1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2008, 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_Aux; use Sem_Aux;
39 with Sem_Ch6; use Sem_Ch6;
40 with Sem_Ch8; use Sem_Ch8;
41 with Sem_Ch12; use Sem_Ch12;
42 with Sem_Disp; use Sem_Disp;
43 with Sem_Dist; use Sem_Dist;
44 with Sem_Util; use Sem_Util;
45 with Stand; use Stand;
46 with Sinfo; use Sinfo;
47 with Snames; use Snames;
49 with Uintp; use Uintp;
51 package body Sem_Type is
57 -- The following data structures establish a mapping between nodes and
58 -- their interpretations. An overloaded node has an entry in Interp_Map,
59 -- which in turn contains a pointer into the All_Interp array. The
60 -- interpretations of a given node are contiguous in All_Interp. Each
61 -- set of interpretations is terminated with the marker No_Interp.
62 -- In order to speed up the retrieval of the interpretations of an
63 -- overloaded node, the Interp_Map table is accessed by means of a simple
64 -- hashing scheme, and the entries in Interp_Map are chained. The heads
65 -- of clash lists are stored in array Headers.
67 -- Headers Interp_Map All_Interp
69 -- _ +-----+ +--------+
70 -- |_| |_____| --->|interp1 |
71 -- |_|---------->|node | | |interp2 |
72 -- |_| |index|---------| |nointerp|
77 -- This scheme does not currently reclaim interpretations. In principle,
78 -- after a unit is compiled, all overloadings have been resolved, and the
79 -- candidate interpretations should be deleted. This should be easier
80 -- now than with the previous scheme???
82 package All_Interp is new Table.Table (
83 Table_Component_Type => Interp,
84 Table_Index_Type => Int,
86 Table_Initial => Alloc.All_Interp_Initial,
87 Table_Increment => Alloc.All_Interp_Increment,
88 Table_Name => "All_Interp");
90 type Interp_Ref is record
96 Header_Size : constant Int := 2 ** 12;
97 No_Entry : constant Int := -1;
98 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
100 package Interp_Map is new Table.Table (
101 Table_Component_Type => Interp_Ref,
102 Table_Index_Type => Int,
103 Table_Low_Bound => 0,
104 Table_Initial => Alloc.Interp_Map_Initial,
105 Table_Increment => Alloc.Interp_Map_Increment,
106 Table_Name => "Interp_Map");
108 function Hash (N : Node_Id) return Int;
109 -- A trivial hashing function for nodes, used to insert an overloaded
110 -- node into the Interp_Map table.
112 -------------------------------------
113 -- Handling of Overload Resolution --
114 -------------------------------------
116 -- Overload resolution uses two passes over the syntax tree of a complete
117 -- context. In the first, bottom-up pass, the types of actuals in calls
118 -- are used to resolve possibly overloaded subprogram and operator names.
119 -- In the second top-down pass, the type of the context (for example the
120 -- condition in a while statement) is used to resolve a possibly ambiguous
121 -- call, and the unique subprogram name in turn imposes a specific context
122 -- on each of its actuals.
124 -- Most expressions are in fact unambiguous, and the bottom-up pass is
125 -- sufficient to resolve most everything. To simplify the common case,
126 -- names and expressions carry a flag Is_Overloaded to indicate whether
127 -- they have more than one interpretation. If the flag is off, then each
128 -- name has already a unique meaning and type, and the bottom-up pass is
129 -- sufficient (and much simpler).
131 --------------------------
132 -- Operator Overloading --
133 --------------------------
135 -- The visibility of operators is handled differently from that of
136 -- other entities. We do not introduce explicit versions of primitive
137 -- operators for each type definition. As a result, there is only one
138 -- entity corresponding to predefined addition on all numeric types, etc.
139 -- The back-end resolves predefined operators according to their type.
140 -- The visibility of primitive operations then reduces to the visibility
141 -- of the resulting type: (a + b) is a legal interpretation of some
142 -- primitive operator + if the type of the result (which must also be
143 -- the type of a and b) is directly visible (i.e. either immediately
144 -- visible or use-visible.)
146 -- User-defined operators are treated like other functions, but the
147 -- visibility of these user-defined operations must be special-cased
148 -- to determine whether they hide or are hidden by predefined operators.
149 -- The form P."+" (x, y) requires additional handling.
151 -- Concatenation is treated more conventionally: for every one-dimensional
152 -- array type we introduce a explicit concatenation operator. This is
153 -- necessary to handle the case of (element & element => array) which
154 -- cannot be handled conveniently if there is no explicit instance of
155 -- resulting type of the operation.
157 -----------------------
158 -- Local Subprograms --
159 -----------------------
161 procedure All_Overloads;
162 pragma Warnings (Off, All_Overloads);
163 -- Debugging procedure: list full contents of Overloads table
165 function Binary_Op_Interp_Has_Abstract_Op
167 E : Entity_Id) return Entity_Id;
168 -- Given the node and entity of a binary operator, determine whether the
169 -- actuals of E contain an abstract interpretation with regards to the
170 -- types of their corresponding formals. Return the abstract operation or
173 function Function_Interp_Has_Abstract_Op
175 E : Entity_Id) return Entity_Id;
176 -- Given the node and entity of a function call, determine whether the
177 -- actuals of E contain an abstract interpretation with regards to the
178 -- types of their corresponding formals. Return the abstract operation or
181 function Has_Abstract_Op
183 Typ : Entity_Id) return Entity_Id;
184 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
185 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
186 -- abstract interpretation which yields type Typ.
188 procedure New_Interps (N : Node_Id);
189 -- Initialize collection of interpretations for the given node, which is
190 -- either an overloaded entity, or an operation whose arguments have
191 -- multiple interpretations. Interpretations can be added to only one
194 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id;
195 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
196 -- or is not a "class" type (any_character, etc).
202 procedure Add_One_Interp
206 Opnd_Type : Entity_Id := Empty)
208 Vis_Type : Entity_Id;
210 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
211 -- Add one interpretation to an overloaded node. Add a new entry if
212 -- not hidden by previous one, and remove previous one if hidden by
215 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
216 -- True if the entity is a predefined operator and the operands have
217 -- a universal Interpretation.
223 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
224 Abstr_Op : Entity_Id := Empty;
228 -- Start of processing for Add_Entry
231 -- Find out whether the new entry references interpretations that
232 -- are abstract or disabled by abstract operators.
234 if Ada_Version >= Ada_05 then
235 if Nkind (N) in N_Binary_Op then
236 Abstr_Op := Binary_Op_Interp_Has_Abstract_Op (N, Name);
237 elsif Nkind (N) = N_Function_Call then
238 Abstr_Op := Function_Interp_Has_Abstract_Op (N, Name);
242 Get_First_Interp (N, I, It);
243 while Present (It.Nam) loop
245 -- A user-defined subprogram hides another declared at an outer
246 -- level, or one that is use-visible. So return if previous
247 -- definition hides new one (which is either in an outer
248 -- scope, or use-visible). Note that for functions use-visible
249 -- is the same as potentially use-visible. If new one hides
250 -- previous one, replace entry in table of interpretations.
251 -- If this is a universal operation, retain the operator in case
252 -- preference rule applies.
254 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
255 and then Ekind (Name) = Ekind (It.Nam))
256 or else (Ekind (Name) = E_Operator
257 and then Ekind (It.Nam) = E_Function))
259 and then Is_Immediately_Visible (It.Nam)
260 and then Type_Conformant (Name, It.Nam)
261 and then Base_Type (It.Typ) = Base_Type (T)
263 if Is_Universal_Operation (Name) then
266 -- If node is an operator symbol, we have no actuals with
267 -- which to check hiding, and this is done in full in the
268 -- caller (Analyze_Subprogram_Renaming) so we include the
269 -- predefined operator in any case.
