) = E_Discriminant
1861         or else Ekind (Def_Id) = E_Component
1862       then
1863          null;
1864
1865       --  If a type is already set, leave it alone (happens whey a type
1866       --  declaration is reanalyzed following a call to the optimizer)
1867
1868       elsif Present (Etype (Def_Id)) then
1869          null;
1870
1871       --  Otherwise, the kind E_Void insures that premature uses of the entity
1872       --  will be detected. Any_Type insures that no cascaded errors will occur
1873
1874       else
1875          Set_Ekind (Def_Id, E_Void);
1876          Set_Etype (Def_Id, Any_Type);
1877       end if;
1878
1879       --  Inherited discriminants and components in derived record types are
1880       --  immediately visible. Itypes are not.
1881
1882       if Ekind (Def_Id) = E_Discriminant
1883         or else Ekind (Def_Id) = E_Component
1884         or else (No (Corresponding_Remote_Type (Def_Id))
1885                  and then not Is_Itype (Def_Id))
1886       then
1887          Set_Is_Immediately_Visible (Def_Id);
1888          Set_Current_Entity         (Def_Id);
1889       end if;
1890
1891       Set_Homonym       (Def_Id, C);
1892       Append_Entity     (Def_Id, S);
1893       Set_Public_Status (Def_Id);
1894
1895       --  Warn if new entity hides an old one
1896
1897       if Warn_On_Hiding
1898         and then Present (C)
1899         and then Length_Of_Name (Chars (C)) /= 1
1900         and then Comes_From_Source (C)
1901         and then Comes_From_Source (Def_Id)
1902         and then In_Extended_Main_Source_Unit (Def_Id)
1903       then
1904          Error_Msg_Sloc := Sloc (C);
1905          Error_Msg_N ("declaration hides &#?", Def_Id);
1906       end if;
1907    end Enter_Name;
1908
1909    --------------------------
1910    -- Explain_Limited_Type --
1911    --------------------------
1912
1913    procedure Explain_Limited_Type (T : Entity_Id; N : Node_Id) is
1914       C : Entity_Id;
1915
1916    begin
1917       --  For array, component type must be limited
1918
1919       if Is_Array_Type (T) then
1920          Error_Msg_Node_2 := T;
1921          Error_Msg_NE
1922            ("component type& of type& is limited", N, Component_Type (T));
1923          Explain_Limited_Type (Component_Type (T), N);
1924
1925       elsif Is_Record_Type (T) then
1926
1927          --  No need for extra messages if explicit limited record
1928
1929          if Is_Limited_Record (Base_Type (T)) then
1930             return;
1931          end if;
1932
1933          --  Otherwise find a limited component. Check only components that
1934          --  come from source, or inherited components that appear in the
1935          --  source of the ancestor.
1936
1937          C := First_Component (T);
1938          while Present (C) loop
1939             if Is_Limited_Type (Etype (C))
1940               and then
1941                 (Comes_From_Source (C)
1942                    or else
1943                      (Present (Original_Record_Component (C))
1944                        and then
1945                          Comes_From_Source (Original_Record_Component (C))))
1946             then
1947                Error_Msg_Node_2 := T;
1948                Error_Msg_NE ("\component& of type& has limited type", N, C);
1949                Explain_Limited_Type (Etype (C), N);
1950                return;
1951             end if;
1952
1953             Next_Component (C);
1954          end loop;
1955
1956          --  The type may be declared explicitly limited, even if no component
1957          --  of it is limited, in which case we fall out of the loop.
1958          return;
1959       end if;
1960    end Explain_Limited_Type;
1961
1962    -------------------------------------
1963    -- Find_Corresponding_Discriminant --
1964    -------------------------------------
1965
1966    function Find_Corresponding_Discriminant
1967      (Id  : Node_Id;
1968       Typ : Entity_Id) return Entity_Id
1969    is
1970       Par_Disc : Entity_Id;
1971       Old_Disc : Entity_Id;
1972       New_Disc : Entity_Id;
1973
1974    begin
1975       Par_Disc := Original_Record_Component (Original_Discriminant (Id));
1976
1977       --  The original type may currently be private, and the discriminant
1978       --  only appear on its full view.
1979
1980       if Is_Private_Type (Scope (Par_Disc))
1981         and then not Has_Discriminants (Scope (Par_Disc))
1982         and then Present (Full_View (Scope (Par_Disc)))
1983       then
1984          Old_Disc := First_Discriminant (Full_View (Scope (Par_Disc)));
1985       else
1986          Old_Disc := First_Discriminant (Scope (Par_Disc));
1987       end if;
1988
1989       if Is_Class_Wide_Type (Typ) then
1990          New_Disc := First_Discriminant (Root_Type (Typ));
1991       else
1992          New_Disc := First_Discriminant (Typ);
1993       end if;
1994
1995       while Present (Old_Disc) and then Present (New_Disc) loop
1996          if Old_Disc = Par_Disc  then
1997             return New_Disc;
1998          else
1999             Next_Discriminant (Old_Disc);
2000             Next_Discriminant (New_Disc);
2001          end if;
2002       end loop;
2003
2004       --  Should always find it
2005
2006       raise Program_Error;
2007    end Find_Corresponding_Discriminant;
2008
2009    -----------------------------
2010    -- Find_Static_Alternative --
2011    -----------------------------
2012
2013    function Find_Static_Alternative (N : Node_Id) return Node_Id is
2014       Expr   : constant Node_Id := Expression (N);
2015       Val    : constant Uint    := Expr_Value (Expr);
2016       Alt    : Node_Id;
2017       Choice : Node_Id;
2018
2019    begin
2020       Alt := First (Alternatives (N));
2021
2022       Search : loop
2023          if Nkind (Alt) /= N_Pragma then
2024             Choice := First (Discrete_Choices (Alt));
2025
2026             while Present (Choice) loop
2027
2028                --  Others choice, always matches
2029
2030                if Nkind (Choice) = N_Others_Choice then
2031                   exit Search;
2032
2033                --  Range, check if value is in the range
2034
2035                elsif Nkind (Choice) = N_Range then
2036                   exit Search when
2037                     Val >= Expr_Value (Low_Bound (Choice))
2038                       and then
2039                     Val <= Expr_Value (High_Bound (Choice));
2040
2041                --  Choice is a subtype name. Note that we know it must
2042                --  be a static subtype, since otherwise it would have
2043                --  been diagnosed as illegal.
2044
2045                elsif Is_Entity_Name (Choice)
2046                  and then Is_Type (Entity (Choice))
2047                then
2048                   exit Search when Is_In_Range (Expr, Etype (Choice));
2049
2050                --  Choice is a subtype indication
2051
2052                elsif Nkind (Choice) = N_Subtype_Indication then
2053                   declare
2054                      C : constant Node_Id := Constraint (Choice);
2055                      R : constant Node_Id := Range_Expression (C);
2056
2057                   begin
2058                      exit Search when
2059                        Val >= Expr_Value (Low_Bound (R))
2060                          and then
2061                        Val <= Expr_Value (High_Bound (R));
2062                   end;
2063
2064                --  Choice is a simple expression
2065
2066                else
2067                   exit Search when Val = Expr_Value (Choice);
2068                end if;
2069
2070                Next (Choice);
2071             end loop;
2072          end if;
2073
2074          Next (Alt);
2075          pragma Assert (Present (Alt));
2076       end loop Search;
2077
2078       --  The above loop *must* terminate by finding a match, since
2079       --  we know the case statement is valid, and the value of the
2080       --  expression is known at compile time. When we fall out of
2081       --  the loop, Alt points to the alternative that we know will
2082       --  be selected at run time.
2083
2084       return Alt;
2085    end Find_Static_Alternative;
2086
2087    ------------------
2088    -- First_Actual --
2089    ------------------
2090
2091    function First_Actual (Node : Node_Id) return Node_Id is
2092       N : Node_Id;
2093
2094    begin
2095       if No (Parameter_Associations (Node)) then
2096          return Empty;
2097       end if;
2098
2099       N := First (Parameter_Associations (Node));
2100
2101       if Nkind (N) = N_Parameter_Association then
2102          return First_Named_Actual (Node);
2103       else
2104          return N;
2105       end if;
2106    end First_Actual;
2107
2108    -------------------------
2109    -- Full_Qualified_Name --
2110    -------------------------
2111
2112    function Full_Qualified_Name (E : Entity_Id) return String_Id is
2113       Res : String_Id;
2114       pragma Warnings (Off, Res);
2115
2116       function Internal_Full_Qualified_Name (E : Entity_Id) return String_Id;
2117       --  Compute recursively the qualified name without NUL at the end
2118
2119       ----------------------------------
2120       -- Internal_Full_Qualified_Name --
2121       ----------------------------------
2122
2123       function Internal_Full_Qualified_Name (E : Entity_Id) return String_Id is
2124          Ent         : Entity_Id := E;
2125          Parent_Name : String_Id := No_String;
2126
2127       begin
2128          --  Deals properly with child units
2129
2130          if Nkind (Ent) = N_Defining_Program_Unit_Name then
2131             Ent := Defining_Identifier (Ent);
2132          end if;
2133
2134          --  Compute recursively the qualification. Only "Standard" has no
2135          --  scope.
2136
2137          if Present (Scope (Scope (Ent))) then
2138             Parent_Name := Internal_Full_Qualified_Name (Scope (Ent));
2139          end if;
2140
2141          --  Every entity should have a name except some expanded blocks
2142          --  don't bother about those.
2143
2144          if Chars (Ent) = No_Name then
2145             return Parent_Name;
2146          end if;
2147
2148          --  Add a period between Name and qualification
2149
2150          if Parent_Name /= No_String then
2151             Start_String (Parent_Name);
2152             Store_String_Char (Get_Char_Code ('.'));
2153
2154          else
2155             Start_String;
2156          end if;
2157
2158          --  Generates the entity name in upper case
2159
2160          Get_Name_String (Chars (Ent));
2161          Set_All_Upper_Case;
2162          Store_String_Chars (Name_Buffer (1 .. Name_Len));
2163          return End_String;
2164       end Internal_Full_Qualified_Name;
2165
2166    --  Start of processing for Full_Qualified_Name
2167
2168    begin
2169       Res := Internal_Full_Qualified_Name (E);
2170       Store_String_Char (Get_Char_Code (ASCII.nul));
2171       return End_String;
2172    end Full_Qualified_Name;
2173
2174    -----------------------
2175    -- Gather_Components --
2176    -----------------------
2177
2178    procedure Gather_Components
2179      (Typ           : Entity_Id;
2180       Comp_List     : Node_Id;
2181       Governed_By   : List_Id;
2182       Into          : Elist_Id;
2183       Report_Errors : out Boolean)
2184    is
2185       Assoc           : Node_Id;
2186       Variant         : Node_Id;
2187       Discrete_Choice : Node_Id;
2188       Comp_Item       : Node_Id;
2189
2190       Discrim       : Entity_Id;
2191       Discrim_Name  : Node_Id;
2192       Discrim_Value : Node_Id;
2193
2194    begin
2195       Report_Errors := False;
2196
2197       if No (Comp_List) or else Null_Present (Comp_List) then
2198          return;
2199
2200       elsif Present (Component_Items (Comp_List)) then
2201          Comp_Item := First (Component_Items (Comp_List));
2202
2203       else
2204          Comp_Item := Empty;
2205       end if;
2206
2207       while Present (Comp_Item) loop
2208
2209          --  Skip the tag of a tagged record, as well as all items
2210          --  that are not user components (anonymous types, rep clauses,
2211          --  Parent field, controller field).
2212
2213          if Nkind (Comp_Item) = N_Component_Declaration
2214            and then Chars (Defining_Identifier (Comp_Item)) /= Name_uTag
2215            and then Chars (Defining_Identifier (Comp_Item)) /= Name_uParent
2216            and then Chars (Defining_Identifier (Comp_Item)) /= Name_uController
2217          then
2218             Append_Elmt (Defining_Identifier (Comp_Item), Into);
2219          end if;
2220
2221          Next (Comp_Item);
2222       end loop;
2223
2224       if No (Variant_Part (Comp_List)) then
2225          return;
2226       else
2227          Discrim_Name := Name (Variant_Part (Comp_List));
2228          Variant := First_Non_Pragma (Variants (Variant_Part (Comp_List)));
2229       end if;
2230
2231       --  Look for the discriminant that governs this variant part.
2232       --  The discriminant *must* be in the Governed_By List
2233
2234       Assoc := First (Governed_By);
2235       Find_Constraint : loop
2236          Discrim := First (Choices (Assoc));
2237          exit Find_Constraint when Chars (Discrim_Name) = Chars (Discrim)
2238            or else (Present (Corresponding_Discriminant (Entity (Discrim)))
2239                       and then
2240                     Chars (Corresponding_Discriminant (Entity (Discrim)))
2241                          = Chars  (Discrim_Name))
2242            or else Chars (Original_Record_Component (Entity (Discrim)))
2243                          = Chars (Discrim_Name);
2244
2245          if No (Next (Assoc)) then
2246             if not Is_Constrained (Typ)
2247               and then Is_Derived_Type (Typ)
2248               and then Present (Stored_Constraint (Typ))
2249             then
2250
2251                --  If the type is a tagged type with inherited discriminants,
2252                --  use the stored constraint on the parent in order to find
2253                --  the values of discriminants that are otherwise hidden by an
2254                --  explicit constraint. Renamed discriminants are handled in
2255                --  the code above.
2256
2257                --  If several parent discriminants are renamed by a single
2258                --  discriminant of the derived type, the call to obtain the
2259                --  Corresponding_Discriminant field only retrieves the last
2260                --  of them. We recover the constraint on the others from the
2261                --  Stored_Constraint as well.
2262
2263                declare
2264                   D : Entity_Id;
2265                   C : Elmt_Id;
2266
2267                begin
2268                   D := First_Discriminant (Etype (Typ));
2269                   C := First_Elmt (Stored_Constraint (Typ));
2270
2271                   while Present (D)
2272                     and then Present (C)
2273                   loop
2274                      if Chars (Discrim_Name) = Chars (D) then
2275                         if Is_Entity_Name (Node (C))
2276                           and then Entity (Node (C)) = Entity (Discrim)
2277                         then
2278                            --  D is renamed by Discrim, whose value is
2279                            --  given in Assoc.
2280
2281                            null;
2282
2283                         else
2284                            Assoc :=
2285                              Make_Component_Association (Sloc (Typ),
2286                                New_List
2287                                  (New_Occurrence_Of (D, Sloc (Typ))),
2288                                   Duplicate_Subexpr_No_Checks (Node (C)));
2289                         end if;
2290                         exit Find_Constraint;
2291                      end if;
2292
2293                      D := Next_Discriminant (D);
2294                      Next_Elmt (C);
2295                   end loop;
2296                end;
2297             end if;
2298          end if;
2299
2300          if No (Next (Assoc)) then
2301             Error_Msg_NE (" missing value for discriminant&",
2302               First (Governed_By), Discrim_Name);
2303             Report_Errors := True;
2304             return;
2305          end if;
2306
2307          Next (Assoc);
2308       end loop Find_Constraint;
2309
2310       Discrim_Value := Expression (Assoc);
2311
2312       if not Is_OK_Static_Expression (Discrim_Value) then
2313          Error_Msg_FE
2314            ("value for discriminant & must be static!",
2315             Discrim_Value, Discrim);
2316          Why_Not_Static (Discrim_Value);
2317          Report_Errors := True;
2318          return;
2319       end if;
2320
2321       Search_For_Discriminant_Value : declare
2322          Low  : Node_Id;
2323          High : Node_Id;
2324
2325          UI_High          : Uint;
2326          UI_Low           : Uint;
2327          UI_Discrim_Value : constant Uint := Expr_Value (Discrim_Value);
2328
2329       begin
2330          Find_Discrete_Value : while Present (Variant) loop
2331             Discrete_Choice := First (Discrete_Choices (Variant));
2332             while Present (Discrete_Choice) loop
2333
2334                exit Find_Discrete_Value when
2335                  Nkind (Discrete_Choice) = N_Others_Choice;
2336
2337                Get_Index_Bounds (Discrete_Choice, Low, High);
2338
2339                UI_Low  := Expr_Value (Low);
2340                UI_High := Expr_Value (High);
2341
2342                exit Find_Discrete_Value when
2343                  UI_Low <= UI_Discrim_Value
2344                    and then
2345                  UI_High >= UI_Discrim_Value;
2346
2347                Next (Discrete_Choice);
2348             end loop;
2349
2350             Next_Non_Pragma (Variant);
2351          end loop Find_Discrete_Value;
2352       end Search_For_Discriminant_Value;
2353
2354       if No (Variant) then
2355          Error_Msg_NE
2356            ("value of discriminant & is out of range", Discrim_Value, Discrim);
2357          Report_Errors := True;
2358          return;
2359       end  if;
2360
2361       --  If we have found the corresponding choice, recursively add its
2362       --  components to the Into list.
2363
2364       Gather_Components (Empty,
2365         Component_List (Variant), Governed_By, Into, Report_Errors);
2366    end Gather_Components;
2367
2368    ------------------------
2369    -- Get_Actual_Subtype --
2370    ------------------------
2371
2372    function Get_Actual_Subtype (N : Node_Id) return Entity_Id is
2373       Typ  : constant Entity_Id := Etype (N);
2374       Utyp : Entity_Id := Underlying_Type (Typ);
2375       Decl : Node_Id;
2376       Atyp : Entity_Id;
2377
2378    begin
2379       if not Present (Utyp) then
2380          Utyp := Typ;
2381       end if;
2382
2383       --  If what we have is an identifier that references a subprogram
2384       --  formal, or a variable or constant object, then we get the actual
2385       --  subtype from the referenced entity if one has been built.
2386
2387       if Nkind (N) = N_Identifier
2388         and then
2389           (Is_Formal (Entity (N))
2390             or else Ekind (Entity (N)) = E_Constant
2391             or else Ekind (Entity (N)) = E_Variable)
2392         and then Present (Actual_Subtype (Entity (N)))
2393       then
2394          return Actual_Subtype (Entity (N));
2395
2396       --  Actual subtype of unchecked union is always itself. We never need
2397       --  the "real" actual subtype. If we did, we couldn't get it anyway
2398       --  because the discriminant is not available. The restrictions on
2399       --  Unchecked_Union are designed to make sure that this is OK.
2400
2401       elsif Is_Unchecked_Union (Base_Type (Utyp)) then
2402          return Typ;
2403
2404       --  Here for the unconstrained case, we must find actual subtype
2405       --  No actual subtype is available, so we must build it on the fly.
2406
2407       --  Checking the type, not the underlying type, for constrainedness
2408       --  seems to be necessary. Maybe all the tests should be on the type???
2409
2410       elsif (not Is_Constrained (Typ))
2411            and then (Is_Array_Type (Utyp)
2412                       or else (Is_Record_Type (Utyp)
2413                                 and then Has_Discriminants (Utyp)))
2414            and then not Has_Unknown_Discriminants (Utyp)
2415            and then not (Ekind (Utyp) = E_String_Literal_Subtype)
2416       then
2417          --  Nothing to do if in default expression
2418
2419          if In_Default_Expression then
2420             return Typ;
2421
2422          elsif Is_Private_Type (Typ)
2423            and then not Has_Discriminants (Typ)
2424          then
2425             --  If the type has no discriminants, there is no subtype to
2426             --  build, even if the underlying type is discriminated.
2427
2428             return Typ;
2429
2430          --  Else build the actual subtype
2431
2432          else
2433             Decl := Build_Actual_Subtype (Typ, N);
2434             Atyp := Defining_Identifier (Decl);
2435
2436             --  If Build_Actual_Subtype generated a new declaration then use it
2437
2438             if Atyp /= Typ then
2439
2440                --  The actual subtype is an Itype, so analyze the declaration,
2441                --  but do not attach it to the tree, to get the type defined.
