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 Get_First_Interp (Name (N), I, It);
501 Add_Entry (It.Nam, Etype (N));
505 -- Overloaded prefix in indexed or selected component,
506 -- or call whose name is an expression or another call.
508 Add_Entry (Etype (N), Etype (N));
522 procedure All_Overloads is
524 for J in All_Interp.First .. All_Interp.Last loop
526 if Present (All_Interp.Table (J).Nam) then
527 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
529 Write_Str ("No Interp");
532 Write_Str ("=================");
537 --------------------------------------
538 -- Binary_Op_Interp_Has_Abstract_Op --
539 --------------------------------------
541 function Binary_Op_Interp_Has_Abstract_Op
543 E : Entity_Id) return Entity_Id
545 Abstr_Op : Entity_Id;
546 E_Left : constant Node_Id := First_Formal (E);
547 E_Right : constant Node_Id := Next_Formal (E_Left);
550 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
551 if Present (Abstr_Op) then
555 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
556 end Binary_Op_Interp_Has_Abstract_Op;
558 ---------------------
559 -- Collect_Interps --
560 ---------------------
562 procedure Collect_Interps (N : Node_Id) is
563 Ent : constant Entity_Id := Entity (N);
565 First_Interp : Interp_Index;
570 -- Unconditionally add the entity that was initially matched
572 First_Interp := All_Interp.Last;
573 Add_One_Interp (N, Ent, Etype (N));
575 -- For expanded name, pick up all additional entities from the
576 -- same scope, since these are obviously also visible. Note that
577 -- these are not necessarily contiguous on the homonym chain.
579 if Nkind (N) = N_Expanded_Name then
581 while Present (H) loop
582 if Scope (H) = Scope (Entity (N)) then
583 Add_One_Interp (N, H, Etype (H));
589 -- Case of direct name
592 -- First, search the homonym chain for directly visible entities
594 H := Current_Entity (Ent);
595 while Present (H) loop
596 exit when (not Is_Overloadable (H))
597 and then Is_Immediately_Visible (H);
599 if Is_Immediately_Visible (H)
602 -- Only add interpretation if not hidden by an inner
603 -- immediately visible one.
605 for J in First_Interp .. All_Interp.Last - 1 loop
607 -- Current homograph is not hidden. Add to overloads
609 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
612 -- Homograph is hidden, unless it is a predefined operator
614 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
616 -- A homograph in the same scope can occur within an
617 -- instantiation, the resulting ambiguity has to be
620 if Scope (H) = Scope (Ent)
622 and then not Is_Inherited_Operation (H)
624 All_Interp.Table (All_Interp.Last) :=
625 (H, Etype (H), Empty);
626 All_Interp.Increment_Last;
627 All_Interp.Table (All_Interp.Last) := No_Interp;
630 elsif Scope (H) /= Standard_Standard then
636 -- On exit, we know that current homograph is not hidden
638 Add_One_Interp (N, H, Etype (H));
641 Write_Str ("Add overloaded Interpretation ");
651 -- Scan list of homographs for use-visible entities only
653 H := Current_Entity (Ent);
655 while Present (H) loop
656 if Is_Potentially_Use_Visible (H)
658 and then Is_Overloadable (H)
660 for J in First_Interp .. All_Interp.Last - 1 loop
662 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
665 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
666 goto Next_Use_Homograph;
670 Add_One_Interp (N, H, Etype (H));
673 <<Next_Use_Homograph>>
678 if All_Interp.Last = First_Interp + 1 then
680 -- The original interpretation is in fact not overloaded
682 Set_Is_Overloaded (N, False);
690 function Covers (T1, T2 : Entity_Id) return Boolean is
695 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
696 -- In an instance the proper view may not always be correct for
697 -- private types, but private and full view are compatible. This
698 -- removes spurious errors from nested instantiations that involve,
699 -- among other things, types derived from private types.
701 ----------------------
702 -- Full_View_Covers --
703 ----------------------
705 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
708 Is_Private_Type (Typ1)
710 ((Present (Full_View (Typ1))
711 and then Covers (Full_View (Typ1), Typ2))
712 or else Base_Type (Typ1) = Typ2
713 or else Base_Type (Typ2) = Typ1);
714 end Full_View_Covers;
716 -- Start of processing for Covers
719 -- If either operand missing, then this is an error, but ignore it (and
720 -- pretend we have a cover) if errors already detected, since this may
721 -- simply mean we have malformed trees.
723 if No (T1) or else No (T2) then
724 if Total_Errors_Detected /= 0 then
731 BT1 := Base_Type (T1);
732 BT2 := Base_Type (T2);
735 -- Simplest case: same types are compatible, and types that have the
736 -- same base type and are not generic actuals are compatible. Generic
737 -- actuals belong to their class but are not compatible with other
738 -- types of their class, and in particular with other generic actuals.
739 -- They are however compatible with their own subtypes, and itypes
740 -- with the same base are compatible as well. Similarly, constrained
741 -- subtypes obtained from expressions of an unconstrained nominal type
742 -- are compatible with the base type (may lead to spurious ambiguities
743 -- in obscure cases ???)
745 -- Generic actuals require special treatment to avoid spurious ambi-
746 -- guities in an instance, when two formal types are instantiated with
747 -- the same actual, so that different subprograms end up with the same
748 -- signature in the instance.
757 if not Is_Generic_Actual_Type (T1) then
760 return (not Is_Generic_Actual_Type (T2)
761 or else Is_Itype (T1)
762 or else Is_Itype (T2)
763 or else Is_Constr_Subt_For_U_Nominal (T1)
764 or else Is_Constr_Subt_For_U_Nominal (T2)
765 or else Scope (T1) /= Scope (T2));
768 -- Literals are compatible with types in a given "class"
770 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
771 or else (T2 = Universal_Real and then Is_Real_Type (T1))
772 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
773 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
774 or else (T2 = Any_String and then Is_String_Type (T1))
775 or else (T2 = Any_Character and then Is_Character_Type (T1))
776 or else (T2 = Any_Access and then Is_Access_Type (T1))
780 -- The context may be class wide
782 elsif Is_Class_Wide_Type (T1)
783 and then Is_Ancestor (Root_Type (T1), T2)
787 elsif Is_Class_Wide_Type (T1)
788 and then Is_Class_Wide_Type (T2)
789 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
793 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
794 -- task_type or protected_type implementing T1
796 elsif Ada_Version >= Ada_05
797 and then Is_Class_Wide_Type (T1)
798 and then Is_Interface (Etype (T1))
799 and then Is_Concurrent_Type (T2)
800 and then Interface_Present_In_Ancestor
801 (Typ => Base_Type (T2),
806 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
807 -- object T2 implementing T1
809 elsif Ada_Version >= Ada_05
810 and then Is_Class_Wide_Type (T1)
811 and then Is_Interface (Etype (T1))
812 and then Is_Tagged_Type (T2)
814 if Interface_Present_In_Ancestor (Typ => T2,
825 if Is_Concurrent_Type (BT2) then
826 E := Corresponding_Record_Type (BT2);
831 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
832 -- covers an object T2 that implements a direct derivation of T1.
833 -- Note: test for presence of E is defense against previous error.
836 and then Present (Abstract_Interfaces (E))
838 Elmt := First_Elmt (Abstract_Interfaces (E));
839 while Present (Elmt) loop
840 if Is_Ancestor (Etype (T1), Node (Elmt)) then
848 -- We should also check the case in which T1 is an ancestor of
849 -- some implemented interface???