271 elsif Nkind (N) = N_Operator_Symbol
272 or else (Nkind (N) = N_Expanded_Name
274 Nkind (Selector_Name (N)) = N_Operator_Symbol)
278 elsif not In_Open_Scopes (Scope (Name))
279 or else Scope_Depth (Scope (Name)) <=
280 Scope_Depth (Scope (It.Nam))
282 -- If ambiguity within instance, and entity is not an
283 -- implicit operation, save for later disambiguation.
285 if Scope (Name) = Scope (It.Nam)
286 and then not Is_Inherited_Operation (Name)
295 All_Interp.Table (I).Nam := Name;
299 -- Avoid making duplicate entries in overloads
302 and then Base_Type (It.Typ) = Base_Type (T)
306 -- Otherwise keep going
309 Get_Next_Interp (I, It);
314 All_Interp.Table (All_Interp.Last) := (Name, Typ, Abstr_Op);
315 All_Interp.Increment_Last;
316 All_Interp.Table (All_Interp.Last) := No_Interp;
319 ----------------------------
320 -- Is_Universal_Operation --
321 ----------------------------
323 function Is_Universal_Operation (Op : Entity_Id) return Boolean is
327 if Ekind (Op) /= E_Operator then
330 elsif Nkind (N) in N_Binary_Op then
331 return Present (Universal_Interpretation (Left_Opnd (N)))
332 and then Present (Universal_Interpretation (Right_Opnd (N)));
334 elsif Nkind (N) in N_Unary_Op then
335 return Present (Universal_Interpretation (Right_Opnd (N)));
337 elsif Nkind (N) = N_Function_Call then
338 Arg := First_Actual (N);
339 while Present (Arg) loop
340 if No (Universal_Interpretation (Arg)) then
352 end Is_Universal_Operation;
354 -- Start of processing for Add_One_Interp
357 -- If the interpretation is a predefined operator, verify that the
358 -- result type is visible, or that the entity has already been
359 -- resolved (case of an instantiation node that refers to a predefined
360 -- operation, or an internally generated operator node, or an operator
361 -- given as an expanded name). If the operator is a comparison or
362 -- equality, it is the type of the operand that matters to determine
363 -- whether the operator is visible. In an instance, the check is not
364 -- performed, given that the operator was visible in the generic.
366 if Ekind (E) = E_Operator then
368 if Present (Opnd_Type) then
369 Vis_Type := Opnd_Type;
371 Vis_Type := Base_Type (T);
374 if In_Open_Scopes (Scope (Vis_Type))
375 or else Is_Potentially_Use_Visible (Vis_Type)
376 or else In_Use (Vis_Type)
377 or else (In_Use (Scope (Vis_Type))
378 and then not Is_Hidden (Vis_Type))
379 or else Nkind (N) = N_Expanded_Name
380 or else (Nkind (N) in N_Op and then E = Entity (N))
382 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
386 -- If the node is given in functional notation and the prefix
387 -- is an expanded name, then the operator is visible if the
388 -- prefix is the scope of the result type as well. If the
389 -- operator is (implicitly) defined in an extension of system,
390 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
392 elsif Nkind (N) = N_Function_Call
393 and then Nkind (Name (N)) = N_Expanded_Name
394 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
395 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
396 or else Scope (Vis_Type) = System_Aux_Id)
400 -- Save type for subsequent error message, in case no other
401 -- interpretation is found.
404 Candidate_Type := Vis_Type;
408 -- In an instance, an abstract non-dispatching operation cannot be a
409 -- candidate interpretation, because it could not have been one in the
410 -- generic (it may be a spurious overloading in the instance).
413 and then Is_Overloadable (E)
414 and then Is_Abstract_Subprogram (E)
415 and then not Is_Dispatching_Operation (E)
419 -- An inherited interface operation that is implemented by some derived
420 -- type does not participate in overload resolution, only the
421 -- implementation operation does.
424 and then Is_Subprogram (E)
425 and then Present (Interface_Alias (E))
427 -- Ada 2005 (AI-251): If this primitive operation corresponds with
428 -- an immediate ancestor interface there is no need to add it to the
429 -- list of interpretations. The corresponding aliased primitive is
430 -- also in this list of primitive operations and will be used instead
431 -- because otherwise we have a dummy ambiguity between the two
432 -- subprograms which are in fact the same.
435 (Find_Dispatching_Type (Interface_Alias (E)),
436 Find_Dispatching_Type (E))
438 Add_One_Interp (N, Interface_Alias (E), T);
443 -- Calling stubs for an RACW operation never participate in resolution,
444 -- they are executed only through dispatching calls.
446 elsif Is_RACW_Stub_Type_Operation (E) then
450 -- If this is the first interpretation of N, N has type Any_Type.
451 -- In that case place the new type on the node. If one interpretation
452 -- already exists, indicate that the node is overloaded, and store
453 -- both the previous and the new interpretation in All_Interp. If
454 -- this is a later interpretation, just add it to the set.
456 if Etype (N) = Any_Type then
461 -- Record both the operator or subprogram name, and its type
463 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
470 -- Either there is no current interpretation in the table for any
471 -- node or the interpretation that is present is for a different
472 -- node. In both cases add a new interpretation to the table.
474 elsif Interp_Map.Last < 0
476 (Interp_Map.Table (Interp_Map.Last).Node /= N
477 and then not Is_Overloaded (N))
481 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
482 and then Present (Entity (N))
484 Add_Entry (Entity (N), Etype (N));
486 elsif (Nkind (N) = N_Function_Call
487 or else Nkind (N) = N_Procedure_Call_Statement)
488 and then (Nkind (Name (N)) = N_Operator_Symbol
489 or else Is_Entity_Name (Name (N)))
491 Add_Entry (Entity (Name (N)), Etype (N));
493 -- If this is an indirect call there will be no name associated
494 -- with the previous entry. To make diagnostics clearer, save
495 -- Subprogram_Type of first interpretation, so that the error will
496 -- point to the anonymous access to subprogram, not to the result
497 -- type of the call itself.
499 elsif (Nkind (N)) = N_Function_Call
500 and then Nkind (Name (N)) = N_Explicit_Dereference
501 and then Is_Overloaded (Name (N))
507 pragma Warnings (Off, Itn);
510 Get_First_Interp (Name (N), Itn, It);
511 Add_Entry (It.Nam, Etype (N));
515 -- Overloaded prefix in indexed or selected component, or call
516 -- whose name is an expression or another call.
518 Add_Entry (Etype (N), Etype (N));
532 procedure All_Overloads is
534 for J in All_Interp.First .. All_Interp.Last loop
536 if Present (All_Interp.Table (J).Nam) then
537 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
539 Write_Str ("No Interp");
543 Write_Str ("=================");
548 --------------------------------------
549 -- Binary_Op_Interp_Has_Abstract_Op --
550 --------------------------------------
552 function Binary_Op_Interp_Has_Abstract_Op
554 E : Entity_Id) return Entity_Id
556 Abstr_Op : Entity_Id;
557 E_Left : constant Node_Id := First_Formal (E);
558 E_Right : constant Node_Id := Next_Formal (E_Left);
561 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
562 if Present (Abstr_Op) then
566 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
567 end Binary_Op_Interp_Has_Abstract_Op;
569 ---------------------
570 -- Collect_Interps --
571 ---------------------
573 procedure Collect_Interps (N : Node_Id) is
574 Ent : constant Entity_Id := Entity (N);
576 First_Interp : Interp_Index;
581 -- Unconditionally add the entity that was initially matched
583 First_Interp := All_Interp.Last;
584 Add_One_Interp (N, Ent, Etype (N));
586 -- For expanded name, pick up all additional entities from the
587 -- same scope, since these are obviously also visible. Note that
588 -- these are not necessarily contiguous on the homonym chain.
