1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Elists; use Elists;
31 with Nlists; use Nlists;
32 with Errout; use Errout;
34 with Namet; use Namet;
36 with Output; use Output;
38 with Sem_Ch6; use Sem_Ch6;
39 with Sem_Ch8; use Sem_Ch8;
40 with Sem_Ch12; use Sem_Ch12;
41 with Sem_Disp; use Sem_Disp;
42 with Sem_Util; use Sem_Util;
43 with Stand; use Stand;
44 with Sinfo; use Sinfo;
45 with Snames; use Snames;
47 with Uintp; use Uintp;
49 package body Sem_Type is
55 -- The following data structures establish a mapping between nodes and
56 -- their interpretations. An overloaded node has an entry in Interp_Map,
57 -- which in turn contains a pointer into the All_Interp array. The
58 -- interpretations of a given node are contiguous in All_Interp. Each
59 -- set of interpretations is terminated with the marker No_Interp.
60 -- In order to speed up the retrieval of the interpretations of an
61 -- overloaded node, the Interp_Map table is accessed by means of a simple
62 -- hashing scheme, and the entries in Interp_Map are chained. The heads
63 -- of clash lists are stored in array Headers.
65 -- Headers Interp_Map All_Interp
67 -- _ +-----+ +--------+
68 -- |_| |_____| --->|interp1 |
69 -- |_|---------->|node | | |interp2 |
70 -- |_| |index|---------| |nointerp|
75 -- This scheme does not currently reclaim interpretations. In principle,
76 -- after a unit is compiled, all overloadings have been resolved, and the
77 -- candidate interpretations should be deleted. This should be easier
78 -- now than with the previous scheme???
80 package All_Interp is new Table.Table (
81 Table_Component_Type => Interp,
82 Table_Index_Type => Int,
84 Table_Initial => Alloc.All_Interp_Initial,
85 Table_Increment => Alloc.All_Interp_Increment,
86 Table_Name => "All_Interp");
88 type Interp_Ref is record
94 Header_Size : constant Int := 2 ** 12;
95 No_Entry : constant Int := -1;
96 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
98 package Interp_Map is new Table.Table (
99 Table_Component_Type => Interp_Ref,
100 Table_Index_Type => Int,
101 Table_Low_Bound => 0,
102 Table_Initial => Alloc.Interp_Map_Initial,
103 Table_Increment => Alloc.Interp_Map_Increment,
104 Table_Name => "Interp_Map");
106 function Hash (N : Node_Id) return Int;
107 -- A trivial hashing function for nodes, used to insert an overloaded
108 -- node into the Interp_Map table.
110 -------------------------------------
111 -- Handling of Overload Resolution --
112 -------------------------------------
114 -- Overload resolution uses two passes over the syntax tree of a complete
115 -- context. In the first, bottom-up pass, the types of actuals in calls
116 -- are used to resolve possibly overloaded subprogram and operator names.
117 -- In the second top-down pass, the type of the context (for example the
118 -- condition in a while statement) is used to resolve a possibly ambiguous
119 -- call, and the unique subprogram name in turn imposes a specific context
120 -- on each of its actuals.
122 -- Most expressions are in fact unambiguous, and the bottom-up pass is
123 -- sufficient to resolve most everything. To simplify the common case,
124 -- names and expressions carry a flag Is_Overloaded to indicate whether
125 -- they have more than one interpretation. If the flag is off, then each
126 -- name has already a unique meaning and type, and the bottom-up pass is
127 -- sufficient (and much simpler).
129 --------------------------
130 -- Operator Overloading --
131 --------------------------
133 -- The visibility of operators is handled differently from that of
134 -- other entities. We do not introduce explicit versions of primitive
135 -- operators for each type definition. As a result, there is only one
136 -- entity corresponding to predefined addition on all numeric types, etc.
137 -- The back-end resolves predefined operators according to their type.
138 -- The visibility of primitive operations then reduces to the visibility
139 -- of the resulting type: (a + b) is a legal interpretation of some
140 -- primitive operator + if the type of the result (which must also be
141 -- the type of a and b) is directly visible (i.e. either immediately
142 -- visible or use-visible.)
144 -- User-defined operators are treated like other functions, but the
145 -- visibility of these user-defined operations must be special-cased
146 -- to determine whether they hide or are hidden by predefined operators.
147 -- The form P."+" (x, y) requires additional handling.
149 -- Concatenation is treated more conventionally: for every one-dimensional
150 -- array type we introduce a explicit concatenation operator. This is
151 -- necessary to handle the case of (element & element => array) which
152 -- cannot be handled conveniently if there is no explicit instance of
153 -- resulting type of the operation.
155 -----------------------
156 -- Local Subprograms --
157 -----------------------
159 procedure All_Overloads;
160 pragma Warnings (Off, All_Overloads);
161 -- Debugging procedure: list full contents of Overloads table
163 function Binary_Op_Interp_Has_Abstract_Op
165 E : Entity_Id) return Entity_Id;
166 -- Given the node and entity of a binary operator, determine whether the
167 -- actuals of E contain an abstract interpretation with regards to the
168 -- types of their corresponding formals. Return the abstract operation or
171 function Function_Interp_Has_Abstract_Op
173 E : Entity_Id) return Entity_Id;
174 -- Given the node and entity of a function call, determine whether the
175 -- actuals of E contain an abstract interpretation with regards to the
176 -- types of their corresponding formals. Return the abstract operation or
179 function Has_Abstract_Op
181 Typ : Entity_Id) return Entity_Id;
182 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
183 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
184 -- abstract interpretation which yields type Typ.
186 procedure New_Interps (N : Node_Id);
187 -- Initialize collection of interpretations for the given node, which is
188 -- either an overloaded entity, or an operation whose arguments have
189 -- multiple interpretations. Interpretations can be added to only one
192 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id;
193 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
194 -- or is not a "class" type (any_character, etc).
200 procedure Add_One_Interp
204 Opnd_Type : Entity_Id := Empty)
206 Vis_Type : Entity_Id;
208 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
209 -- Add one interpretation to an overloaded node. Add a new entry if
210 -- not hidden by previous one, and remove previous one if hidden by
213 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
214 -- True if the entity is a predefined operator and the operands have
215 -- a universal Interpretation.
221 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
222 Abstr_Op : Entity_Id := Empty;
226 -- Start of processing for Add_Entry
229 -- Find out whether the new entry references interpretations that
230 -- are abstract or disabled by abstract operators.
232 if Ada_Version >= Ada_05 then
233 if Nkind (N) in N_Binary_Op then
234 Abstr_Op := Binary_Op_Interp_Has_Abstract_Op (N, Name);
235 elsif Nkind (N) = N_Function_Call then
236 Abstr_Op := Function_Interp_Has_Abstract_Op (N, Name);
240 Get_First_Interp (N, I, It);
241 while Present (It.Nam) loop
243 -- A user-defined subprogram hides another declared at an outer
244 -- level, or one that is use-visible. So return if previous
245 -- definition hides new one (which is either in an outer
246 -- scope, or use-visible). Note that for functions use-visible
247 -- is the same as potentially use-visible. If new one hides
248 -- previous one, replace entry in table of interpretations.
249 -- If this is a universal operation, retain the operator in case
250 -- preference rule applies.
252 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
253 and then Ekind (Name) = Ekind (It.Nam))
254 or else (Ekind (Name) = E_Operator
255 and then Ekind (It.Nam) = E_Function))
257 and then Is_Immediately_Visible (It.Nam)
258 and then Type_Conformant (Name, It.Nam)
259 and then Base_Type (It.Typ) = Base_Type (T)
261 if Is_Universal_Operation (Name) then
264 -- If node is an operator symbol, we have no actuals with
265 -- which to check hiding, and this is done in full in the
266 -- caller (Analyze_Subprogram_Renaming) so we include the
267 -- predefined operator in any case.
269 elsif Nkind (N) = N_Operator_Symbol
270 or else (Nkind (N) = N_Expanded_Name
272 Nkind (Selector_Name (N)) = N_Operator_Symbol)
276 elsif not In_Open_Scopes (Scope (Name))
277 or else Scope_Depth (Scope (Name)) <=
278 Scope_Depth (Scope (It.Nam))
280 -- If ambiguity within instance, and entity is not an
281 -- implicit operation, save for later disambiguation.
283 if Scope (Name) = Scope (It.Nam)
284 and then not Is_Inherited_Operation (Name)
293 All_Interp.Table (I).Nam := Name;
297 -- Avoid making duplicate entries in overloads
300 and then Base_Type (It.Typ) = Base_Type (T)
304 -- Otherwise keep going
307 Get_Next_Interp (I, It);
312 All_Interp.Table (All_Interp.Last) := (Name, Typ, Abstr_Op);
313 All_Interp.Increment_Last;
314 All_Interp.Table (All_Interp.Last) := No_Interp;
317 ----------------------------
318 -- Is_Universal_Operation --
319 ----------------------------
321 function Is_Universal_Operation (Op : Entity_Id) return Boolean is
325 if Ekind (Op) /= E_Operator then
328 elsif Nkind (N) in N_Binary_Op then
329 return Present (Universal_Interpretation (Left_Opnd (N)))
330 and then Present (Universal_Interpretation (Right_Opnd (N)));
332 elsif Nkind (N) in N_Unary_Op then
333 return Present (Universal_Interpretation (Right_Opnd (N)));
335 elsif Nkind (N) = N_Function_Call then
336 Arg := First_Actual (N);
337 while Present (Arg) loop
338 if No (Universal_Interpretation (Arg)) then
350 end Is_Universal_Operation;
352 -- Start of processing for Add_One_Interp
355 -- If the interpretation is a predefined operator, verify that the
356 -- result type is visible, or that the entity has already been
357 -- resolved (case of an instantiation node that refers to a predefined
358 -- operation, or an internally generated operator node, or an operator
359 -- given as an expanded name). If the operator is a comparison or
360 -- equality, it is the type of the operand that matters to determine
361 -- whether the operator is visible. In an instance, the check is not
362 -- performed, given that the operator was visible in the generic.