854 -- In a dispatching call the actual may be class-wide
856 elsif Is_Class_Wide_Type (T2)
857 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
861 -- Some contexts require a class of types rather than a specific type
863 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
864 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
865 or else (T1 = Any_Real and then Is_Real_Type (T2))
866 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
867 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
871 -- An aggregate is compatible with an array or record type
873 elsif T2 = Any_Composite
874 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
878 -- If the expected type is an anonymous access, the designated type must
879 -- cover that of the expression. Use the base type for this check: even
880 -- though access subtypes are rare in sources, they are generated for
881 -- actuals in instantiations.
883 elsif Ekind (BT1) = E_Anonymous_Access_Type
884 and then Is_Access_Type (T2)
885 and then Covers (Designated_Type (T1), Designated_Type (T2))
889 -- An Access_To_Subprogram is compatible with itself, or with an
890 -- anonymous type created for an attribute reference Access.
892 elsif (Ekind (BT1) = E_Access_Subprogram_Type
894 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
895 and then Is_Access_Type (T2)
896 and then (not Comes_From_Source (T1)
897 or else not Comes_From_Source (T2))
898 and then (Is_Overloadable (Designated_Type (T2))
900 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
902 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
904 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
908 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
909 -- with itself, or with an anonymous type created for an attribute
912 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
915 = E_Anonymous_Access_Protected_Subprogram_Type)
916 and then Is_Access_Type (T2)
917 and then (not Comes_From_Source (T1)
918 or else not Comes_From_Source (T2))
919 and then (Is_Overloadable (Designated_Type (T2))
921 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
923 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
925 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
929 -- The context can be a remote access type, and the expression the
930 -- corresponding source type declared in a categorized package, or
933 elsif Is_Record_Type (T1)
934 and then (Is_Remote_Call_Interface (T1)
935 or else Is_Remote_Types (T1))
936 and then Present (Corresponding_Remote_Type (T1))
938 return Covers (Corresponding_Remote_Type (T1), T2);
940 elsif Is_Record_Type (T2)
941 and then (Is_Remote_Call_Interface (T2)
942 or else Is_Remote_Types (T2))
943 and then Present (Corresponding_Remote_Type (T2))
945 return Covers (Corresponding_Remote_Type (T2), T1);
947 elsif Ekind (T2) = E_Access_Attribute_Type
948 and then (Ekind (BT1) = E_General_Access_Type
949 or else Ekind (BT1) = E_Access_Type)
950 and then Covers (Designated_Type (T1), Designated_Type (T2))
952 -- If the target type is a RACW type while the source is an access
953 -- attribute type, we are building a RACW that may be exported.
955 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
956 Set_Has_RACW (Current_Sem_Unit);
961 elsif Ekind (T2) = E_Allocator_Type
962 and then Is_Access_Type (T1)
964 return Covers (Designated_Type (T1), Designated_Type (T2))
966 (From_With_Type (Designated_Type (T1))
967 and then Covers (Designated_Type (T2), Designated_Type (T1)));
969 -- A boolean operation on integer literals is compatible with modular
972 elsif T2 = Any_Modular
973 and then Is_Modular_Integer_Type (T1)
977 -- The actual type may be the result of a previous error
979 elsif Base_Type (T2) = Any_Type then
982 -- A packed array type covers its corresponding non-packed type. This is
983 -- not legitimate Ada, but allows the omission of a number of otherwise
984 -- useless unchecked conversions, and since this can only arise in
985 -- (known correct) expanded code, no harm is done
987 elsif Is_Array_Type (T2)
988 and then Is_Packed (T2)
989 and then T1 = Packed_Array_Type (T2)
993 -- Similarly an array type covers its corresponding packed array type
995 elsif Is_Array_Type (T1)
996 and then Is_Packed (T1)
997 and then T2 = Packed_Array_Type (T1)
1001 -- In instances, or with types exported from instantiations, check
1002 -- whether a partial and a full view match. Verify that types are
1003 -- legal, to prevent cascaded errors.
1007 (Full_View_Covers (T1, T2)
1008 or else Full_View_Covers (T2, T1))
1013 and then Is_Generic_Actual_Type (T2)
1014 and then Full_View_Covers (T1, T2)
1019 and then Is_Generic_Actual_Type (T1)
1020 and then Full_View_Covers (T2, T1)
1024 -- In the expansion of inlined bodies, types are compatible if they
1025 -- are structurally equivalent.
1027 elsif In_Inlined_Body
1028 and then (Underlying_Type (T1) = Underlying_Type (T2)
1029 or else (Is_Access_Type (T1)
1030 and then Is_Access_Type (T2)
1032 Designated_Type (T1) = Designated_Type (T2))
1033 or else (T1 = Any_Access
1034 and then Is_Access_Type (Underlying_Type (T2)))
1035 or else (T2 = Any_Composite
1037 Is_Composite_Type (Underlying_Type (T1))))
1041 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1042 -- compatible with its real entity.
1044 elsif From_With_Type (T1) then
1046 -- If the expected type is the non-limited view of a type, the
1047 -- expression may have the limited view. If that one in turn is
1048 -- incomplete, get full view if available.
1050 if Is_Incomplete_Type (T1) then
1051 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1053 elsif Ekind (T1) = E_Class_Wide_Type then
1055 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1060 elsif From_With_Type (T2) then
1062 -- If units in the context have Limited_With clauses on each other,
1063 -- either type might have a limited view. Checks performed elsewhere
1064 -- verify that the context type is the non-limited view.
1066 if Is_Incomplete_Type (T2) then
1067 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1069 elsif Ekind (T2) = E_Class_Wide_Type then
1071 Present (Non_Limited_View (Etype (T2)))
1073 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1078 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1080 elsif Ekind (T1) = E_Incomplete_Subtype then
1081 return Covers (Full_View (Etype (T1)), T2);
1083 elsif Ekind (T2) = E_Incomplete_Subtype then
1084 return Covers (T1, Full_View (Etype (T2)));
1086 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1087 -- and actual anonymous access types in the context of generic
1088 -- instantiation. We have the following situation:
1091 -- type Formal is private;
1092 -- Formal_Obj : access Formal; -- T1
1096 -- type Actual is ...
1097 -- Actual_Obj : access Actual; -- T2
1098 -- package Instance is new G (Formal => Actual,
1099 -- Formal_Obj => Actual_Obj);
1101 elsif Ada_Version >= Ada_05
1102 and then Ekind (T1) = E_Anonymous_Access_Type
1103 and then Ekind (T2) = E_Anonymous_Access_Type
1104 and then Is_Generic_Type (Directly_Designated_Type (T1))
1105 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1106 Directly_Designated_Type (T2)
1110 -- Otherwise it doesn't cover!
1121 function Disambiguate
1123 I1, I2 : Interp_Index;
1130 Nam1, Nam2 : Entity_Id;
1131 Predef_Subp : Entity_Id;
1132 User_Subp : Entity_Id;
1134 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1135 -- Determine whether one of the candidates is an operation inherited by
1136 -- a type that is derived from an actual in an instantiation.
1138 function In_Generic_Actual (Exp : Node_Id) return Boolean;
1139 -- Determine whether the expression is part of a generic actual. At
1140 -- the time the actual is resolved the scope is already that of the
1141 -- instance, but conceptually the resolution of the actual takes place
1142 -- in the enclosing context, and no special disambiguation rules should
1145 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1146 -- Determine whether a subprogram is an actual in an enclosing instance.