590 if Nkind (N) = N_Expanded_Name then
592 while Present (H) loop
593 if Scope (H) = Scope (Entity (N)) then
594 Add_One_Interp (N, H, Etype (H));
600 -- Case of direct name
603 -- First, search the homonym chain for directly visible entities
605 H := Current_Entity (Ent);
606 while Present (H) loop
607 exit when (not Is_Overloadable (H))
608 and then Is_Immediately_Visible (H);
610 if Is_Immediately_Visible (H)
613 -- Only add interpretation if not hidden by an inner
614 -- immediately visible one.
616 for J in First_Interp .. All_Interp.Last - 1 loop
618 -- Current homograph is not hidden. Add to overloads
620 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
623 -- Homograph is hidden, unless it is a predefined operator
625 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
627 -- A homograph in the same scope can occur within an
628 -- instantiation, the resulting ambiguity has to be
631 if Scope (H) = Scope (Ent)
633 and then not Is_Inherited_Operation (H)
635 All_Interp.Table (All_Interp.Last) :=
636 (H, Etype (H), Empty);
637 All_Interp.Increment_Last;
638 All_Interp.Table (All_Interp.Last) := No_Interp;
641 elsif Scope (H) /= Standard_Standard then
647 -- On exit, we know that current homograph is not hidden
649 Add_One_Interp (N, H, Etype (H));
652 Write_Str ("Add overloaded interpretation ");
662 -- Scan list of homographs for use-visible entities only
664 H := Current_Entity (Ent);
666 while Present (H) loop
667 if Is_Potentially_Use_Visible (H)
669 and then Is_Overloadable (H)
671 for J in First_Interp .. All_Interp.Last - 1 loop
673 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
676 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
677 goto Next_Use_Homograph;
681 Add_One_Interp (N, H, Etype (H));
684 <<Next_Use_Homograph>>
689 if All_Interp.Last = First_Interp + 1 then
691 -- The final interpretation is in fact not overloaded. Note that the
692 -- unique legal interpretation may or may not be the original one,
693 -- so we need to update N's entity and etype now, because once N
694 -- is marked as not overloaded it is also expected to carry the
695 -- proper interpretation.
697 Set_Is_Overloaded (N, False);
698 Set_Entity (N, All_Interp.Table (First_Interp).Nam);
699 Set_Etype (N, All_Interp.Table (First_Interp).Typ);
707 function Covers (T1, T2 : Entity_Id) return Boolean is
712 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
713 -- In an instance the proper view may not always be correct for
714 -- private types, but private and full view are compatible. This
715 -- removes spurious errors from nested instantiations that involve,
716 -- among other things, types derived from private types.
718 ----------------------
719 -- Full_View_Covers --
720 ----------------------
722 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
725 Is_Private_Type (Typ1)
727 ((Present (Full_View (Typ1))
728 and then Covers (Full_View (Typ1), Typ2))
729 or else Base_Type (Typ1) = Typ2
730 or else Base_Type (Typ2) = Typ1);
731 end Full_View_Covers;
733 -- Start of processing for Covers
736 -- If either operand missing, then this is an error, but ignore it (and
737 -- pretend we have a cover) if errors already detected, since this may
738 -- simply mean we have malformed trees.
740 if No (T1) or else No (T2) then
741 if Total_Errors_Detected /= 0 then
748 BT1 := Base_Type (T1);
749 BT2 := Base_Type (T2);
752 -- Simplest case: same types are compatible, and types that have the
753 -- same base type and are not generic actuals are compatible. Generic
754 -- actuals belong to their class but are not compatible with other
755 -- types of their class, and in particular with other generic actuals.
756 -- They are however compatible with their own subtypes, and itypes
757 -- with the same base are compatible as well. Similarly, constrained
758 -- subtypes obtained from expressions of an unconstrained nominal type
759 -- are compatible with the base type (may lead to spurious ambiguities
760 -- in obscure cases ???)
762 -- Generic actuals require special treatment to avoid spurious ambi-
763 -- guities in an instance, when two formal types are instantiated with
764 -- the same actual, so that different subprograms end up with the same
765 -- signature in the instance.
774 if not Is_Generic_Actual_Type (T1) then
777 return (not Is_Generic_Actual_Type (T2)
778 or else Is_Itype (T1)
779 or else Is_Itype (T2)
780 or else Is_Constr_Subt_For_U_Nominal (T1)
781 or else Is_Constr_Subt_For_U_Nominal (T2)
782 or else Scope (T1) /= Scope (T2));
785 -- Literals are compatible with types in a given "class"
787 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
788 or else (T2 = Universal_Real and then Is_Real_Type (T1))
789 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
790 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
791 or else (T2 = Any_String and then Is_String_Type (T1))
792 or else (T2 = Any_Character and then Is_Character_Type (T1))
793 or else (T2 = Any_Access and then Is_Access_Type (T1))
797 -- The context may be class wide
799 elsif Is_Class_Wide_Type (T1)
800 and then Is_Ancestor (Root_Type (T1), T2)
804 elsif Is_Class_Wide_Type (T1)
805 and then Is_Class_Wide_Type (T2)
806 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
810 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
811 -- task_type or protected_type implementing T1
813 elsif Ada_Version >= Ada_05
814 and then Is_Class_Wide_Type (T1)
815 and then Is_Interface (Etype (T1))
816 and then Is_Concurrent_Type (T2)
817 and then Interface_Present_In_Ancestor
818 (Typ => Base_Type (T2),
823 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
824 -- object T2 implementing T1
826 elsif Ada_Version >= Ada_05
827 and then Is_Class_Wide_Type (T1)
828 and then Is_Interface (Etype (T1))
829 and then Is_Tagged_Type (T2)
831 if Interface_Present_In_Ancestor (Typ => T2,
842 if Is_Concurrent_Type (BT2) then
843 E := Corresponding_Record_Type (BT2);
848 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
849 -- covers an object T2 that implements a direct derivation of T1.
850 -- Note: test for presence of E is defense against previous error.
853 and then Present (Interfaces (E))
855 Elmt := First_Elmt (Interfaces (E));
856 while Present (Elmt) loop
857 if Is_Ancestor (Etype (T1), Node (Elmt)) then
865 -- We should also check the case in which T1 is an ancestor of
866 -- some implemented interface???
871 -- In a dispatching call the actual may be class-wide
873 elsif Is_Class_Wide_Type (T2)
874 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
878 -- Some contexts require a class of types rather than a specific type
880 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
881 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
882 or else (T1 = Any_Real and then Is_Real_Type (T2))
883 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
884 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
888 -- An aggregate is compatible with an array or record type
890 elsif T2 = Any_Composite
891 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
895 -- If the expected type is an anonymous access, the designated type must
896 -- cover that of the expression. Use the base type for this check: even
897 -- though access subtypes are rare in sources, they are generated for
898 -- actuals in instantiations.
900 elsif Ekind (BT1) = E_Anonymous_Access_Type
901 and then Is_Access_Type (T2)
902 and then Covers (Designated_Type (T1), Designated_Type (T2))
906 -- An Access_To_Subprogram is compatible with itself, or with an
907 -- anonymous type created for an attribute reference Access.