364 if Ekind (E) = E_Operator then
366 if Present (Opnd_Type) then
367 Vis_Type := Opnd_Type;
369 Vis_Type := Base_Type (T);
372 if In_Open_Scopes (Scope (Vis_Type))
373 or else Is_Potentially_Use_Visible (Vis_Type)
374 or else In_Use (Vis_Type)
375 or else (In_Use (Scope (Vis_Type))
376 and then not Is_Hidden (Vis_Type))
377 or else Nkind (N) = N_Expanded_Name
378 or else (Nkind (N) in N_Op and then E = Entity (N))
380 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
384 -- If the node is given in functional notation and the prefix
385 -- is an expanded name, then the operator is visible if the
386 -- prefix is the scope of the result type as well. If the
387 -- operator is (implicitly) defined in an extension of system,
388 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
390 elsif Nkind (N) = N_Function_Call
391 and then Nkind (Name (N)) = N_Expanded_Name
392 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
393 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
394 or else Scope (Vis_Type) = System_Aux_Id)
398 -- Save type for subsequent error message, in case no other
399 -- interpretation is found.
402 Candidate_Type := Vis_Type;
406 -- In an instance, an abstract non-dispatching operation cannot
407 -- be a candidate interpretation, because it could not have been
408 -- one in the generic (it may be a spurious overloading in the
412 and then Is_Overloadable (E)
413 and then Is_Abstract_Subprogram (E)
414 and then not Is_Dispatching_Operation (E)
418 -- An inherited interface operation that is implemented by some
419 -- derived type does not participate in overload resolution, only
420 -- the implementation operation does.
423 and then Is_Subprogram (E)
424 and then Present (Abstract_Interface_Alias (E))
426 -- Ada 2005 (AI-251): If this primitive operation corresponds with
427 -- an inmediate ancestor interface there is no need to add it to the
428 -- list of interpretations; the corresponding aliased primitive is
429 -- also in this list of primitive operations and will be used instead
430 -- because otherwise we have a dummy between the two subprograms that
431 -- are in fact the same.
434 (Find_Dispatching_Type (Abstract_Interface_Alias (E)),
435 Find_Dispatching_Type (E))
437 Add_One_Interp (N, Abstract_Interface_Alias (E), T);
443 -- If this is the first interpretation of N, N has type Any_Type.
444 -- In that case place the new type on the node. If one interpretation
445 -- already exists, indicate that the node is overloaded, and store
446 -- both the previous and the new interpretation in All_Interp. If
447 -- this is a later interpretation, just add it to the set.
449 if Etype (N) = Any_Type then
454 -- Record both the operator or subprogram name, and its type
456 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
463 -- Either there is no current interpretation in the table for any
464 -- node or the interpretation that is present is for a different
465 -- node. In both cases add a new interpretation to the table.
467 elsif Interp_Map.Last < 0
469 (Interp_Map.Table (Interp_Map.Last).Node /= N
470 and then not Is_Overloaded (N))
474 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
475 and then Present (Entity (N))
477 Add_Entry (Entity (N), Etype (N));
479 elsif (Nkind (N) = N_Function_Call
480 or else Nkind (N) = N_Procedure_Call_Statement)
481 and then (Nkind (Name (N)) = N_Operator_Symbol
482 or else Is_Entity_Name (Name (N)))
484 Add_Entry (Entity (Name (N)), Etype (N));
486 -- If this is an indirect call there will be no name associated
487 -- with the previous entry. To make diagnostics clearer, save
488 -- Subprogram_Type of first interpretation, so that the error will
489 -- point to the anonymous access to subprogram, not to the result
490 -- type of the call itself.
492 elsif (Nkind (N)) = N_Function_Call
493 and then Nkind (Name (N)) = N_Explicit_Dereference
494 and then Is_Overloaded (Name (N))
500 pragma Warnings (Off, Itn);
503 Get_First_Interp (Name (N), Itn, It);
504 Add_Entry (It.Nam, Etype (N));
508 -- Overloaded prefix in indexed or selected component,
509 -- or call whose name is an expression or another call.
511 Add_Entry (Etype (N), Etype (N));
525 procedure All_Overloads is
527 for J in All_Interp.First .. All_Interp.Last loop
529 if Present (All_Interp.Table (J).Nam) then
530 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
532 Write_Str ("No Interp");
535 Write_Str ("=================");
540 --------------------------------------
541 -- Binary_Op_Interp_Has_Abstract_Op --
542 --------------------------------------
544 function Binary_Op_Interp_Has_Abstract_Op
546 E : Entity_Id) return Entity_Id
548 Abstr_Op : Entity_Id;
549 E_Left : constant Node_Id := First_Formal (E);
550 E_Right : constant Node_Id := Next_Formal (E_Left);
553 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
554 if Present (Abstr_Op) then
558 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
559 end Binary_Op_Interp_Has_Abstract_Op;
561 ---------------------
562 -- Collect_Interps --
563 ---------------------
565 procedure Collect_Interps (N : Node_Id) is
566 Ent : constant Entity_Id := Entity (N);
568 First_Interp : Interp_Index;
573 -- Unconditionally add the entity that was initially matched
575 First_Interp := All_Interp.Last;
576 Add_One_Interp (N, Ent, Etype (N));
578 -- For expanded name, pick up all additional entities from the
579 -- same scope, since these are obviously also visible. Note that
580 -- these are not necessarily contiguous on the homonym chain.
582 if Nkind (N) = N_Expanded_Name then
584 while Present (H) loop
585 if Scope (H) = Scope (Entity (N)) then
586 Add_One_Interp (N, H, Etype (H));
592 -- Case of direct name
595 -- First, search the homonym chain for directly visible entities
597 H := Current_Entity (Ent);
598 while Present (H) loop
599 exit when (not Is_Overloadable (H))
600 and then Is_Immediately_Visible (H);
602 if Is_Immediately_Visible (H)
605 -- Only add interpretation if not hidden by an inner
606 -- immediately visible one.
608 for J in First_Interp .. All_Interp.Last - 1 loop
610 -- Current homograph is not hidden. Add to overloads
612 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
615 -- Homograph is hidden, unless it is a predefined operator
617 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
619 -- A homograph in the same scope can occur within an
620 -- instantiation, the resulting ambiguity has to be
623 if Scope (H) = Scope (Ent)
625 and then not Is_Inherited_Operation (H)
627 All_Interp.Table (All_Interp.Last) :=
628 (H, Etype (H), Empty);
629 All_Interp.Increment_Last;
630 All_Interp.Table (All_Interp.Last) := No_Interp;
633 elsif Scope (H) /= Standard_Standard then
639 -- On exit, we know that current homograph is not hidden
641 Add_One_Interp (N, H, Etype (H));
644 Write_Str ("Add overloaded Interpretation ");
654 -- Scan list of homographs for use-visible entities only
656 H := Current_Entity (Ent);
658 while Present (H) loop
659 if Is_Potentially_Use_Visible (H)
661 and then Is_Overloadable (H)
663 for J in First_Interp .. All_Interp.Last - 1 loop
665 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
668 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
669 goto Next_Use_Homograph;
673 Add_One_Interp (N, H, Etype (H));
676 <<Next_Use_Homograph>>
681 if All_Interp.Last = First_Interp + 1 then
683 -- The original interpretation is in fact not overloaded
685 Set_Is_Overloaded (N, False);
693 function Covers (T1, T2 : Entity_Id) return Boolean is
698 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
699 -- In an instance the proper view may not always be correct for
700 -- private types, but private and full view are compatible. This
701 -- removes spurious errors from nested instantiations that involve,
702 -- among other things, types derived from private types.
704 ----------------------
705 -- Full_View_Covers --
706 ----------------------
708 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
711 Is_Private_Type (Typ1)
713 ((Present (Full_View (Typ1))
714 and then Covers (Full_View (Typ1), Typ2))
715 or else Base_Type (Typ1) = Typ2
716 or else Base_Type (Typ2) = Typ1);
717 end Full_View_Covers;
719 -- Start of processing for Covers
722 -- If either operand missing, then this is an error, but ignore it (and
723 -- pretend we have a cover) if errors already detected, since this may
724 -- simply mean we have malformed trees.
726 if No (T1) or else No (T2) then
727 if Total_Errors_Detected /= 0 then
734 BT1 := Base_Type (T1);
735 BT2 := Base_Type (T2);
738 -- Simplest case: same types are compatible, and types that have the
739 -- same base type and are not generic actuals are compatible. Generic
740 -- actuals belong to their class but are not compatible with other
741 -- types of their class, and in particular with other generic actuals.