2442
2443                Set_Parent (Decl, N);
2444                Set_Is_Itype (Atyp);
2445                Analyze (Decl, Suppress => All_Checks);
2446                Set_Associated_Node_For_Itype (Atyp, N);
2447                Set_Has_Delayed_Freeze (Atyp, False);
2448
2449                --  We need to freeze the actual subtype immediately. This is
2450                --  needed, because otherwise this Itype will not get frozen
2451                --  at all, and it is always safe to freeze on creation because
2452                --  any associated types must be frozen at this point.
2453
2454                Freeze_Itype (Atyp, N);
2455                return Atyp;
2456
2457             --  Otherwise we did not build a declaration, so return original
2458
2459             else
2460                return Typ;
2461             end if;
2462          end if;
2463
2464       --  For all remaining cases, the actual subtype is the same as
2465       --  the nominal type.
2466
2467       else
2468          return Typ;
2469       end if;
2470    end Get_Actual_Subtype;
2471
2472    -------------------------------------
2473    -- Get_Actual_Subtype_If_Available --
2474    -------------------------------------
2475
2476    function Get_Actual_Subtype_If_Available (N : Node_Id) return Entity_Id is
2477       Typ  : constant Entity_Id := Etype (N);
2478
2479    begin
2480       --  If what we have is an identifier that references a subprogram
2481       --  formal, or a variable or constant object, then we get the actual
2482       --  subtype from the referenced entity if one has been built.
2483
2484       if Nkind (N) = N_Identifier
2485         and then
2486           (Is_Formal (Entity (N))
2487             or else Ekind (Entity (N)) = E_Constant
2488             or else Ekind (Entity (N)) = E_Variable)
2489         and then Present (Actual_Subtype (Entity (N)))
2490       then
2491          return Actual_Subtype (Entity (N));
2492
2493       --  Otherwise the Etype of N is returned unchanged
2494
2495       else
2496          return Typ;
2497       end if;
2498    end Get_Actual_Subtype_If_Available;
2499
2500    -------------------------------
2501    -- Get_Default_External_Name --
2502    -------------------------------
2503
2504    function Get_Default_External_Name (E : Node_Or_Entity_Id) return Node_Id is
2505    begin
2506       Get_Decoded_Name_String (Chars (E));
2507
2508       if Opt.External_Name_Imp_Casing = Uppercase then
2509          Set_Casing (All_Upper_Case);
2510       else
2511          Set_Casing (All_Lower_Case);
2512       end if;
2513
2514       return
2515         Make_String_Literal (Sloc (E),
2516           Strval => String_From_Name_Buffer);
2517    end Get_Default_External_Name;
2518
2519    ---------------------------
2520    -- Get_Enum_Lit_From_Pos --
2521    ---------------------------
2522
2523    function Get_Enum_Lit_From_Pos
2524      (T   : Entity_Id;
2525       Pos : Uint;
2526       Loc : Source_Ptr) return Node_Id
2527    is
2528       Lit : Node_Id;
2529       P   : constant Nat := UI_To_Int (Pos);
2530
2531    begin
2532       --  In the case where the literal is either of type Wide_Character
2533       --  or Character or of a type derived from them, there needs to be
2534       --  some special handling since there is no explicit chain of
2535       --  literals to search. Instead, an N_Character_Literal node is
2536       --  created with the appropriate Char_Code and Chars fields.
2537
2538       if Root_Type (T) = Standard_Character
2539         or else Root_Type (T) = Standard_Wide_Character
2540       then
2541          Set_Character_Literal_Name (Char_Code (P));
2542          return
2543            Make_Character_Literal (Loc,
2544              Chars => Name_Find,
2545              Char_Literal_Value => Char_Code (P));
2546
2547       --  For all other cases, we have a complete table of literals, and
2548       --  we simply iterate through the chain of literal until the one
2549       --  with the desired position value is found.
2550       --
2551
2552       else
2553          Lit := First_Literal (Base_Type (T));
2554          for J in 1 .. P loop
2555             Next_Literal (Lit);
2556          end loop;
2557
2558          return New_Occurrence_Of (Lit, Loc);
2559       end if;
2560    end Get_Enum_Lit_From_Pos;
2561
2562    ------------------------
2563    -- Get_Generic_Entity --
2564    ------------------------
2565
2566    function Get_Generic_Entity (N : Node_Id) return Entity_Id is
2567       Ent : constant Entity_Id := Entity (Name (N));
2568
2569    begin
2570       if Present (Renamed_Object (Ent)) then
2571          return Renamed_Object (Ent);
2572       else
2573          return Ent;
2574       end if;
2575    end Get_Generic_Entity;
2576
2577    ----------------------
2578    -- Get_Index_Bounds --
2579    ----------------------
2580
2581    procedure Get_Index_Bounds (N : Node_Id; L, H : out Node_Id) is
2582       Kind : constant Node_Kind := Nkind (N);
2583       R    : Node_Id;
2584
2585    begin
2586       if Kind = N_Range then
2587          L := Low_Bound (N);
2588          H := High_Bound (N);
2589
2590       elsif Kind = N_Subtype_Indication then
2591          R := Range_Expression (Constraint (N));
2592
2593          if R = Error then
2594             L := Error;
2595             H := Error;
2596             return;
2597
2598          else
2599             L := Low_Bound  (Range_Expression (Constraint (N)));
2600             H := High_Bound (Range_Expression (Constraint (N)));
2601          end if;
2602
2603       elsif Is_Entity_Name (N) and then Is_Type (Entity (N)) then
2604          if Error_Posted (Scalar_Range (Entity (N))) then
2605             L := Error;
2606             H := Error;
2607
2608          elsif Nkind (Scalar_Range (Entity (N))) = N_Subtype_Indication then
2609             Get_Index_Bounds (Scalar_Range (Entity (N)), L, H);
2610
2611          else
2612             L := Low_Bound  (Scalar_Range (Entity (N)));
2613             H := High_Bound (Scalar_Range (Entity (N)));
2614          end if;
2615
2616       else
2617          --  N is an expression, indicating a range with one value
2618
2619          L := N;
2620          H := N;
2621       end if;
2622    end Get_Index_Bounds;
2623
2624    ----------------------------------
2625    -- Get_Library_Unit_Name_string --
2626    ----------------------------------
2627
2628    procedure Get_Library_Unit_Name_String (Decl_Node : Node_Id) is
2629       Unit_Name_Id : constant Unit_Name_Type := Get_Unit_Name (Decl_Node);
2630
2631    begin
2632       Get_Unit_Name_String (Unit_Name_Id);
2633
2634       --  Remove seven last character (" (spec)" or " (body)")
2635
2636       Name_Len := Name_Len - 7;
2637       pragma Assert (Name_Buffer (Name_Len + 1) = ' ');
2638    end Get_Library_Unit_Name_String;
2639
2640    ------------------------
2641    -- Get_Name_Entity_Id --
2642    ------------------------
2643
2644    function Get_Name_Entity_Id (Id : Name_Id) return Entity_Id is
2645    begin
2646       return Entity_Id (Get_Name_Table_Info (Id));
2647    end Get_Name_Entity_Id;
2648
2649    ---------------------------
2650    -- Get_Referenced_Object --
2651    ---------------------------
2652
2653    function Get_Referenced_Object (N : Node_Id) return Node_Id is
2654       R   : Node_Id := N;
2655
2656    begin
2657       while Is_Entity_Name (R)
2658         and then Present (Renamed_Object (Entity (R)))
2659       loop
2660          R := Renamed_Object (Entity (R));
2661       end loop;
2662
2663       return R;
2664    end Get_Referenced_Object;
2665
2666    -------------------------
2667    -- Get_Subprogram_Body --
2668    -------------------------
2669
2670    function Get_Subprogram_Body (E : Entity_Id) return Node_Id is
2671       Decl : Node_Id;
2672
2673    begin
2674       Decl := Unit_Declaration_Node (E);
2675
2676       if Nkind (Decl) = N_Subprogram_Body then
2677          return Decl;
2678
2679       --  The below comment is bad, because it is possible for
2680       --  Nkind (Decl) to be an N_Subprogram_Body_Stub ???
2681
2682       else           --  Nkind (Decl) = N_Subprogram_Declaration
2683
2684          if Present (Corresponding_Body (Decl)) then
2685             return Unit_Declaration_Node (Corresponding_Body (Decl));
2686
2687          --  Imported subprogram case
2688
2689          else
2690             return Empty;
2691          end if;
2692       end if;
2693    end Get_Subprogram_Body;
2694
2695    -----------------------------
2696    -- Get_Task_Body_Procedure --
2697    -----------------------------
2698
2699    function Get_Task_Body_Procedure (E : Entity_Id) return Node_Id is
2700    begin
2701       return Task_Body_Procedure (Declaration_Node (Root_Type (E)));
2702    end Get_Task_Body_Procedure;
2703
2704    -----------------------
2705    -- Has_Access_Values --
2706    -----------------------
2707
2708    function Has_Access_Values (T : Entity_Id) return Boolean is
2709       Typ : constant Entity_Id := Underlying_Type (T);
2710
2711    begin
2712       --  Case of a private type which is not completed yet. This can only
2713       --  happen in the case of a generic format type appearing directly, or
2714       --  as a component of the type to which this function is being applied
2715       --  at the top level. Return False in this case, since we certainly do
2716       --  not know that the type contains access types.
2717
2718       if No (Typ) then
2719          return False;
2720
2721       elsif Is_Access_Type (Typ) then
2722          return True;
2723
2724       elsif Is_Array_Type (Typ) then
2725          return Has_Access_Values (Component_Type (Typ));
2726
2727       elsif Is_Record_Type (Typ) then
2728          declare
2729             Comp : Entity_Id;
2730
2731          begin
2732             Comp := First_Entity (Typ);
2733             while Present (Comp) loop
2734                if (Ekind (Comp) = E_Component
2735                      or else
2736                    Ekind (Comp) = E_Discriminant)
2737                  and then Has_Access_Values (Etype (Comp))
2738                then
2739                   return True;
2740                end if;
2741
2742                Next_Entity (Comp);
2743             end loop;
2744          end;
2745
2746          return False;
2747
2748       else
2749          return False;
2750       end if;
2751    end Has_Access_Values;
2752
2753    ----------------------
2754    -- Has_Declarations --
2755    ----------------------
2756
2757    function Has_Declarations (N : Node_Id) return Boolean is
2758       K : constant Node_Kind := Nkind (N);
2759    begin
2760       return    K = N_Accept_Statement
2761         or else K = N_Block_Statement
2762         or else K = N_Compilation_Unit_Aux
2763         or else K = N_Entry_Body
2764         or else K = N_Package_Body
2765         or else K = N_Protected_Body
2766         or else K = N_Subprogram_Body
2767         or else K = N_Task_Body
2768         or else K = N_Package_Specification;
2769    end Has_Declarations;
2770
2771    --------------------
2772    -- Has_Infinities --
2773    --------------------
2774
2775    function Has_Infinities (E : Entity_Id) return Boolean is
2776    begin
2777       return
2778         Is_Floating_Point_Type (E)
2779           and then Nkind (Scalar_Range (E)) = N_Range
2780           and then Includes_Infinities (Scalar_Range (E));
2781    end Has_Infinities;
2782
2783    ------------------------
2784    -- Has_Null_Extension --
2785    ------------------------
2786
2787    function Has_Null_Extension (T : Entity_Id) return Boolean is
2788       B     : constant Entity_Id := Base_Type (T);
2789       Comps : Node_Id;
2790       Ext   : Node_Id;
2791
2792    begin
2793       if Nkind (Parent (B)) = N_Full_Type_Declaration
2794         and then Present (Record_Extension_Part (Type_Definition (Parent (B))))
2795       then
2796          Ext := Record_Extension_Part (Type_Definition (Parent (B)));
2797
2798          if Present (Ext) then
2799             if Null_Present (Ext) then
2800                return True;
2801             else
2802                Comps := Component_List (Ext);
2803
2804                --  The null component list is rewritten during analysis to
2805                --  include the parent component. Any other component indicates
2806                --  that the extension was not originally null.
2807
2808                return Null_Present (Comps)
2809                  or else No (Next (First (Component_Items (Comps))));
2810             end if;
2811          else
2812             return False;
2813          end if;
2814
2815       else
2816          return False;
2817       end if;
2818    end Has_Null_Extension;
2819
2820    ---------------------------
2821    -- Has_Private_Component --
2822    ---------------------------
2823
2824    function Has_Private_Component (Type_Id : Entity_Id) return Boolean is
2825       Btype     : Entity_Id := Base_Type (Type_Id);
2826       Component : Entity_Id;
2827
2828    begin
2829       if Error_Posted (Type_Id)
2830         or else Error_Posted (Btype)
2831       then
2832          return False;
2833       end if;
2834
2835       if Is_Class_Wide_Type (Btype) then
2836          Btype := Root_Type (Btype);
2837       end if;
2838
2839       if Is_Private_Type (Btype) then
2840          declare
2841             UT : constant Entity_Id := Underlying_Type (Btype);
2842          begin
2843             if No (UT) then
2844
2845                if No (Full_View (Btype)) then
2846                   return not Is_Generic_Type (Btype)
2847                     and then not Is_Generic_Type (Root_Type (Btype));
2848
2849                else
2850                   return not Is_Generic_Type (Root_Type (Full_View (Btype)));
2851                end if;
2852
2853             else
2854                return not Is_Frozen (UT) and then Has_Private_Component (UT);
2855             end if;
2856          end;
2857       elsif Is_Array_Type (Btype) then
2858          return Has_Private_Component (Component_Type (Btype));
2859
2860       elsif Is_Record_Type (Btype) then
2861
2862          Component := First_Component (Btype);
2863          while Present (Component) loop
2864
2865             if Has_Private_Component (Etype (Component)) then
2866                return True;
2867             end if;
2868
2869             Next_Component (Component);
2870          end loop;
2871
2872          return False;
2873
2874       elsif Is_Protected_Type (Btype)
2875         and then Present (Corresponding_Record_Type (Btype))
2876       then
2877          return Has_Private_Component (Corresponding_Record_Type (Btype));
2878
2879       else
2880          return False;
2881       end if;
2882    end Has_Private_Component;
2883
2884    ----------------
2885    -- Has_Stream --
2886    ----------------
2887
2888    function Has_Stream (T : Entity_Id) return Boolean is
2889       E : Entity_Id;
2890
2891    begin
2892       if No (T) then
2893          return False;
2894
2895       elsif Is_RTE (Root_Type (T), RE_Root_Stream_Type) then
2896          return True;
2897
2898       elsif Is_Array_Type (T) then
2899          return Has_Stream (Component_Type (T));
2900
2901       elsif Is_Record_Type (T) then
2902          E := First_Component (T);
2903          while Present (E) loop
2904             if Has_Stream (Etype (E)) then
2905                return True;
2906             else
2907                Next_Component (E);
2908             end if;
2909          end loop;
2910
2911          return False;
2912
2913       elsif Is_Private_Type (T) then
2914          return Has_Stream (Underlying_Type (T));
2915
2916       else
2917          return False;
2918       end if;
2919    end Has_Stream;
2920
2921    --------------------------
2922    -- Has_Tagged_Component --
2923    --------------------------
2924
2925    function Has_Tagged_Component (Typ : Entity_Id) return Boolean is
2926       Comp : Entity_Id;
2927
2928    begin
2929       if Is_Private_Type (Typ)
2930         and then Present (Underlying_Type (Typ))
2931       then
2932          return Has_Tagged_Component (Underlying_Type (Typ));
2933
2934       elsif Is_Array_Type (Typ) then
2935          return Has_Tagged_Component (Component_Type (Typ));
2936
2937       elsif Is_Tagged_Type (Typ) then
2938          return True;
2939
2940       elsif Is_Record_Type (Typ) then
2941          Comp := First_Component (Typ);
2942
2943          while Present (Comp) loop
2944             if Has_Tagged_Component (Etype (Comp)) then
2945                return True;
2946             end if;
2947
2948             Comp := Next_Component (Typ);
2949          end loop;
2950
2951          return False;
2952
2953       else
2954          return False;
2955       end if;
2956    end Has_Tagged_Component;
2957
2958    -----------------
2959    -- In_Instance --
2960    -----------------
2961
2962    function In_Instance return Boolean is
2963       S : Entity_Id := Current_Scope;
2964
2965    begin
2966       while Present (S)
2967         and then S /= Standard_Standard
2968       loop
2969          if (Ekind (S) = E_Function
2970               or else Ekind (S) = E_Package
2971               or else Ekind (S) = E_Procedure)
2972            and then Is_Generic_Instance (S)
2973          then
2974             return True;
2975          end if;
2976
2977          S := Scope (S);
2978       end loop;
2979
2980       return False;
2981    end In_Instance;
2982
2983    ----------------------
2984    -- In_Instance_Body --
2985    ----------------------
2986
2987    function In_Instance_Body return Boolean is
2988       S : Entity_Id := Current_Scope;
2989
2990    begin
2991       while Present (S)
2992         and then S /= Standard_Standard
2993       loop
2994          if (Ekind (S) = E_Function
2995               or else Ekind (S) = E_Procedure)
2996            and then Is_Generic_Instance (S)
2997          then
2998             return True;
2999
3000          elsif Ekind (S) = E_Package
3001            and then In_Package_Body (S)
3002            and then Is_Generic_Instance (S)
3003          then
3004             return True;
3005          end if;
3006
3007          S := Scope (S);
3008       end loop;
3009
3010       return False;
3011    end In_Instance_Body;
3012
3013    -----------------------------
3014    -- In_Instance_Not_Visible --
3015    -----------------------------
3016
3017    function In_Instance_Not_Visible return Boolean is
3018       S : Entity_Id := Current_Scope;
3019
3020    begin
3021       while Present (S)
3022         and then S /= Standard_Standard
3023       loop
3024          if (Ekind (S) = E_Function
3025               or else Ekind (S) = E_Procedure)
3026            and then Is_Generic_Instance (S)
3027          then
3028             return True;
3029
3030          elsif Ekind (S) = E_Package
3031            and then (In_Package_Body (S) or else In_Private_Part (S))
3032            and then Is_Generic_Instance (S)
3033          then
3034             return True;
3035          end if;
3036
3037          S := Scope (S);
3038       end loop;
3039
3040       return False;
3041    end In_Instance_Not_Visible;
3042
3043    ------------------------------
3044    -- In_Instance_Visible_Part --
3045    ------------------------------
3046
3047    function In_Instance_Visible_Part return Boolean is
3048       S : Entity_Id := Current_Scope;
3049
3050    begin
3051       while Present (S)
3052         and then S /= Standard_Standard
3053       loop
3054          if Ekind (S) = E_Package
3055            and then Is_Generic_Instance (S)
3056            and then not In_Package_Body (S)
3057            and then not In_Private_Part (S)
3058          then
3059             return True;
3060          end if;
3061
3062          S := Scope (S);
3063       end loop;
3064
3065       return False;
3066    end In_Instance_Visible_Part;
3067
3068    ----------------------
3069    -- In_Packiage_Body --
3070    ----------------------
3071
3072    function In_Package_Body return Boolean is
3073       S : Entity_Id := Current_Scope;
3074
3075    begin
3076       while Present (S)
3077         and then S /= Standard_Standard
3078       loop
3079          if Ekind (S) = E_Package
3080            and then In_Package_Body (S)
3081          then
3082             return True;
3083          else
3084             S := Scope (S);
3085          end if;
3086       end loop;
3087
3088       return False;
3089    end In_Package_Body;
3090
3091    --------------------------------------
3092    -- In_Subprogram_Or_Concurrent_Unit --
3093    --------------------------------------
3094
3095    function In_Subprogram_Or_Concurrent_Unit return Boolean is
3096       E : Entity_Id;
3097       K : Entity_Kind;
3098
3099    begin
3100       --  Use scope chain to check successively outer scopes
3101
3102       E := Current_Scope;
3103       loop
3104          K := Ekind (E);
3105
3106          if K in Subprogram_Kind
3107            or else K in Concurrent_Kind
3108            or else K in Generic_Subprogram_Kind
3109          then
3110             return True;
3111
3112          elsif E = Standard_Standard then
3113             return False;
3114          end if;
3115
3116          E := Scope (E);
3117       end loop;
3118    end In_Subprogram_Or_Concurrent_Unit;
3119
3120    ---------------------
3121    -- In_Visible_Part --
3122    ---------------------
3123
3124    function In_Visible_Part (Scope_Id : Entity_Id) return Boolean is
3125    begin
3126       return
3127         Is_Package (Scope_Id)
3128           and then In_Open_Scopes (Scope_Id)
3129           and then not In_Package_Body (Scope_Id)
3130           and then not In_Private_Part (Scope_Id);
3131    end In_Visible_Part;
3132
3133    ---------------------------------
3134    -- Insert_Explicit_Dereference --
3135    ---------------------------------
3136
3137    procedure Insert_Explicit_Dereference (N : Node_Id) is
3138       New_Prefix : constant Node_Id := Relocate_Node (N);
3139       Ent        : Entity_Id := Empty;
3140       I          : Interp_Index;
3141       It         : Interp;
3142       T          : Entity_Id;
3143
3144    begin
3145       Save_Interps (N, New_Prefix);
3146       Rewrite (N,
3147         Make_Explicit_Dereference (Sloc (N), Prefix => New_Prefix));
3148
3149       Set_Etype (N, Designated_Type (Etype (New_Prefix)));
3150
3151       if Is_Overloaded (New_Prefix) then
3152
3153          --  The deference is also overloaded, and its interpretations are the
3154          --  designated types of the interpretations of the original node.