909 elsif (Ekind (BT1) = E_Access_Subprogram_Type
911 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
912 and then Is_Access_Type (T2)
913 and then (not Comes_From_Source (T1)
914 or else not Comes_From_Source (T2))
915 and then (Is_Overloadable (Designated_Type (T2))
917 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
919 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
921 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
925 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
926 -- with itself, or with an anonymous type created for an attribute
929 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
932 = E_Anonymous_Access_Protected_Subprogram_Type)
933 and then Is_Access_Type (T2)
934 and then (not Comes_From_Source (T1)
935 or else not Comes_From_Source (T2))
936 and then (Is_Overloadable (Designated_Type (T2))
938 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
940 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
942 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
946 -- The context can be a remote access type, and the expression the
947 -- corresponding source type declared in a categorized package, or
950 elsif Is_Record_Type (T1)
951 and then (Is_Remote_Call_Interface (T1)
952 or else Is_Remote_Types (T1))
953 and then Present (Corresponding_Remote_Type (T1))
955 return Covers (Corresponding_Remote_Type (T1), T2);
957 elsif Is_Record_Type (T2)
958 and then (Is_Remote_Call_Interface (T2)
959 or else Is_Remote_Types (T2))
960 and then Present (Corresponding_Remote_Type (T2))
962 return Covers (Corresponding_Remote_Type (T2), T1);
964 elsif Ekind (T2) = E_Access_Attribute_Type
965 and then (Ekind (BT1) = E_General_Access_Type
966 or else Ekind (BT1) = E_Access_Type)
967 and then Covers (Designated_Type (T1), Designated_Type (T2))
969 -- If the target type is a RACW type while the source is an access
970 -- attribute type, we are building a RACW that may be exported.
972 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
973 Set_Has_RACW (Current_Sem_Unit);
978 elsif Ekind (T2) = E_Allocator_Type
979 and then Is_Access_Type (T1)
981 return Covers (Designated_Type (T1), Designated_Type (T2))
983 (From_With_Type (Designated_Type (T1))
984 and then Covers (Designated_Type (T2), Designated_Type (T1)));
986 -- A boolean operation on integer literals is compatible with modular
989 elsif T2 = Any_Modular
990 and then Is_Modular_Integer_Type (T1)
994 -- The actual type may be the result of a previous error
996 elsif Base_Type (T2) = Any_Type then
999 -- A packed array type covers its corresponding non-packed type. This is
1000 -- not legitimate Ada, but allows the omission of a number of otherwise
1001 -- useless unchecked conversions, and since this can only arise in
1002 -- (known correct) expanded code, no harm is done
1004 elsif Is_Array_Type (T2)
1005 and then Is_Packed (T2)
1006 and then T1 = Packed_Array_Type (T2)
1010 -- Similarly an array type covers its corresponding packed array type
1012 elsif Is_Array_Type (T1)
1013 and then Is_Packed (T1)
1014 and then T2 = Packed_Array_Type (T1)
1018 -- In instances, or with types exported from instantiations, check
1019 -- whether a partial and a full view match. Verify that types are
1020 -- legal, to prevent cascaded errors.
1024 (Full_View_Covers (T1, T2)
1025 or else Full_View_Covers (T2, T1))
1030 and then Is_Generic_Actual_Type (T2)
1031 and then Full_View_Covers (T1, T2)
1036 and then Is_Generic_Actual_Type (T1)
1037 and then Full_View_Covers (T2, T1)
1041 -- In the expansion of inlined bodies, types are compatible if they
1042 -- are structurally equivalent.
1044 elsif In_Inlined_Body
1045 and then (Underlying_Type (T1) = Underlying_Type (T2)
1046 or else (Is_Access_Type (T1)
1047 and then Is_Access_Type (T2)
1049 Designated_Type (T1) = Designated_Type (T2))
1050 or else (T1 = Any_Access
1051 and then Is_Access_Type (Underlying_Type (T2)))
1052 or else (T2 = Any_Composite
1054 Is_Composite_Type (Underlying_Type (T1))))
1058 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1059 -- compatible with its real entity.
1061 elsif From_With_Type (T1) then
1063 -- If the expected type is the non-limited view of a type, the
1064 -- expression may have the limited view. If that one in turn is
1065 -- incomplete, get full view if available.
1067 if Is_Incomplete_Type (T1) then
1068 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1070 elsif Ekind (T1) = E_Class_Wide_Type then
1072 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1077 elsif From_With_Type (T2) then
1079 -- If units in the context have Limited_With clauses on each other,
1080 -- either type might have a limited view. Checks performed elsewhere
1081 -- verify that the context type is the non-limited view.
1083 if Is_Incomplete_Type (T2) then
1084 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1086 elsif Ekind (T2) = E_Class_Wide_Type then
1088 Present (Non_Limited_View (Etype (T2)))
1090 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1095 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1097 elsif Ekind (T1) = E_Incomplete_Subtype then
1098 return Covers (Full_View (Etype (T1)), T2);
1100 elsif Ekind (T2) = E_Incomplete_Subtype then
1101 return Covers (T1, Full_View (Etype (T2)));
1103 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1104 -- and actual anonymous access types in the context of generic
1105 -- instantiation. We have the following situation:
1108 -- type Formal is private;
1109 -- Formal_Obj : access Formal; -- T1
1113 -- type Actual is ...
1114 -- Actual_Obj : access Actual; -- T2
1115 -- package Instance is new G (Formal => Actual,
1116 -- Formal_Obj => Actual_Obj);
1118 elsif Ada_Version >= Ada_05
1119 and then Ekind (T1) = E_Anonymous_Access_Type
1120 and then Ekind (T2) = E_Anonymous_Access_Type
1121 and then Is_Generic_Type (Directly_Designated_Type (T1))
1122 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1123 Directly_Designated_Type (T2)
1127 -- Otherwise it doesn't cover!
1138 function Disambiguate
1140 I1, I2 : Interp_Index;
1147 Nam1, Nam2 : Entity_Id;
1148 Predef_Subp : Entity_Id;
1149 User_Subp : Entity_Id;
1151 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1152 -- Determine whether one of the candidates is an operation inherited by
1153 -- a type that is derived from an actual in an instantiation.
1155 function In_Generic_Actual (Exp : Node_Id) return Boolean;
1156 -- Determine whether the expression is part of a generic actual. At
1157 -- the time the actual is resolved the scope is already that of the
1158 -- instance, but conceptually the resolution of the actual takes place
1159 -- in the enclosing context, and no special disambiguation rules should
1162 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1163 -- Determine whether a subprogram is an actual in an enclosing instance.
1164 -- An overloading between such a subprogram and one declared outside the
1165 -- instance is resolved in favor of the first, because it resolved in
1168 function Matches (Actual, Formal : Node_Id) return Boolean;
1169 -- Look for exact type match in an instance, to remove spurious
1170 -- ambiguities when two formal types have the same actual.
1172 function Standard_Operator return Boolean;
1173 -- Check whether subprogram is predefined operator declared in Standard.
1174 -- It may given by an operator name, or by an expanded name whose prefix
1177 function Remove_Conversions return Interp;
1178 -- Last chance for pathological cases involving comparisons on literals,
1179 -- and user overloadings of the same operator. Such pathologies have
1180 -- been removed from the ACVC, but still appear in two DEC tests, with
1181 -- the following notable quote from Ben Brosgol:
1183 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1184 -- this example; Robert Dewar brought it to our attention, since it is
1185 -- apparently found in the ACVC 1.5. I did not attempt to find the
1186 -- reason in the Reference Manual that makes the example legal, since I
1187 -- was too nauseated by it to want to pursue it further.]
1189 -- Accordingly, this is not a fully recursive solution, but it handles
1190 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1191 -- pathology in the other direction with calls whose multiple overloaded
1192 -- actuals make them truly unresolvable.