1147 -- An overloading between such a subprogram and one declared outside the
1148 -- instance is resolved in favor of the first, because it resolved in
1151 function Matches (Actual, Formal : Node_Id) return Boolean;
1152 -- Look for exact type match in an instance, to remove spurious
1153 -- ambiguities when two formal types have the same actual.
1155 function Standard_Operator return Boolean;
1156 -- Check whether subprogram is predefined operator declared in Standard.
1157 -- It may given by an operator name, or by an expanded name whose prefix
1160 function Remove_Conversions return Interp;
1161 -- Last chance for pathological cases involving comparisons on literals,
1162 -- and user overloadings of the same operator. Such pathologies have
1163 -- been removed from the ACVC, but still appear in two DEC tests, with
1164 -- the following notable quote from Ben Brosgol:
1166 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1167 -- this example; Robert Dewar brought it to our attention, since it is
1168 -- apparently found in the ACVC 1.5. I did not attempt to find the
1169 -- reason in the Reference Manual that makes the example legal, since I
1170 -- was too nauseated by it to want to pursue it further.]
1172 -- Accordingly, this is not a fully recursive solution, but it handles
1173 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1174 -- pathology in the other direction with calls whose multiple overloaded
1175 -- actuals make them truly unresolvable.
1177 -- The new rules concerning abstract operations create additional need
1178 -- for special handling of expressions with universal operands, see
1179 -- comments to Has_Abstract_Interpretation below.
1181 ------------------------
1182 -- In_Generic_Actual --
1183 ------------------------
1185 function In_Generic_Actual (Exp : Node_Id) return Boolean is
1186 Par : constant Node_Id := Parent (Exp);
1192 elsif Nkind (Par) in N_Declaration then
1193 if Nkind (Par) = N_Object_Declaration
1194 or else Nkind (Par) = N_Object_Renaming_Declaration
1196 return Present (Corresponding_Generic_Association (Par));
1201 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
1205 return In_Generic_Actual (Parent (Par));
1207 end In_Generic_Actual;
1209 ---------------------------
1210 -- Inherited_From_Actual --
1211 ---------------------------
1213 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1214 Par : constant Node_Id := Parent (S);
1216 if Nkind (Par) /= N_Full_Type_Declaration
1217 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1221 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1223 Is_Generic_Actual_Type (
1224 Entity (Subtype_Indication (Type_Definition (Par))));
1226 end Inherited_From_Actual;
1228 --------------------------
1229 -- Is_Actual_Subprogram --
1230 --------------------------
1232 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1234 return In_Open_Scopes (Scope (S))
1236 (Is_Generic_Instance (Scope (S))
1237 or else Is_Wrapper_Package (Scope (S)));
1238 end Is_Actual_Subprogram;
1244 function Matches (Actual, Formal : Node_Id) return Boolean is
1245 T1 : constant Entity_Id := Etype (Actual);
1246 T2 : constant Entity_Id := Etype (Formal);
1250 (Is_Numeric_Type (T2)
1252 (T1 = Universal_Real or else T1 = Universal_Integer));
1255 ------------------------
1256 -- Remove_Conversions --
1257 ------------------------
1259 function Remove_Conversions return Interp is
1267 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1268 -- If an operation has universal operands the universal operation
1269 -- is present among its interpretations. If there is an abstract
1270 -- interpretation for the operator, with a numeric result, this
1271 -- interpretation was already removed in sem_ch4, but the universal
1272 -- one is still visible. We must rescan the list of operators and
1273 -- remove the universal interpretation to resolve the ambiguity.
1275 ---------------------------------
1276 -- Has_Abstract_Interpretation --
1277 ---------------------------------
1279 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1283 if Nkind (N) not in N_Op
1284 or else Ada_Version < Ada_05
1285 or else not Is_Overloaded (N)
1286 or else No (Universal_Interpretation (N))
1291 E := Get_Name_Entity_Id (Chars (N));
1292 while Present (E) loop
1293 if Is_Overloadable (E)
1294 and then Is_Abstract_Subprogram (E)
1295 and then Is_Numeric_Type (Etype (E))
1303 -- Finally, if an operand of the binary operator is itself
1304 -- an operator, recurse to see whether its own abstract
1305 -- interpretation is responsible for the spurious ambiguity.
1307 if Nkind (N) in N_Binary_Op then
1308 return Has_Abstract_Interpretation (Left_Opnd (N))
1309 or else Has_Abstract_Interpretation (Right_Opnd (N));
1311 elsif Nkind (N) in N_Unary_Op then
1312 return Has_Abstract_Interpretation (Right_Opnd (N));
1318 end Has_Abstract_Interpretation;
1320 -- Start of processing for Remove_Conversions
1325 Get_First_Interp (N, I, It);
1326 while Present (It.Typ) loop
1327 if not Is_Overloadable (It.Nam) then
1331 F1 := First_Formal (It.Nam);
1337 if Nkind (N) = N_Function_Call
1338 or else Nkind (N) = N_Procedure_Call_Statement
1340 Act1 := First_Actual (N);
1342 if Present (Act1) then
1343 Act2 := Next_Actual (Act1);
1348 elsif Nkind (N) in N_Unary_Op then
1349 Act1 := Right_Opnd (N);
1352 elsif Nkind (N) in N_Binary_Op then
1353 Act1 := Left_Opnd (N);
1354 Act2 := Right_Opnd (N);
1356 -- Use type of second formal, so as to include
1357 -- exponentiation, where the exponent may be
1358 -- ambiguous and the result non-universal.
1366 if Nkind (Act1) in N_Op
1367 and then Is_Overloaded (Act1)
1368 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1369 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1370 and then Has_Compatible_Type (Act1, Standard_Boolean)
1371 and then Etype (F1) = Standard_Boolean
1373 -- If the two candidates are the original ones, the
1374 -- ambiguity is real. Otherwise keep the original, further
1375 -- calls to Disambiguate will take care of others in the
1376 -- list of candidates.
1378 if It1 /= No_Interp then
1379 if It = Disambiguate.It1
1380 or else It = Disambiguate.It2
1382 if It1 = Disambiguate.It1
1383 or else It1 = Disambiguate.It2
1391 elsif Present (Act2)
1392 and then Nkind (Act2) in N_Op
1393 and then Is_Overloaded (Act2)
1394 and then (Nkind (Right_Opnd (Act2)) = N_Integer_Literal
1396 Nkind (Right_Opnd (Act2)) = N_Real_Literal)
1397 and then Has_Compatible_Type (Act2, Standard_Boolean)
1399 -- The preference rule on the first actual is not
1400 -- sufficient to disambiguate.
1408 elsif Is_Numeric_Type (Etype (F1))
1410 (Has_Abstract_Interpretation (Act1)
1411 or else Has_Abstract_Interpretation (Act2))
1413 if It = Disambiguate.It1 then
1414 return Disambiguate.It2;
1415 elsif It = Disambiguate.It2 then
1416 return Disambiguate.It1;
1422 Get_Next_Interp (I, It);
1425 -- After some error, a formal may have Any_Type and yield a spurious
1426 -- match. To avoid cascaded errors if possible, check for such a
1427 -- formal in either candidate.