742 -- They are however compatible with their own subtypes, and itypes
743 -- with the same base are compatible as well. Similarly, constrained
744 -- subtypes obtained from expressions of an unconstrained nominal type
745 -- are compatible with the base type (may lead to spurious ambiguities
746 -- in obscure cases ???)
748 -- Generic actuals require special treatment to avoid spurious ambi-
749 -- guities in an instance, when two formal types are instantiated with
750 -- the same actual, so that different subprograms end up with the same
751 -- signature in the instance.
760 if not Is_Generic_Actual_Type (T1) then
763 return (not Is_Generic_Actual_Type (T2)
764 or else Is_Itype (T1)
765 or else Is_Itype (T2)
766 or else Is_Constr_Subt_For_U_Nominal (T1)
767 or else Is_Constr_Subt_For_U_Nominal (T2)
768 or else Scope (T1) /= Scope (T2));
771 -- Literals are compatible with types in a given "class"
773 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
774 or else (T2 = Universal_Real and then Is_Real_Type (T1))
775 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
776 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
777 or else (T2 = Any_String and then Is_String_Type (T1))
778 or else (T2 = Any_Character and then Is_Character_Type (T1))
779 or else (T2 = Any_Access and then Is_Access_Type (T1))
783 -- The context may be class wide
785 elsif Is_Class_Wide_Type (T1)
786 and then Is_Ancestor (Root_Type (T1), T2)
790 elsif Is_Class_Wide_Type (T1)
791 and then Is_Class_Wide_Type (T2)
792 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
796 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
797 -- task_type or protected_type implementing T1
799 elsif Ada_Version >= Ada_05
800 and then Is_Class_Wide_Type (T1)
801 and then Is_Interface (Etype (T1))
802 and then Is_Concurrent_Type (T2)
803 and then Interface_Present_In_Ancestor
804 (Typ => Base_Type (T2),
809 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
810 -- object T2 implementing T1
812 elsif Ada_Version >= Ada_05
813 and then Is_Class_Wide_Type (T1)
814 and then Is_Interface (Etype (T1))
815 and then Is_Tagged_Type (T2)
817 if Interface_Present_In_Ancestor (Typ => T2,
828 if Is_Concurrent_Type (BT2) then
829 E := Corresponding_Record_Type (BT2);
834 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
835 -- covers an object T2 that implements a direct derivation of T1.
836 -- Note: test for presence of E is defense against previous error.
839 and then Present (Abstract_Interfaces (E))
841 Elmt := First_Elmt (Abstract_Interfaces (E));
842 while Present (Elmt) loop
843 if Is_Ancestor (Etype (T1), Node (Elmt)) then
851 -- We should also check the case in which T1 is an ancestor of
852 -- some implemented interface???
857 -- In a dispatching call the actual may be class-wide
859 elsif Is_Class_Wide_Type (T2)
860 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
864 -- Some contexts require a class of types rather than a specific type
866 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
867 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
868 or else (T1 = Any_Real and then Is_Real_Type (T2))
869 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
870 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
874 -- An aggregate is compatible with an array or record type
876 elsif T2 = Any_Composite
877 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
881 -- If the expected type is an anonymous access, the designated type must
882 -- cover that of the expression. Use the base type for this check: even
883 -- though access subtypes are rare in sources, they are generated for
884 -- actuals in instantiations.
886 elsif Ekind (BT1) = E_Anonymous_Access_Type
887 and then Is_Access_Type (T2)
888 and then Covers (Designated_Type (T1), Designated_Type (T2))
892 -- An Access_To_Subprogram is compatible with itself, or with an
893 -- anonymous type created for an attribute reference Access.
895 elsif (Ekind (BT1) = E_Access_Subprogram_Type
897 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
898 and then Is_Access_Type (T2)
899 and then (not Comes_From_Source (T1)
900 or else not Comes_From_Source (T2))
901 and then (Is_Overloadable (Designated_Type (T2))
903 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
905 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
907 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
911 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
912 -- with itself, or with an anonymous type created for an attribute
915 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
918 = E_Anonymous_Access_Protected_Subprogram_Type)
919 and then Is_Access_Type (T2)
920 and then (not Comes_From_Source (T1)
921 or else not Comes_From_Source (T2))
922 and then (Is_Overloadable (Designated_Type (T2))
924 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
926 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
928 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
932 -- The context can be a remote access type, and the expression the
933 -- corresponding source type declared in a categorized package, or
936 elsif Is_Record_Type (T1)
937 and then (Is_Remote_Call_Interface (T1)
938 or else Is_Remote_Types (T1))
939 and then Present (Corresponding_Remote_Type (T1))
941 return Covers (Corresponding_Remote_Type (T1), T2);
943 elsif Is_Record_Type (T2)
944 and then (Is_Remote_Call_Interface (T2)
945 or else Is_Remote_Types (T2))
946 and then Present (Corresponding_Remote_Type (T2))
948 return Covers (Corresponding_Remote_Type (T2), T1);
950 elsif Ekind (T2) = E_Access_Attribute_Type
951 and then (Ekind (BT1) = E_General_Access_Type
952 or else Ekind (BT1) = E_Access_Type)
953 and then Covers (Designated_Type (T1), Designated_Type (T2))
955 -- If the target type is a RACW type while the source is an access
956 -- attribute type, we are building a RACW that may be exported.
958 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
959 Set_Has_RACW (Current_Sem_Unit);
964 elsif Ekind (T2) = E_Allocator_Type
965 and then Is_Access_Type (T1)
967 return Covers (Designated_Type (T1), Designated_Type (T2))
969 (From_With_Type (Designated_Type (T1))
970 and then Covers (Designated_Type (T2), Designated_Type (T1)));
972 -- A boolean operation on integer literals is compatible with modular
975 elsif T2 = Any_Modular
976 and then Is_Modular_Integer_Type (T1)
980 -- The actual type may be the result of a previous error
982 elsif Base_Type (T2) = Any_Type then
985 -- A packed array type covers its corresponding non-packed type. This is
986 -- not legitimate Ada, but allows the omission of a number of otherwise
987 -- useless unchecked conversions, and since this can only arise in
988 -- (known correct) expanded code, no harm is done
990 elsif Is_Array_Type (T2)
991 and then Is_Packed (T2)
992 and then T1 = Packed_Array_Type (T2)
996 -- Similarly an array type covers its corresponding packed array type
998 elsif Is_Array_Type (T1)
999 and then Is_Packed (T1)
1000 and then T2 = Packed_Array_Type (T1)
1004 -- In instances, or with types exported from instantiations, check
1005 -- whether a partial and a full view match. Verify that types are
1006 -- legal, to prevent cascaded errors.
1010 (Full_View_Covers (T1, T2)
1011 or else Full_View_Covers (T2, T1))
1016 and then Is_Generic_Actual_Type (T2)
1017 and then Full_View_Covers (T1, T2)
1022 and then Is_Generic_Actual_Type (T1)
1023 and then Full_View_Covers (T2, T1)
1027 -- In the expansion of inlined bodies, types are compatible if they
1028 -- are structurally equivalent.
1030 elsif In_Inlined_Body
1031 and then (Underlying_Type (T1) = Underlying_Type (T2)
1032 or else (Is_Access_Type (T1)
1033 and then Is_Access_Type (T2)
1035 Designated_Type (T1) = Designated_Type (T2))
1036 or else (T1 = Any_Access
1037 and then Is_Access_Type (Underlying_Type (T2)))
1038 or else (T2 = Any_Composite
1040 Is_Composite_Type (Underlying_Type (T1))))
1044 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1045 -- compatible with its real entity.
1047 elsif From_With_Type (T1) then
1049 -- If the expected type is the non-limited view of a type, the
1050 -- expression may have the limited view. If that one in turn is
1051 -- incomplete, get full view if available.
1053 if Is_Incomplete_Type (T1) then
1054 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1056 elsif Ekind (T1) = E_Class_Wide_Type then
1058 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1063 elsif From_With_Type (T2) then
1065 -- If units in the context have Limited_With clauses on each other,
1066 -- either type might have a limited view. Checks performed elsewhere
1067 -- verify that the context type is the non-limited view.
1069 if Is_Incomplete_Type (T2) then
1070 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1072 elsif Ekind (T2) = E_Class_Wide_Type then
1074 Present (Non_Limited_View (Etype (T2)))
1076 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1081 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1083 elsif Ekind (T1) = E_Incomplete_Subtype then
1084 return Covers (Full_View (Etype (T1)), T2);
1086 elsif Ekind (T2) = E_Incomplete_Subtype then
1087 return Covers (T1, Full_View (Etype (T2)));
1089 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1090 -- and actual anonymous access types in the context of generic
1091 -- instantiation. We have the following situation:
1094 -- type Formal is private;
1095 -- Formal_Obj : access Formal; -- T1
1099 -- type Actual is ...