3155
3156          Set_Etype (N, Any_Type);
3157          Get_First_Interp (New_Prefix, I, It);
3158
3159          while Present (It.Nam) loop
3160             T := It.Typ;
3161
3162             if Is_Access_Type (T) then
3163                Add_One_Interp (N, Designated_Type (T), Designated_Type (T));
3164             end if;
3165
3166             Get_Next_Interp (I, It);
3167          end loop;
3168
3169          End_Interp_List;
3170
3171       else
3172          --  Prefix is unambiguous: mark the original prefix (which might
3173          --  Come_From_Source) as a reference, since the new (relocated) one
3174          --  won't be taken into account.
3175
3176          if Is_Entity_Name (New_Prefix) then
3177             Ent := Entity (New_Prefix);
3178          elsif Nkind (New_Prefix) = N_Selected_Component then
3179             Ent := Entity (Selector_Name (New_Prefix));
3180          end if;
3181
3182          if Present (Ent) then
3183             Generate_Reference (Ent, New_Prefix);
3184          end if;
3185       end if;
3186    end Insert_Explicit_Dereference;
3187
3188    -------------------
3189    -- Is_AAMP_Float --
3190    -------------------
3191
3192    function Is_AAMP_Float (E : Entity_Id) return Boolean is
3193    begin
3194       pragma Assert (Is_Type (E));
3195
3196       return AAMP_On_Target
3197          and then Is_Floating_Point_Type (E)
3198          and then E = Base_Type (E);
3199    end Is_AAMP_Float;
3200
3201    -------------------------
3202    -- Is_Actual_Parameter --
3203    -------------------------
3204
3205    function Is_Actual_Parameter (N : Node_Id) return Boolean is
3206       PK : constant Node_Kind := Nkind (Parent (N));
3207
3208    begin
3209       case PK is
3210          when N_Parameter_Association =>
3211             return N = Explicit_Actual_Parameter (Parent (N));
3212
3213          when N_Function_Call | N_Procedure_Call_Statement =>
3214             return Is_List_Member (N)
3215               and then
3216                 List_Containing (N) = Parameter_Associations (Parent (N));
3217
3218          when others =>
3219             return False;
3220       end case;
3221    end Is_Actual_Parameter;
3222
3223    ---------------------
3224    -- Is_Aliased_View --
3225    ---------------------
3226
3227    function Is_Aliased_View (Obj : Node_Id) return Boolean is
3228       E : Entity_Id;
3229
3230    begin
3231       if Is_Entity_Name (Obj) then
3232
3233          E := Entity (Obj);
3234
3235          return
3236            (Is_Object (E)
3237              and then
3238                (Is_Aliased (E)
3239                   or else (Present (Renamed_Object (E))
3240                              and then Is_Aliased_View (Renamed_Object (E)))))
3241
3242            or else ((Is_Formal (E)
3243                       or else Ekind (E) = E_Generic_In_Out_Parameter
3244                       or else Ekind (E) = E_Generic_In_Parameter)
3245                     and then Is_Tagged_Type (Etype (E)))
3246
3247            or else ((Ekind (E) = E_Task_Type
3248                       or else Ekind (E) = E_Protected_Type)
3249                     and then In_Open_Scopes (E))
3250
3251             --  Current instance of type
3252
3253            or else (Is_Type (E) and then E = Current_Scope)
3254            or else (Is_Incomplete_Or_Private_Type (E)
3255                      and then Full_View (E) = Current_Scope);
3256
3257       elsif Nkind (Obj) = N_Selected_Component then
3258          return Is_Aliased (Entity (Selector_Name (Obj)));
3259
3260       elsif Nkind (Obj) = N_Indexed_Component then
3261          return Has_Aliased_Components (Etype (Prefix (Obj)))
3262            or else
3263              (Is_Access_Type (Etype (Prefix (Obj)))
3264                and then
3265               Has_Aliased_Components
3266                 (Designated_Type (Etype (Prefix (Obj)))));
3267
3268       elsif Nkind (Obj) = N_Unchecked_Type_Conversion
3269         or else Nkind (Obj) = N_Type_Conversion
3270       then
3271          return Is_Tagged_Type (Etype (Obj))
3272            and then Is_Aliased_View (Expression (Obj));
3273
3274       elsif Nkind (Obj) = N_Explicit_Dereference then
3275          return Nkind (Original_Node (Obj)) /= N_Function_Call;
3276
3277       else
3278          return False;
3279       end if;
3280    end Is_Aliased_View;
3281
3282    -------------------------
3283    -- Is_Ancestor_Package --
3284    -------------------------
3285
3286    function Is_Ancestor_Package
3287      (E1  : Entity_Id;
3288       E2  : Entity_Id) return Boolean
3289    is
3290       Par : Entity_Id;
3291
3292    begin
3293       Par := E2;
3294       while Present (Par)
3295         and then Par /= Standard_Standard
3296       loop
3297          if Par = E1 then
3298             return True;
3299          end if;
3300
3301          Par := Scope (Par);
3302       end loop;
3303
3304       return False;
3305    end Is_Ancestor_Package;
3306
3307    ----------------------
3308    -- Is_Atomic_Object --
3309    ----------------------
3310
3311    function Is_Atomic_Object (N : Node_Id) return Boolean is
3312
3313       function Object_Has_Atomic_Components (N : Node_Id) return Boolean;
3314       --  Determines if given object has atomic components
3315
3316       function Is_Atomic_Prefix (N : Node_Id) return Boolean;
3317       --  If prefix is an implicit dereference, examine designated type
3318
3319       function Is_Atomic_Prefix (N : Node_Id) return Boolean is
3320       begin
3321          if Is_Access_Type (Etype (N)) then
3322             return
3323               Has_Atomic_Components (Designated_Type (Etype (N)));
3324          else
3325             return Object_Has_Atomic_Components (N);
3326          end if;
3327       end Is_Atomic_Prefix;
3328
3329       function Object_Has_Atomic_Components (N : Node_Id) return Boolean is
3330       begin
3331          if Has_Atomic_Components (Etype (N))
3332            or else Is_Atomic (Etype (N))
3333          then
3334             return True;
3335
3336          elsif Is_Entity_Name (N)
3337            and then (Has_Atomic_Components (Entity (N))
3338                       or else Is_Atomic (Entity (N)))
3339          then
3340             return True;
3341
3342          elsif Nkind (N) = N_Indexed_Component
3343            or else Nkind (N) = N_Selected_Component
3344          then
3345             return Is_Atomic_Prefix (Prefix (N));
3346
3347          else
3348             return False;
3349          end if;
3350       end Object_Has_Atomic_Components;
3351
3352    --  Start of processing for Is_Atomic_Object
3353
3354    begin
3355       if Is_Atomic (Etype (N))
3356         or else (Is_Entity_Name (N) and then Is_Atomic (Entity (N)))
3357       then
3358          return True;
3359
3360       elsif Nkind (N) = N_Indexed_Component
3361         or else Nkind (N) = N_Selected_Component
3362       then
3363          return Is_Atomic_Prefix (Prefix (N));
3364
3365       else
3366          return False;
3367       end if;
3368    end Is_Atomic_Object;
3369
3370    ----------------------------------------------
3371    -- Is_Dependent_Component_Of_Mutable_Object --
3372    ----------------------------------------------
3373
3374    function Is_Dependent_Component_Of_Mutable_Object
3375      (Object : Node_Id) return   Boolean
3376    is
3377       P           : Node_Id;
3378       Prefix_Type : Entity_Id;
3379       P_Aliased   : Boolean := False;
3380       Comp        : Entity_Id;
3381
3382       function Has_Dependent_Constraint (Comp : Entity_Id) return Boolean;
3383       --  Returns True if and only if Comp has a constrained subtype
3384       --  that depends on a discriminant.
3385
3386       function Is_Declared_Within_Variant (Comp : Entity_Id) return Boolean;
3387       --  Returns True if and only if Comp is declared within a variant part
3388
3389       ------------------------------
3390       -- Has_Dependent_Constraint --
3391       ------------------------------
3392
3393       function Has_Dependent_Constraint (Comp : Entity_Id) return Boolean is
3394          Comp_Decl  : constant Node_Id := Parent (Comp);
3395          Subt_Indic : constant Node_Id :=
3396                         Subtype_Indication (Component_Definition (Comp_Decl));
3397          Constr     : Node_Id;
3398          Assn       : Node_Id;
3399
3400       begin
3401          if Nkind (Subt_Indic) = N_Subtype_Indication then
3402             Constr := Constraint (Subt_Indic);
3403
3404             if Nkind (Constr) = N_Index_Or_Discriminant_Constraint then
3405                Assn := First (Constraints (Constr));
3406                while Present (Assn) loop
3407                   case Nkind (Assn) is
3408                      when N_Subtype_Indication |
3409                           N_Range              |
3410                           N_Identifier
3411                      =>
3412                         if Depends_On_Discriminant (Assn) then
3413                            return True;
3414                         end if;
3415
3416                      when N_Discriminant_Association =>
3417                         if Depends_On_Discriminant (Expression (Assn)) then
3418                            return True;
3419                         end if;
3420
3421                      when others =>
3422                         null;
3423
3424                   end case;
3425
3426                   Next (Assn);
3427                end loop;
3428             end if;
3429          end if;
3430
3431          return False;
3432       end Has_Dependent_Constraint;
3433
3434       --------------------------------
3435       -- Is_Declared_Within_Variant --
3436       --------------------------------
3437
3438       function Is_Declared_Within_Variant (Comp : Entity_Id) return Boolean is
3439          Comp_Decl : constant Node_Id   := Parent (Comp);
3440          Comp_List : constant Node_Id   := Parent (Comp_Decl);
3441
3442       begin
3443          return Nkind (Parent (Comp_List)) = N_Variant;
3444       end Is_Declared_Within_Variant;
3445
3446    --  Start of processing for Is_Dependent_Component_Of_Mutable_Object
3447
3448    begin
3449       if Is_Variable (Object) then
3450
3451          if Nkind (Object) = N_Selected_Component then
3452             P := Prefix (Object);
3453             Prefix_Type := Etype (P);
3454
3455             if Is_Entity_Name (P) then
3456
3457                if Ekind (Entity (P)) = E_Generic_In_Out_Parameter then
3458                   Prefix_Type := Base_Type (Prefix_Type);
3459                end if;
3460
3461                if Is_Aliased (Entity (P)) then
3462                   P_Aliased := True;
3463                end if;
3464
3465             --  A discriminant check on a selected component may be
3466             --  expanded into a dereference when removing side-effects.
3467             --  Recover the original node and its type, which may be
3468             --  unconstrained.
3469
3470             elsif Nkind (P) = N_Explicit_Dereference
3471               and then not (Comes_From_Source (P))
3472             then
3473                P := Original_Node (P);
3474                Prefix_Type := Etype (P);
3475
3476             else
3477                --  Check for prefix being an aliased component ???
3478                null;
3479
3480             end if;
3481
3482             if Is_Access_Type (Prefix_Type)
3483               or else Nkind (P) = N_Explicit_Dereference
3484             then
3485                return False;
3486             end if;
3487
3488             Comp :=
3489               Original_Record_Component (Entity (Selector_Name (Object)));
3490
3491             --  As per AI-0017, the renaming is illegal in a generic body,
3492             --  even if the subtype is indefinite.
3493
3494             if not Is_Constrained (Prefix_Type)
3495               and then (not Is_Indefinite_Subtype (Prefix_Type)
3496                          or else
3497                           (Is_Generic_Type (Prefix_Type)
3498                             and then Ekind (Current_Scope) = E_Generic_Package
3499                             and then In_Package_Body (Current_Scope)))
3500
3501               and then (Is_Declared_Within_Variant (Comp)
3502                           or else Has_Dependent_Constraint (Comp))
3503               and then not P_Aliased
3504             then
3505                return True;
3506
3507             else
3508                return
3509                  Is_Dependent_Component_Of_Mutable_Object (Prefix (Object));
3510
3511             end if;
3512
3513          elsif Nkind (Object) = N_Indexed_Component
3514            or else Nkind (Object) = N_Slice
3515          then
3516             return Is_Dependent_Component_Of_Mutable_Object (Prefix (Object));
3517
3518          --  A type conversion that Is_Variable is a view conversion:
3519          --  go back to the denoted object.
3520
3521          elsif Nkind (Object) = N_Type_Conversion then
3522             return
3523               Is_Dependent_Component_Of_Mutable_Object (Expression (Object));
3524          end if;
3525       end if;
3526
3527       return False;
3528    end Is_Dependent_Component_Of_Mutable_Object;
3529
3530    ---------------------
3531    -- Is_Dereferenced --
3532    ---------------------
3533
3534    function Is_Dereferenced (N : Node_Id) return Boolean is
3535       P : constant Node_Id := Parent (N);
3536
3537    begin
3538       return
3539          (Nkind (P) = N_Selected_Component
3540             or else
3541           Nkind (P) = N_Explicit_Dereference
3542             or else
3543           Nkind (P) = N_Indexed_Component
3544             or else
3545           Nkind (P) = N_Slice)
3546         and then Prefix (P) = N;
3547    end Is_Dereferenced;
3548
3549    ----------------------
3550    -- Is_Descendent_Of --
3551    ----------------------
3552
3553    function Is_Descendent_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
3554       T    : Entity_Id;
3555       Etyp : Entity_Id;
3556
3557    begin
3558       pragma Assert (Nkind (T1) in N_Entity);
3559       pragma Assert (Nkind (T2) in N_Entity);
3560
3561       T := Base_Type (T1);
3562
3563       --  Immediate return if the types match
3564
3565       if T = T2 then
3566          return True;
3567
3568       --  Comment needed here ???
3569
3570       elsif Ekind (T) = E_Class_Wide_Type then
3571          return Etype (T) = T2;
3572
3573       --  All other cases
3574
3575       else
3576          loop
3577             Etyp := Etype (T);
3578
3579             --  Done if we found the type we are looking for
3580
3581             if Etyp = T2 then
3582                return True;
3583
3584             --  Done if no more derivations to check
3585
3586             elsif T = T1
3587               or else T = Etyp
3588             then
3589                return False;
3590
3591             --  Following test catches error cases resulting from prev errors
3592
3593             elsif No (Etyp) then
3594                return False;
3595
3596             elsif Is_Private_Type (T) and then Etyp = Full_View (T) then
3597                return False;
3598
3599             elsif Is_Private_Type (Etyp) and then Full_View (Etyp) = T then
3600                return False;
3601             end if;
3602
3603             T := Base_Type (Etyp);
3604          end loop;
3605       end if;
3606
3607       raise Program_Error;
3608    end Is_Descendent_Of;
3609
3610    ------------------------------
3611    -- Is_Descendent_Of_Address --
3612    ------------------------------
3613
3614    function Is_Descendent_Of_Address (T1 : Entity_Id) return Boolean is
3615    begin
3616       --  If Address has not been loaded, answer must be False
3617
3618       if not RTU_Loaded (System) then
3619          return False;
3620
3621       --  Otherwise we can get the entity we are interested in without
3622       --  causing an unwanted dependency on System, and do the test.
3623
3624       else
3625          return Is_Descendent_Of (T1, Base_Type (RTE (RE_Address)));
3626       end if;
3627    end Is_Descendent_Of_Address;
3628
3629    --------------
3630    -- Is_False --
3631    --------------
3632
3633    function Is_False (U : Uint) return Boolean is
3634    begin
3635       return (U = 0);
3636    end Is_False;
3637
3638    ---------------------------
3639    -- Is_Fixed_Model_Number --
3640    ---------------------------
3641
3642    function Is_Fixed_Model_Number (U : Ureal; T : Entity_Id) return Boolean is
3643       S : constant Ureal := Small_Value (T);
3644       M : Urealp.Save_Mark;
3645       R : Boolean;
3646
3647    begin
3648       M := Urealp.Mark;
3649       R := (U = UR_Trunc (U / S) * S);
3650       Urealp.Release (M);
3651       return R;
3652    end Is_Fixed_Model_Number;
3653
3654    -------------------------------
3655    -- Is_Fully_Initialized_Type --
3656    -------------------------------
3657
3658    function Is_Fully_Initialized_Type (Typ : Entity_Id) return Boolean is
3659    begin
3660       if Is_Scalar_Type (Typ) then
3661          return False;
3662
3663       elsif Is_Access_Type (Typ) then
3664          return True;
3665
3666       elsif Is_Array_Type (Typ) then
3667          if Is_Fully_Initialized_Type (Component_Type (Typ)) then
3668             return True;
3669          end if;
3670
3671          --  An interesting case, if we have a constrained type one of whose
3672          --  bounds is known to be null, then there are no elements to be
3673          --  initialized, so all the elements are initialized!
3674
3675          if Is_Constrained (Typ) then
3676             declare
3677                Indx     : Node_Id;
3678                Indx_Typ : Entity_Id;
3679                Lbd, Hbd : Node_Id;
3680
3681             begin
3682                Indx := First_Index (Typ);
3683                while Present (Indx) loop
3684
3685                   if Etype (Indx) = Any_Type then
3686                      return False;
3687
3688                   --  If index is a range, use directly
3689
3690                   elsif Nkind (Indx) = N_Range then
3691                      Lbd := Low_Bound  (Indx);
3692                      Hbd := High_Bound (Indx);
3693
3694                   else
3695                      Indx_Typ := Etype (Indx);
3696
3697                      if Is_Private_Type (Indx_Typ)  then
3698                         Indx_Typ := Full_View (Indx_Typ);
3699                      end if;
3700
3701                      if No (Indx_Typ) then
3702                         return False;
3703                      else
3704                         Lbd := Type_Low_Bound  (Indx_Typ);
3705                         Hbd := Type_High_Bound (Indx_Typ);
3706                      end if;
3707                   end if;
3708
3709                   if Compile_Time_Known_Value (Lbd)
3710                     and then Compile_Time_Known_Value (Hbd)
3711                   then
3712                      if Expr_Value (Hbd) < Expr_Value (Lbd) then
3713                         return True;
3714                      end if;
3715                   end if;
3716
3717                   Next_Index (Indx);
3718                end loop;
3719             end;
3720          end if;
3721
3722          --  If no null indexes, then type is not fully initialized
3723
3724          return False;
3725
3726       --  Record types
3727
3728       elsif Is_Record_Type (Typ) then
3729          if Has_Discriminants (Typ)
3730            and then
3731              Present (Discriminant_Default_Value (First_Discriminant (Typ)))
3732            and then Is_Fully_Initialized_Variant (Typ)
3733          then
3734             return True;
3735          end if;
3736
3737          --  Controlled records are considered to be fully initialized if
3738          --  there is a user defined Initialize routine. This may not be
3739          --  entirely correct, but as the spec notes, we are guessing here
3740          --  what is best from the point of view of issuing warnings.