1429 if Serious_Errors_Detected > 0 then
1434 Formal := First_Formal (Nam1);
1435 while Present (Formal) loop
1436 if Etype (Formal) = Any_Type then
1437 return Disambiguate.It2;
1440 Next_Formal (Formal);
1443 Formal := First_Formal (Nam2);
1444 while Present (Formal) loop
1445 if Etype (Formal) = Any_Type then
1446 return Disambiguate.It1;
1449 Next_Formal (Formal);
1455 end Remove_Conversions;
1457 -----------------------
1458 -- Standard_Operator --
1459 -----------------------
1461 function Standard_Operator return Boolean is
1465 if Nkind (N) in N_Op then
1468 elsif Nkind (N) = N_Function_Call then
1471 if Nkind (Nam) /= N_Expanded_Name then
1474 return Entity (Prefix (Nam)) = Standard_Standard;
1479 end Standard_Operator;
1481 -- Start of processing for Disambiguate
1484 -- Recover the two legal interpretations
1486 Get_First_Interp (N, I, It);
1488 Get_Next_Interp (I, It);
1494 Get_Next_Interp (I, It);
1500 if Ada_Version < Ada_05 then
1502 -- Check whether one of the entities is an Ada 2005 entity and we are
1503 -- operating in an earlier mode, in which case we discard the Ada
1504 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1506 if Is_Ada_2005_Only (Nam1) then
1508 elsif Is_Ada_2005_Only (Nam2) then
1513 -- Check for overloaded CIL convention stuff because the CIL libraries
1514 -- do sick things like Console.WriteLine where it matches
1515 -- two different overloads, so just pick the first ???
1517 if Convention (Nam1) = Convention_CIL
1518 and then Convention (Nam2) = Convention_CIL
1519 and then Ekind (Nam1) = Ekind (Nam2)
1520 and then (Ekind (Nam1) = E_Procedure
1521 or else Ekind (Nam1) = E_Function)
1526 -- If the context is universal, the predefined operator is preferred.
1527 -- This includes bounds in numeric type declarations, and expressions
1528 -- in type conversions. If no interpretation yields a universal type,
1529 -- then we must check whether the user-defined entity hides the prede-
1532 if Chars (Nam1) in Any_Operator_Name
1533 and then Standard_Operator
1535 if Typ = Universal_Integer
1536 or else Typ = Universal_Real
1537 or else Typ = Any_Integer
1538 or else Typ = Any_Discrete
1539 or else Typ = Any_Real
1540 or else Typ = Any_Type
1542 -- Find an interpretation that yields the universal type, or else
1543 -- a predefined operator that yields a predefined numeric type.
1546 Candidate : Interp := No_Interp;
1549 Get_First_Interp (N, I, It);
1550 while Present (It.Typ) loop
1551 if (Covers (Typ, It.Typ)
1552 or else Typ = Any_Type)
1554 (It.Typ = Universal_Integer
1555 or else It.Typ = Universal_Real)
1559 elsif Covers (Typ, It.Typ)
1560 and then Scope (It.Typ) = Standard_Standard
1561 and then Scope (It.Nam) = Standard_Standard
1562 and then Is_Numeric_Type (It.Typ)
1567 Get_Next_Interp (I, It);
1570 if Candidate /= No_Interp then
1575 elsif Chars (Nam1) /= Name_Op_Not
1576 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1578 -- Equality or comparison operation. Choose predefined operator if
1579 -- arguments are universal. The node may be an operator, name, or
1580 -- a function call, so unpack arguments accordingly.
1583 Arg1, Arg2 : Node_Id;
1586 if Nkind (N) in N_Op then
1587 Arg1 := Left_Opnd (N);
1588 Arg2 := Right_Opnd (N);
1590 elsif Is_Entity_Name (N)
1591 or else Nkind (N) = N_Operator_Symbol
1593 Arg1 := First_Entity (Entity (N));
1594 Arg2 := Next_Entity (Arg1);
1597 Arg1 := First_Actual (N);
1598 Arg2 := Next_Actual (Arg1);
1602 and then Present (Universal_Interpretation (Arg1))
1603 and then Universal_Interpretation (Arg2) =
1604 Universal_Interpretation (Arg1)
1606 Get_First_Interp (N, I, It);
1607 while Scope (It.Nam) /= Standard_Standard loop
1608 Get_Next_Interp (I, It);
1617 -- If no universal interpretation, check whether user-defined operator
1618 -- hides predefined one, as well as other special cases. If the node
1619 -- is a range, then one or both bounds are ambiguous. Each will have
1620 -- to be disambiguated w.r.t. the context type. The type of the range
1621 -- itself is imposed by the context, so we can return either legal
1624 if Ekind (Nam1) = E_Operator then
1625 Predef_Subp := Nam1;
1628 elsif Ekind (Nam2) = E_Operator then
1629 Predef_Subp := Nam2;
1632 elsif Nkind (N) = N_Range then
1635 -- If two user defined-subprograms are visible, it is a true ambiguity,
1636 -- unless one of them is an entry and the context is a conditional or
1637 -- timed entry call, or unless we are within an instance and this is
1638 -- results from two formals types with the same actual.
1641 if Nkind (N) = N_Procedure_Call_Statement
1642 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1643 and then N = Entry_Call_Statement (Parent (N))
1645 if Ekind (Nam2) = E_Entry then
1647 elsif Ekind (Nam1) = E_Entry then
1653 -- If the ambiguity occurs within an instance, it is due to several
1654 -- formal types with the same actual. Look for an exact match between
1655 -- the types of the formals of the overloadable entities, and the
1656 -- actuals in the call, to recover the unambiguous match in the
1657 -- original generic.
1659 -- The ambiguity can also be due to an overloading between a formal
1660 -- subprogram and a subprogram declared outside the generic. If the
1661 -- node is overloaded, it did not resolve to the global entity in
1662 -- the generic, and we choose the formal subprogram.
1664 -- Finally, the ambiguity can be between an explicit subprogram and
1665 -- one inherited (with different defaults) from an actual. In this
1666 -- case the resolution was to the explicit declaration in the
1667 -- generic, and remains so in the instance.
1670 and then not In_Generic_Actual (N)
1672 if Nkind (N) = N_Function_Call
1673 or else Nkind (N) = N_Procedure_Call_Statement
1678 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1679 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1682 if Is_Act1 and then not Is_Act2 then
1685 elsif Is_Act2 and then not Is_Act1 then
1688 elsif Inherited_From_Actual (Nam1)
1689 and then Comes_From_Source (Nam2)
1693 elsif Inherited_From_Actual (Nam2)
1694 and then Comes_From_Source (Nam1)
1699 Actual := First_Actual (N);
1700 Formal := First_Formal (Nam1);
1701 while Present (Actual) loop
1702 if Etype (Actual) /= Etype (Formal) then
1706 Next_Actual (Actual);
1707 Next_Formal (Formal);
1713 elsif Nkind (N) in N_Binary_Op then
1714 if Matches (Left_Opnd (N), First_Formal (Nam1))
1716 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1723 elsif Nkind (N) in N_Unary_Op then
1724 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1731 return Remove_Conversions;
1734 return Remove_Conversions;
1738 -- An implicit concatenation operator on a string type cannot be
1739 -- disambiguated from the predefined concatenation. This can only
1740 -- happen with concatenation of string literals.
1742 if Chars (User_Subp) = Name_Op_Concat
1743 and then Ekind (User_Subp) = E_Operator
1744 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1748 -- If the user-defined operator is in an open scope, or in the scope
1749 -- of the resulting type, or given by an expanded name that names its
1750 -- scope, it hides the predefined operator for the type. Exponentiation
1751 -- has to be special-cased because the implicit operator does not have
1752 -- a symmetric signature, and may not be hidden by the explicit one.