1194 -- The new rules concerning abstract operations create additional need
1195 -- for special handling of expressions with universal operands, see
1196 -- comments to Has_Abstract_Interpretation below.
1198 ------------------------
1199 -- In_Generic_Actual --
1200 ------------------------
1202 function In_Generic_Actual (Exp : Node_Id) return Boolean is
1203 Par : constant Node_Id := Parent (Exp);
1209 elsif Nkind (Par) in N_Declaration then
1210 if Nkind (Par) = N_Object_Declaration
1211 or else Nkind (Par) = N_Object_Renaming_Declaration
1213 return Present (Corresponding_Generic_Association (Par));
1218 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
1222 return In_Generic_Actual (Parent (Par));
1224 end In_Generic_Actual;
1226 ---------------------------
1227 -- Inherited_From_Actual --
1228 ---------------------------
1230 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1231 Par : constant Node_Id := Parent (S);
1233 if Nkind (Par) /= N_Full_Type_Declaration
1234 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1238 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1240 Is_Generic_Actual_Type (
1241 Entity (Subtype_Indication (Type_Definition (Par))));
1243 end Inherited_From_Actual;
1245 --------------------------
1246 -- Is_Actual_Subprogram --
1247 --------------------------
1249 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1251 return In_Open_Scopes (Scope (S))
1253 (Is_Generic_Instance (Scope (S))
1254 or else Is_Wrapper_Package (Scope (S)));
1255 end Is_Actual_Subprogram;
1261 function Matches (Actual, Formal : Node_Id) return Boolean is
1262 T1 : constant Entity_Id := Etype (Actual);
1263 T2 : constant Entity_Id := Etype (Formal);
1267 (Is_Numeric_Type (T2)
1269 (T1 = Universal_Real or else T1 = Universal_Integer));
1272 ------------------------
1273 -- Remove_Conversions --
1274 ------------------------
1276 function Remove_Conversions return Interp is
1284 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1285 -- If an operation has universal operands the universal operation
1286 -- is present among its interpretations. If there is an abstract
1287 -- interpretation for the operator, with a numeric result, this
1288 -- interpretation was already removed in sem_ch4, but the universal
1289 -- one is still visible. We must rescan the list of operators and
1290 -- remove the universal interpretation to resolve the ambiguity.
1292 ---------------------------------
1293 -- Has_Abstract_Interpretation --
1294 ---------------------------------
1296 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1300 if Nkind (N) not in N_Op
1301 or else Ada_Version < Ada_05
1302 or else not Is_Overloaded (N)
1303 or else No (Universal_Interpretation (N))
1308 E := Get_Name_Entity_Id (Chars (N));
1309 while Present (E) loop
1310 if Is_Overloadable (E)
1311 and then Is_Abstract_Subprogram (E)
1312 and then Is_Numeric_Type (Etype (E))
1320 -- Finally, if an operand of the binary operator is itself
1321 -- an operator, recurse to see whether its own abstract
1322 -- interpretation is responsible for the spurious ambiguity.
1324 if Nkind (N) in N_Binary_Op then
1325 return Has_Abstract_Interpretation (Left_Opnd (N))
1326 or else Has_Abstract_Interpretation (Right_Opnd (N));
1328 elsif Nkind (N) in N_Unary_Op then
1329 return Has_Abstract_Interpretation (Right_Opnd (N));
1335 end Has_Abstract_Interpretation;
1337 -- Start of processing for Remove_Conversions
1342 Get_First_Interp (N, I, It);
1343 while Present (It.Typ) loop
1344 if not Is_Overloadable (It.Nam) then
1348 F1 := First_Formal (It.Nam);
1354 if Nkind (N) = N_Function_Call
1355 or else Nkind (N) = N_Procedure_Call_Statement
1357 Act1 := First_Actual (N);
1359 if Present (Act1) then
1360 Act2 := Next_Actual (Act1);
1365 elsif Nkind (N) in N_Unary_Op then
1366 Act1 := Right_Opnd (N);
1369 elsif Nkind (N) in N_Binary_Op then
1370 Act1 := Left_Opnd (N);
1371 Act2 := Right_Opnd (N);
1373 -- Use type of second formal, so as to include
1374 -- exponentiation, where the exponent may be
1375 -- ambiguous and the result non-universal.
1383 if Nkind (Act1) in N_Op
1384 and then Is_Overloaded (Act1)
1385 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1386 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1387 and then Has_Compatible_Type (Act1, Standard_Boolean)
1388 and then Etype (F1) = Standard_Boolean
1390 -- If the two candidates are the original ones, the
1391 -- ambiguity is real. Otherwise keep the original, further
1392 -- calls to Disambiguate will take care of others in the
1393 -- list of candidates.
1395 if It1 /= No_Interp then
1396 if It = Disambiguate.It1
1397 or else It = Disambiguate.It2
1399 if It1 = Disambiguate.It1
1400 or else It1 = Disambiguate.It2
1408 elsif Present (Act2)
1409 and then Nkind (Act2) in N_Op
1410 and then Is_Overloaded (Act2)
1411 and then (Nkind (Right_Opnd (Act2)) = N_Integer_Literal
1413 Nkind (Right_Opnd (Act2)) = N_Real_Literal)
1414 and then Has_Compatible_Type (Act2, Standard_Boolean)
1416 -- The preference rule on the first actual is not
1417 -- sufficient to disambiguate.
1425 elsif Is_Numeric_Type (Etype (F1))
1427 (Has_Abstract_Interpretation (Act1)
1428 or else Has_Abstract_Interpretation (Act2))
1430 if It = Disambiguate.It1 then
1431 return Disambiguate.It2;
1432 elsif It = Disambiguate.It2 then
1433 return Disambiguate.It1;
1439 Get_Next_Interp (I, It);
1442 -- After some error, a formal may have Any_Type and yield a spurious
1443 -- match. To avoid cascaded errors if possible, check for such a
1444 -- formal in either candidate.
1446 if Serious_Errors_Detected > 0 then
1451 Formal := First_Formal (Nam1);
1452 while Present (Formal) loop
1453 if Etype (Formal) = Any_Type then
1454 return Disambiguate.It2;
1457 Next_Formal (Formal);
1460 Formal := First_Formal (Nam2);
1461 while Present (Formal) loop
1462 if Etype (Formal) = Any_Type then
1463 return Disambiguate.It1;
1466 Next_Formal (Formal);
1472 end Remove_Conversions;
1474 -----------------------
1475 -- Standard_Operator --
1476 -----------------------
1478 function Standard_Operator return Boolean is
1482 if Nkind (N) in N_Op then
1485 elsif Nkind (N) = N_Function_Call then
1488 if Nkind (Nam) /= N_Expanded_Name then
1491 return Entity (Prefix (Nam)) = Standard_Standard;
1496 end Standard_Operator;
1498 -- Start of processing for Disambiguate
1501 -- Recover the two legal interpretations
1503 Get_First_Interp (N, I, It);
1505 Get_Next_Interp (I, It);
1511 Get_Next_Interp (I, It);
1517 if Ada_Version < Ada_05 then
1519 -- Check whether one of the entities is an Ada 2005 entity and we are
1520 -- operating in an earlier mode, in which case we discard the Ada
1521 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1523 if Is_Ada_2005_Only (Nam1) then
1525 elsif Is_Ada_2005_Only (Nam2) then
1530 -- Check for overloaded CIL convention stuff because the CIL libraries
1531 -- do sick things like Console.Write_Line where it matches two different
1532 -- overloads, so just pick the first ???