3741
3742          if Is_Controlled (Typ) then
3743             declare
3744                Utyp : constant Entity_Id := Underlying_Type (Typ);
3745
3746             begin
3747                if Present (Utyp) then
3748                   declare
3749                      Init : constant Entity_Id :=
3750                               (Find_Prim_Op
3751                                  (Underlying_Type (Typ), Name_Initialize));
3752
3753                   begin
3754                      if Present (Init)
3755                        and then Comes_From_Source (Init)
3756                        and then not
3757                          Is_Predefined_File_Name
3758                            (File_Name (Get_Source_File_Index (Sloc (Init))))
3759                      then
3760                         return True;
3761
3762                      elsif Has_Null_Extension (Typ)
3763                         and then
3764                           Is_Fully_Initialized_Type
3765                             (Etype (Base_Type (Typ)))
3766                      then
3767                         return True;
3768                      end if;
3769                   end;
3770                end if;
3771             end;
3772          end if;
3773
3774          --  Otherwise see if all record components are initialized
3775
3776          declare
3777             Ent : Entity_Id;
3778
3779          begin
3780             Ent := First_Entity (Typ);
3781
3782             while Present (Ent) loop
3783                if Chars (Ent) = Name_uController then
3784                   null;
3785
3786                elsif Ekind (Ent) = E_Component
3787                  and then (No (Parent (Ent))
3788                              or else No (Expression (Parent (Ent))))
3789                  and then not Is_Fully_Initialized_Type (Etype (Ent))
3790                then
3791                   return False;
3792                end if;
3793
3794                Next_Entity (Ent);
3795             end loop;
3796          end;
3797
3798          --  No uninitialized components, so type is fully initialized.
3799          --  Note that this catches the case of no components as well.
3800
3801          return True;
3802
3803       elsif Is_Concurrent_Type (Typ) then
3804          return True;
3805
3806       elsif Is_Private_Type (Typ) then
3807          declare
3808             U : constant Entity_Id := Underlying_Type (Typ);
3809
3810          begin
3811             if No (U) then
3812                return False;
3813             else
3814                return Is_Fully_Initialized_Type (U);
3815             end if;
3816          end;
3817
3818       else
3819          return False;
3820       end if;
3821    end Is_Fully_Initialized_Type;
3822
3823    ----------------------------------
3824    -- Is_Fully_Initialized_Variant --
3825    ----------------------------------
3826
3827    function Is_Fully_Initialized_Variant (Typ : Entity_Id) return Boolean is
3828       Loc           : constant Source_Ptr := Sloc (Typ);
3829       Constraints   : constant List_Id    := New_List;
3830       Components    : constant Elist_Id   := New_Elmt_List;
3831       Comp_Elmt     : Elmt_Id;
3832       Comp_Id       : Node_Id;
3833       Comp_List     : Node_Id;
3834       Discr         : Entity_Id;
3835       Discr_Val     : Node_Id;
3836       Report_Errors : Boolean;
3837
3838    begin
3839       if Serious_Errors_Detected > 0 then
3840          return False;
3841       end if;
3842
3843       if Is_Record_Type (Typ)
3844         and then Nkind (Parent (Typ)) = N_Full_Type_Declaration
3845         and then Nkind (Type_Definition (Parent (Typ))) = N_Record_Definition
3846       then
3847          Comp_List := Component_List (Type_Definition (Parent (Typ)));
3848          Discr := First_Discriminant (Typ);
3849
3850          while Present (Discr) loop
3851             if Nkind (Parent (Discr)) = N_Discriminant_Specification then
3852                Discr_Val := Expression (Parent (Discr));
3853
3854                if Present (Discr_Val)
3855                  and then Is_OK_Static_Expression (Discr_Val)
3856                then
3857                   Append_To (Constraints,
3858                     Make_Component_Association (Loc,
3859                       Choices    => New_List (New_Occurrence_Of (Discr, Loc)),
3860                       Expression => New_Copy (Discr_Val)));
3861                else
3862                   return False;
3863                end if;
3864             else
3865                return False;
3866             end if;
3867
3868             Next_Discriminant (Discr);
3869          end loop;
3870
3871          Gather_Components
3872            (Typ           => Typ,
3873             Comp_List     => Comp_List,
3874             Governed_By   => Constraints,
3875             Into          => Components,
3876             Report_Errors => Report_Errors);
3877
3878          --  Check that each component present is fully initialized
3879
3880          Comp_Elmt := First_Elmt (Components);
3881
3882          while Present (Comp_Elmt) loop
3883             Comp_Id := Node (Comp_Elmt);
3884
3885             if Ekind (Comp_Id) = E_Component
3886               and then (No (Parent (Comp_Id))
3887                          or else No (Expression (Parent (Comp_Id))))
3888               and then not Is_Fully_Initialized_Type (Etype (Comp_Id))
3889             then
3890                return False;
3891             end if;
3892
3893             Next_Elmt (Comp_Elmt);
3894          end loop;
3895
3896          return True;
3897
3898       elsif Is_Private_Type (Typ) then
3899          declare
3900             U : constant Entity_Id := Underlying_Type (Typ);
3901
3902          begin
3903             if No (U) then
3904                return False;
3905             else
3906                return Is_Fully_Initialized_Variant (U);
3907             end if;
3908          end;
3909       else
3910          return False;
3911       end if;
3912    end Is_Fully_Initialized_Variant;
3913
3914    ----------------------------
3915    -- Is_Inherited_Operation --
3916    ----------------------------
3917
3918    function Is_Inherited_Operation (E : Entity_Id) return Boolean is
3919       Kind : constant Node_Kind := Nkind (Parent (E));
3920
3921    begin
3922       pragma Assert (Is_Overloadable (E));
3923       return Kind = N_Full_Type_Declaration
3924         or else Kind = N_Private_Extension_Declaration
3925         or else Kind = N_Subtype_Declaration
3926         or else (Ekind (E) = E_Enumeration_Literal
3927                   and then Is_Derived_Type (Etype (E)));
3928    end Is_Inherited_Operation;
3929
3930    -----------------------------
3931    -- Is_Library_Level_Entity --
3932    -----------------------------
3933
3934    function Is_Library_Level_Entity (E : Entity_Id) return Boolean is
3935    begin
3936       --  The following is a small optimization, and it also handles
3937       --  properly discriminals, which in task bodies might appear in
3938       --  expressions before the corresponding procedure has been
3939       --  created, and which therefore do not have an assigned scope.
3940
3941       if Ekind (E) in Formal_Kind then
3942          return False;
3943       end if;
3944
3945       --  Normal test is simply that the enclosing dynamic scope is Standard
3946
3947       return Enclosing_Dynamic_Scope (E) = Standard_Standard;
3948    end Is_Library_Level_Entity;
3949
3950    ---------------------------------
3951    -- Is_Local_Variable_Reference --
3952    ---------------------------------
3953
3954    function Is_Local_Variable_Reference (Expr : Node_Id) return Boolean is
3955    begin
3956       if not Is_Entity_Name (Expr) then
3957          return False;
3958
3959       else
3960          declare
3961             Ent : constant Entity_Id := Entity (Expr);
3962             Sub : constant Entity_Id := Enclosing_Subprogram (Ent);
3963
3964          begin
3965             if Ekind (Ent) /= E_Variable
3966                  and then
3967                Ekind (Ent) /= E_In_Out_Parameter
3968             then
3969                return False;
3970
3971             else
3972                return Present (Sub) and then Sub = Current_Subprogram;
3973             end if;
3974          end;
3975       end if;
3976    end Is_Local_Variable_Reference;
3977
3978    ---------------
3979    -- Is_Lvalue --
3980    ---------------
3981
3982    function Is_Lvalue (N : Node_Id) return Boolean is
3983       P : constant Node_Id := Parent (N);
3984
3985    begin
3986       case Nkind (P) is
3987
3988          --  Test left side of assignment
3989
3990          when N_Assignment_Statement =>
3991             return N = Name (P);
3992
3993          --  Test prefix of component or attribute
3994
3995          when N_Attribute_Reference  |
3996               N_Expanded_Name        |
3997               N_Explicit_Dereference |
3998               N_Indexed_Component    |
3999               N_Reference            |
4000               N_Selected_Component   |
4001               N_Slice                =>
4002             return N = Prefix (P);
4003
4004          --  Test subprogram parameter (we really should check the
4005          --  parameter mode, but it is not worth the trouble)
4006
4007          when N_Function_Call            |
4008               N_Procedure_Call_Statement |
4009               N_Accept_Statement         |
4010               N_Parameter_Association    =>
4011             return True;
4012
4013          --  Test for appearing in a conversion that itself appears
4014          --  in an lvalue context, since this should be an lvalue.
4015
4016          when N_Type_Conversion =>
4017             return Is_Lvalue (P);
4018
4019          --  Test for appearence in object renaming declaration
4020
4021          when N_Object_Renaming_Declaration =>
4022             return True;
4023
4024          --  All other references are definitely not Lvalues
4025
4026          when others =>
4027             return False;
4028
4029       end case;
4030    end Is_Lvalue;
4031
4032    -------------------------
4033    -- Is_Object_Reference --
4034    -------------------------
4035
4036    function Is_Object_Reference (N : Node_Id) return Boolean is
4037    begin
4038       if Is_Entity_Name (N) then
4039          return Is_Object (Entity (N));
4040
4041       else
4042          case Nkind (N) is
4043             when N_Indexed_Component | N_Slice =>
4044                return Is_Object_Reference (Prefix (N));
4045
4046             --  In Ada95, a function call is a constant object
4047
4048             when N_Function_Call =>
4049                return True;
4050
4051             --  A reference to the stream attribute Input is a function call
4052
4053             when N_Attribute_Reference =>
4054                return Attribute_Name (N) = Name_Input;
4055
4056             when N_Selected_Component =>
4057                return
4058                  Is_Object_Reference (Selector_Name (N))
4059                    and then Is_Object_Reference (Prefix (N));
4060
4061             when N_Explicit_Dereference =>
4062                return True;
4063
4064             --  A view conversion of a tagged object is an object reference
4065
4066             when N_Type_Conversion =>
4067                return Is_Tagged_Type (Etype (Subtype_Mark (N)))
4068                  and then Is_Tagged_Type (Etype (Expression (N)))
4069                  and then Is_Object_Reference (Expression (N));
4070
4071             --  An unchecked type conversion is considered to be an object if
4072             --  the operand is an object (this construction arises only as a
4073             --  result of expansion activities).
4074
4075             when N_Unchecked_Type_Conversion =>
4076                return True;
4077
4078             when others =>
4079                return False;
4080          end case;
4081       end if;
4082    end Is_Object_Reference;
4083
4084    -----------------------------------
4085    -- Is_OK_Variable_For_Out_Formal --
4086    -----------------------------------
4087
4088    function Is_OK_Variable_For_Out_Formal (AV : Node_Id) return Boolean is
4089    begin
4090       Note_Possible_Modification (AV);
4091
4092       --  We must reject parenthesized variable names. The check for
4093       --  Comes_From_Source is present because there are currently
4094       --  cases where the compiler violates this rule (e.g. passing
4095       --  a task object to its controlled Initialize routine).
4096
4097       if Paren_Count (AV) > 0 and then Comes_From_Source (AV) then
4098          return False;
4099
4100       --  A variable is always allowed
4101
4102       elsif Is_Variable (AV) then
4103          return True;
4104
4105       --  Unchecked conversions are allowed only if they come from the
4106       --  generated code, which sometimes uses unchecked conversions for
4107       --  out parameters in cases where code generation is unaffected.
4108       --  We tell source unchecked conversions by seeing if they are
4109       --  rewrites of an original UC function call, or of an explicit
4110       --  conversion of a function call.
4111
4112       elsif Nkind (AV) = N_Unchecked_Type_Conversion then
4113          if Nkind (Original_Node (AV)) = N_Function_Call then
4114             return False;
4115
4116          elsif Comes_From_Source (AV)
4117            and then Nkind (Original_Node (Expression (AV))) = N_Function_Call
4118          then
4119             return False;
4120
4121          elsif Nkind (Original_Node (AV)) = N_Type_Conversion then
4122             return Is_OK_Variable_For_Out_Formal (Expression (AV));
4123
4124          else
4125             return True;
4126          end if;
4127
4128       --  Normal type conversions are allowed if argument is a variable
4129
4130       elsif Nkind (AV) = N_Type_Conversion then
4131          if Is_Variable (Expression (AV))
4132            and then Paren_Count (Expression (AV)) = 0
4133          then
4134             Note_Possible_Modification (Expression (AV));
4135             return True;
4136
4137          --  We also allow a non-parenthesized expression that raises
4138          --  constraint error if it rewrites what used to be a variable
4139
4140          elsif Raises_Constraint_Error (Expression (AV))
4141             and then Paren_Count (Expression (AV)) = 0
4142             and then Is_Variable (Original_Node (Expression (AV)))
4143          then
4144             return True;
4145
4146          --  Type conversion of something other than a variable
4147
4148          else
4149             return False;
4150          end if;
4151
4152       --  If this node is rewritten, then test the original form, if that is
4153       --  OK, then we consider the rewritten node OK (for example, if the
4154       --  original node is a conversion, then Is_Variable will not be true
4155       --  but we still want to allow the conversion if it converts a variable).
4156
4157       elsif Original_Node (AV) /= AV then
4158          return Is_OK_Variable_For_Out_Formal (Original_Node (AV));
4159
4160       --  All other non-variables are rejected
4161
4162       else
4163          return False;
4164       end if;
4165    end Is_OK_Variable_For_Out_Formal;
4166
4167    -----------------------------------
4168    -- Is_Partially_Initialized_Type --
4169    -----------------------------------
4170
4171    function Is_Partially_Initialized_Type (Typ : Entity_Id) return Boolean is
4172    begin
4173       if Is_Scalar_Type (Typ) then
4174          return False;
4175
4176       elsif Is_Access_Type (Typ) then
4177          return True;
4178
4179       elsif Is_Array_Type (Typ) then
4180
4181          --  If component type is partially initialized, so is array type
4182
4183          if Is_Partially_Initialized_Type (Component_Type (Typ)) then
4184             return True;
4185
4186          --  Otherwise we are only partially initialized if we are fully
4187          --  initialized (this is the empty array case, no point in us
4188          --  duplicating that code here).
4189
4190          else
4191             return Is_Fully_Initialized_Type (Typ);
4192          end if;
4193
4194       elsif Is_Record_Type (Typ) then
4195
4196          --  A discriminated type is always partially initialized
4197
4198          if Has_Discriminants (Typ) then
4199             return True;
4200
4201          --  A tagged type is always partially initialized
4202
4203          elsif Is_Tagged_Type (Typ) then
4204             return True;
4205
4206          --  Case of non-discriminated record
4207
4208          else
4209             declare
4210                Ent : Entity_Id;
4211
4212                Component_Present : Boolean := False;
4213                --  Set True if at least one component is present. If no
4214                --  components are present, then record type is fully
4215                --  initialized (another odd case, like the null array).
4216
4217             begin
4218                --  Loop through components
4219
4220                Ent := First_Entity (Typ);
4221                while Present (Ent) loop
4222                   if Ekind (Ent) = E_Component then
4223                      Component_Present := True;
4224
4225                      --  If a component has an initialization expression then
4226                      --  the enclosing record type is partially initialized
4227
4228                      if Present (Parent (Ent))
4229                        and then Present (Expression (Parent (Ent)))
4230                      then
4231                         return True;
4232
4233                      --  If a component is of a type which is itself partially
4234                      --  initialized, then the enclosing record type is also.
4235
4236                      elsif Is_Partially_Initialized_Type (Etype (Ent)) then
4237                         return True;
4238                      end if;
4239                   end if;
4240
4241                   Next_Entity (Ent);
4242                end loop;
4243
4244                --  No initialized components found. If we found any components
4245                --  they were all uninitialized so the result is false.
4246
4247                if Component_Present then
4248                   return False;
4249
4250                --  But if we found no components, then all the components are
4251                --  initialized so we consider the type to be initialized.
4252
4253                else
4254                   return True;
4255                end if;
4256             end;
4257          end if;
4258
4259       --  Concurrent types are always fully initialized
4260
4261       elsif Is_Concurrent_Type (Typ) then
4262          return True;
4263
4264       --  For a private type, go to underlying type. If there is no underlying
4265       --  type then just assume this partially initialized. Not clear if this
4266       --  can happen in a non-error case, but no harm in testing for this.
4267
4268       elsif Is_Private_Type (Typ) then
4269          declare
4270             U : constant Entity_Id := Underlying_Type (Typ);
4271
4272          begin
4273             if No (U) then
4274                return True;
4275             else
4276                return Is_Partially_Initialized_Type (U);
4277             end if;
4278          end;
4279
4280       --  For any other type (are there any?) assume partially initialized
4281
4282       else
4283          return True;
4284       end if;
4285    end Is_Partially_Initialized_Type;
4286
4287    -----------------------------
4288    -- Is_RCI_Pkg_Spec_Or_Body --
4289    -----------------------------
4290
4291    function Is_RCI_Pkg_Spec_Or_Body (Cunit : Node_Id) return Boolean is
4292
4293       function Is_RCI_Pkg_Decl_Cunit (Cunit : Node_Id) return Boolean;
4294       --  Return True if the unit of Cunit is an RCI package declaration
4295
4296       ---------------------------
4297       -- Is_RCI_Pkg_Decl_Cunit --
4298       ---------------------------
4299
4300       function Is_RCI_Pkg_Decl_Cunit (Cunit : Node_Id) return Boolean is
4301          The_Unit : constant Node_Id := Unit (Cunit);
4302
4303       begin
4304          if Nkind (The_Unit) /= N_Package_Declaration then
4305             return False;
4306          end if;
4307          return Is_Remote_Call_Interface (Defining_Entity (The_Unit));
4308       end Is_RCI_Pkg_Decl_Cunit;
4309
4310    --  Start of processing for Is_RCI_Pkg_Spec_Or_Body
4311
4312    begin
4313       return Is_RCI_Pkg_Decl_Cunit (Cunit)
4314         or else
4315          (Nkind (Unit (Cunit)) = N_Package_Body
4316            and then Is_RCI_Pkg_Decl_Cunit (Library_Unit (Cunit)));
4317    end Is_RCI_Pkg_Spec_Or_Body;
4318
4319    -----------------------------------------
4320    -- Is_Remote_Access_To_Class_Wide_Type --
4321    -----------------------------------------
4322
4323    function Is_Remote_Access_To_Class_Wide_Type
4324      (E : Entity_Id) return Boolean
4325    is
4326       D : Entity_Id;
4327
4328       function Comes_From_Limited_Private_Type_Declaration
4329         (E    : Entity_Id)
4330          return Boolean;
4331       --  Check that the type is declared by a limited type declaration,
4332       --  or else is derived from a Remote_Type ancestor through private
4333       --  extensions.