1100 -- Actual_Obj : access Actual; -- T2
1101 -- package Instance is new G (Formal => Actual,
1102 -- Formal_Obj => Actual_Obj);
1104 elsif Ada_Version >= Ada_05
1105 and then Ekind (T1) = E_Anonymous_Access_Type
1106 and then Ekind (T2) = E_Anonymous_Access_Type
1107 and then Is_Generic_Type (Directly_Designated_Type (T1))
1108 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1109 Directly_Designated_Type (T2)
1113 -- Otherwise it doesn't cover!
1124 function Disambiguate
1126 I1, I2 : Interp_Index;
1133 Nam1, Nam2 : Entity_Id;
1134 Predef_Subp : Entity_Id;
1135 User_Subp : Entity_Id;
1137 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1138 -- Determine whether one of the candidates is an operation inherited by
1139 -- a type that is derived from an actual in an instantiation.
1141 function In_Generic_Actual (Exp : Node_Id) return Boolean;
1142 -- Determine whether the expression is part of a generic actual. At
1143 -- the time the actual is resolved the scope is already that of the
1144 -- instance, but conceptually the resolution of the actual takes place
1145 -- in the enclosing context, and no special disambiguation rules should
1148 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1149 -- Determine whether a subprogram is an actual in an enclosing instance.
1150 -- An overloading between such a subprogram and one declared outside the
1151 -- instance is resolved in favor of the first, because it resolved in
1154 function Matches (Actual, Formal : Node_Id) return Boolean;
1155 -- Look for exact type match in an instance, to remove spurious
1156 -- ambiguities when two formal types have the same actual.
1158 function Standard_Operator return Boolean;
1159 -- Check whether subprogram is predefined operator declared in Standard.
1160 -- It may given by an operator name, or by an expanded name whose prefix
1163 function Remove_Conversions return Interp;
1164 -- Last chance for pathological cases involving comparisons on literals,
1165 -- and user overloadings of the same operator. Such pathologies have
1166 -- been removed from the ACVC, but still appear in two DEC tests, with
1167 -- the following notable quote from Ben Brosgol:
1169 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1170 -- this example; Robert Dewar brought it to our attention, since it is
1171 -- apparently found in the ACVC 1.5. I did not attempt to find the
1172 -- reason in the Reference Manual that makes the example legal, since I
1173 -- was too nauseated by it to want to pursue it further.]
1175 -- Accordingly, this is not a fully recursive solution, but it handles
1176 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1177 -- pathology in the other direction with calls whose multiple overloaded
1178 -- actuals make them truly unresolvable.
1180 -- The new rules concerning abstract operations create additional need
1181 -- for special handling of expressions with universal operands, see
1182 -- comments to Has_Abstract_Interpretation below.
1184 ------------------------
1185 -- In_Generic_Actual --
1186 ------------------------
1188 function In_Generic_Actual (Exp : Node_Id) return Boolean is
1189 Par : constant Node_Id := Parent (Exp);
1195 elsif Nkind (Par) in N_Declaration then
1196 if Nkind (Par) = N_Object_Declaration
1197 or else Nkind (Par) = N_Object_Renaming_Declaration
1199 return Present (Corresponding_Generic_Association (Par));
1204 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
1208 return In_Generic_Actual (Parent (Par));
1210 end In_Generic_Actual;
1212 ---------------------------
1213 -- Inherited_From_Actual --
1214 ---------------------------
1216 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1217 Par : constant Node_Id := Parent (S);
1219 if Nkind (Par) /= N_Full_Type_Declaration
1220 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1224 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1226 Is_Generic_Actual_Type (
1227 Entity (Subtype_Indication (Type_Definition (Par))));
1229 end Inherited_From_Actual;
1231 --------------------------
1232 -- Is_Actual_Subprogram --
1233 --------------------------
1235 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1237 return In_Open_Scopes (Scope (S))
1239 (Is_Generic_Instance (Scope (S))
1240 or else Is_Wrapper_Package (Scope (S)));
1241 end Is_Actual_Subprogram;
1247 function Matches (Actual, Formal : Node_Id) return Boolean is
1248 T1 : constant Entity_Id := Etype (Actual);
1249 T2 : constant Entity_Id := Etype (Formal);
1253 (Is_Numeric_Type (T2)
1255 (T1 = Universal_Real or else T1 = Universal_Integer));
1258 ------------------------
1259 -- Remove_Conversions --
1260 ------------------------
1262 function Remove_Conversions return Interp is
1270 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1271 -- If an operation has universal operands the universal operation
1272 -- is present among its interpretations. If there is an abstract
1273 -- interpretation for the operator, with a numeric result, this
1274 -- interpretation was already removed in sem_ch4, but the universal
1275 -- one is still visible. We must rescan the list of operators and
1276 -- remove the universal interpretation to resolve the ambiguity.
1278 ---------------------------------
1279 -- Has_Abstract_Interpretation --
1280 ---------------------------------
1282 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1286 if Nkind (N) not in N_Op
1287 or else Ada_Version < Ada_05
1288 or else not Is_Overloaded (N)
1289 or else No (Universal_Interpretation (N))
1294 E := Get_Name_Entity_Id (Chars (N));
1295 while Present (E) loop
1296 if Is_Overloadable (E)
1297 and then Is_Abstract_Subprogram (E)
1298 and then Is_Numeric_Type (Etype (E))
1306 -- Finally, if an operand of the binary operator is itself
1307 -- an operator, recurse to see whether its own abstract
1308 -- interpretation is responsible for the spurious ambiguity.
1310 if Nkind (N) in N_Binary_Op then
1311 return Has_Abstract_Interpretation (Left_Opnd (N))
1312 or else Has_Abstract_Interpretation (Right_Opnd (N));
1314 elsif Nkind (N) in N_Unary_Op then
1315 return Has_Abstract_Interpretation (Right_Opnd (N));
1321 end Has_Abstract_Interpretation;
1323 -- Start of processing for Remove_Conversions
1328 Get_First_Interp (N, I, It);
1329 while Present (It.Typ) loop
1330 if not Is_Overloadable (It.Nam) then
1334 F1 := First_Formal (It.Nam);
1340 if Nkind (N) = N_Function_Call
1341 or else Nkind (N) = N_Procedure_Call_Statement
1343 Act1 := First_Actual (N);
1345 if Present (Act1) then
1346 Act2 := Next_Actual (Act1);
1351 elsif Nkind (N) in N_Unary_Op then
1352 Act1 := Right_Opnd (N);
1355 elsif Nkind (N) in N_Binary_Op then
1356 Act1 := Left_Opnd (N);
1357 Act2 := Right_Opnd (N);
1359 -- Use type of second formal, so as to include
1360 -- exponentiation, where the exponent may be
1361 -- ambiguous and the result non-universal.
1369 if Nkind (Act1) in N_Op
1370 and then Is_Overloaded (Act1)
1371 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1372 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1373 and then Has_Compatible_Type (Act1, Standard_Boolean)
1374 and then Etype (F1) = Standard_Boolean
1376 -- If the two candidates are the original ones, the
1377 -- ambiguity is real. Otherwise keep the original, further
1378 -- calls to Disambiguate will take care of others in the
1379 -- list of candidates.
1381 if It1 /= No_Interp then
1382 if It = Disambiguate.It1
1383 or else It = Disambiguate.It2
1385 if It1 = Disambiguate.It1
1386 or else It1 = Disambiguate.It2
1394 elsif Present (Act2)
1395 and then Nkind (Act2) in N_Op
1396 and then Is_Overloaded (Act2)
1397 and then (Nkind (Right_Opnd (Act2)) = N_Integer_Literal
1399 Nkind (Right_Opnd (Act2)) = N_Real_Literal)
1400 and then Has_Compatible_Type (Act2, Standard_Boolean)
1402 -- The preference rule on the first actual is not
1403 -- sufficient to disambiguate.
1411 elsif Is_Numeric_Type (Etype (F1))
1413 (Has_Abstract_Interpretation (Act1)
1414 or else Has_Abstract_Interpretation (Act2))
1416 if It = Disambiguate.It1 then
1417 return Disambiguate.It2;
1418 elsif It = Disambiguate.It2 then
1419 return Disambiguate.It1;
1425 Get_Next_Interp (I, It);
1428 -- After some error, a formal may have Any_Type and yield a spurious
1429 -- match. To avoid cascaded errors if possible, check for such a
1430 -- formal in either candidate.
1432 if Serious_Errors_Detected > 0 then
1437 Formal := First_Formal (Nam1);
1438 while Present (Formal) loop
1439 if Etype (Formal) = Any_Type then
1440 return Disambiguate.It2;
1443 Next_Formal (Formal);
1446 Formal := First_Formal (Nam2);
1447 while Present (Formal) loop
1448 if Etype (Formal) = Any_Type then
1449 return Disambiguate.It1;
1452 Next_Formal (Formal);
1458 end Remove_Conversions;
1460 -----------------------
1461 -- Standard_Operator --
1462 -----------------------
1464 function Standard_Operator return Boolean is
1468 if Nkind (N) in N_Op then
1471 elsif Nkind (N) = N_Function_Call then
1474 if Nkind (Nam) /= N_Expanded_Name then
1477 return Entity (Prefix (Nam)) = Standard_Standard;
1482 end Standard_Operator;
1484 -- Start of processing for Disambiguate
1487 -- Recover the two legal interpretations
1489 Get_First_Interp (N, I, It);
1491 Get_Next_Interp (I, It);
1497 Get_Next_Interp (I, It);
1503 if Ada_Version < Ada_05 then
1505 -- Check whether one of the entities is an Ada 2005 entity and we are
1506 -- operating in an earlier mode, in which case we discard the Ada
1507 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1509 if Is_Ada_2005_Only (Nam1) then
1511 elsif Is_Ada_2005_Only (Nam2) then
1516 -- Check for overloaded CIL convention stuff because the CIL libraries
1517 -- do sick things like Console.WriteLine where it matches
1518 -- two different overloads, so just pick the first ???