1534 if Convention (Nam1) = Convention_CIL
1535 and then Convention (Nam2) = Convention_CIL
1536 and then Ekind (Nam1) = Ekind (Nam2)
1537 and then (Ekind (Nam1) = E_Procedure
1538 or else Ekind (Nam1) = E_Function)
1543 -- If the context is universal, the predefined operator is preferred.
1544 -- This includes bounds in numeric type declarations, and expressions
1545 -- in type conversions. If no interpretation yields a universal type,
1546 -- then we must check whether the user-defined entity hides the prede-
1549 if Chars (Nam1) in Any_Operator_Name
1550 and then Standard_Operator
1552 if Typ = Universal_Integer
1553 or else Typ = Universal_Real
1554 or else Typ = Any_Integer
1555 or else Typ = Any_Discrete
1556 or else Typ = Any_Real
1557 or else Typ = Any_Type
1559 -- Find an interpretation that yields the universal type, or else
1560 -- a predefined operator that yields a predefined numeric type.
1563 Candidate : Interp := No_Interp;
1566 Get_First_Interp (N, I, It);
1567 while Present (It.Typ) loop
1568 if (Covers (Typ, It.Typ)
1569 or else Typ = Any_Type)
1571 (It.Typ = Universal_Integer
1572 or else It.Typ = Universal_Real)
1576 elsif Covers (Typ, It.Typ)
1577 and then Scope (It.Typ) = Standard_Standard
1578 and then Scope (It.Nam) = Standard_Standard
1579 and then Is_Numeric_Type (It.Typ)
1584 Get_Next_Interp (I, It);
1587 if Candidate /= No_Interp then
1592 elsif Chars (Nam1) /= Name_Op_Not
1593 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1595 -- Equality or comparison operation. Choose predefined operator if
1596 -- arguments are universal. The node may be an operator, name, or
1597 -- a function call, so unpack arguments accordingly.
1600 Arg1, Arg2 : Node_Id;
1603 if Nkind (N) in N_Op then
1604 Arg1 := Left_Opnd (N);
1605 Arg2 := Right_Opnd (N);
1607 elsif Is_Entity_Name (N)
1608 or else Nkind (N) = N_Operator_Symbol
1610 Arg1 := First_Entity (Entity (N));
1611 Arg2 := Next_Entity (Arg1);
1614 Arg1 := First_Actual (N);
1615 Arg2 := Next_Actual (Arg1);
1619 and then Present (Universal_Interpretation (Arg1))
1620 and then Universal_Interpretation (Arg2) =
1621 Universal_Interpretation (Arg1)
1623 Get_First_Interp (N, I, It);
1624 while Scope (It.Nam) /= Standard_Standard loop
1625 Get_Next_Interp (I, It);
1634 -- If no universal interpretation, check whether user-defined operator
1635 -- hides predefined one, as well as other special cases. If the node
1636 -- is a range, then one or both bounds are ambiguous. Each will have
1637 -- to be disambiguated w.r.t. the context type. The type of the range
1638 -- itself is imposed by the context, so we can return either legal
1641 if Ekind (Nam1) = E_Operator then
1642 Predef_Subp := Nam1;
1645 elsif Ekind (Nam2) = E_Operator then
1646 Predef_Subp := Nam2;
1649 elsif Nkind (N) = N_Range then
1652 -- If two user defined-subprograms are visible, it is a true ambiguity,
1653 -- unless one of them is an entry and the context is a conditional or
1654 -- timed entry call, or unless we are within an instance and this is
1655 -- results from two formals types with the same actual.
1658 if Nkind (N) = N_Procedure_Call_Statement
1659 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1660 and then N = Entry_Call_Statement (Parent (N))
1662 if Ekind (Nam2) = E_Entry then
1664 elsif Ekind (Nam1) = E_Entry then
1670 -- If the ambiguity occurs within an instance, it is due to several
1671 -- formal types with the same actual. Look for an exact match between
1672 -- the types of the formals of the overloadable entities, and the
1673 -- actuals in the call, to recover the unambiguous match in the
1674 -- original generic.
1676 -- The ambiguity can also be due to an overloading between a formal
1677 -- subprogram and a subprogram declared outside the generic. If the
1678 -- node is overloaded, it did not resolve to the global entity in
1679 -- the generic, and we choose the formal subprogram.
1681 -- Finally, the ambiguity can be between an explicit subprogram and
1682 -- one inherited (with different defaults) from an actual. In this
1683 -- case the resolution was to the explicit declaration in the
1684 -- generic, and remains so in the instance.
1687 and then not In_Generic_Actual (N)
1689 if Nkind (N) = N_Function_Call
1690 or else Nkind (N) = N_Procedure_Call_Statement
1695 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1696 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1699 if Is_Act1 and then not Is_Act2 then
1702 elsif Is_Act2 and then not Is_Act1 then
1705 elsif Inherited_From_Actual (Nam1)
1706 and then Comes_From_Source (Nam2)
1710 elsif Inherited_From_Actual (Nam2)
1711 and then Comes_From_Source (Nam1)
1716 Actual := First_Actual (N);
1717 Formal := First_Formal (Nam1);
1718 while Present (Actual) loop
1719 if Etype (Actual) /= Etype (Formal) then
1723 Next_Actual (Actual);
1724 Next_Formal (Formal);
1730 elsif Nkind (N) in N_Binary_Op then
1731 if Matches (Left_Opnd (N), First_Formal (Nam1))
1733 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1740 elsif Nkind (N) in N_Unary_Op then
1741 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1748 return Remove_Conversions;
1751 return Remove_Conversions;
1755 -- An implicit concatenation operator on a string type cannot be
1756 -- disambiguated from the predefined concatenation. This can only
1757 -- happen with concatenation of string literals.
1759 if Chars (User_Subp) = Name_Op_Concat
1760 and then Ekind (User_Subp) = E_Operator
1761 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1765 -- If the user-defined operator is in an open scope, or in the scope
1766 -- of the resulting type, or given by an expanded name that names its
1767 -- scope, it hides the predefined operator for the type. Exponentiation
1768 -- has to be special-cased because the implicit operator does not have
1769 -- a symmetric signature, and may not be hidden by the explicit one.
1771 elsif (Nkind (N) = N_Function_Call
1772 and then Nkind (Name (N)) = N_Expanded_Name
1773 and then (Chars (Predef_Subp) /= Name_Op_Expon
1774 or else Hides_Op (User_Subp, Predef_Subp))
1775 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1776 or else Hides_Op (User_Subp, Predef_Subp)
1778 if It1.Nam = User_Subp then
1784 -- Otherwise, the predefined operator has precedence, or if the user-
1785 -- defined operation is directly visible we have a true ambiguity. If
1786 -- this is a fixed-point multiplication and division in Ada83 mode,
1787 -- exclude the universal_fixed operator, which often causes ambiguities
1791 if (In_Open_Scopes (Scope (User_Subp))
1792 or else Is_Potentially_Use_Visible (User_Subp))
1793 and then not In_Instance
1795 if Is_Fixed_Point_Type (Typ)
1796 and then (Chars (Nam1) = Name_Op_Multiply
1797 or else Chars (Nam1) = Name_Op_Divide)
1798 and then Ada_Version = Ada_83
1800 if It2.Nam = Predef_Subp then
1806 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1807 -- states that the operator defined in Standard is not available
1808 -- if there is a user-defined equality with the proper signature,
1809 -- declared in the same declarative list as the type. The node
1810 -- may be an operator or a function call.