4334
4335       -------------------------------------------------
4336       -- Comes_From_Limited_Private_Type_Declaration --
4337       -------------------------------------------------
4338
4339       function Comes_From_Limited_Private_Type_Declaration (E : in Entity_Id)
4340         return Boolean
4341       is
4342          N : constant Node_Id := Declaration_Node (E);
4343       begin
4344          if Nkind (N) = N_Private_Type_Declaration
4345            and then Limited_Present (N)
4346          then
4347             return True;
4348          end if;
4349
4350          if Nkind (N) = N_Private_Extension_Declaration then
4351             return
4352               Comes_From_Limited_Private_Type_Declaration (Etype (E))
4353                 or else
4354                  (Is_Remote_Types (Etype (E))
4355                     and then Is_Limited_Record (Etype (E))
4356                     and then Has_Private_Declaration (Etype (E)));
4357          end if;
4358
4359          return False;
4360       end Comes_From_Limited_Private_Type_Declaration;
4361
4362    --  Start of processing for Is_Remote_Access_To_Class_Wide_Type
4363
4364    begin
4365       if not (Is_Remote_Call_Interface (E)
4366                or else Is_Remote_Types (E))
4367         or else Ekind (E) /= E_General_Access_Type
4368       then
4369          return False;
4370       end if;
4371
4372       D := Designated_Type (E);
4373
4374       if Ekind (D) /= E_Class_Wide_Type then
4375          return False;
4376       end if;
4377
4378       return Comes_From_Limited_Private_Type_Declaration
4379                (Defining_Identifier (Parent (D)));
4380    end Is_Remote_Access_To_Class_Wide_Type;
4381
4382    -----------------------------------------
4383    -- Is_Remote_Access_To_Subprogram_Type --
4384    -----------------------------------------
4385
4386    function Is_Remote_Access_To_Subprogram_Type
4387      (E : Entity_Id) return Boolean
4388    is
4389    begin
4390       return (Ekind (E) = E_Access_Subprogram_Type
4391                 or else (Ekind (E) = E_Record_Type
4392                            and then Present (Corresponding_Remote_Type (E))))
4393         and then (Is_Remote_Call_Interface (E)
4394                    or else Is_Remote_Types (E));
4395    end Is_Remote_Access_To_Subprogram_Type;
4396
4397    --------------------
4398    -- Is_Remote_Call --
4399    --------------------
4400
4401    function Is_Remote_Call (N : Node_Id) return Boolean is
4402    begin
4403       if Nkind (N) /= N_Procedure_Call_Statement
4404         and then Nkind (N) /= N_Function_Call
4405       then
4406          --  An entry call cannot be remote
4407
4408          return False;
4409
4410       elsif Nkind (Name (N)) in N_Has_Entity
4411         and then Is_Remote_Call_Interface (Entity (Name (N)))
4412       then
4413          --  A subprogram declared in the spec of a RCI package is remote
4414
4415          return True;
4416
4417       elsif Nkind (Name (N)) = N_Explicit_Dereference
4418         and then Is_Remote_Access_To_Subprogram_Type
4419           (Etype (Prefix (Name (N))))
4420       then
4421          --  The dereference of a RAS is a remote call
4422
4423          return True;
4424
4425       elsif Present (Controlling_Argument (N))
4426         and then Is_Remote_Access_To_Class_Wide_Type
4427           (Etype (Controlling_Argument (N)))
4428       then
4429          --  Any primitive operation call with a controlling argument of
4430          --  a RACW type is a remote call.
4431
4432          return True;
4433       end if;
4434
4435       --  All other calls are local calls
4436
4437       return False;
4438    end Is_Remote_Call;
4439
4440    ----------------------
4441    -- Is_Selector_Name --
4442    ----------------------
4443
4444    function Is_Selector_Name (N : Node_Id) return Boolean is
4445
4446    begin
4447       if not Is_List_Member (N) then
4448          declare
4449             P : constant Node_Id   := Parent (N);
4450             K : constant Node_Kind := Nkind (P);
4451
4452          begin
4453             return
4454               (K = N_Expanded_Name          or else
4455                K = N_Generic_Association    or else
4456                K = N_Parameter_Association  or else
4457                K = N_Selected_Component)
4458               and then Selector_Name (P) = N;
4459          end;
4460
4461       else
4462          declare
4463             L : constant List_Id := List_Containing (N);
4464             P : constant Node_Id := Parent (L);
4465
4466          begin
4467             return (Nkind (P) = N_Discriminant_Association
4468                      and then Selector_Names (P) = L)
4469               or else
4470                    (Nkind (P) = N_Component_Association
4471                      and then Choices (P) = L);
4472          end;
4473       end if;
4474    end Is_Selector_Name;
4475
4476    ------------------
4477    -- Is_Statement --
4478    ------------------
4479
4480    function Is_Statement (N : Node_Id) return Boolean is
4481    begin
4482       return
4483         Nkind (N) in N_Statement_Other_Than_Procedure_Call
4484           or else Nkind (N) = N_Procedure_Call_Statement;
4485    end Is_Statement;
4486
4487    -----------------
4488    -- Is_Transfer --
4489    -----------------
4490
4491    function Is_Transfer (N : Node_Id) return Boolean is
4492       Kind : constant Node_Kind := Nkind (N);
4493
4494    begin
4495       if Kind = N_Return_Statement
4496            or else
4497          Kind = N_Goto_Statement
4498            or else
4499          Kind = N_Raise_Statement
4500            or else
4501          Kind = N_Requeue_Statement
4502       then
4503          return True;
4504
4505       elsif (Kind = N_Exit_Statement or else Kind in N_Raise_xxx_Error)
4506         and then No (Condition (N))
4507       then
4508          return True;
4509
4510       elsif Kind = N_Procedure_Call_Statement
4511         and then Is_Entity_Name (Name (N))
4512         and then Present (Entity (Name (N)))
4513         and then No_Return (Entity (Name (N)))
4514       then
4515          return True;
4516
4517       elsif Nkind (Original_Node (N)) = N_Raise_Statement then
4518          return True;
4519
4520       else
4521          return False;
4522       end if;
4523    end Is_Transfer;
4524
4525    -------------
4526    -- Is_True --
4527    -------------
4528
4529    function Is_True (U : Uint) return Boolean is
4530    begin
4531       return (U /= 0);
4532    end Is_True;
4533
4534    -----------------
4535    -- Is_Variable --
4536    -----------------
4537
4538    function Is_Variable (N : Node_Id) return Boolean is
4539
4540       Orig_Node : constant Node_Id := Original_Node (N);
4541       --  We do the test on the original node, since this is basically a
4542       --  test of syntactic categories, so it must not be disturbed by
4543       --  whatever rewriting might have occurred. For example, an aggregate,
4544       --  which is certainly NOT a variable, could be turned into a variable
4545       --  by expansion.
4546
4547       function In_Protected_Function (E : Entity_Id) return Boolean;
4548       --  Within a protected function, the private components of the
4549       --  enclosing protected type are constants. A function nested within
4550       --  a (protected) procedure is not itself protected.
4551
4552       function Is_Variable_Prefix (P : Node_Id) return Boolean;
4553       --  Prefixes can involve implicit dereferences, in which case we
4554       --  must test for the case of a reference of a constant access
4555       --  type, which can never be a variable.
4556
4557       ---------------------------
4558       -- In_Protected_Function --
4559       ---------------------------
4560
4561       function In_Protected_Function (E : Entity_Id) return Boolean is
4562          Prot : constant Entity_Id := Scope (E);
4563          S    : Entity_Id;
4564
4565       begin
4566          if not Is_Protected_Type (Prot) then
4567             return False;
4568          else
4569             S := Current_Scope;
4570
4571             while Present (S) and then S /= Prot loop
4572
4573                if Ekind (S) = E_Function
4574                  and then Scope (S) = Prot
4575                then
4576                   return True;
4577                end if;
4578
4579                S := Scope (S);
4580             end loop;
4581
4582             return False;
4583          end if;
4584       end In_Protected_Function;
4585
4586       ------------------------
4587       -- Is_Variable_Prefix --
4588       ------------------------
4589
4590       function Is_Variable_Prefix (P : Node_Id) return Boolean is
4591       begin
4592          if Is_Access_Type (Etype (P)) then
4593             return not Is_Access_Constant (Root_Type (Etype (P)));
4594          else
4595             return Is_Variable (P);
4596          end if;
4597       end Is_Variable_Prefix;
4598
4599    --  Start of processing for Is_Variable
4600
4601    begin
4602       --  Definitely OK if Assignment_OK is set. Since this is something that
4603       --  only gets set for expanded nodes, the test is on N, not Orig_Node.
4604
4605       if Nkind (N) in N_Subexpr and then Assignment_OK (N) then
4606          return True;
4607
4608       --  Normally we go to the original node, but there is one exception
4609       --  where we use the rewritten node, namely when it is an explicit
4610       --  dereference. The generated code may rewrite a prefix which is an
4611       --  access type with an explicit dereference. The dereference is a
4612       --  variable, even though the original node may not be (since it could
4613       --  be a constant of the access type).
4614
4615       elsif Nkind (N) = N_Explicit_Dereference
4616         and then Nkind (Orig_Node) /= N_Explicit_Dereference
4617         and then Is_Access_Type (Etype (Orig_Node))
4618       then
4619          return Is_Variable_Prefix (Original_Node (Prefix (N)));
4620
4621       --  All remaining checks use the original node
4622
4623       elsif Is_Entity_Name (Orig_Node) then
4624          declare
4625             E : constant Entity_Id := Entity (Orig_Node);
4626             K : constant Entity_Kind := Ekind (E);
4627
4628          begin
4629             return (K = E_Variable
4630                       and then Nkind (Parent (E)) /= N_Exception_Handler)
4631               or else  (K = E_Component
4632                           and then not In_Protected_Function (E))
4633               or else  K = E_Out_Parameter
4634               or else  K = E_In_Out_Parameter
4635               or else  K = E_Generic_In_Out_Parameter
4636
4637                --  Current instance of type:
4638
4639               or else (Is_Type (E) and then In_Open_Scopes (E))
4640               or else (Is_Incomplete_Or_Private_Type (E)
4641                         and then In_Open_Scopes (Full_View (E)));
4642          end;
4643
4644       else
4645          case Nkind (Orig_Node) is
4646             when N_Indexed_Component | N_Slice =>
4647                return Is_Variable_Prefix (Prefix (Orig_Node));
4648
4649             when N_Selected_Component =>
4650                return Is_Variable_Prefix (Prefix (Orig_Node))
4651                  and then Is_Variable (Selector_Name (Orig_Node));
4652
4653             --  For an explicit dereference, the type of the prefix cannot
4654             --  be an access to constant or an access to subprogram.
4655
4656             when N_Explicit_Dereference =>
4657                declare
4658                   Typ : constant Entity_Id := Etype (Prefix (Orig_Node));
4659
4660                begin
4661                   return Is_Access_Type (Typ)
4662                     and then not Is_Access_Constant (Root_Type (Typ))
4663                     and then Ekind (Typ) /= E_Access_Subprogram_Type;
4664                end;
4665
4666             --  The type conversion is the case where we do not deal with the
4667             --  context dependent special case of an actual parameter. Thus
4668             --  the type conversion is only considered a variable for the
4669             --  purposes of this routine if the target type is tagged. However,
4670             --  a type conversion is considered to be a variable if it does not
4671             --  come from source (this deals for example with the conversions
4672             --  of expressions to their actual subtypes).
4673
4674             when N_Type_Conversion =>
4675                return Is_Variable (Expression (Orig_Node))
4676                  and then
4677                    (not Comes_From_Source (Orig_Node)
4678                       or else
4679                         (Is_Tagged_Type (Etype (Subtype_Mark (Orig_Node)))
4680                           and then
4681                          Is_Tagged_Type (Etype (Expression (Orig_Node)))));
4682
4683             --  GNAT allows an unchecked type conversion as a variable. This
4684             --  only affects the generation of internal expanded code, since
4685             --  calls to instantiations of Unchecked_Conversion are never
4686             --  considered variables (since they are function calls).
4687             --  This is also true for expression actions.
4688
4689             when N_Unchecked_Type_Conversion =>
4690                return Is_Variable (Expression (Orig_Node));
4691
4692             when others =>
4693                return False;
4694          end case;
4695       end if;
4696    end Is_Variable;
4697
4698    ------------------------
4699    -- Is_Volatile_Object --
4700    ------------------------
4701
4702    function Is_Volatile_Object (N : Node_Id) return Boolean is
4703
4704       function Object_Has_Volatile_Components (N : Node_Id) return Boolean;
4705       --  Determines if given object has volatile components
4706
4707       function Is_Volatile_Prefix (N : Node_Id) return Boolean;
4708       --  If prefix is an implicit dereference, examine designated type
4709
4710       ------------------------
4711       -- Is_Volatile_Prefix --
4712       ------------------------
4713
4714       function Is_Volatile_Prefix (N : Node_Id) return Boolean is
4715          Typ  : constant Entity_Id := Etype (N);
4716
4717       begin
4718          if Is_Access_Type (Typ) then
4719             declare
4720                Dtyp : constant Entity_Id := Designated_Type (Typ);
4721
4722             begin
4723                return Is_Volatile (Dtyp)
4724                  or else Has_Volatile_Components (Dtyp);
4725             end;
4726
4727          else
4728             return Object_Has_Volatile_Components (N);
4729          end if;
4730       end Is_Volatile_Prefix;
4731
4732       ------------------------------------
4733       -- Object_Has_Volatile_Components --
4734       ------------------------------------
4735
4736       function Object_Has_Volatile_Components (N : Node_Id) return Boolean is
4737          Typ : constant Entity_Id := Etype (N);
4738
4739       begin
4740          if Is_Volatile (Typ)
4741            or else Has_Volatile_Components (Typ)
4742          then
4743             return True;
4744
4745          elsif Is_Entity_Name (N)
4746            and then (Has_Volatile_Components (Entity (N))
4747                       or else Is_Volatile (Entity (N)))
4748          then
4749             return True;
4750
4751          elsif Nkind (N) = N_Indexed_Component
4752            or else Nkind (N) = N_Selected_Component
4753          then
4754             return Is_Volatile_Prefix (Prefix (N));
4755
4756          else
4757             return False;
4758          end if;
4759       end Object_Has_Volatile_Components;
4760
4761    --  Start of processing for Is_Volatile_Object
4762
4763    begin
4764       if Is_Volatile (Etype (N))
4765         or else (Is_Entity_Name (N) and then Is_Volatile (Entity (N)))
4766       then
4767          return True;
4768
4769       elsif Nkind (N) = N_Indexed_Component
4770         or else Nkind (N) = N_Selected_Component
4771       then
4772          return Is_Volatile_Prefix (Prefix (N));
4773
4774       else
4775          return False;
4776       end if;
4777    end Is_Volatile_Object;
4778
4779    -------------------------
4780    -- Kill_Current_Values --
4781    -------------------------
4782
4783    procedure Kill_Current_Values is
4784       S : Entity_Id;
4785
4786       procedure Kill_Current_Values_For_Entity_Chain (E : Entity_Id);
4787       --  Clear current value for entity E and all entities chained to E
4788
4789       ------------------------------------------
4790       -- Kill_Current_Values_For_Entity_Chain --
4791       ------------------------------------------
4792
4793       procedure Kill_Current_Values_For_Entity_Chain (E : Entity_Id) is
4794          Ent : Entity_Id;
4795
4796       begin
4797          Ent := E;
4798          while Present (Ent) loop
4799             if Is_Object (Ent) then
4800                Set_Current_Value (Ent, Empty);
4801
4802                if not Can_Never_Be_Null (Ent) then
4803                   Set_Is_Known_Non_Null (Ent, False);
4804                end if;
4805             end if;
4806
4807             Next_Entity (Ent);
4808          end loop;
4809       end Kill_Current_Values_For_Entity_Chain;
4810
4811    --  Start of processing for Kill_Current_Values
4812
4813    begin
4814       --  Kill all saved checks, a special case of killing saved values
4815
4816       Kill_All_Checks;
4817
4818       --  Loop through relevant scopes, which includes the current scope and
4819       --  any parent scopes if the current scope is a block or a package.
4820
4821       S := Current_Scope;
4822       Scope_Loop : loop
4823
4824          --  Clear current values of all entities in current scope
4825
4826          Kill_Current_Values_For_Entity_Chain (First_Entity (S));
4827
4828          --  If scope is a package, also clear current values of all
4829          --  private entities in the scope.
4830
4831          if Ekind (S) = E_Package
4832               or else
4833             Ekind (S) = E_Generic_Package
4834               or else
4835             Is_Concurrent_Type (S)
4836          then
4837             Kill_Current_Values_For_Entity_Chain (First_Private_Entity (S));
4838          end if;
4839
4840          --  If this is a block or nested package, deal with parent
4841
4842          if Ekind (S) = E_Block
4843            or else (Ekind (S) = E_Package
4844                       and then not Is_Library_Level_Entity (S))
4845          then
4846             S := Scope (S);
4847          else
4848             exit Scope_Loop;
4849          end if;
4850       end loop Scope_Loop;
4851    end Kill_Current_Values;
4852
4853    --------------------------
4854    -- Kill_Size_Check_Code --
4855    --------------------------
4856
4857    procedure Kill_Size_Check_Code (E : Entity_Id) is
4858    begin
4859       if (Ekind (E) = E_Constant or else Ekind (E) = E_Variable)
4860         and then Present (Size_Check_Code (E))
4861       then
4862          Remove (Size_Check_Code (E));
4863          Set_Size_Check_Code (E, Empty);
4864       end if;
4865    end Kill_Size_Check_Code;
4866
4867    -------------------------
4868    -- New_External_Entity --
4869    -------------------------
4870
4871    function New_External_Entity
4872      (Kind         : Entity_Kind;
4873       Scope_Id     : Entity_Id;
4874       Sloc_Value   : Source_Ptr;
4875       Related_Id   : Entity_Id;
4876       Suffix       : Character;
4877       Suffix_Index : Nat := 0;
4878       Prefix       : Character := ' ') return Entity_Id
4879    is
4880       N : constant Entity_Id :=
4881             Make_Defining_Identifier (Sloc_Value,
4882               New_External_Name
4883                 (Chars (Related_Id), Suffix, Suffix_Index, Prefix));
4884
4885    begin
4886       Set_Ekind          (N, Kind);
4887       Set_Is_Internal    (N, True);
4888       Append_Entity      (N, Scope_Id);
4889       Set_Public_Status  (N);
4890
4891       if Kind in Type_Kind then
4892          Init_Size_Align (N);
4893       end if;
4894
4895       return N;
4896    end New_External_Entity;
4897
4898    -------------------------
4899    -- New_Internal_Entity --
4900    -------------------------
4901
4902    function New_Internal_Entity
4903      (Kind       : Entity_Kind;
4904       Scope_Id   : Entity_Id;
4905       Sloc_Value : Source_Ptr;
4906       Id_Char    : Character) return Entity_Id
4907    is
4908       N : constant Entity_Id :=
4909             Make_Defining_Identifier (Sloc_Value, New_Internal_Name (Id_Char));
4910
4911    begin
4912       Set_Ekind          (N, Kind);
4913       Set_Is_Internal    (N, True);
4914       Append_Entity      (N, Scope_Id);
4915
4916       if Kind in Type_Kind then
4917          Init_Size_Align (N);
4918       end if;
4919
4920       return N;
4921    end New_Internal_Entity;
4922
4923    -----------------
4924    -- Next_Actual --
4925    -----------------
4926
4927    function Next_Actual (Actual_Id : Node_Id) return Node_Id is
4928       N  : Node_Id;
4929
4930    begin
4931       --  If we are pointing at a positional parameter, it is a member of
4932       --  a node list (the list of parameters), and the next parameter
4933       --  is the next node on the list, unless we hit a parameter
4934       --  association, in which case we shift to using the chain whose
4935       --  head is the First_Named_Actual in the parent, and then is
4936       --  threaded using the Next_Named_Actual of the Parameter_Association.
4937       --  All this fiddling is because the original node list is in the
4938       --  textual call order, and what we need is the declaration order.
4939
4940       if Is_List_Member (Actual_Id) then
4941          N := Next (Actual_Id);
4942
4943          if Nkind (N) = N_Parameter_Association then
4944             return First_Named_Actual (Parent (Actual_Id));
4945          else
4946             return N;
4947          end if;
4948
4949       else
4950          return Next_Named_Actual (Parent (Actual_Id));
4951       end if;
4952    end Next_Actual;
4953
4954    procedure Next_Actual (Actual_Id : in out Node_Id) is
4955    begin
4956       Actual_Id := Next_Actual (Actual_Id);
4957    end Next_Actual;
4958
4959    -----------------------
4960    -- Normalize_Actuals --
4961    -----------------------
4962
4963    --  Chain actuals according to formals of subprogram. If there are
4964    --  no named associations, the chain is simply the list of Parameter
4965    --  Associations, since the order is the same as the declaration order.
4966    --  If there are named associations, then the First_Named_Actual field
4967    --  in the N_Procedure_Call_Statement node or N_Function_Call node
4968    --  points to the Parameter_Association node for the parameter that
4969    --  comes first in declaration order. The remaining named parameters
4970    --  are then chained in declaration order using Next_Named_Actual.