1754 elsif (Nkind (N) = N_Function_Call
1755 and then Nkind (Name (N)) = N_Expanded_Name
1756 and then (Chars (Predef_Subp) /= Name_Op_Expon
1757 or else Hides_Op (User_Subp, Predef_Subp))
1758 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1759 or else Hides_Op (User_Subp, Predef_Subp)
1761 if It1.Nam = User_Subp then
1767 -- Otherwise, the predefined operator has precedence, or if the user-
1768 -- defined operation is directly visible we have a true ambiguity. If
1769 -- this is a fixed-point multiplication and division in Ada83 mode,
1770 -- exclude the universal_fixed operator, which often causes ambiguities
1774 if (In_Open_Scopes (Scope (User_Subp))
1775 or else Is_Potentially_Use_Visible (User_Subp))
1776 and then not In_Instance
1778 if Is_Fixed_Point_Type (Typ)
1779 and then (Chars (Nam1) = Name_Op_Multiply
1780 or else Chars (Nam1) = Name_Op_Divide)
1781 and then Ada_Version = Ada_83
1783 if It2.Nam = Predef_Subp then
1789 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1790 -- states that the operator defined in Standard is not available
1791 -- if there is a user-defined equality with the proper signature,
1792 -- declared in the same declarative list as the type. The node
1793 -- may be an operator or a function call.
1795 elsif (Chars (Nam1) = Name_Op_Eq
1797 Chars (Nam1) = Name_Op_Ne)
1798 and then Ada_Version >= Ada_05
1799 and then Etype (User_Subp) = Standard_Boolean
1804 if Nkind (N) = N_Function_Call then
1805 Opnd := First_Actual (N);
1807 Opnd := Left_Opnd (N);
1810 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1812 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1813 = List_Containing (Unit_Declaration_Node (User_Subp))
1815 if It2.Nam = Predef_Subp then
1821 return Remove_Conversions;
1829 elsif It1.Nam = Predef_Subp then
1838 ---------------------
1839 -- End_Interp_List --
1840 ---------------------
1842 procedure End_Interp_List is
1844 All_Interp.Table (All_Interp.Last) := No_Interp;
1845 All_Interp.Increment_Last;
1846 end End_Interp_List;
1848 -------------------------
1849 -- Entity_Matches_Spec --
1850 -------------------------
1852 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1854 -- Simple case: same entity kinds, type conformance is required. A
1855 -- parameterless function can also rename a literal.
1857 if Ekind (Old_S) = Ekind (New_S)
1858 or else (Ekind (New_S) = E_Function
1859 and then Ekind (Old_S) = E_Enumeration_Literal)
1861 return Type_Conformant (New_S, Old_S);
1863 elsif Ekind (New_S) = E_Function
1864 and then Ekind (Old_S) = E_Operator
1866 return Operator_Matches_Spec (Old_S, New_S);
1868 elsif Ekind (New_S) = E_Procedure
1869 and then Is_Entry (Old_S)
1871 return Type_Conformant (New_S, Old_S);
1876 end Entity_Matches_Spec;
1878 ----------------------
1879 -- Find_Unique_Type --
1880 ----------------------
1882 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1883 T : constant Entity_Id := Etype (L);
1886 TR : Entity_Id := Any_Type;
1889 if Is_Overloaded (R) then
1890 Get_First_Interp (R, I, It);
1891 while Present (It.Typ) loop
1892 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1894 -- If several interpretations are possible and L is universal,
1895 -- apply preference rule.
1897 if TR /= Any_Type then
1899 if (T = Universal_Integer or else T = Universal_Real)
1910 Get_Next_Interp (I, It);
1915 -- In the non-overloaded case, the Etype of R is already set correctly
1921 -- If one of the operands is Universal_Fixed, the type of the other
1922 -- operand provides the context.
1924 if Etype (R) = Universal_Fixed then
1927 elsif T = Universal_Fixed then
1930 -- Ada 2005 (AI-230): Support the following operators:
1932 -- function "=" (L, R : universal_access) return Boolean;
1933 -- function "/=" (L, R : universal_access) return Boolean;
1935 -- Pool specific access types (E_Access_Type) are not covered by these
1936 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1937 -- of the equality operators for universal_access shall be convertible
1938 -- to one another (see 4.6)". For example, considering the type decla-
1939 -- ration "type P is access Integer" and an anonymous access to Integer,
1940 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1941 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1943 elsif Ada_Version >= Ada_05
1945 (Ekind (Etype (L)) = E_Anonymous_Access_Type
1947 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
1948 and then Is_Access_Type (Etype (R))
1949 and then Ekind (Etype (R)) /= E_Access_Type
1953 elsif Ada_Version >= Ada_05
1955 (Ekind (Etype (R)) = E_Anonymous_Access_Type
1956 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
1957 and then Is_Access_Type (Etype (L))
1958 and then Ekind (Etype (L)) /= E_Access_Type
1963 return Specific_Type (T, Etype (R));
1965 end Find_Unique_Type;
1967 -------------------------------------
1968 -- Function_Interp_Has_Abstract_Op --
1969 -------------------------------------
1971 function Function_Interp_Has_Abstract_Op
1973 E : Entity_Id) return Entity_Id
1975 Abstr_Op : Entity_Id;
1978 Form_Parm : Node_Id;
1981 if Is_Overloaded (N) then
1982 Act_Parm := First_Actual (N);
1983 Form_Parm := First_Formal (E);
1984 while Present (Act_Parm)
1985 and then Present (Form_Parm)
1989 if Nkind (Act) = N_Parameter_Association then
1990 Act := Explicit_Actual_Parameter (Act);
1993 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
1995 if Present (Abstr_Op) then
1999 Next_Actual (Act_Parm);
2000 Next_Formal (Form_Parm);
2005 end Function_Interp_Has_Abstract_Op;
2007 ----------------------
2008 -- Get_First_Interp --
2009 ----------------------
2011 procedure Get_First_Interp
2013 I : out Interp_Index;
2016 Int_Ind : Interp_Index;
2021 -- If a selected component is overloaded because the selector has
2022 -- multiple interpretations, the node is a call to a protected
2023 -- operation or an indirect call. Retrieve the interpretation from
2024 -- the selector name. The selected component may be overloaded as well
2025 -- if the prefix is overloaded. That case is unchanged.
2027 if Nkind (N) = N_Selected_Component
2028 and then Is_Overloaded (Selector_Name (N))
2030 O_N := Selector_Name (N);
2035 Map_Ptr := Headers (Hash (O_N));
2036 while Present (Interp_Map.Table (Map_Ptr).Node) loop
2037 if Interp_Map.Table (Map_Ptr).Node = O_N then
2038 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2039 It := All_Interp.Table (Int_Ind);
2043 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2047 -- Procedure should never be called if the node has no interpretations
2049 raise Program_Error;
2050 end Get_First_Interp;
2052 ---------------------
2053 -- Get_Next_Interp --
2054 ---------------------
2056 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2059 It := All_Interp.Table (I);
2060 end Get_Next_Interp;
2062 -------------------------
2063 -- Has_Compatible_Type --
2064 -------------------------
2066 function Has_Compatible_Type
2079 if Nkind (N) = N_Subtype_Indication
2080 or else not Is_Overloaded (N)
2083 Covers (Typ, Etype (N))
2085 -- Ada 2005 (AI-345) The context may be a synchronized interface.
2086 -- If the type is already frozen use the corresponding_record
2087 -- to check whether it is a proper descendant.