1520 if Convention (Nam1) = Convention_CIL
1521 and then Convention (Nam2) = Convention_CIL
1522 and then Ekind (Nam1) = Ekind (Nam2)
1523 and then (Ekind (Nam1) = E_Procedure
1524 or else Ekind (Nam1) = E_Function)
1529 -- If the context is universal, the predefined operator is preferred.
1530 -- This includes bounds in numeric type declarations, and expressions
1531 -- in type conversions. If no interpretation yields a universal type,
1532 -- then we must check whether the user-defined entity hides the prede-
1535 if Chars (Nam1) in Any_Operator_Name
1536 and then Standard_Operator
1538 if Typ = Universal_Integer
1539 or else Typ = Universal_Real
1540 or else Typ = Any_Integer
1541 or else Typ = Any_Discrete
1542 or else Typ = Any_Real
1543 or else Typ = Any_Type
1545 -- Find an interpretation that yields the universal type, or else
1546 -- a predefined operator that yields a predefined numeric type.
1549 Candidate : Interp := No_Interp;
1552 Get_First_Interp (N, I, It);
1553 while Present (It.Typ) loop
1554 if (Covers (Typ, It.Typ)
1555 or else Typ = Any_Type)
1557 (It.Typ = Universal_Integer
1558 or else It.Typ = Universal_Real)
1562 elsif Covers (Typ, It.Typ)
1563 and then Scope (It.Typ) = Standard_Standard
1564 and then Scope (It.Nam) = Standard_Standard
1565 and then Is_Numeric_Type (It.Typ)
1570 Get_Next_Interp (I, It);
1573 if Candidate /= No_Interp then
1578 elsif Chars (Nam1) /= Name_Op_Not
1579 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1581 -- Equality or comparison operation. Choose predefined operator if
1582 -- arguments are universal. The node may be an operator, name, or
1583 -- a function call, so unpack arguments accordingly.
1586 Arg1, Arg2 : Node_Id;
1589 if Nkind (N) in N_Op then
1590 Arg1 := Left_Opnd (N);
1591 Arg2 := Right_Opnd (N);
1593 elsif Is_Entity_Name (N)
1594 or else Nkind (N) = N_Operator_Symbol
1596 Arg1 := First_Entity (Entity (N));
1597 Arg2 := Next_Entity (Arg1);
1600 Arg1 := First_Actual (N);
1601 Arg2 := Next_Actual (Arg1);
1605 and then Present (Universal_Interpretation (Arg1))
1606 and then Universal_Interpretation (Arg2) =
1607 Universal_Interpretation (Arg1)
1609 Get_First_Interp (N, I, It);
1610 while Scope (It.Nam) /= Standard_Standard loop
1611 Get_Next_Interp (I, It);
1620 -- If no universal interpretation, check whether user-defined operator
1621 -- hides predefined one, as well as other special cases. If the node
1622 -- is a range, then one or both bounds are ambiguous. Each will have
1623 -- to be disambiguated w.r.t. the context type. The type of the range
1624 -- itself is imposed by the context, so we can return either legal
1627 if Ekind (Nam1) = E_Operator then
1628 Predef_Subp := Nam1;
1631 elsif Ekind (Nam2) = E_Operator then
1632 Predef_Subp := Nam2;
1635 elsif Nkind (N) = N_Range then
1638 -- If two user defined-subprograms are visible, it is a true ambiguity,
1639 -- unless one of them is an entry and the context is a conditional or
1640 -- timed entry call, or unless we are within an instance and this is
1641 -- results from two formals types with the same actual.
1644 if Nkind (N) = N_Procedure_Call_Statement
1645 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1646 and then N = Entry_Call_Statement (Parent (N))
1648 if Ekind (Nam2) = E_Entry then
1650 elsif Ekind (Nam1) = E_Entry then
1656 -- If the ambiguity occurs within an instance, it is due to several
1657 -- formal types with the same actual. Look for an exact match between
1658 -- the types of the formals of the overloadable entities, and the
1659 -- actuals in the call, to recover the unambiguous match in the
1660 -- original generic.
1662 -- The ambiguity can also be due to an overloading between a formal
1663 -- subprogram and a subprogram declared outside the generic. If the
1664 -- node is overloaded, it did not resolve to the global entity in
1665 -- the generic, and we choose the formal subprogram.
1667 -- Finally, the ambiguity can be between an explicit subprogram and
1668 -- one inherited (with different defaults) from an actual. In this
1669 -- case the resolution was to the explicit declaration in the
1670 -- generic, and remains so in the instance.
1673 and then not In_Generic_Actual (N)
1675 if Nkind (N) = N_Function_Call
1676 or else Nkind (N) = N_Procedure_Call_Statement
1681 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1682 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1685 if Is_Act1 and then not Is_Act2 then
1688 elsif Is_Act2 and then not Is_Act1 then
1691 elsif Inherited_From_Actual (Nam1)
1692 and then Comes_From_Source (Nam2)
1696 elsif Inherited_From_Actual (Nam2)
1697 and then Comes_From_Source (Nam1)
1702 Actual := First_Actual (N);
1703 Formal := First_Formal (Nam1);
1704 while Present (Actual) loop
1705 if Etype (Actual) /= Etype (Formal) then
1709 Next_Actual (Actual);
1710 Next_Formal (Formal);
1716 elsif Nkind (N) in N_Binary_Op then
1717 if Matches (Left_Opnd (N), First_Formal (Nam1))
1719 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1726 elsif Nkind (N) in N_Unary_Op then
1727 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1734 return Remove_Conversions;
1737 return Remove_Conversions;
1741 -- An implicit concatenation operator on a string type cannot be
1742 -- disambiguated from the predefined concatenation. This can only
1743 -- happen with concatenation of string literals.
1745 if Chars (User_Subp) = Name_Op_Concat
1746 and then Ekind (User_Subp) = E_Operator
1747 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1751 -- If the user-defined operator is in an open scope, or in the scope
1752 -- of the resulting type, or given by an expanded name that names its
1753 -- scope, it hides the predefined operator for the type. Exponentiation
1754 -- has to be special-cased because the implicit operator does not have
1755 -- a symmetric signature, and may not be hidden by the explicit one.
1757 elsif (Nkind (N) = N_Function_Call
1758 and then Nkind (Name (N)) = N_Expanded_Name
1759 and then (Chars (Predef_Subp) /= Name_Op_Expon
1760 or else Hides_Op (User_Subp, Predef_Subp))
1761 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1762 or else Hides_Op (User_Subp, Predef_Subp)
1764 if It1.Nam = User_Subp then
1770 -- Otherwise, the predefined operator has precedence, or if the user-
1771 -- defined operation is directly visible we have a true ambiguity. If
1772 -- this is a fixed-point multiplication and division in Ada83 mode,
1773 -- exclude the universal_fixed operator, which often causes ambiguities
1777 if (In_Open_Scopes (Scope (User_Subp))
1778 or else Is_Potentially_Use_Visible (User_Subp))
1779 and then not In_Instance
1781 if Is_Fixed_Point_Type (Typ)
1782 and then (Chars (Nam1) = Name_Op_Multiply
1783 or else Chars (Nam1) = Name_Op_Divide)
1784 and then Ada_Version = Ada_83
1786 if It2.Nam = Predef_Subp then
1792 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1793 -- states that the operator defined in Standard is not available
1794 -- if there is a user-defined equality with the proper signature,
1795 -- declared in the same declarative list as the type. The node
1796 -- may be an operator or a function call.
1798 elsif (Chars (Nam1) = Name_Op_Eq
1800 Chars (Nam1) = Name_Op_Ne)
1801 and then Ada_Version >= Ada_05
1802 and then Etype (User_Subp) = Standard_Boolean
1807 if Nkind (N) = N_Function_Call then
1808 Opnd := First_Actual (N);
1810 Opnd := Left_Opnd (N);
1813 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1815 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1816 = List_Containing (Unit_Declaration_Node (User_Subp))
1818 if It2.Nam = Predef_Subp then
1824 return Remove_Conversions;
1832 elsif It1.Nam = Predef_Subp then
1841 ---------------------
1842 -- End_Interp_List --
1843 ---------------------
1845 procedure End_Interp_List is
1847 All_Interp.Table (All_Interp.Last) := No_Interp;
1848 All_Interp.Increment_Last;
1849 end End_Interp_List;
1851 -------------------------
1852 -- Entity_Matches_Spec --
1853 -------------------------
1855 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1857 -- Simple case: same entity kinds, type conformance is required. A
1858 -- parameterless function can also rename a literal.