4971
4972    --  This routine also verifies that the number of actuals is compatible
4973    --  with the number and default values of formals, but performs no type
4974    --  checking (type checking is done by the caller).
4975
4976    --  If the matching succeeds, Success is set to True, and the caller
4977    --  proceeds with type-checking. If the match is unsuccessful, then
4978    --  Success is set to False, and the caller attempts a different
4979    --  interpretation, if there is one.
4980
4981    --  If the flag Report is on, the call is not overloaded, and a failure
4982    --  to match can be reported here, rather than in the caller.
4983
4984    procedure Normalize_Actuals
4985      (N       : Node_Id;
4986       S       : Entity_Id;
4987       Report  : Boolean;
4988       Success : out Boolean)
4989    is
4990       Actuals     : constant List_Id := Parameter_Associations (N);
4991       Actual      : Node_Id   := Empty;
4992       Formal      : Entity_Id;
4993       Last        : Node_Id := Empty;
4994       First_Named : Node_Id := Empty;
4995       Found       : Boolean;
4996
4997       Formals_To_Match : Integer := 0;
4998       Actuals_To_Match : Integer := 0;
4999
5000       procedure Chain (A : Node_Id);
5001       --  Add named actual at the proper place in the list, using the
5002       --  Next_Named_Actual link.
5003
5004       function Reporting return Boolean;
5005       --  Determines if an error is to be reported. To report an error, we
5006       --  need Report to be True, and also we do not report errors caused
5007       --  by calls to init procs that occur within other init procs. Such
5008       --  errors must always be cascaded errors, since if all the types are
5009       --  declared correctly, the compiler will certainly build decent calls!
5010
5011       -----------
5012       -- Chain --
5013       -----------
5014
5015       procedure Chain (A : Node_Id) is
5016       begin
5017          if No (Last) then
5018
5019             --  Call node points to first actual in list
5020
5021             Set_First_Named_Actual (N, Explicit_Actual_Parameter (A));
5022
5023          else
5024             Set_Next_Named_Actual (Last, Explicit_Actual_Parameter (A));
5025          end if;
5026
5027          Last := A;
5028          Set_Next_Named_Actual (Last, Empty);
5029       end Chain;
5030
5031       ---------------
5032       -- Reporting --
5033       ---------------
5034
5035       function Reporting return Boolean is
5036       begin
5037          if not Report then
5038             return False;
5039
5040          elsif not Within_Init_Proc then
5041             return True;
5042
5043          elsif Is_Init_Proc (Entity (Name (N))) then
5044             return False;
5045
5046          else
5047             return True;
5048          end if;
5049       end Reporting;
5050
5051    --  Start of processing for Normalize_Actuals
5052
5053    begin
5054       if Is_Access_Type (S) then
5055
5056          --  The name in the call is a function call that returns an access
5057          --  to subprogram. The designated type has the list of formals.
5058
5059          Formal := First_Formal (Designated_Type (S));
5060       else
5061          Formal := First_Formal (S);
5062       end if;
5063
5064       while Present (Formal) loop
5065          Formals_To_Match := Formals_To_Match + 1;
5066          Next_Formal (Formal);
5067       end loop;
5068
5069       --  Find if there is a named association, and verify that no positional
5070       --  associations appear after named ones.
5071
5072       if Present (Actuals) then
5073          Actual := First (Actuals);
5074       end if;
5075
5076       while Present (Actual)
5077         and then Nkind (Actual) /= N_Parameter_Association
5078       loop
5079          Actuals_To_Match := Actuals_To_Match + 1;
5080          Next (Actual);
5081       end loop;
5082
5083       if No (Actual) and Actuals_To_Match = Formals_To_Match then
5084
5085          --  Most common case: positional notation, no defaults
5086
5087          Success := True;
5088          return;
5089
5090       elsif Actuals_To_Match > Formals_To_Match then
5091
5092          --  Too many actuals: will not work
5093
5094          if Reporting then
5095             if Is_Entity_Name (Name (N)) then
5096                Error_Msg_N ("too many arguments in call to&", Name (N));
5097             else
5098                Error_Msg_N ("too many arguments in call", N);
5099             end if;
5100          end if;
5101
5102          Success := False;
5103          return;
5104       end if;
5105
5106       First_Named := Actual;
5107
5108       while Present (Actual) loop
5109          if Nkind (Actual) /= N_Parameter_Association then
5110             Error_Msg_N
5111               ("positional parameters not allowed after named ones", Actual);
5112             Success := False;
5113             return;
5114
5115          else
5116             Actuals_To_Match := Actuals_To_Match + 1;
5117          end if;
5118
5119          Next (Actual);
5120       end loop;
5121
5122       if Present (Actuals) then
5123          Actual := First (Actuals);
5124       end if;
5125
5126       Formal := First_Formal (S);
5127       while Present (Formal) loop
5128
5129          --  Match the formals in order. If the corresponding actual
5130          --  is positional,  nothing to do. Else scan the list of named
5131          --  actuals to find the one with the right name.
5132
5133          if Present (Actual)
5134            and then Nkind (Actual) /= N_Parameter_Association
5135          then
5136             Next (Actual);
5137             Actuals_To_Match := Actuals_To_Match - 1;
5138             Formals_To_Match := Formals_To_Match - 1;
5139
5140          else
5141             --  For named parameters, search the list of actuals to find
5142             --  one that matches the next formal name.
5143
5144             Actual := First_Named;
5145             Found  := False;
5146
5147             while Present (Actual) loop
5148                if Chars (Selector_Name (Actual)) = Chars (Formal) then
5149                   Found := True;
5150                   Chain (Actual);
5151                   Actuals_To_Match := Actuals_To_Match - 1;
5152                   Formals_To_Match := Formals_To_Match - 1;
5153                   exit;
5154                end if;
5155
5156                Next (Actual);
5157             end loop;
5158
5159             if not Found then
5160                if Ekind (Formal) /= E_In_Parameter
5161                  or else No (Default_Value (Formal))
5162                then
5163                   if Reporting then
5164                      if (Comes_From_Source (S)
5165                           or else Sloc (S) = Standard_Location)
5166                        and then Is_Overloadable (S)
5167                      then
5168                         if No (Actuals)
5169                           and then
5170                            (Nkind (Parent (N)) = N_Procedure_Call_Statement
5171                              or else
5172                            (Nkind (Parent (N)) = N_Function_Call
5173                              or else
5174                             Nkind (Parent (N)) = N_Parameter_Association))
5175                           and then Ekind (S) /= E_Function
5176                         then
5177                            Set_Etype (N, Etype (S));
5178                         else
5179                            Error_Msg_Name_1 := Chars (S);
5180                            Error_Msg_Sloc := Sloc (S);
5181                            Error_Msg_NE
5182                              ("missing argument for parameter & " &
5183                                 "in call to % declared #", N, Formal);
5184                         end if;
5185
5186                      elsif Is_Overloadable (S) then
5187                         Error_Msg_Name_1 := Chars (S);
5188
5189                         --  Point to type derivation that generated the
5190                         --  operation.
5191
5192                         Error_Msg_Sloc := Sloc (Parent (S));
5193
5194                         Error_Msg_NE
5195                           ("missing argument for parameter & " &
5196                              "in call to % (inherited) #", N, Formal);
5197
5198                      else
5199                         Error_Msg_NE
5200                           ("missing argument for parameter &", N, Formal);
5201                      end if;
5202                   end if;
5203
5204                   Success := False;
5205                   return;
5206
5207                else
5208                   Formals_To_Match := Formals_To_Match - 1;
5209                end if;
5210             end if;
5211          end if;
5212
5213          Next_Formal (Formal);
5214       end loop;
5215
5216       if  Formals_To_Match = 0 and then Actuals_To_Match = 0 then
5217          Success := True;
5218          return;
5219
5220       else
5221          if Reporting then
5222
5223             --  Find some superfluous named actual that did not get
5224             --  attached to the list of associations.
5225
5226             Actual := First (Actuals);
5227
5228             while Present (Actual) loop
5229                if Nkind (Actual) = N_Parameter_Association
5230                  and then Actual /= Last
5231                  and then No (Next_Named_Actual (Actual))
5232                then
5233                   Error_Msg_N ("unmatched actual & in call",
5234                     Selector_Name (Actual));
5235                   exit;
5236                end if;
5237
5238                Next (Actual);
5239             end loop;
5240          end if;
5241
5242          Success := False;
5243          return;
5244       end if;
5245    end Normalize_Actuals;
5246
5247    --------------------------------
5248    -- Note_Possible_Modification --
5249    --------------------------------
5250
5251    procedure Note_Possible_Modification (N : Node_Id) is
5252       Modification_Comes_From_Source : constant Boolean :=
5253                                          Comes_From_Source (Parent (N));
5254
5255       Ent : Entity_Id;
5256       Exp : Node_Id;
5257
5258    begin
5259       --  Loop to find referenced entity, if there is one
5260
5261       Exp := N;
5262       loop
5263          <<Continue>>
5264          Ent := Empty;
5265
5266          if Is_Entity_Name (Exp) then
5267             Ent := Entity (Exp);
5268
5269          elsif Nkind (Exp) = N_Explicit_Dereference then
5270             declare
5271                P : constant Node_Id := Prefix (Exp);
5272
5273             begin
5274                if Nkind (P) = N_Selected_Component
5275                  and then Present (
5276                    Entry_Formal (Entity (Selector_Name (P))))
5277                then
5278                   --  Case of a reference to an entry formal
5279
5280                   Ent := Entry_Formal (Entity (Selector_Name (P)));
5281
5282                elsif Nkind (P) = N_Identifier
5283                  and then Nkind (Parent (Entity (P))) = N_Object_Declaration
5284                  and then Present (Expression (Parent (Entity (P))))
5285                  and then Nkind (Expression (Parent (Entity (P))))
5286                    = N_Reference
5287                then
5288                   --  Case of a reference to a value on which
5289                   --  side effects have been removed.
5290
5291                   Exp := Prefix (Expression (Parent (Entity (P))));
5292
5293                else
5294                   return;
5295
5296                end if;
5297             end;
5298
5299          elsif     Nkind (Exp) = N_Type_Conversion
5300            or else Nkind (Exp) = N_Unchecked_Type_Conversion
5301          then
5302             Exp := Expression (Exp);
5303
5304          elsif     Nkind (Exp) = N_Slice
5305            or else Nkind (Exp) = N_Indexed_Component
5306            or else Nkind (Exp) = N_Selected_Component
5307          then
5308             Exp := Prefix (Exp);
5309
5310          else
5311             return;
5312
5313          end if;
5314
5315          --  Now look for entity being referenced
5316
5317          if Present (Ent) then
5318
5319             if Is_Object (Ent) then
5320                if Comes_From_Source (Exp)
5321                  or else Modification_Comes_From_Source
5322                then
5323                   Set_Never_Set_In_Source (Ent, False);
5324                end if;
5325
5326                Set_Is_True_Constant    (Ent, False);
5327                Set_Current_Value       (Ent, Empty);
5328
5329                if not Can_Never_Be_Null (Ent) then
5330                   Set_Is_Known_Non_Null (Ent, False);
5331                end if;
5332
5333                if (Ekind (Ent) = E_Variable or else Ekind (Ent) = E_Constant)
5334                  and then Present (Renamed_Object (Ent))
5335                then
5336                   Exp := Renamed_Object (Ent);
5337                   goto Continue;
5338                end if;
5339
5340                --  Generate a reference only if the assignment comes from
5341                --  source. This excludes, for example, calls to a dispatching
5342                --  assignment operation when the left-hand side is tagged.
5343
5344                if Modification_Comes_From_Source then
5345                   Generate_Reference (Ent, Exp, 'm');
5346                end if;
5347             end if;
5348
5349             Kill_Checks (Ent);
5350             return;
5351          end if;
5352       end loop;
5353    end Note_Possible_Modification;
5354
5355    -------------------------
5356    -- Object_Access_Level --
5357    -------------------------
5358
5359    function Object_Access_Level (Obj : Node_Id) return Uint is
5360       E : Entity_Id;
5361
5362    --  Returns the static accessibility level of the view denoted
5363    --  by Obj.  Note that the value returned is the result of a
5364    --  call to Scope_Depth.  Only scope depths associated with
5365    --  dynamic scopes can actually be returned.  Since only
5366    --  relative levels matter for accessibility checking, the fact
5367    --  that the distance between successive levels of accessibility
5368    --  is not always one is immaterial (invariant: if level(E2) is
5369    --  deeper than level(E1), then Scope_Depth(E1) < Scope_Depth(E2)).
5370
5371    begin
5372       if Is_Entity_Name (Obj) then
5373          E := Entity (Obj);
5374
5375          --  If E is a type then it denotes a current instance.
5376          --  For this case we add one to the normal accessibility
5377          --  level of the type to ensure that current instances
5378          --  are treated as always being deeper than than the level
5379          --  of any visible named access type (see 3.10.2(21)).
5380
5381          if Is_Type (E) then
5382             return Type_Access_Level (E) +  1;
5383
5384          elsif Present (Renamed_Object (E)) then
5385             return Object_Access_Level (Renamed_Object (E));
5386
5387          --  Similarly, if E is a component of the current instance of a
5388          --  protected type, any instance of it is assumed to be at a deeper
5389          --  level than the type. For a protected object (whose type is an
5390          --  anonymous protected type) its components are at the same level
5391          --  as the type itself.
5392
5393          elsif not Is_Overloadable (E)
5394            and then Ekind (Scope (E)) = E_Protected_Type
5395            and then Comes_From_Source (Scope (E))
5396          then
5397             return Type_Access_Level (Scope (E)) + 1;
5398
5399          else
5400             return Scope_Depth (Enclosing_Dynamic_Scope (E));
5401          end if;
5402
5403       elsif Nkind (Obj) = N_Selected_Component then
5404          if Is_Access_Type (Etype (Prefix (Obj))) then
5405             return Type_Access_Level (Etype (Prefix (Obj)));
5406          else
5407             return Object_Access_Level (Prefix (Obj));
5408          end if;
5409
5410       elsif Nkind (Obj) = N_Indexed_Component then
5411          if Is_Access_Type (Etype (Prefix (Obj))) then
5412             return Type_Access_Level (Etype (Prefix (Obj)));
5413          else
5414             return Object_Access_Level (Prefix (Obj));
5415          end if;
5416
5417       elsif Nkind (Obj) = N_Explicit_Dereference then
5418
5419          --  If the prefix is a selected access discriminant then
5420          --  we make a recursive call on the prefix, which will
5421          --  in turn check the level of the prefix object of
5422          --  the selected discriminant.
5423
5424          if Nkind (Prefix (Obj)) = N_Selected_Component
5425            and then Ekind (Etype (Prefix (Obj))) = E_Anonymous_Access_Type
5426            and then
5427              Ekind (Entity (Selector_Name (Prefix (Obj)))) = E_Discriminant
5428          then
5429             return Object_Access_Level (Prefix (Obj));
5430          else
5431             return Type_Access_Level (Etype (Prefix (Obj)));
5432          end if;
5433
5434       elsif Nkind (Obj) = N_Type_Conversion
5435         or else Nkind (Obj) = N_Unchecked_Type_Conversion
5436       then
5437          return Object_Access_Level (Expression (Obj));
5438
5439       --  Function results are objects, so we get either the access level
5440       --  of the function or, in the case of an indirect call, the level of
5441       --  of the access-to-subprogram type.
5442
5443       elsif Nkind (Obj) = N_Function_Call then
5444          if Is_Entity_Name (Name (Obj)) then
5445             return Subprogram_Access_Level (Entity (Name (Obj)));
5446          else
5447             return Type_Access_Level (Etype (Prefix (Name (Obj))));
5448          end if;
5449
5450       --  For convenience we handle qualified expressions, even though
5451       --  they aren't technically object names.
5452
5453       elsif Nkind (Obj) = N_Qualified_Expression then
5454          return Object_Access_Level (Expression (Obj));
5455
5456       --  Otherwise return the scope level of Standard.
5457       --  (If there are cases that fall through
5458       --  to this point they will be treated as
5459       --  having global accessibility for now. ???)
5460
5461       else
5462          return Scope_Depth (Standard_Standard);
5463       end if;
5464    end Object_Access_Level;
5465
5466    -----------------------
5467    -- Private_Component --
5468    -----------------------
5469
5470    function Private_Component (Type_Id : Entity_Id) return Entity_Id is
5471       Ancestor  : constant Entity_Id := Base_Type (Type_Id);
5472
5473       function Trace_Components
5474         (T     : Entity_Id;
5475          Check : Boolean) return Entity_Id;
5476       --  Recursive function that does the work, and checks against circular
5477       --  definition for each subcomponent type.
5478
5479       ----------------------
5480       -- Trace_Components --
5481       ----------------------
5482
5483       function Trace_Components
5484          (T     : Entity_Id;
5485           Check : Boolean) return Entity_Id
5486        is
5487          Btype     : constant Entity_Id := Base_Type (T);
5488          Component : Entity_Id;
5489          P         : Entity_Id;
5490          Candidate : Entity_Id := Empty;
5491
5492       begin
5493          if Check and then Btype = Ancestor then
5494             Error_Msg_N ("circular type definition", Type_Id);
5495             return Any_Type;
5496          end if;
5497
5498          if Is_Private_Type (Btype)
5499            and then not Is_Generic_Type (Btype)
5500          then
5501             if Present (Full_View (Btype))
5502               and then Is_Record_Type (Full_View (Btype))
5503               and then not Is_Frozen (Btype)
5504             then
5505                --  To indicate that the ancestor depends on a private type,
5506                --  the current Btype is sufficient. However, to check for
5507                --  circular definition we must recurse on the full view.
5508
5509                Candidate := Trace_Components (Full_View (Btype), True);
5510
5511                if Candidate = Any_Type then
5512                   return Any_Type;
5513                else
5514                   return Btype;
5515                end if;
5516
5517             else
5518                return Btype;
5519             end if;
5520
5521          elsif Is_Array_Type (Btype) then
5522             return Trace_Components (Component_Type (Btype), True);
5523
5524          elsif Is_Record_Type (Btype) then
5525             Component := First_Entity (Btype);
5526             while Present (Component) loop
5527
5528                --  Skip anonymous types generated by constrained components
5529
5530                if not Is_Type (Component) then
5531                   P := Trace_Components (Etype (Component), True);
5532
5533                   if Present (P) then
5534                      if P = Any_Type then
5535                         return P;
5536                      else
5537                         Candidate := P;
5538                      end if;
5539                   end if;
5540                end if;
5541
5542                Next_Entity (Component);
5543             end loop;
5544
5545             return Candidate;
5546
5547          else
5548             return Empty;
5549          end if;
5550       end Trace_Components;
5551
5552    --  Start of processing for Private_Component
5553
5554    begin
5555       return Trace_Components (Type_Id, False);
5556    end Private_Component;
5557
5558    -----------------------
5559    -- Process_End_Label --
5560    -----------------------
5561
5562    procedure Process_End_Label
5563      (N   : Node_Id;
5564       Typ : Character;
5565       Ent  : Entity_Id)
5566    is
5567       Loc  : Source_Ptr;
5568       Nam  : Node_Id;
5569
5570       Label_Ref : Boolean;
5571       --  Set True if reference to end label itself is required
5572
5573       Endl : Node_Id;
5574       --  Gets set to the operator symbol or identifier that references
5575       --  the entity Ent. For the child unit case, this is the identifier
5576       --  from the designator. For other cases, this is simply Endl.
5577
5578       procedure Generate_Parent_Ref (N : Node_Id);
5579       --  N is an identifier node that appears as a parent unit reference
5580       --  in the case where Ent is a child unit. This procedure generates
5581       --  an appropriate cross-reference entry.
5582
5583       -------------------------
5584       -- Generate_Parent_Ref --
5585       -------------------------
5586
5587       procedure Generate_Parent_Ref (N : Node_Id) is
5588          Parent_Ent : Entity_Id;
5589
5590       begin
5591          --  Search up scope stack. The reason we do this is that normal
5592          --  visibility analysis would not work for two reasons. First in
5593          --  some subunit cases, the entry for the parent unit may not be
5594          --  visible, and in any case there can be a local entity that
5595          --  hides the scope entity.