2090 (Is_Concurrent_Type (Etype (N))
2091 and then Present (Corresponding_Record_Type (Etype (N)))
2092 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2095 (not Is_Tagged_Type (Typ)
2096 and then Ekind (Typ) /= E_Anonymous_Access_Type
2097 and then Covers (Etype (N), Typ));
2100 Get_First_Interp (N, I, It);
2101 while Present (It.Typ) loop
2102 if (Covers (Typ, It.Typ)
2104 (Scope (It.Nam) /= Standard_Standard
2105 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2107 -- Ada 2005 (AI-345)
2110 (Is_Concurrent_Type (It.Typ)
2111 and then Present (Corresponding_Record_Type
2113 and then Covers (Typ, Corresponding_Record_Type
2116 or else (not Is_Tagged_Type (Typ)
2117 and then Ekind (Typ) /= E_Anonymous_Access_Type
2118 and then Covers (It.Typ, Typ))
2123 Get_Next_Interp (I, It);
2128 end Has_Compatible_Type;
2130 ---------------------
2131 -- Has_Abstract_Op --
2132 ---------------------
2134 function Has_Abstract_Op
2136 Typ : Entity_Id) return Entity_Id
2142 if Is_Overloaded (N) then
2143 Get_First_Interp (N, I, It);
2144 while Present (It.Nam) loop
2145 if Present (It.Abstract_Op)
2146 and then Etype (It.Abstract_Op) = Typ
2148 return It.Abstract_Op;
2151 Get_Next_Interp (I, It);
2156 end Has_Abstract_Op;
2162 function Hash (N : Node_Id) return Int is
2164 -- Nodes have a size that is power of two, so to select significant
2165 -- bits only we remove the low-order bits.
2167 return ((Int (N) / 2 ** 5) mod Header_Size);
2174 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2175 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2177 return Operator_Matches_Spec (Op, F)
2178 and then (In_Open_Scopes (Scope (F))
2179 or else Scope (F) = Scope (Btyp)
2180 or else (not In_Open_Scopes (Scope (Btyp))
2181 and then not In_Use (Btyp)
2182 and then not In_Use (Scope (Btyp))));
2185 ------------------------
2186 -- Init_Interp_Tables --
2187 ------------------------
2189 procedure Init_Interp_Tables is
2193 Headers := (others => No_Entry);
2194 end Init_Interp_Tables;
2196 -----------------------------------
2197 -- Interface_Present_In_Ancestor --
2198 -----------------------------------
2200 function Interface_Present_In_Ancestor
2202 Iface : Entity_Id) return Boolean
2204 Target_Typ : Entity_Id;
2205 Iface_Typ : Entity_Id;
2207 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2208 -- Returns True if Typ or some ancestor of Typ implements Iface
2210 -------------------------------
2211 -- Iface_Present_In_Ancestor --
2212 -------------------------------
2214 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2220 if Typ = Iface_Typ then
2224 -- Handle private types
2226 if Present (Full_View (Typ))
2227 and then not Is_Concurrent_Type (Full_View (Typ))
2229 E := Full_View (Typ);
2235 if Present (Abstract_Interfaces (E))
2236 and then Present (Abstract_Interfaces (E))
2237 and then not Is_Empty_Elmt_List (Abstract_Interfaces (E))
2239 Elmt := First_Elmt (Abstract_Interfaces (E));
2240 while Present (Elmt) loop
2243 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2251 exit when Etype (E) = E
2253 -- Handle private types
2255 or else (Present (Full_View (Etype (E)))
2256 and then Full_View (Etype (E)) = E);
2258 -- Check if the current type is a direct derivation of the
2261 if Etype (E) = Iface_Typ then
2265 -- Climb to the immediate ancestor handling private types
2267 if Present (Full_View (Etype (E))) then
2268 E := Full_View (Etype (E));
2275 end Iface_Present_In_Ancestor;
2277 -- Start of processing for Interface_Present_In_Ancestor
2280 if Is_Class_Wide_Type (Iface) then
2281 Iface_Typ := Etype (Iface);
2288 Iface_Typ := Base_Type (Iface_Typ);
2290 if Is_Access_Type (Typ) then
2291 Target_Typ := Etype (Directly_Designated_Type (Typ));
2296 if Is_Concurrent_Record_Type (Target_Typ) then
2297 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2300 Target_Typ := Base_Type (Target_Typ);
2302 -- In case of concurrent types we can't use the Corresponding Record_Typ
2303 -- to look for the interface because it is built by the expander (and
2304 -- hence it is not always available). For this reason we traverse the
2305 -- list of interfaces (available in the parent of the concurrent type)
2307 if Is_Concurrent_Type (Target_Typ) then
2308 if Present (Interface_List (Parent (Target_Typ))) then
2313 AI := First (Interface_List (Parent (Target_Typ)));
2314 while Present (AI) loop
2315 if Etype (AI) = Iface_Typ then
2318 elsif Present (Abstract_Interfaces (Etype (AI)))
2319 and then Iface_Present_In_Ancestor (Etype (AI))
2332 if Is_Class_Wide_Type (Target_Typ) then
2333 Target_Typ := Etype (Target_Typ);
2336 if Ekind (Target_Typ) = E_Incomplete_Type then
2337 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2338 Target_Typ := Non_Limited_View (Target_Typ);
2340 -- Protect the frontend against previously detected errors
2342 if Ekind (Target_Typ) = E_Incomplete_Type then
2347 return Iface_Present_In_Ancestor (Target_Typ);
2348 end Interface_Present_In_Ancestor;
2350 ---------------------
2351 -- Intersect_Types --
2352 ---------------------
2354 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2355 Index : Interp_Index;
2359 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2360 -- Find interpretation of right arg that has type compatible with T
2362 --------------------------
2363 -- Check_Right_Argument --
2364 --------------------------
2366 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2367 Index : Interp_Index;
2372 if not Is_Overloaded (R) then
2373 return Specific_Type (T, Etype (R));
2376 Get_First_Interp (R, Index, It);
2378 T2 := Specific_Type (T, It.Typ);
2380 if T2 /= Any_Type then
2384 Get_Next_Interp (Index, It);
2385 exit when No (It.Typ);
2390 end Check_Right_Argument;
2392 -- Start processing for Intersect_Types
2395 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2399 if not Is_Overloaded (L) then
2400 Typ := Check_Right_Argument (Etype (L));
2404 Get_First_Interp (L, Index, It);
2405 while Present (It.Typ) loop
2406 Typ := Check_Right_Argument (It.Typ);
2407 exit when Typ /= Any_Type;
2408 Get_Next_Interp (Index, It);
2413 -- If Typ is Any_Type, it means no compatible pair of types was found
2415 if Typ = Any_Type then
2416 if Nkind (Parent (L)) in N_Op then
2417 Error_Msg_N ("incompatible types for operator", Parent (L));
2419 elsif Nkind (Parent (L)) = N_Range then
2420 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2422 -- Ada 2005 (AI-251): Complete the error notification
2424 elsif Is_Class_Wide_Type (Etype (R))
2425 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2427 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2428 L, Etype (Class_Wide_Type (Etype (R))));
2431 Error_Msg_N ("incompatible types", Parent (L));
2436 end Intersect_Types;
2442 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2446 if Base_Type (T1) = Base_Type (T2) then
2449 elsif Is_Private_Type (T1)
2450 and then Present (Full_View (T1))
2451 and then Base_Type (T2) = Base_Type (Full_View (T1))
2459 -- If there was a error on the type declaration, do not recurse
2461 if Error_Posted (Par) then
2464 elsif Base_Type (T1) = Base_Type (Par)
2465 or else (Is_Private_Type (T1)
2466 and then Present (Full_View (T1))
2467 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2471 elsif Is_Private_Type (Par)
2472 and then Present (Full_View (Par))
2473 and then Full_View (Par) = Base_Type (T1)
2477 elsif Etype (Par) /= Par then
2486 ---------------------------
2487 -- Is_Invisible_Operator --
2488 ---------------------------
2490 function Is_Invisible_Operator
2495 Orig_Node : constant Node_Id := Original_Node (N);
2498 if Nkind (N) not in N_Op then
2501 elsif not Comes_From_Source (N) then
2504 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2507 elsif Nkind (N) in N_Binary_Op
2508 and then No (Universal_Interpretation (Left_Opnd (N)))
2513 return Is_Numeric_Type (T)
2514 and then not In_Open_Scopes (Scope (T))
2515 and then not Is_Potentially_Use_Visible (T)
2516 and then not In_Use (T)
2517 and then not In_Use (Scope (T))
2519 (Nkind (Orig_Node) /= N_Function_Call
2520 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2521 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2522 and then not In_Instance;
2524 end Is_Invisible_Operator;
2530 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2534 S := Ancestor_Subtype (T1);
2535 while Present (S) loop
2539 S := Ancestor_Subtype (S);
2550 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2551 Index : Interp_Index;
2555 Get_First_Interp (Nam, Index, It);
2556 while Present (It.Nam) loop
2557 if Scope (It.Nam) = Standard_Standard
2558 and then Scope (It.Typ) /= Standard_Standard
2560 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2561 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2564 Error_Msg_Sloc := Sloc (It.Nam);
2565 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2568 Get_Next_Interp (Index, It);
2576 procedure New_Interps (N : Node_Id) is
2580 All_Interp.Increment_Last;
2581 All_Interp.Table (All_Interp.Last) := No_Interp;
2583 Map_Ptr := Headers (Hash (N));
2585 if Map_Ptr = No_Entry then
2587 -- Place new node at end of table
2589 Interp_Map.Increment_Last;
2590 Headers (Hash (N)) := Interp_Map.Last;
2593 -- Place node at end of chain, or locate its previous entry
2596 if Interp_Map.Table (Map_Ptr).Node = N then
2598 -- Node is already in the table, and is being rewritten.