1860 if Ekind (Old_S) = Ekind (New_S)
1861 or else (Ekind (New_S) = E_Function
1862 and then Ekind (Old_S) = E_Enumeration_Literal)
1864 return Type_Conformant (New_S, Old_S);
1866 elsif Ekind (New_S) = E_Function
1867 and then Ekind (Old_S) = E_Operator
1869 return Operator_Matches_Spec (Old_S, New_S);
1871 elsif Ekind (New_S) = E_Procedure
1872 and then Is_Entry (Old_S)
1874 return Type_Conformant (New_S, Old_S);
1879 end Entity_Matches_Spec;
1881 ----------------------
1882 -- Find_Unique_Type --
1883 ----------------------
1885 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1886 T : constant Entity_Id := Etype (L);
1889 TR : Entity_Id := Any_Type;
1892 if Is_Overloaded (R) then
1893 Get_First_Interp (R, I, It);
1894 while Present (It.Typ) loop
1895 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1897 -- If several interpretations are possible and L is universal,
1898 -- apply preference rule.
1900 if TR /= Any_Type then
1902 if (T = Universal_Integer or else T = Universal_Real)
1913 Get_Next_Interp (I, It);
1918 -- In the non-overloaded case, the Etype of R is already set correctly
1924 -- If one of the operands is Universal_Fixed, the type of the other
1925 -- operand provides the context.
1927 if Etype (R) = Universal_Fixed then
1930 elsif T = Universal_Fixed then
1933 -- Ada 2005 (AI-230): Support the following operators:
1935 -- function "=" (L, R : universal_access) return Boolean;
1936 -- function "/=" (L, R : universal_access) return Boolean;
1938 -- Pool specific access types (E_Access_Type) are not covered by these
1939 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1940 -- of the equality operators for universal_access shall be convertible
1941 -- to one another (see 4.6)". For example, considering the type decla-
1942 -- ration "type P is access Integer" and an anonymous access to Integer,
1943 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1944 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1946 elsif Ada_Version >= Ada_05
1948 (Ekind (Etype (L)) = E_Anonymous_Access_Type
1950 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
1951 and then Is_Access_Type (Etype (R))
1952 and then Ekind (Etype (R)) /= E_Access_Type
1956 elsif Ada_Version >= Ada_05
1958 (Ekind (Etype (R)) = E_Anonymous_Access_Type
1959 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
1960 and then Is_Access_Type (Etype (L))
1961 and then Ekind (Etype (L)) /= E_Access_Type
1966 return Specific_Type (T, Etype (R));
1968 end Find_Unique_Type;
1970 -------------------------------------
1971 -- Function_Interp_Has_Abstract_Op --
1972 -------------------------------------
1974 function Function_Interp_Has_Abstract_Op
1976 E : Entity_Id) return Entity_Id
1978 Abstr_Op : Entity_Id;
1981 Form_Parm : Node_Id;
1984 if Is_Overloaded (N) then
1985 Act_Parm := First_Actual (N);
1986 Form_Parm := First_Formal (E);
1987 while Present (Act_Parm)
1988 and then Present (Form_Parm)
1992 if Nkind (Act) = N_Parameter_Association then
1993 Act := Explicit_Actual_Parameter (Act);
1996 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
1998 if Present (Abstr_Op) then
2002 Next_Actual (Act_Parm);
2003 Next_Formal (Form_Parm);
2008 end Function_Interp_Has_Abstract_Op;
2010 ----------------------
2011 -- Get_First_Interp --
2012 ----------------------
2014 procedure Get_First_Interp
2016 I : out Interp_Index;
2019 Int_Ind : Interp_Index;
2024 -- If a selected component is overloaded because the selector has
2025 -- multiple interpretations, the node is a call to a protected
2026 -- operation or an indirect call. Retrieve the interpretation from
2027 -- the selector name. The selected component may be overloaded as well
2028 -- if the prefix is overloaded. That case is unchanged.
2030 if Nkind (N) = N_Selected_Component
2031 and then Is_Overloaded (Selector_Name (N))
2033 O_N := Selector_Name (N);
2038 Map_Ptr := Headers (Hash (O_N));
2039 while Present (Interp_Map.Table (Map_Ptr).Node) loop
2040 if Interp_Map.Table (Map_Ptr).Node = O_N then
2041 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2042 It := All_Interp.Table (Int_Ind);
2046 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2050 -- Procedure should never be called if the node has no interpretations
2052 raise Program_Error;
2053 end Get_First_Interp;
2055 ---------------------
2056 -- Get_Next_Interp --
2057 ---------------------
2059 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2062 It := All_Interp.Table (I);
2063 end Get_Next_Interp;
2065 -------------------------
2066 -- Has_Compatible_Type --
2067 -------------------------
2069 function Has_Compatible_Type
2082 if Nkind (N) = N_Subtype_Indication
2083 or else not Is_Overloaded (N)
2086 Covers (Typ, Etype (N))
2088 -- Ada 2005 (AI-345) The context may be a synchronized interface.
2089 -- If the type is already frozen use the corresponding_record
2090 -- to check whether it is a proper descendant.
2093 (Is_Concurrent_Type (Etype (N))
2094 and then Present (Corresponding_Record_Type (Etype (N)))
2095 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2098 (not Is_Tagged_Type (Typ)
2099 and then Ekind (Typ) /= E_Anonymous_Access_Type
2100 and then Covers (Etype (N), Typ));
2103 Get_First_Interp (N, I, It);
2104 while Present (It.Typ) loop
2105 if (Covers (Typ, It.Typ)
2107 (Scope (It.Nam) /= Standard_Standard
2108 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2110 -- Ada 2005 (AI-345)
2113 (Is_Concurrent_Type (It.Typ)
2114 and then Present (Corresponding_Record_Type
2116 and then Covers (Typ, Corresponding_Record_Type
2119 or else (not Is_Tagged_Type (Typ)
2120 and then Ekind (Typ) /= E_Anonymous_Access_Type
2121 and then Covers (It.Typ, Typ))
2126 Get_Next_Interp (I, It);
2131 end Has_Compatible_Type;
2133 ---------------------
2134 -- Has_Abstract_Op --
2135 ---------------------
2137 function Has_Abstract_Op
2139 Typ : Entity_Id) return Entity_Id
2145 if Is_Overloaded (N) then
2146 Get_First_Interp (N, I, It);
2147 while Present (It.Nam) loop
2148 if Present (It.Abstract_Op)
2149 and then Etype (It.Abstract_Op) = Typ
2151 return It.Abstract_Op;
2154 Get_Next_Interp (I, It);
2159 end Has_Abstract_Op;
2165 function Hash (N : Node_Id) return Int is
2167 -- Nodes have a size that is power of two, so to select significant
2168 -- bits only we remove the low-order bits.