5596
5597          Parent_Ent := Current_Scope;
5598          while Present (Parent_Ent) loop
5599             if Chars (Parent_Ent) = Chars (N) then
5600
5601                --  Generate the reference. We do NOT consider this as a
5602                --  reference for unreferenced symbol purposes, but we do
5603                --  force a cross-reference even if the end line does not
5604                --  come from source (the caller already generated the
5605                --  appropriate Typ for this situation).
5606
5607                Generate_Reference
5608                  (Parent_Ent, N, 'r', Set_Ref => False, Force => True);
5609                Style.Check_Identifier (N, Parent_Ent);
5610                return;
5611             end if;
5612
5613             Parent_Ent := Scope (Parent_Ent);
5614          end loop;
5615
5616          --  Fall through means entity was not found -- that's odd, but
5617          --  the appropriate thing is simply to ignore and not generate
5618          --  any cross-reference for this entry.
5619
5620          return;
5621       end Generate_Parent_Ref;
5622
5623    --  Start of processing for Process_End_Label
5624
5625    begin
5626       --  If no node, ignore. This happens in some error situations,
5627       --  and also for some internally generated structures where no
5628       --  end label references are required in any case.
5629
5630       if No (N) then
5631          return;
5632       end if;
5633
5634       --  Nothing to do if no End_Label, happens for internally generated
5635       --  constructs where we don't want an end label reference anyway.
5636       --  Also nothing to do if Endl is a string literal, which means
5637       --  there was some prior error (bad operator symbol)
5638
5639       Endl := End_Label (N);
5640
5641       if No (Endl) or else Nkind (Endl) = N_String_Literal then
5642          return;
5643       end if;
5644
5645       --  Reference node is not in extended main source unit
5646
5647       if not In_Extended_Main_Source_Unit (N) then
5648
5649          --  Generally we do not collect references except for the
5650          --  extended main source unit. The one exception is the 'e'
5651          --  entry for a package spec, where it is useful for a client
5652          --  to have the ending information to define scopes.
5653
5654          if Typ /= 'e' then
5655             return;
5656
5657          else
5658             Label_Ref := False;
5659
5660             --  For this case, we can ignore any parent references,
5661             --  but we need the package name itself for the 'e' entry.
5662
5663             if Nkind (Endl) = N_Designator then
5664                Endl := Identifier (Endl);
5665             end if;
5666          end if;
5667
5668       --  Reference is in extended main source unit
5669
5670       else
5671          Label_Ref := True;
5672
5673          --  For designator, generate references for the parent entries
5674
5675          if Nkind (Endl) = N_Designator then
5676
5677             --  Generate references for the prefix if the END line comes
5678             --  from source (otherwise we do not need these references)
5679
5680             if Comes_From_Source (Endl) then
5681                Nam := Name (Endl);
5682                while Nkind (Nam) = N_Selected_Component loop
5683                   Generate_Parent_Ref (Selector_Name (Nam));
5684                   Nam := Prefix (Nam);
5685                end loop;
5686
5687                Generate_Parent_Ref (Nam);
5688             end if;
5689
5690             Endl := Identifier (Endl);
5691          end if;
5692       end if;
5693
5694       --  If the end label is not for the given entity, then either we have
5695       --  some previous error, or this is a generic instantiation for which
5696       --  we do not need to make a cross-reference in this case anyway. In
5697       --  either case we simply ignore the call.
5698
5699       if Chars (Ent) /= Chars (Endl) then
5700          return;
5701       end if;
5702
5703       --  If label was really there, then generate a normal reference
5704       --  and then adjust the location in the end label to point past
5705       --  the name (which should almost always be the semicolon).
5706
5707       Loc := Sloc (Endl);
5708
5709       if Comes_From_Source (Endl) then
5710
5711          --  If a label reference is required, then do the style check
5712          --  and generate an l-type cross-reference entry for the label
5713
5714          if Label_Ref then
5715             if Style_Check then
5716                Style.Check_Identifier (Endl, Ent);
5717             end if;
5718             Generate_Reference (Ent, Endl, 'l', Set_Ref => False);
5719          end if;
5720
5721          --  Set the location to point past the label (normally this will
5722          --  mean the semicolon immediately following the label). This is
5723          --  done for the sake of the 'e' or 't' entry generated below.
5724
5725          Get_Decoded_Name_String (Chars (Endl));
5726          Set_Sloc (Endl, Sloc (Endl) + Source_Ptr (Name_Len));
5727       end if;
5728
5729       --  Now generate the e/t reference
5730
5731       Generate_Reference (Ent, Endl, Typ, Set_Ref => False, Force => True);
5732
5733       --  Restore Sloc, in case modified above, since we have an identifier
5734       --  and the normal Sloc should be left set in the tree.
5735
5736       Set_Sloc (Endl, Loc);
5737    end Process_End_Label;
5738
5739    ------------------
5740    -- Real_Convert --
5741    ------------------
5742
5743    --  We do the conversion to get the value of the real string by using
5744    --  the scanner, see Sinput for details on use of the internal source
5745    --  buffer for scanning internal strings.
5746
5747    function Real_Convert (S : String) return Node_Id is
5748       Save_Src : constant Source_Buffer_Ptr := Source;
5749       Negative : Boolean;
5750
5751    begin
5752       Source := Internal_Source_Ptr;
5753       Scan_Ptr := 1;
5754
5755       for J in S'Range loop
5756          Source (Source_Ptr (J)) := S (J);
5757       end loop;
5758
5759       Source (S'Length + 1) := EOF;
5760
5761       if Source (Scan_Ptr) = '-' then
5762          Negative := True;
5763          Scan_Ptr := Scan_Ptr + 1;
5764       else
5765          Negative := False;
5766       end if;
5767
5768       Scan;
5769
5770       if Negative then
5771          Set_Realval (Token_Node, UR_Negate (Realval (Token_Node)));
5772       end if;
5773
5774       Source := Save_Src;
5775       return Token_Node;
5776    end Real_Convert;
5777
5778    ---------------------
5779    -- Rep_To_Pos_Flag --
5780    ---------------------
5781
5782    function Rep_To_Pos_Flag (E : Entity_Id; Loc : Source_Ptr) return Node_Id is
5783    begin
5784       return New_Occurrence_Of
5785                (Boolean_Literals (not Range_Checks_Suppressed (E)), Loc);
5786    end Rep_To_Pos_Flag;
5787
5788    --------------------
5789    -- Require_Entity --
5790    --------------------
5791
5792    procedure Require_Entity (N : Node_Id) is
5793    begin
5794       if Is_Entity_Name (N) and then No (Entity (N)) then
5795          if Total_Errors_Detected /= 0 then
5796             Set_Entity (N, Any_Id);
5797          else
5798             raise Program_Error;
5799          end if;
5800       end if;
5801    end Require_Entity;
5802
5803    ------------------------------
5804    -- Requires_Transient_Scope --
5805    ------------------------------
5806
5807    --  A transient scope is required when variable-sized temporaries are
5808    --  allocated in the primary or secondary stack, or when finalization
5809    --  actions must be generated before the next instruction.
5810
5811    function Requires_Transient_Scope (Id : Entity_Id) return Boolean is
5812       Typ : constant Entity_Id := Underlying_Type (Id);
5813
5814    --  Start of processing for Requires_Transient_Scope
5815
5816    begin
5817       --  This is a private type which is not completed yet. This can only
5818       --  happen in a default expression (of a formal parameter or of a
5819       --  record component). Do not expand transient scope in this case
5820
5821       if No (Typ) then
5822          return False;
5823
5824       --  Do not expand transient scope for non-existent procedure return
5825
5826       elsif Typ = Standard_Void_Type then
5827          return False;
5828
5829       --  Elementary types do not require a transient scope
5830
5831       elsif Is_Elementary_Type (Typ) then
5832          return False;
5833
5834       --  Generally, indefinite subtypes require a transient scope, since the
5835       --  back end cannot generate temporaries, since this is not a valid type
5836       --  for declaring an object. It might be possible to relax this in the
5837       --  future, e.g. by declaring the maximum possible space for the type.
5838
5839       elsif Is_Indefinite_Subtype (Typ) then
5840          return True;
5841
5842       --  Functions returning tagged types may dispatch on result so their
5843       --  returned value is allocated on the secondary stack. Controlled
5844       --  type temporaries need finalization.
5845
5846       elsif Is_Tagged_Type (Typ)
5847         or else Has_Controlled_Component (Typ)
5848       then
5849          return True;
5850
5851       --  Record type
5852
5853       elsif Is_Record_Type (Typ) then
5854
5855          --  In GCC 2, discriminated records always require a transient
5856          --  scope because the back end otherwise tries to allocate a
5857          --  variable length temporary for the particular variant.
5858
5859          if Opt.GCC_Version = 2
5860            and then Has_Discriminants (Typ)
5861          then
5862             return True;
5863
5864          --  For GCC 3, or for a non-discriminated record in GCC 2, we are
5865          --  OK if none of the component types requires a transient scope.
5866          --  Note that we already know that this is a definite type (i.e.
5867          --  has discriminant defaults if it is a discriminated record).
5868
5869          else
5870             declare
5871                Comp : Entity_Id;
5872             begin
5873                Comp := First_Entity (Typ);
5874                while Present (Comp) loop
5875                   if Requires_Transient_Scope (Etype (Comp)) then
5876                      return True;
5877                   else
5878                      Next_Entity (Comp);
5879                   end if;
5880                end loop;
5881             end;
5882
5883             return False;
5884          end if;
5885
5886       --  String literal types never require transient scope
5887
5888       elsif Ekind (Typ) = E_String_Literal_Subtype then
5889          return False;
5890
5891       --  Array type. Note that we already know that this is a constrained
5892       --  array, since unconstrained arrays will fail the indefinite test.
5893
5894       elsif Is_Array_Type (Typ) then
5895
5896          --  If component type requires a transient scope, the array does too
5897
5898          if Requires_Transient_Scope (Component_Type (Typ)) then
5899             return True;
5900
5901          --  Otherwise, we only need a transient scope if the size is not
5902          --  known at compile time.
5903
5904          else
5905             return not Size_Known_At_Compile_Time (Typ);
5906          end if;
5907
5908       --  All other cases do not require a transient scope
5909
5910       else
5911          return False;
5912       end if;
5913    end Requires_Transient_Scope;
5914
5915    --------------------------
5916    -- Reset_Analyzed_Flags --
5917    --------------------------
5918
5919    procedure Reset_Analyzed_Flags (N : Node_Id) is
5920
5921       function Clear_Analyzed
5922         (N : Node_Id) return Traverse_Result;
5923       --  Function used to reset Analyzed flags in tree. Note that we do
5924       --  not reset Analyzed flags in entities, since there is no need to
5925       --  renalalyze entities, and indeed, it is wrong to do so, since it
5926       --  can result in generating auxiliary stuff more than once.
5927
5928       --------------------
5929       -- Clear_Analyzed --
5930       --------------------
5931
5932       function Clear_Analyzed
5933         (N : Node_Id) return Traverse_Result
5934       is
5935       begin
5936          if not Has_Extension (N) then
5937             Set_Analyzed (N, False);
5938          end if;
5939
5940          return OK;
5941       end Clear_Analyzed;
5942
5943       function Reset_Analyzed is
5944         new Traverse_Func (Clear_Analyzed);
5945
5946       Discard : Traverse_Result;
5947       pragma Warnings (Off, Discard);
5948
5949    --  Start of processing for Reset_Analyzed_Flags
5950
5951    begin
5952       Discard := Reset_Analyzed (N);
5953    end Reset_Analyzed_Flags;
5954
5955    ---------------------------
5956    -- Safe_To_Capture_Value --
5957    ---------------------------
5958
5959    function Safe_To_Capture_Value
5960      (N   : Node_Id;
5961       Ent : Entity_Id) return Boolean
5962    is
5963    begin
5964       --  The only entities for which we track constant values are variables,
5965       --  out parameters and in out parameters, so check if we have this case.
5966
5967       if Ekind (Ent) /= E_Variable
5968            and then
5969          Ekind (Ent) /= E_Out_Parameter
5970            and then
5971          Ekind (Ent) /= E_In_Out_Parameter
5972       then
5973          return False;
5974       end if;
5975
5976       --  Skip volatile and aliased variables, since funny things might
5977       --  be going on in these cases which we cannot necessarily track.
5978
5979       if Treat_As_Volatile (Ent) or else Is_Aliased (Ent) then
5980          return False;
5981       end if;
5982
5983       --  OK, all above conditions are met. We also require that the scope
5984       --  of the reference be the same as the scope of the entity, not
5985       --  counting packages and blocks.
5986
5987       declare
5988          E_Scope : constant Entity_Id := Scope (Ent);
5989          R_Scope : Entity_Id;
5990
5991       begin
5992          R_Scope := Current_Scope;
5993          while R_Scope /= Standard_Standard loop
5994             exit when R_Scope = E_Scope;
5995
5996             if Ekind (R_Scope) /= E_Package
5997                  and then
5998                Ekind (R_Scope) /= E_Block
5999             then
6000                return False;
6001             else
6002                R_Scope := Scope (R_Scope);
6003             end if;
6004          end loop;
6005       end;
6006
6007       --  We also require that the reference does not appear in a context
6008       --  where it is not sure to be executed (i.e. a conditional context
6009       --  or an exception handler).
6010
6011       declare
6012          P : Node_Id;
6013
6014       begin
6015          P := Parent (N);
6016          while Present (P) loop
6017             if Nkind (P) = N_If_Statement
6018                  or else
6019                Nkind (P) = N_Case_Statement
6020                  or else
6021                Nkind (P) = N_Exception_Handler
6022                  or else
6023                Nkind (P) = N_Selective_Accept
6024                  or else
6025                Nkind (P) = N_Conditional_Entry_Call
6026                  or else
6027                Nkind (P) = N_Timed_Entry_Call
6028                  or else
6029                Nkind (P) = N_Asynchronous_Select
6030             then
6031                return False;
6032             else
6033                P := Parent (P);
6034             end if;
6035          end loop;
6036       end;
6037
6038       --  OK, looks safe to set value
6039
6040       return True;
6041    end Safe_To_Capture_Value;
6042
6043    ---------------
6044    -- Same_Name --
6045    ---------------
6046
6047    function Same_Name (N1, N2 : Node_Id) return Boolean is
6048       K1 : constant Node_Kind := Nkind (N1);
6049       K2 : constant Node_Kind := Nkind (N2);
6050
6051    begin
6052       if (K1 = N_Identifier or else K1 = N_Defining_Identifier)
6053         and then (K2 = N_Identifier or else K2 = N_Defining_Identifier)
6054       then
6055          return Chars (N1) = Chars (N2);
6056
6057       elsif (K1 = N_Selected_Component or else K1 = N_Expanded_Name)
6058         and then (K2 = N_Selected_Component or else K2 = N_Expanded_Name)
6059       then
6060          return Same_Name (Selector_Name (N1), Selector_Name (N2))
6061            and then Same_Name (Prefix (N1), Prefix (N2));
6062
6063       else
6064          return False;
6065       end if;
6066    end Same_Name;
6067
6068    ---------------
6069    -- Same_Type --
6070    ---------------
6071
6072    function Same_Type (T1, T2 : Entity_Id) return Boolean is
6073    begin
6074       if T1 = T2 then
6075          return True;
6076
6077       elsif not Is_Constrained (T1)
6078         and then not Is_Constrained (T2)
6079         and then Base_Type (T1) = Base_Type (T2)
6080       then
6081          return True;
6082
6083       --  For now don't bother with case of identical constraints, to be
6084       --  fiddled with later on perhaps (this is only used for optimization
6085       --  purposes, so it is not critical to do a best possible job)
6086
6087       else
6088          return False;
6089       end if;
6090    end Same_Type;
6091
6092    ------------------------
6093    -- Scope_Is_Transient --
6094    ------------------------
6095
6096    function Scope_Is_Transient  return Boolean is
6097    begin
6098       return Scope_Stack.Table (Scope_Stack.Last).Is_Transient;
6099    end Scope_Is_Transient;
6100
6101    ------------------
6102    -- Scope_Within --
6103    ------------------
6104
6105    function Scope_Within (Scope1, Scope2 : Entity_Id) return Boolean is
6106       Scop : Entity_Id;
6107
6108    begin
6109       Scop := Scope1;
6110       while Scop /= Standard_Standard loop
6111          Scop := Scope (Scop);
6112
6113          if Scop = Scope2 then
6114             return True;
6115          end if;
6116       end loop;
6117
6118       return False;
6119    end Scope_Within;
6120
6121    --------------------------
6122    -- Scope_Within_Or_Same --
6123    --------------------------
6124
6125    function Scope_Within_Or_Same (Scope1, Scope2 : Entity_Id) return Boolean is
6126       Scop : Entity_Id;
6127
6128    begin
6129       Scop := Scope1;
6130       while Scop /= Standard_Standard loop
6131          if Scop = Scope2 then
6132             return True;
6133          else
6134             Scop := Scope (Scop);
6135          end if;
6136       end loop;
6137
6138       return False;
6139    end Scope_Within_Or_Same;
6140
6141    ------------------------
6142    -- Set_Current_Entity --
6143    ------------------------
6144
6145    --  The given entity is to be set as the currently visible definition
6146    --  of its associated name (i.e. the Node_Id associated with its name).
6147    --  All we have to do is to get the name from the identifier, and
6148    --  then set the associated Node_Id to point to the given entity.
6149
6150    procedure Set_Current_Entity (E : Entity_Id) is
6151    begin
6152       Set_Name_Entity_Id (Chars (E), E);
6153    end Set_Current_Entity;
6154
6155    ---------------------------------
6156    -- Set_Entity_With_Style_Check --
6157    ---------------------------------
6158
6159    procedure Set_Entity_With_Style_Check (N : Node_Id; Val : Entity_Id) is
6160       Val_Actual : Entity_Id;
6161       Nod        : Node_Id;
6162
6163    begin
6164       Set_Entity (N, Val);
6165
6166       if Style_Check
6167         and then not Suppress_Style_Checks (Val)
6168         and then not In_Instance
6169       then
6170          if Nkind (N) = N_Identifier then
6171             Nod := N;
6172
6173          elsif Nkind (N) = N_Expanded_Name then
6174             Nod := Selector_Name (N);
6175
6176          else
6177             return;
6178          end if;
6179
6180          Val_Actual := Val;
6181
6182          --  A special situation arises for derived operations, where we want
6183          --  to do the check against the parent (since the Sloc of the derived
6184          --  operation points to the derived type declaration itself).
6185
6186          while not Comes_From_Source (Val_Actual)
6187            and then Nkind (Val_Actual) in N_Entity
6188            and then (Ekind (Val_Actual) = E_Enumeration_Literal
6189                       or else Is_Subprogram (Val_Actual)
6190                       or else Is_Generic_Subprogram (Val_Actual))
6191            and then Present (Alias (Val_Actual))
6192          loop
6193             Val_Actual := Alias (Val_Actual);
6194          end loop;
6195
6196          --  Renaming declarations for generic actuals do not come from source,
6197          --  and have a different name from that of the entity they rename, so
6198          --  there is no style check to perform here.
6199
6200          if Chars (Nod) = Chars (Val_Actual) then
6201             Style.Check_Identifier (Nod, Val_Actual);
6202          end if;
6203       end if;
6204
6205       Set_Entity (N, Val);
6206    end Set_Entity_With_Style_Check;
6207
6208    ------------------------
6209    -- Set_Name_Entity_Id --
6210    ------------------------
6211
6212    procedure Set_Name_Entity_Id (Id : Name_Id; Val : Entity_Id) is
6213    begin
6214       Set_Name_Table_Info (Id, Int (Val));
6215    end Set_Name_Entity_Id;
6216
6217    ---------------------
6218    -- Set_Next_Actual --
6219    ---------------------
6220
6221    procedure Set_Next_Actual (Ass1_Id : Node_Id; Ass2_Id : Node_Id) is
6222    begin
6223       if Nkind (Parent (Ass1_Id)) = N_Parameter_Association then
6224          Set_First_Named_Actual (Parent (Ass1_Id), Ass2_Id);
6225       end if;
6226    end Set_Next_Actual;
6227
6228    -----------------------
6229    -- Set_Public_Status --
6230    -----------------------
6231
6232    procedure Set_Public_Status (Id : Entity_Id) is
6233       S : constant Entity_Id := Current_Scope;
6234
6235    begin
6236       if S = Standard_Standard
6237         or else (Is_Public (S)
6238                   and then (Ekind (S) = E_Package
6239                              or else Is_Record_Type (S)
6240                              or else Ekind (S) = E_Void))
6241       then
6242          Set_Is_Public (Id);
6243
6244       --  The bounds of an entry family declaration can generate object
6245       --  declarations that are visible to the back-end, e.g. in the
6246       --  the declaration of a composite type that contains tasks.