2599 -- Start a new interp section, retain hash link.
2601 Interp_Map.Table (Map_Ptr).Node := N;
2602 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2603 Set_Is_Overloaded (N, True);
2607 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2608 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2612 -- Chain the new node
2614 Interp_Map.Increment_Last;
2615 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2618 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2619 Set_Is_Overloaded (N, True);
2622 ---------------------------
2623 -- Operator_Matches_Spec --
2624 ---------------------------
2626 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2627 Op_Name : constant Name_Id := Chars (Op);
2628 T : constant Entity_Id := Etype (New_S);
2636 -- To verify that a predefined operator matches a given signature,
2637 -- do a case analysis of the operator classes. Function can have one
2638 -- or two formals and must have the proper result type.
2640 New_F := First_Formal (New_S);
2641 Old_F := First_Formal (Op);
2643 while Present (New_F) and then Present (Old_F) loop
2645 Next_Formal (New_F);
2646 Next_Formal (Old_F);
2649 -- Definite mismatch if different number of parameters
2651 if Present (Old_F) or else Present (New_F) then
2657 T1 := Etype (First_Formal (New_S));
2659 if Op_Name = Name_Op_Subtract
2660 or else Op_Name = Name_Op_Add
2661 or else Op_Name = Name_Op_Abs
2663 return Base_Type (T1) = Base_Type (T)
2664 and then Is_Numeric_Type (T);
2666 elsif Op_Name = Name_Op_Not then
2667 return Base_Type (T1) = Base_Type (T)
2668 and then Valid_Boolean_Arg (Base_Type (T));
2677 T1 := Etype (First_Formal (New_S));
2678 T2 := Etype (Next_Formal (First_Formal (New_S)));
2680 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2681 or else Op_Name = Name_Op_Xor
2683 return Base_Type (T1) = Base_Type (T2)
2684 and then Base_Type (T1) = Base_Type (T)
2685 and then Valid_Boolean_Arg (Base_Type (T));
2687 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2688 return Base_Type (T1) = Base_Type (T2)
2689 and then not Is_Limited_Type (T1)
2690 and then Is_Boolean_Type (T);
2692 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2693 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2695 return Base_Type (T1) = Base_Type (T2)
2696 and then Valid_Comparison_Arg (T1)
2697 and then Is_Boolean_Type (T);
2699 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2700 return Base_Type (T1) = Base_Type (T2)
2701 and then Base_Type (T1) = Base_Type (T)
2702 and then Is_Numeric_Type (T);
2704 -- for division and multiplication, a user-defined function does
2705 -- not match the predefined universal_fixed operation, except in
2708 elsif Op_Name = Name_Op_Divide then
2709 return (Base_Type (T1) = Base_Type (T2)
2710 and then Base_Type (T1) = Base_Type (T)
2711 and then Is_Numeric_Type (T)
2712 and then (not Is_Fixed_Point_Type (T)
2713 or else Ada_Version = Ada_83))
2715 -- Mixed_Mode operations on fixed-point types
2717 or else (Base_Type (T1) = Base_Type (T)
2718 and then Base_Type (T2) = Base_Type (Standard_Integer)
2719 and then Is_Fixed_Point_Type (T))
2721 -- A user defined operator can also match (and hide) a mixed
2722 -- operation on universal literals.
2724 or else (Is_Integer_Type (T2)
2725 and then Is_Floating_Point_Type (T1)
2726 and then Base_Type (T1) = Base_Type (T));
2728 elsif Op_Name = Name_Op_Multiply then
2729 return (Base_Type (T1) = Base_Type (T2)
2730 and then Base_Type (T1) = Base_Type (T)
2731 and then Is_Numeric_Type (T)
2732 and then (not Is_Fixed_Point_Type (T)
2733 or else Ada_Version = Ada_83))
2735 -- Mixed_Mode operations on fixed-point types
2737 or else (Base_Type (T1) = Base_Type (T)
2738 and then Base_Type (T2) = Base_Type (Standard_Integer)
2739 and then Is_Fixed_Point_Type (T))
2741 or else (Base_Type (T2) = Base_Type (T)
2742 and then Base_Type (T1) = Base_Type (Standard_Integer)
2743 and then Is_Fixed_Point_Type (T))
2745 or else (Is_Integer_Type (T2)
2746 and then Is_Floating_Point_Type (T1)
2747 and then Base_Type (T1) = Base_Type (T))
2749 or else (Is_Integer_Type (T1)
2750 and then Is_Floating_Point_Type (T2)
2751 and then Base_Type (T2) = Base_Type (T));
2753 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2754 return Base_Type (T1) = Base_Type (T2)
2755 and then Base_Type (T1) = Base_Type (T)
2756 and then Is_Integer_Type (T);
2758 elsif Op_Name = Name_Op_Expon then
2759 return Base_Type (T1) = Base_Type (T)
2760 and then Is_Numeric_Type (T)
2761 and then Base_Type (T2) = Base_Type (Standard_Integer);
2763 elsif Op_Name = Name_Op_Concat then
2764 return Is_Array_Type (T)
2765 and then (Base_Type (T) = Base_Type (Etype (Op)))
2766 and then (Base_Type (T1) = Base_Type (T)
2768 Base_Type (T1) = Base_Type (Component_Type (T)))
2769 and then (Base_Type (T2) = Base_Type (T)
2771 Base_Type (T2) = Base_Type (Component_Type (T)));
2777 end Operator_Matches_Spec;
2783 procedure Remove_Interp (I : in out Interp_Index) is
2787 -- Find end of Interp list and copy downward to erase the discarded one
2790 while Present (All_Interp.Table (II).Typ) loop
2794 for J in I + 1 .. II loop
2795 All_Interp.Table (J - 1) := All_Interp.Table (J);
2798 -- Back up interp. index to insure that iterator will pick up next
2799 -- available interpretation.