2170 return ((Int (N) / 2 ** 5) mod Header_Size);
2177 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2178 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2180 return Operator_Matches_Spec (Op, F)
2181 and then (In_Open_Scopes (Scope (F))
2182 or else Scope (F) = Scope (Btyp)
2183 or else (not In_Open_Scopes (Scope (Btyp))
2184 and then not In_Use (Btyp)
2185 and then not In_Use (Scope (Btyp))));
2188 ------------------------
2189 -- Init_Interp_Tables --
2190 ------------------------
2192 procedure Init_Interp_Tables is
2196 Headers := (others => No_Entry);
2197 end Init_Interp_Tables;
2199 -----------------------------------
2200 -- Interface_Present_In_Ancestor --
2201 -----------------------------------
2203 function Interface_Present_In_Ancestor
2205 Iface : Entity_Id) return Boolean
2207 Target_Typ : Entity_Id;
2208 Iface_Typ : Entity_Id;
2210 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2211 -- Returns True if Typ or some ancestor of Typ implements Iface
2213 -------------------------------
2214 -- Iface_Present_In_Ancestor --
2215 -------------------------------
2217 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2223 if Typ = Iface_Typ then
2227 -- Handle private types
2229 if Present (Full_View (Typ))
2230 and then not Is_Concurrent_Type (Full_View (Typ))
2232 E := Full_View (Typ);
2238 if Present (Abstract_Interfaces (E))
2239 and then Present (Abstract_Interfaces (E))
2240 and then not Is_Empty_Elmt_List (Abstract_Interfaces (E))
2242 Elmt := First_Elmt (Abstract_Interfaces (E));
2243 while Present (Elmt) loop
2246 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2254 exit when Etype (E) = E
2256 -- Handle private types
2258 or else (Present (Full_View (Etype (E)))
2259 and then Full_View (Etype (E)) = E);
2261 -- Check if the current type is a direct derivation of the
2264 if Etype (E) = Iface_Typ then
2268 -- Climb to the immediate ancestor handling private types
2270 if Present (Full_View (Etype (E))) then
2271 E := Full_View (Etype (E));
2278 end Iface_Present_In_Ancestor;
2280 -- Start of processing for Interface_Present_In_Ancestor
2283 if Is_Class_Wide_Type (Iface) then
2284 Iface_Typ := Etype (Iface);
2291 Iface_Typ := Base_Type (Iface_Typ);
2293 if Is_Access_Type (Typ) then
2294 Target_Typ := Etype (Directly_Designated_Type (Typ));
2299 if Is_Concurrent_Record_Type (Target_Typ) then
2300 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2303 Target_Typ := Base_Type (Target_Typ);
2305 -- In case of concurrent types we can't use the Corresponding Record_Typ
2306 -- to look for the interface because it is built by the expander (and
2307 -- hence it is not always available). For this reason we traverse the
2308 -- list of interfaces (available in the parent of the concurrent type)
2310 if Is_Concurrent_Type (Target_Typ) then
2311 if Present (Interface_List (Parent (Target_Typ))) then
2316 AI := First (Interface_List (Parent (Target_Typ)));
2317 while Present (AI) loop
2318 if Etype (AI) = Iface_Typ then
2321 elsif Present (Abstract_Interfaces (Etype (AI)))
2322 and then Iface_Present_In_Ancestor (Etype (AI))
2335 if Is_Class_Wide_Type (Target_Typ) then
2336 Target_Typ := Etype (Target_Typ);
2339 if Ekind (Target_Typ) = E_Incomplete_Type then
2340 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2341 Target_Typ := Non_Limited_View (Target_Typ);
2343 -- Protect the frontend against previously detected errors
2345 if Ekind (Target_Typ) = E_Incomplete_Type then
2350 return Iface_Present_In_Ancestor (Target_Typ);
2351 end Interface_Present_In_Ancestor;
2353 ---------------------
2354 -- Intersect_Types --
2355 ---------------------
2357 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2358 Index : Interp_Index;
2362 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2363 -- Find interpretation of right arg that has type compatible with T
2365 --------------------------
2366 -- Check_Right_Argument --
2367 --------------------------
2369 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2370 Index : Interp_Index;
2375 if not Is_Overloaded (R) then
2376 return Specific_Type (T, Etype (R));
2379 Get_First_Interp (R, Index, It);
2381 T2 := Specific_Type (T, It.Typ);
2383 if T2 /= Any_Type then
2387 Get_Next_Interp (Index, It);
2388 exit when No (It.Typ);
2393 end Check_Right_Argument;
2395 -- Start processing for Intersect_Types
2398 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2402 if not Is_Overloaded (L) then
2403 Typ := Check_Right_Argument (Etype (L));
2407 Get_First_Interp (L, Index, It);
2408 while Present (It.Typ) loop
2409 Typ := Check_Right_Argument (It.Typ);
2410 exit when Typ /= Any_Type;
2411 Get_Next_Interp (Index, It);
2416 -- If Typ is Any_Type, it means no compatible pair of types was found
2418 if Typ = Any_Type then
2419 if Nkind (Parent (L)) in N_Op then
2420 Error_Msg_N ("incompatible types for operator", Parent (L));
2422 elsif Nkind (Parent (L)) = N_Range then
2423 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2425 -- Ada 2005 (AI-251): Complete the error notification
2427 elsif Is_Class_Wide_Type (Etype (R))
2428 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2430 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2431 L, Etype (Class_Wide_Type (Etype (R))));
2434 Error_Msg_N ("incompatible types", Parent (L));
2439 end Intersect_Types;
2445 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2449 if Base_Type (T1) = Base_Type (T2) then
2452 elsif Is_Private_Type (T1)
2453 and then Present (Full_View (T1))
2454 and then Base_Type (T2) = Base_Type (Full_View (T1))
2462 -- If there was a error on the type declaration, do not recurse
2464 if Error_Posted (Par) then
2467 elsif Base_Type (T1) = Base_Type (Par)
2468 or else (Is_Private_Type (T1)
2469 and then Present (Full_View (T1))
2470 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2474 elsif Is_Private_Type (Par)
2475 and then Present (Full_View (Par))
2476 and then Full_View (Par) = Base_Type (T1)
2480 elsif Etype (Par) /= Par then
2489 ---------------------------
2490 -- Is_Invisible_Operator --
2491 ---------------------------
2493 function Is_Invisible_Operator
2498 Orig_Node : constant Node_Id := Original_Node (N);
2501 if Nkind (N) not in N_Op then
2504 elsif not Comes_From_Source (N) then
2507 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2510 elsif Nkind (N) in N_Binary_Op
2511 and then No (Universal_Interpretation (Left_Opnd (N)))
2516 return Is_Numeric_Type (T)
2517 and then not In_Open_Scopes (Scope (T))
2518 and then not Is_Potentially_Use_Visible (T)
2519 and then not In_Use (T)
2520 and then not In_Use (Scope (T))
2522 (Nkind (Orig_Node) /= N_Function_Call
2523 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2524 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2525 and then not In_Instance;
2527 end Is_Invisible_Operator;
2533 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2537 S := Ancestor_Subtype (T1);
2538 while Present (S) loop
2542 S := Ancestor_Subtype (S);
2553 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2554 Index : Interp_Index;
2558 Get_First_Interp (Nam, Index, It);
2559 while Present (It.Nam) loop
2560 if Scope (It.Nam) = Standard_Standard
2561 and then Scope (It.Typ) /= Standard_Standard
2563 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2564 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2567 Error_Msg_Sloc := Sloc (It.Nam);
2568 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2571 Get_Next_Interp (Index, It);
2579 procedure New_Interps (N : Node_Id) is
2583 All_Interp.Increment_Last;
2584 All_Interp.Table (All_Interp.Last) := No_Interp;
2586 Map_Ptr := Headers (Hash (N));
2588 if Map_Ptr = No_Entry then
2590 -- Place new node at end of table
2592 Interp_Map.Increment_Last;
2593 Headers (Hash (N)) := Interp_Map.Last;
2596 -- Place node at end of chain, or locate its previous entry
2599 if Interp_Map.Table (Map_Ptr).Node = N then
2601 -- Node is already in the table, and is being rewritten.
2602 -- Start a new interp section, retain hash link.
2604 Interp_Map.Table (Map_Ptr).Node := N;
2605 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2606 Set_Is_Overloaded (N, True);
2610 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2611 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2615 -- Chain the new node
2617 Interp_Map.Increment_Last;
2618 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2621 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2622 Set_Is_Overloaded (N, True);
2625 ---------------------------
2626 -- Operator_Matches_Spec --
2627 ---------------------------
2629 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2630 Op_Name : constant Name_Id := Chars (Op);
2631 T : constant Entity_Id := Etype (New_S);
2639 -- To verify that a predefined operator matches a given signature,
2640 -- do a case analysis of the operator classes. Function can have one
2641 -- or two formals and must have the proper result type.
2643 New_F := First_Formal (New_S);
2644 Old_F := First_Formal (Op);
2646 while Present (New_F) and then Present (Old_F) loop
2648 Next_Formal (New_F);
2649 Next_Formal (Old_F);
2652 -- Definite mismatch if different number of parameters
2654 if Present (Old_F) or else Present (New_F) then
2660 T1 := Etype (First_Formal (New_S));
2662 if Op_Name = Name_Op_Subtract
2663 or else Op_Name = Name_Op_Add
2664 or else Op_Name = Name_Op_Abs
2666 return Base_Type (T1) = Base_Type (T)
2667 and then Is_Numeric_Type (T);
2669 elsif Op_Name = Name_Op_Not then
2670 return Base_Type (T1) = Base_Type (T)
2671 and then Valid_Boolean_Arg (Base_Type (T));
2680 T1 := Etype (First_Formal (New_S));
2681 T2 := Etype (Next_Formal (First_Formal (New_S)));
2683 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2684 or else Op_Name = Name_Op_Xor
2686 return Base_Type (T1) = Base_Type (T2)
2687 and then Base_Type (T1) = Base_Type (T)
2688 and then Valid_Boolean_Arg (Base_Type (T));
2690 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2691 return Base_Type (T1) = Base_Type (T2)
2692 and then not Is_Limited_Type (T1)
2693 and then Is_Boolean_Type (T);
2695 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2696 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2698 return Base_Type (T1) = Base_Type (T2)
2699 and then Valid_Comparison_Arg (T1)
2700 and then Is_Boolean_Type (T);
2702 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2703 return Base_Type (T1) = Base_Type (T2)
2704 and then Base_Type (T1) = Base_Type (T)
2705 and then Is_Numeric_Type (T);
2707 -- for division and multiplication, a user-defined function does
2708 -- not match the predefined universal_fixed operation, except in
2711 elsif Op_Name = Name_Op_Divide then
2712 return (Base_Type (T1) = Base_Type (T2)
2713 and then Base_Type (T1) = Base_Type (T)
2714 and then Is_Numeric_Type (T)
2715 and then (not Is_Fixed_Point_Type (T)
2716 or else Ada_Version = Ada_83))
2718 -- Mixed_Mode operations on fixed-point types
2720 or else (Base_Type (T1) = Base_Type (T)
2721 and then Base_Type (T2) = Base_Type (Standard_Integer)
2722 and then Is_Fixed_Point_Type (T))
2724 -- A user defined operator can also match (and hide) a mixed
2725 -- operation on universal literals.