1812 elsif (Chars (Nam1) = Name_Op_Eq
1814 Chars (Nam1) = Name_Op_Ne)
1815 and then Ada_Version >= Ada_05
1816 and then Etype (User_Subp) = Standard_Boolean
1821 if Nkind (N) = N_Function_Call then
1822 Opnd := First_Actual (N);
1824 Opnd := Left_Opnd (N);
1827 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1829 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1830 = List_Containing (Unit_Declaration_Node (User_Subp))
1832 if It2.Nam = Predef_Subp then
1838 return Remove_Conversions;
1846 elsif It1.Nam = Predef_Subp then
1855 ---------------------
1856 -- End_Interp_List --
1857 ---------------------
1859 procedure End_Interp_List is
1861 All_Interp.Table (All_Interp.Last) := No_Interp;
1862 All_Interp.Increment_Last;
1863 end End_Interp_List;
1865 -------------------------
1866 -- Entity_Matches_Spec --
1867 -------------------------
1869 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1871 -- Simple case: same entity kinds, type conformance is required. A
1872 -- parameterless function can also rename a literal.
1874 if Ekind (Old_S) = Ekind (New_S)
1875 or else (Ekind (New_S) = E_Function
1876 and then Ekind (Old_S) = E_Enumeration_Literal)
1878 return Type_Conformant (New_S, Old_S);
1880 elsif Ekind (New_S) = E_Function
1881 and then Ekind (Old_S) = E_Operator
1883 return Operator_Matches_Spec (Old_S, New_S);
1885 elsif Ekind (New_S) = E_Procedure
1886 and then Is_Entry (Old_S)
1888 return Type_Conformant (New_S, Old_S);
1893 end Entity_Matches_Spec;
1895 ----------------------
1896 -- Find_Unique_Type --
1897 ----------------------
1899 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1900 T : constant Entity_Id := Etype (L);
1903 TR : Entity_Id := Any_Type;
1906 if Is_Overloaded (R) then
1907 Get_First_Interp (R, I, It);
1908 while Present (It.Typ) loop
1909 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1911 -- If several interpretations are possible and L is universal,
1912 -- apply preference rule.
1914 if TR /= Any_Type then
1916 if (T = Universal_Integer or else T = Universal_Real)
1927 Get_Next_Interp (I, It);
1932 -- In the non-overloaded case, the Etype of R is already set correctly
1938 -- If one of the operands is Universal_Fixed, the type of the other
1939 -- operand provides the context.
1941 if Etype (R) = Universal_Fixed then
1944 elsif T = Universal_Fixed then
1947 -- Ada 2005 (AI-230): Support the following operators:
1949 -- function "=" (L, R : universal_access) return Boolean;
1950 -- function "/=" (L, R : universal_access) return Boolean;
1952 -- Pool specific access types (E_Access_Type) are not covered by these
1953 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1954 -- of the equality operators for universal_access shall be convertible
1955 -- to one another (see 4.6)". For example, considering the type decla-
1956 -- ration "type P is access Integer" and an anonymous access to Integer,
1957 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1958 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1960 elsif Ada_Version >= Ada_05
1962 (Ekind (Etype (L)) = E_Anonymous_Access_Type
1964 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
1965 and then Is_Access_Type (Etype (R))
1966 and then Ekind (Etype (R)) /= E_Access_Type
1970 elsif Ada_Version >= Ada_05
1972 (Ekind (Etype (R)) = E_Anonymous_Access_Type
1973 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
1974 and then Is_Access_Type (Etype (L))
1975 and then Ekind (Etype (L)) /= E_Access_Type
1980 return Specific_Type (T, Etype (R));
1982 end Find_Unique_Type;
1984 -------------------------------------
1985 -- Function_Interp_Has_Abstract_Op --
1986 -------------------------------------
1988 function Function_Interp_Has_Abstract_Op
1990 E : Entity_Id) return Entity_Id
1992 Abstr_Op : Entity_Id;
1995 Form_Parm : Node_Id;
1998 -- Why is check on E needed below ???
1999 -- In any case this para needs comments ???
2001 if Is_Overloaded (N) and then Is_Overloadable (E) then
2002 Act_Parm := First_Actual (N);
2003 Form_Parm := First_Formal (E);
2004 while Present (Act_Parm)
2005 and then Present (Form_Parm)
2009 if Nkind (Act) = N_Parameter_Association then
2010 Act := Explicit_Actual_Parameter (Act);
2013 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2015 if Present (Abstr_Op) then
2019 Next_Actual (Act_Parm);
2020 Next_Formal (Form_Parm);
2025 end Function_Interp_Has_Abstract_Op;
2027 ----------------------
2028 -- Get_First_Interp --
2029 ----------------------
2031 procedure Get_First_Interp
2033 I : out Interp_Index;
2036 Int_Ind : Interp_Index;
2041 -- If a selected component is overloaded because the selector has
2042 -- multiple interpretations, the node is a call to a protected
2043 -- operation or an indirect call. Retrieve the interpretation from
2044 -- the selector name. The selected component may be overloaded as well
2045 -- if the prefix is overloaded. That case is unchanged.
2047 if Nkind (N) = N_Selected_Component
2048 and then Is_Overloaded (Selector_Name (N))
2050 O_N := Selector_Name (N);
2055 Map_Ptr := Headers (Hash (O_N));
2056 while Present (Interp_Map.Table (Map_Ptr).Node) loop
2057 if Interp_Map.Table (Map_Ptr).Node = O_N then
2058 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2059 It := All_Interp.Table (Int_Ind);
2063 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2067 -- Procedure should never be called if the node has no interpretations
2069 raise Program_Error;
2070 end Get_First_Interp;
2072 ---------------------
2073 -- Get_Next_Interp --
2074 ---------------------
2076 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2079 It := All_Interp.Table (I);
2080 end Get_Next_Interp;
2082 -------------------------
2083 -- Has_Compatible_Type --
2084 -------------------------
2086 function Has_Compatible_Type
2099 if Nkind (N) = N_Subtype_Indication
2100 or else not Is_Overloaded (N)
2103 Covers (Typ, Etype (N))
2105 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2106 -- If the type is already frozen use the corresponding_record
2107 -- to check whether it is a proper descendant.
2110 (Is_Record_Type (Typ)
2111 and then Is_Concurrent_Type (Etype (N))
2112 and then Present (Corresponding_Record_Type (Etype (N)))
2113 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2116 (Is_Concurrent_Type (Typ)
2117 and then Is_Record_Type (Etype (N))
2118 and then Present (Corresponding_Record_Type (Typ))
2119 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2122 (not Is_Tagged_Type (Typ)
2123 and then Ekind (Typ) /= E_Anonymous_Access_Type
2124 and then Covers (Etype (N), Typ));
2127 Get_First_Interp (N, I, It);
2128 while Present (It.Typ) loop
2129 if (Covers (Typ, It.Typ)
2131 (Scope (It.Nam) /= Standard_Standard
2132 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2134 -- Ada 2005 (AI-345)
2137 (Is_Concurrent_Type (It.Typ)
2138 and then Present (Corresponding_Record_Type
2140 and then Covers (Typ, Corresponding_Record_Type
2143 or else (not Is_Tagged_Type (Typ)
2144 and then Ekind (Typ) /= E_Anonymous_Access_Type
2145 and then Covers (It.Typ, Typ))
2150 Get_Next_Interp (I, It);
2155 end Has_Compatible_Type;
2157 ---------------------
2158 -- Has_Abstract_Op --
2159 ---------------------
2161 function Has_Abstract_Op
2163 Typ : Entity_Id) return Entity_Id
2169 if Is_Overloaded (N) then
2170 Get_First_Interp (N, I, It);
2171 while Present (It.Nam) loop
2172 if Present (It.Abstract_Op)
2173 and then Etype (It.Abstract_Op) = Typ
2175 return It.Abstract_Op;
2178 Get_Next_Interp (I, It);
2183 end Has_Abstract_Op;
2189 function Hash (N : Node_Id) return Int is
2191 -- Nodes have a size that is power of two, so to select significant
2192 -- bits only we remove the low-order bits.