6247
6248       elsif Is_Public (S)
6249         and then Is_Concurrent_Type (S)
6250         and then not Has_Completion (S)
6251         and then Nkind (Parent (Id)) = N_Object_Declaration
6252       then
6253          Set_Is_Public (Id);
6254       end if;
6255    end Set_Public_Status;
6256
6257    ----------------------------
6258    -- Set_Scope_Is_Transient --
6259    ----------------------------
6260
6261    procedure Set_Scope_Is_Transient (V : Boolean := True) is
6262    begin
6263       Scope_Stack.Table (Scope_Stack.Last).Is_Transient := V;
6264    end Set_Scope_Is_Transient;
6265
6266    -------------------
6267    -- Set_Size_Info --
6268    -------------------
6269
6270    procedure Set_Size_Info (T1, T2 : Entity_Id) is
6271    begin
6272       --  We copy Esize, but not RM_Size, since in general RM_Size is
6273       --  subtype specific and does not get inherited by all subtypes.
6274
6275       Set_Esize                     (T1, Esize                     (T2));
6276       Set_Has_Biased_Representation (T1, Has_Biased_Representation (T2));
6277
6278       if Is_Discrete_Or_Fixed_Point_Type (T1)
6279            and then
6280          Is_Discrete_Or_Fixed_Point_Type (T2)
6281       then
6282          Set_Is_Unsigned_Type       (T1, Is_Unsigned_Type          (T2));
6283       end if;
6284       Set_Alignment                 (T1, Alignment                 (T2));
6285    end Set_Size_Info;
6286
6287    --------------------
6288    -- Static_Integer --
6289    --------------------
6290
6291    function Static_Integer (N : Node_Id) return Uint is
6292    begin
6293       Analyze_And_Resolve (N, Any_Integer);
6294
6295       if N = Error
6296         or else Error_Posted (N)
6297         or else Etype (N) = Any_Type
6298       then
6299          return No_Uint;
6300       end if;
6301
6302       if Is_Static_Expression (N) then
6303          if not Raises_Constraint_Error (N) then
6304             return Expr_Value (N);
6305          else
6306             return No_Uint;
6307          end if;
6308
6309       elsif Etype (N) = Any_Type then
6310          return No_Uint;
6311
6312       else
6313          Flag_Non_Static_Expr
6314            ("static integer expression required here", N);
6315          return No_Uint;
6316       end if;
6317    end Static_Integer;
6318
6319    --------------------------
6320    -- Statically_Different --
6321    --------------------------
6322
6323    function Statically_Different (E1, E2 : Node_Id) return Boolean is
6324       R1 : constant Node_Id := Get_Referenced_Object (E1);
6325       R2 : constant Node_Id := Get_Referenced_Object (E2);
6326
6327    begin
6328       return     Is_Entity_Name (R1)
6329         and then Is_Entity_Name (R2)
6330         and then Entity (R1) /= Entity (R2)
6331         and then not Is_Formal (Entity (R1))
6332         and then not Is_Formal (Entity (R2));
6333    end Statically_Different;
6334
6335    -----------------------------
6336    -- Subprogram_Access_Level --
6337    -----------------------------
6338
6339    function Subprogram_Access_Level (Subp : Entity_Id) return Uint is
6340    begin
6341       if Present (Alias (Subp)) then
6342          return Subprogram_Access_Level (Alias (Subp));
6343       else
6344          return Scope_Depth (Enclosing_Dynamic_Scope (Subp));
6345       end if;
6346    end Subprogram_Access_Level;
6347
6348    -----------------
6349    -- Trace_Scope --
6350    -----------------
6351
6352    procedure Trace_Scope (N : Node_Id; E : Entity_Id; Msg : String) is
6353    begin
6354       if Debug_Flag_W then
6355          for J in 0 .. Scope_Stack.Last loop
6356             Write_Str ("  ");
6357          end loop;
6358
6359          Write_Str (Msg);
6360          Write_Name (Chars (E));
6361          Write_Str ("   line ");
6362          Write_Int (Int (Get_Logical_Line_Number (Sloc (N))));
6363          Write_Eol;
6364       end if;
6365    end Trace_Scope;
6366
6367    -----------------------
6368    -- Transfer_Entities --
6369    -----------------------
6370
6371    procedure Transfer_Entities (From : Entity_Id; To : Entity_Id) is
6372       Ent      : Entity_Id := First_Entity (From);
6373
6374    begin
6375       if No (Ent) then
6376          return;
6377       end if;
6378
6379       if (Last_Entity (To)) = Empty then
6380          Set_First_Entity (To, Ent);
6381       else
6382          Set_Next_Entity (Last_Entity (To), Ent);
6383       end if;
6384
6385       Set_Last_Entity (To, Last_Entity (From));
6386
6387       while Present (Ent) loop
6388          Set_Scope (Ent, To);
6389
6390          if not Is_Public (Ent) then
6391             Set_Public_Status (Ent);
6392
6393             if Is_Public (Ent)
6394               and then Ekind (Ent) = E_Record_Subtype
6395
6396             then
6397                --  The components of the propagated Itype must be public
6398                --  as well.
6399
6400                declare
6401                   Comp : Entity_Id;
6402
6403                begin
6404                   Comp := First_Entity (Ent);
6405
6406                   while Present (Comp) loop
6407                      Set_Is_Public (Comp);
6408                      Next_Entity (Comp);
6409                   end loop;
6410                end;
6411             end if;
6412          end if;
6413
6414          Next_Entity (Ent);
6415       end loop;
6416
6417       Set_First_Entity (From, Empty);
6418       Set_Last_Entity (From, Empty);
6419    end Transfer_Entities;
6420
6421    -----------------------
6422    -- Type_Access_Level --
6423    -----------------------
6424
6425    function Type_Access_Level (Typ : Entity_Id) return Uint is
6426       Btyp : Entity_Id;
6427
6428    begin
6429       --  If the type is an anonymous access type we treat it as being
6430       --  declared at the library level to ensure that names such as
6431       --  X.all'access don't fail static accessibility checks.
6432
6433       --  Ada 2005 (AI-230): In case of anonymous access types that are
6434       --  component_definition or discriminants of a nonlimited type,
6435       --  the level is the same as that of the enclosing component type.
6436
6437       Btyp := Base_Type (Typ);
6438       if Ekind (Btyp) in Access_Kind then
6439          if Ekind (Btyp) = E_Anonymous_Access_Type
6440            and then not Is_Array_Type (Scope (Btyp))      -- Ada 2005 (AI-230)
6441            and then Ekind (Scope (Btyp)) /= E_Record_Type -- Ada 2005 (AI-230)
6442          then
6443             return Scope_Depth (Standard_Standard);
6444          end if;
6445
6446          Btyp := Root_Type (Btyp);
6447       end if;
6448
6449       return Scope_Depth (Enclosing_Dynamic_Scope (Btyp));
6450    end Type_Access_Level;
6451
6452    --------------------------
6453    -- Unit_Declaration_Node --
6454    --------------------------
6455
6456    function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id is
6457       N : Node_Id := Parent (Unit_Id);
6458
6459    begin
6460       --  Predefined operators do not have a full function declaration
6461
6462       if Ekind (Unit_Id) = E_Operator then
6463          return N;
6464       end if;
6465
6466       while Nkind (N) /= N_Abstract_Subprogram_Declaration
6467         and then Nkind (N) /= N_Formal_Package_Declaration
6468         and then Nkind (N) /= N_Formal_Subprogram_Declaration
6469         and then Nkind (N) /= N_Function_Instantiation
6470         and then Nkind (N) /= N_Generic_Package_Declaration
6471         and then Nkind (N) /= N_Generic_Subprogram_Declaration
6472         and then Nkind (N) /= N_Package_Declaration
6473         and then Nkind (N) /= N_Package_Body
6474         and then Nkind (N) /= N_Package_Instantiation
6475         and then Nkind (N) /= N_Package_Renaming_Declaration
6476         and then Nkind (N) /= N_Procedure_Instantiation
6477         and then Nkind (N) /= N_Protected_Body
6478         and then Nkind (N) /= N_Subprogram_Declaration
6479         and then Nkind (N) /= N_Subprogram_Body
6480         and then Nkind (N) /= N_Subprogram_Body_Stub
6481         and then Nkind (N) /= N_Subprogram_Renaming_Declaration
6482         and then Nkind (N) /= N_Task_Body
6483         and then Nkind (N) /= N_Task_Type_Declaration
6484         and then Nkind (N) not in N_Generic_Renaming_Declaration
6485       loop
6486          N := Parent (N);
6487          pragma Assert (Present (N));
6488       end loop;
6489
6490       return N;
6491    end Unit_Declaration_Node;
6492
6493    ------------------------------
6494    -- Universal_Interpretation --
6495    ------------------------------
6496
6497    function Universal_Interpretation (Opnd : Node_Id) return Entity_Id is
6498       Index : Interp_Index;
6499       It    : Interp;
6500
6501    begin
6502       --  The argument may be a formal parameter of an operator or subprogram
6503       --  with multiple interpretations, or else an expression for an actual.
6504
6505       if Nkind (Opnd) = N_Defining_Identifier
6506         or else not Is_Overloaded (Opnd)
6507       then
6508          if Etype (Opnd) = Universal_Integer
6509            or else Etype (Opnd) = Universal_Real
6510          then
6511             return Etype (Opnd);
6512          else
6513             return Empty;
6514          end if;
6515
6516       else
6517          Get_First_Interp (Opnd, Index, It);
6518
6519          while Present (It.Typ) loop
6520
6521             if It.Typ = Universal_Integer
6522               or else It.Typ = Universal_Real
6523             then
6524                return It.Typ;
6525             end if;
6526
6527             Get_Next_Interp (Index, It);
6528          end loop;
6529
6530          return Empty;
6531       end if;
6532    end Universal_Interpretation;
6533
6534    ----------------------
6535    -- Within_Init_Proc --
6536    ----------------------
6537
6538    function Within_Init_Proc return Boolean is
6539       S : Entity_Id;
6540
6541    begin
6542       S := Current_Scope;
6543       while not Is_Overloadable (S) loop
6544          if S = Standard_Standard then
6545             return False;
6546          else
6547             S := Scope (S);
6548          end if;
6549       end loop;
6550
6551       return Is_Init_Proc (S);
6552    end Within_Init_Proc;
6553
6554    ----------------
6555    -- Wrong_Type --
6556    ----------------
6557
6558    procedure Wrong_Type (Expr : Node_Id; Expected_Type : Entity_Id) is
6559       Found_Type : constant Entity_Id := First_Subtype (Etype (Expr));
6560       Expec_Type : constant Entity_Id := First_Subtype (Expected_Type);
6561
6562       function Has_One_Matching_Field return Boolean;
6563       --  Determines whether Expec_Type is a record type with a single
6564       --  component or discriminant whose type matches the found type or
6565       --  is a one dimensional array whose component type matches the
6566       --  found type.
6567
6568       function Has_One_Matching_Field return Boolean is
6569          E : Entity_Id;
6570
6571       begin
6572          if Is_Array_Type (Expec_Type)
6573            and then Number_Dimensions (Expec_Type) = 1
6574            and then
6575              Covers (Etype (Component_Type (Expec_Type)), Found_Type)
6576          then
6577             return True;
6578
6579          elsif not Is_Record_Type (Expec_Type) then
6580             return False;
6581
6582          else
6583             E := First_Entity (Expec_Type);
6584
6585             loop
6586                if No (E) then
6587                   return False;
6588
6589                elsif (Ekind (E) /= E_Discriminant
6590                        and then Ekind (E) /= E_Component)
6591                  or else (Chars (E) = Name_uTag
6592                            or else Chars (E) = Name_uParent)
6593                then
6594                   Next_Entity (E);
6595
6596                else
6597                   exit;
6598                end if;
6599             end loop;
6600
6601             if not Covers (Etype (E), Found_Type) then
6602                return False;
6603
6604             elsif Present (Next_Entity (E)) then
6605                return False;
6606
6607             else
6608                return True;
6609             end if;
6610          end if;
6611       end Has_One_Matching_Field;
6612
6613    --  Start of processing for Wrong_Type
6614
6615    begin
6616       --  Don't output message if either type is Any_Type, or if a message
6617       --  has already been posted for this node. We need to do the latter
6618       --  check explicitly (it is ordinarily done in Errout), because we
6619       --  are using ! to force the output of the error messages.
6620
6621       if Expec_Type = Any_Type
6622         or else Found_Type = Any_Type
6623         or else Error_Posted (Expr)
6624       then
6625          return;
6626
6627       --  In  an instance, there is an ongoing problem with completion of
6628       --  type derived from private types. Their structure is what Gigi
6629       --  expects, but the  Etype is the parent type rather than the
6630       --  derived private type itself. Do not flag error in this case. The
6631       --  private completion is an entity without a parent, like an Itype.
6632       --  Similarly, full and partial views may be incorrect in the instance.
6633       --  There is no simple way to insure that it is consistent ???
6634
6635       elsif In_Instance then
6636
6637          if Etype (Etype (Expr)) = Etype (Expected_Type)
6638            and then
6639              (Has_Private_Declaration (Expected_Type)
6640                or else Has_Private_Declaration (Etype (Expr)))
6641            and then No (Parent (Expected_Type))
6642          then
6643             return;
6644          end if;
6645       end if;
6646
6647       --  An interesting special check. If the expression is parenthesized
6648       --  and its type corresponds to the type of the sole component of the
6649       --  expected record type, or to the component type of the expected one
6650       --  dimensional array type, then assume we have a bad aggregate attempt.
6651
6652       if Nkind (Expr) in N_Subexpr
6653         and then Paren_Count (Expr) /= 0
6654         and then Has_One_Matching_Field
6655       then
6656          Error_Msg_N ("positional aggregate cannot have one component", Expr);
6657
6658       --  Another special check, if we are looking for a pool-specific access
6659       --  type and we found an E_Access_Attribute_Type, then we have the case
6660       --  of an Access attribute being used in a context which needs a pool-
6661       --  specific type, which is never allowed. The one extra check we make
6662       --  is that the expected designated type covers the Found_Type.
6663
6664       elsif Is_Access_Type (Expec_Type)
6665         and then Ekind (Found_Type) = E_Access_Attribute_Type
6666         and then Ekind (Base_Type (Expec_Type)) /= E_General_Access_Type
6667         and then Ekind (Base_Type (Expec_Type)) /= E_Anonymous_Access_Type
6668         and then Covers
6669           (Designated_Type (Expec_Type), Designated_Type (Found_Type))
6670       then
6671          Error_Msg_N ("result must be general access type!", Expr);
6672          Error_Msg_NE ("add ALL to }!", Expr, Expec_Type);
6673
6674       --  If the expected type is an anonymous access type, as for access
6675       --  parameters and discriminants, the error is on the designated types.
6676
6677       elsif Ekind (Expec_Type) = E_Anonymous_Access_Type then
6678          if Comes_From_Source (Expec_Type) then
6679             Error_Msg_NE ("expected}!", Expr, Expec_Type);
6680          else
6681             Error_Msg_NE
6682               ("expected an access type with designated}",
6683                  Expr, Designated_Type (Expec_Type));
6684          end if;
6685
6686          if Is_Access_Type (Found_Type)
6687            and then not Comes_From_Source (Found_Type)
6688          then
6689             Error_Msg_NE
6690               ("found an access type with designated}!",
6691                 Expr, Designated_Type (Found_Type));
6692          else
6693             if From_With_Type (Found_Type) then
6694                Error_Msg_NE ("found incomplete}!", Expr, Found_Type);
6695                Error_Msg_NE
6696                  ("\possibly missing with_clause on&", Expr,
6697                    Scope (Found_Type));
6698             else
6699                Error_Msg_NE ("found}!", Expr, Found_Type);
6700             end if;
6701          end if;
6702
6703       --  Normal case of one type found, some other type expected
6704
6705       else
6706          --  If the names of the two types are the same, see if some
6707          --  number of levels of qualification will help. Don't try
6708          --  more than three levels, and if we get to standard, it's
6709          --  no use (and probably represents an error in the compiler)
6710          --  Also do not bother with internal scope names.
6711
6712          declare
6713             Expec_Scope : Entity_Id;
6714             Found_Scope : Entity_Id;
6715
6716          begin
6717             Expec_Scope := Expec_Type;
6718             Found_Scope := Found_Type;
6719
6720             for Levels in Int range 0 .. 3 loop
6721                if Chars (Expec_Scope) /= Chars (Found_Scope) then
6722                   Error_Msg_Qual_Level := Levels;
6723                   exit;
6724                end if;
6725
6726                Expec_Scope := Scope (Expec_Scope);
6727                Found_Scope := Scope (Found_Scope);
6728
6729                exit when Expec_Scope = Standard_Standard
6730                            or else
6731                          Found_Scope = Standard_Standard
6732                            or else
6733                          not Comes_From_Source (Expec_Scope)
6734                            or else
6735                          not Comes_From_Source (Found_Scope);
6736             end loop;
6737          end;
6738
6739          Error_Msg_NE ("expected}!", Expr, Expec_Type);
6740
6741          if Is_Entity_Name (Expr)
6742            and then Is_Package (Entity (Expr))
6743          then
6744             Error_Msg_N ("found package name!", Expr);
6745
6746          elsif Is_Entity_Name (Expr)
6747            and then
6748              (Ekind (Entity (Expr)) = E_Procedure
6749                 or else
6750               Ekind (Entity (Expr)) = E_Generic_Procedure)
6751          then
6752             if Ekind (Expec_Type) = E_Access_Subprogram_Type then
6753                Error_Msg_N
6754                  ("found procedure name, possibly missing Access attribute!",
6755                    Expr);
6756             else
6757                Error_Msg_N ("found procedure name instead of function!", Expr);
6758             end if;
6759
6760          elsif Nkind (Expr) = N_Function_Call
6761            and then Ekind (Expec_Type) = E_Access_Subprogram_Type
6762            and then Etype (Designated_Type (Expec_Type)) = Etype (Expr)
6763            and then No (Parameter_Associations (Expr))
6764          then
6765                Error_Msg_N
6766                  ("found function name, possibly missing Access attribute!",
6767                    Expr);
6768
6769          --  Catch common error: a prefix or infix operator which is not
6770          --  directly visible because the type isn't.
6771
6772          elsif Nkind (Expr) in N_Op
6773             and then Is_Overloaded (Expr)
6774             and then not Is_Immediately_Visible (Expec_Type)
6775             and then not Is_Potentially_Use_Visible (Expec_Type)
6776             and then not In_Use (Expec_Type)
6777             and then Has_Compatible_Type (Right_Opnd (Expr), Expec_Type)
6778          then
6779             Error_Msg_N (
6780               "operator of the type is not directly visible!", Expr);
6781
6782          elsif Ekind (Found_Type) = E_Void
6783            and then Present (Parent (Found_Type))
6784            and then Nkind (Parent (Found_Type)) = N_Full_Type_Declaration
6785          then
6786             Error_Msg_NE ("found premature usage of}!", Expr, Found_Type);
6787
6788          else
6789             Error_Msg_NE ("found}!", Expr, Found_Type);
6790          end if;
6791
6792          Error_Msg_Qual_Level := 0;
6793       end if;
6794    end Wrong_Type;
6795
6796 end Sem_Util;