2727 or else (Is_Integer_Type (T2)
2728 and then Is_Floating_Point_Type (T1)
2729 and then Base_Type (T1) = Base_Type (T));
2731 elsif Op_Name = Name_Op_Multiply then
2732 return (Base_Type (T1) = Base_Type (T2)
2733 and then Base_Type (T1) = Base_Type (T)
2734 and then Is_Numeric_Type (T)
2735 and then (not Is_Fixed_Point_Type (T)
2736 or else Ada_Version = Ada_83))
2738 -- Mixed_Mode operations on fixed-point types
2740 or else (Base_Type (T1) = Base_Type (T)
2741 and then Base_Type (T2) = Base_Type (Standard_Integer)
2742 and then Is_Fixed_Point_Type (T))
2744 or else (Base_Type (T2) = Base_Type (T)
2745 and then Base_Type (T1) = Base_Type (Standard_Integer)
2746 and then Is_Fixed_Point_Type (T))
2748 or else (Is_Integer_Type (T2)
2749 and then Is_Floating_Point_Type (T1)
2750 and then Base_Type (T1) = Base_Type (T))
2752 or else (Is_Integer_Type (T1)
2753 and then Is_Floating_Point_Type (T2)
2754 and then Base_Type (T2) = Base_Type (T));
2756 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2757 return Base_Type (T1) = Base_Type (T2)
2758 and then Base_Type (T1) = Base_Type (T)
2759 and then Is_Integer_Type (T);
2761 elsif Op_Name = Name_Op_Expon then
2762 return Base_Type (T1) = Base_Type (T)
2763 and then Is_Numeric_Type (T)
2764 and then Base_Type (T2) = Base_Type (Standard_Integer);
2766 elsif Op_Name = Name_Op_Concat then
2767 return Is_Array_Type (T)
2768 and then (Base_Type (T) = Base_Type (Etype (Op)))
2769 and then (Base_Type (T1) = Base_Type (T)
2771 Base_Type (T1) = Base_Type (Component_Type (T)))
2772 and then (Base_Type (T2) = Base_Type (T)
2774 Base_Type (T2) = Base_Type (Component_Type (T)));
2780 end Operator_Matches_Spec;
2786 procedure Remove_Interp (I : in out Interp_Index) is
2790 -- Find end of Interp list and copy downward to erase the discarded one
2793 while Present (All_Interp.Table (II).Typ) loop
2797 for J in I + 1 .. II loop
2798 All_Interp.Table (J - 1) := All_Interp.Table (J);
2801 -- Back up interp. index to insure that iterator will pick up next
2802 -- available interpretation.
2811 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2813 O_N : Node_Id := Old_N;
2816 if Is_Overloaded (Old_N) then
2817 if Nkind (Old_N) = N_Selected_Component
2818 and then Is_Overloaded (Selector_Name (Old_N))
2820 O_N := Selector_Name (Old_N);
2823 Map_Ptr := Headers (Hash (O_N));
2825 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2826 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2827 pragma Assert (Map_Ptr /= No_Entry);
2830 New_Interps (New_N);
2831 Interp_Map.Table (Interp_Map.Last).Index :=
2832 Interp_Map.Table (Map_Ptr).Index;
2840 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2841 T1 : constant Entity_Id := Available_View (Typ_1);
2842 T2 : constant Entity_Id := Available_View (Typ_2);
2843 B1 : constant Entity_Id := Base_Type (T1);
2844 B2 : constant Entity_Id := Base_Type (T2);
2846 function Is_Remote_Access (T : Entity_Id) return Boolean;
2847 -- Check whether T is the equivalent type of a remote access type.
2848 -- If distribution is enabled, T is a legal context for Null.
2850 ----------------------
2851 -- Is_Remote_Access --
2852 ----------------------
2854 function Is_Remote_Access (T : Entity_Id) return Boolean is
2856 return Is_Record_Type (T)
2857 and then (Is_Remote_Call_Interface (T)
2858 or else Is_Remote_Types (T))
2859 and then Present (Corresponding_Remote_Type (T))
2860 and then Is_Access_Type (Corresponding_Remote_Type (T));
2861 end Is_Remote_Access;
2863 -- Start of processing for Specific_Type
2866 if T1 = Any_Type or else T2 = Any_Type then
2873 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2874 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2875 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2876 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2880 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2881 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2882 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2883 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2887 elsif T2 = Any_String and then Is_String_Type (T1) then
2890 elsif T1 = Any_String and then Is_String_Type (T2) then
2893 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2896 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2899 elsif T1 = Any_Access
2900 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2904 elsif T2 = Any_Access
2905 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
2909 elsif T2 = Any_Composite
2910 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
2914 elsif T1 = Any_Composite
2915 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
2919 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
2922 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
2925 -- ----------------------------------------------------------
2926 -- Special cases for equality operators (all other predefined
2927 -- operators can never apply to tagged types)
2928 -- ----------------------------------------------------------
2930 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
2933 elsif Is_Class_Wide_Type (T1)
2934 and then Is_Class_Wide_Type (T2)
2935 and then Is_Interface (Etype (T2))
2939 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
2940 -- class-wide interface T2
2942 elsif Is_Class_Wide_Type (T2)
2943 and then Is_Interface (Etype (T2))
2944 and then Interface_Present_In_Ancestor (Typ => T1,
2945 Iface => Etype (T2))
2949 elsif Is_Class_Wide_Type (T1)
2950 and then Is_Ancestor (Root_Type (T1), T2)
2954 elsif Is_Class_Wide_Type (T2)
2955 and then Is_Ancestor (Root_Type (T2), T1)
2959 elsif (Ekind (B1) = E_Access_Subprogram_Type
2961 Ekind (B1) = E_Access_Protected_Subprogram_Type)
2962 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
2963 and then Is_Access_Type (T2)
2967 elsif (Ekind (B2) = E_Access_Subprogram_Type
2969 Ekind (B2) = E_Access_Protected_Subprogram_Type)
2970 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
2971 and then Is_Access_Type (T1)
2975 elsif (Ekind (T1) = E_Allocator_Type
2976 or else Ekind (T1) = E_Access_Attribute_Type
2977 or else Ekind (T1) = E_Anonymous_Access_Type)
2978 and then Is_Access_Type (T2)
2982 elsif (Ekind (T2) = E_Allocator_Type
2983 or else Ekind (T2) = E_Access_Attribute_Type
2984 or else Ekind (T2) = E_Anonymous_Access_Type)
2985 and then Is_Access_Type (T1)
2989 -- If none of the above cases applies, types are not compatible
2996 ---------------------
2997 -- Set_Abstract_Op --
2998 ---------------------
3000 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3002 All_Interp.Table (I).Abstract_Op := V;
3003 end Set_Abstract_Op;
3005 -----------------------
3006 -- Valid_Boolean_Arg --
3007 -----------------------
3009 -- In addition to booleans and arrays of booleans, we must include
3010 -- aggregates as valid boolean arguments, because in the first pass of
3011 -- resolution their components are not examined. If it turns out not to be
3012 -- an aggregate of booleans, this will be diagnosed in Resolve.
3013 -- Any_Composite must be checked for prior to the array type checks because
3014 -- Any_Composite does not have any associated indexes.
3016 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3018 return Is_Boolean_Type (T)
3019 or else T = Any_Composite
3020 or else (Is_Array_Type (T)
3021 and then T /= Any_String
3022 and then Number_Dimensions (T) = 1
3023 and then Is_Boolean_Type (Component_Type (T))
3024 and then (not Is_Private_Composite (T)
3025 or else In_Instance)
3026 and then (not Is_Limited_Composite (T)
3027 or else In_Instance))
3028 or else Is_Modular_Integer_Type (T)
3029 or else T = Universal_Integer;
3030 end Valid_Boolean_Arg;
3032 --------------------------
3033 -- Valid_Comparison_Arg --
3034 --------------------------
3036 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3039 if T = Any_Composite then
3041 elsif Is_Discrete_Type (T)
3042 or else Is_Real_Type (T)
3045 elsif Is_Array_Type (T)
3046 and then Number_Dimensions (T) = 1
3047 and then Is_Discrete_Type (Component_Type (T))
3048 and then (not Is_Private_Composite (T)
3049 or else In_Instance)
3050 and then (not Is_Limited_Composite (T)
3051 or else In_Instance)
3054 elsif Is_String_Type (T) then
3059 end Valid_Comparison_Arg;
3061 ----------------------
3062 -- Write_Interp_Ref --
3063 ----------------------
3065 procedure Write_Interp_Ref (Map_Ptr : Int) is
3067 Write_Str (" Node: ");
3068 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3069 Write_Str (" Index: ");
3070 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3071 Write_Str (" Next: ");
3072 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3074 end Write_Interp_Ref;
3076 ---------------------
3077 -- Write_Overloads --
3078 ---------------------
3080 procedure Write_Overloads (N : Node_Id) is
3086 if not Is_Overloaded (N) then
3087 Write_Str ("Non-overloaded entity ");
3089 Write_Entity_Info (Entity (N), " ");
3092 Get_First_Interp (N, I, It);
3093 Write_Str ("Overloaded entity ");
3095 Write_Str (" Name Type Abstract Op");
3097 Write_Str ("===============================================");
3101 while Present (Nam) loop
3102 Write_Int (Int (Nam));
3104 Write_Name (Chars (Nam));
3106 Write_Int (Int (It.Typ));
3108 Write_Name (Chars (It.Typ));
3110 if Present (It.Abstract_Op) then
3112 Write_Int (Int (It.Abstract_Op));
3114 Write_Name (Chars (It.Abstract_Op));
3118 Get_Next_Interp (I, It);
3122 end Write_Overloads;