2808 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2810 O_N : Node_Id := Old_N;
2813 if Is_Overloaded (Old_N) then
2814 if Nkind (Old_N) = N_Selected_Component
2815 and then Is_Overloaded (Selector_Name (Old_N))
2817 O_N := Selector_Name (Old_N);
2820 Map_Ptr := Headers (Hash (O_N));
2822 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2823 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2824 pragma Assert (Map_Ptr /= No_Entry);
2827 New_Interps (New_N);
2828 Interp_Map.Table (Interp_Map.Last).Index :=
2829 Interp_Map.Table (Map_Ptr).Index;
2837 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2838 T1 : constant Entity_Id := Available_View (Typ_1);
2839 T2 : constant Entity_Id := Available_View (Typ_2);
2840 B1 : constant Entity_Id := Base_Type (T1);
2841 B2 : constant Entity_Id := Base_Type (T2);
2843 function Is_Remote_Access (T : Entity_Id) return Boolean;
2844 -- Check whether T is the equivalent type of a remote access type.
2845 -- If distribution is enabled, T is a legal context for Null.
2847 ----------------------
2848 -- Is_Remote_Access --
2849 ----------------------
2851 function Is_Remote_Access (T : Entity_Id) return Boolean is
2853 return Is_Record_Type (T)
2854 and then (Is_Remote_Call_Interface (T)
2855 or else Is_Remote_Types (T))
2856 and then Present (Corresponding_Remote_Type (T))
2857 and then Is_Access_Type (Corresponding_Remote_Type (T));
2858 end Is_Remote_Access;
2860 -- Start of processing for Specific_Type
2863 if T1 = Any_Type or else T2 = Any_Type then
2870 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2871 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2872 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2873 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2877 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2878 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2879 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2880 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2884 elsif T2 = Any_String and then Is_String_Type (T1) then
2887 elsif T1 = Any_String and then Is_String_Type (T2) then
2890 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2893 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2896 elsif T1 = Any_Access
2897 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2901 elsif T2 = Any_Access
2902 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
2906 elsif T2 = Any_Composite
2907 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
2911 elsif T1 = Any_Composite
2912 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
2916 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
2919 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
2922 -- ----------------------------------------------------------
2923 -- Special cases for equality operators (all other predefined
2924 -- operators can never apply to tagged types)
2925 -- ----------------------------------------------------------
2927 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
2930 elsif Is_Class_Wide_Type (T1)
2931 and then Is_Class_Wide_Type (T2)
2932 and then Is_Interface (Etype (T2))
2936 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
2937 -- class-wide interface T2
2939 elsif Is_Class_Wide_Type (T2)
2940 and then Is_Interface (Etype (T2))
2941 and then Interface_Present_In_Ancestor (Typ => T1,
2942 Iface => Etype (T2))
2946 elsif Is_Class_Wide_Type (T1)
2947 and then Is_Ancestor (Root_Type (T1), T2)
2951 elsif Is_Class_Wide_Type (T2)
2952 and then Is_Ancestor (Root_Type (T2), T1)
2956 elsif (Ekind (B1) = E_Access_Subprogram_Type
2958 Ekind (B1) = E_Access_Protected_Subprogram_Type)
2959 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
2960 and then Is_Access_Type (T2)
2964 elsif (Ekind (B2) = E_Access_Subprogram_Type
2966 Ekind (B2) = E_Access_Protected_Subprogram_Type)
2967 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
2968 and then Is_Access_Type (T1)
2972 elsif (Ekind (T1) = E_Allocator_Type
2973 or else Ekind (T1) = E_Access_Attribute_Type
2974 or else Ekind (T1) = E_Anonymous_Access_Type)
2975 and then Is_Access_Type (T2)
2979 elsif (Ekind (T2) = E_Allocator_Type
2980 or else Ekind (T2) = E_Access_Attribute_Type
2981 or else Ekind (T2) = E_Anonymous_Access_Type)
2982 and then Is_Access_Type (T1)
2986 -- If none of the above cases applies, types are not compatible
2993 ---------------------
2994 -- Set_Abstract_Op --
2995 ---------------------
2997 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
2999 All_Interp.Table (I).Abstract_Op := V;
3000 end Set_Abstract_Op;
3002 -----------------------
3003 -- Valid_Boolean_Arg --
3004 -----------------------
3006 -- In addition to booleans and arrays of booleans, we must include
3007 -- aggregates as valid boolean arguments, because in the first pass of
3008 -- resolution their components are not examined. If it turns out not to be
3009 -- an aggregate of booleans, this will be diagnosed in Resolve.
3010 -- Any_Composite must be checked for prior to the array type checks because
3011 -- Any_Composite does not have any associated indexes.
3013 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3015 return Is_Boolean_Type (T)
3016 or else T = Any_Composite
3017 or else (Is_Array_Type (T)
3018 and then T /= Any_String
3019 and then Number_Dimensions (T) = 1
3020 and then Is_Boolean_Type (Component_Type (T))
3021 and then (not Is_Private_Composite (T)
3022 or else In_Instance)
3023 and then (not Is_Limited_Composite (T)
3024 or else In_Instance))
3025 or else Is_Modular_Integer_Type (T)
3026 or else T = Universal_Integer;
3027 end Valid_Boolean_Arg;
3029 --------------------------
3030 -- Valid_Comparison_Arg --
3031 --------------------------
3033 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3036 if T = Any_Composite then
3038 elsif Is_Discrete_Type (T)
3039 or else Is_Real_Type (T)
3042 elsif Is_Array_Type (T)
3043 and then Number_Dimensions (T) = 1
3044 and then Is_Discrete_Type (Component_Type (T))
3045 and then (not Is_Private_Composite (T)
3046 or else In_Instance)
3047 and then (not Is_Limited_Composite (T)
3048 or else In_Instance)
3051 elsif Is_String_Type (T) then
3056 end Valid_Comparison_Arg;
3058 ----------------------
3059 -- Write_Interp_Ref --
3060 ----------------------
3062 procedure Write_Interp_Ref (Map_Ptr : Int) is
3064 Write_Str (" Node: ");
3065 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3066 Write_Str (" Index: ");
3067 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3068 Write_Str (" Next: ");
3069 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3071 end Write_Interp_Ref;
3073 ---------------------
3074 -- Write_Overloads --
3075 ---------------------
3077 procedure Write_Overloads (N : Node_Id) is
3083 if not Is_Overloaded (N) then
3084 Write_Str ("Non-overloaded entity ");
3086 Write_Entity_Info (Entity (N), " ");
3089 Get_First_Interp (N, I, It);
3090 Write_Str ("Overloaded entity ");
3092 Write_Str (" Name Type Abstract Op");
3094 Write_Str ("===============================================");
3098 while Present (Nam) loop
3099 Write_Int (Int (Nam));
3101 Write_Name (Chars (Nam));
3103 Write_Int (Int (It.Typ));
3105 Write_Name (Chars (It.Typ));
3107 if Present (It.Abstract_Op) then
3109 Write_Int (Int (It.Abstract_Op));
3111 Write_Name (Chars (It.Abstract_Op));
3115 Get_Next_Interp (I, It);
3119 end Write_Overloads;