2194 return ((Int (N) / 2 ** 5) mod Header_Size);
2201 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2202 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2204 return Operator_Matches_Spec (Op, F)
2205 and then (In_Open_Scopes (Scope (F))
2206 or else Scope (F) = Scope (Btyp)
2207 or else (not In_Open_Scopes (Scope (Btyp))
2208 and then not In_Use (Btyp)
2209 and then not In_Use (Scope (Btyp))));
2212 ------------------------
2213 -- Init_Interp_Tables --
2214 ------------------------
2216 procedure Init_Interp_Tables is
2220 Headers := (others => No_Entry);
2221 end Init_Interp_Tables;
2223 -----------------------------------
2224 -- Interface_Present_In_Ancestor --
2225 -----------------------------------
2227 function Interface_Present_In_Ancestor
2229 Iface : Entity_Id) return Boolean
2231 Target_Typ : Entity_Id;
2232 Iface_Typ : Entity_Id;
2234 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2235 -- Returns True if Typ or some ancestor of Typ implements Iface
2237 -------------------------------
2238 -- Iface_Present_In_Ancestor --
2239 -------------------------------
2241 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2247 if Typ = Iface_Typ then
2251 -- Handle private types
2253 if Present (Full_View (Typ))
2254 and then not Is_Concurrent_Type (Full_View (Typ))
2256 E := Full_View (Typ);
2262 if Present (Interfaces (E))
2263 and then Present (Interfaces (E))
2264 and then not Is_Empty_Elmt_List (Interfaces (E))
2266 Elmt := First_Elmt (Interfaces (E));
2267 while Present (Elmt) loop
2270 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2278 exit when Etype (E) = E
2280 -- Handle private types
2282 or else (Present (Full_View (Etype (E)))
2283 and then Full_View (Etype (E)) = E);
2285 -- Check if the current type is a direct derivation of the
2288 if Etype (E) = Iface_Typ then
2292 -- Climb to the immediate ancestor handling private types
2294 if Present (Full_View (Etype (E))) then
2295 E := Full_View (Etype (E));
2302 end Iface_Present_In_Ancestor;
2304 -- Start of processing for Interface_Present_In_Ancestor
2307 if Is_Class_Wide_Type (Iface) then
2308 Iface_Typ := Etype (Iface);
2315 Iface_Typ := Base_Type (Iface_Typ);
2317 if Is_Access_Type (Typ) then
2318 Target_Typ := Etype (Directly_Designated_Type (Typ));
2323 if Is_Concurrent_Record_Type (Target_Typ) then
2324 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2327 Target_Typ := Base_Type (Target_Typ);
2329 -- In case of concurrent types we can't use the Corresponding Record_Typ
2330 -- to look for the interface because it is built by the expander (and
2331 -- hence it is not always available). For this reason we traverse the
2332 -- list of interfaces (available in the parent of the concurrent type)
2334 if Is_Concurrent_Type (Target_Typ) then
2335 if Present (Interface_List (Parent (Target_Typ))) then
2340 AI := First (Interface_List (Parent (Target_Typ)));
2341 while Present (AI) loop
2342 if Etype (AI) = Iface_Typ then
2345 elsif Present (Interfaces (Etype (AI)))
2346 and then Iface_Present_In_Ancestor (Etype (AI))
2359 if Is_Class_Wide_Type (Target_Typ) then
2360 Target_Typ := Etype (Target_Typ);
2363 if Ekind (Target_Typ) = E_Incomplete_Type then
2364 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2365 Target_Typ := Non_Limited_View (Target_Typ);
2367 -- Protect the frontend against previously detected errors
2369 if Ekind (Target_Typ) = E_Incomplete_Type then
2374 return Iface_Present_In_Ancestor (Target_Typ);
2375 end Interface_Present_In_Ancestor;
2377 ---------------------
2378 -- Intersect_Types --
2379 ---------------------
2381 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2382 Index : Interp_Index;
2386 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2387 -- Find interpretation of right arg that has type compatible with T
2389 --------------------------
2390 -- Check_Right_Argument --
2391 --------------------------
2393 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2394 Index : Interp_Index;
2399 if not Is_Overloaded (R) then
2400 return Specific_Type (T, Etype (R));
2403 Get_First_Interp (R, Index, It);
2405 T2 := Specific_Type (T, It.Typ);
2407 if T2 /= Any_Type then
2411 Get_Next_Interp (Index, It);
2412 exit when No (It.Typ);
2417 end Check_Right_Argument;
2419 -- Start processing for Intersect_Types
2422 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2426 if not Is_Overloaded (L) then
2427 Typ := Check_Right_Argument (Etype (L));
2431 Get_First_Interp (L, Index, It);
2432 while Present (It.Typ) loop
2433 Typ := Check_Right_Argument (It.Typ);
2434 exit when Typ /= Any_Type;
2435 Get_Next_Interp (Index, It);
2440 -- If Typ is Any_Type, it means no compatible pair of types was found
2442 if Typ = Any_Type then
2443 if Nkind (Parent (L)) in N_Op then
2444 Error_Msg_N ("incompatible types for operator", Parent (L));
2446 elsif Nkind (Parent (L)) = N_Range then
2447 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2449 -- Ada 2005 (AI-251): Complete the error notification
2451 elsif Is_Class_Wide_Type (Etype (R))
2452 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2454 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2455 L, Etype (Class_Wide_Type (Etype (R))));
2458 Error_Msg_N ("incompatible types", Parent (L));
2463 end Intersect_Types;
2469 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2473 if Base_Type (T1) = Base_Type (T2) then
2476 elsif Is_Private_Type (T1)
2477 and then Present (Full_View (T1))
2478 and then Base_Type (T2) = Base_Type (Full_View (T1))
2486 -- If there was a error on the type declaration, do not recurse
2488 if Error_Posted (Par) then
2491 elsif Base_Type (T1) = Base_Type (Par)
2492 or else (Is_Private_Type (T1)
2493 and then Present (Full_View (T1))
2494 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2498 elsif Is_Private_Type (Par)
2499 and then Present (Full_View (Par))
2500 and then Full_View (Par) = Base_Type (T1)
2504 elsif Etype (Par) /= Par then
2513 ---------------------------
2514 -- Is_Invisible_Operator --
2515 ---------------------------
2517 function Is_Invisible_Operator
2522 Orig_Node : constant Node_Id := Original_Node (N);
2525 if Nkind (N) not in N_Op then
2528 elsif not Comes_From_Source (N) then
2531 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2534 elsif Nkind (N) in N_Binary_Op
2535 and then No (Universal_Interpretation (Left_Opnd (N)))
2540 return Is_Numeric_Type (T)
2541 and then not In_Open_Scopes (Scope (T))
2542 and then not Is_Potentially_Use_Visible (T)
2543 and then not In_Use (T)
2544 and then not In_Use (Scope (T))
2546 (Nkind (Orig_Node) /= N_Function_Call
2547 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2548 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2549 and then not In_Instance;
2551 end Is_Invisible_Operator;
2557 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2561 S := Ancestor_Subtype (T1);
2562 while Present (S) loop
2566 S := Ancestor_Subtype (S);
2577 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2578 Index : Interp_Index;
2582 Get_First_Interp (Nam, Index, It);
2583 while Present (It.Nam) loop
2584 if Scope (It.Nam) = Standard_Standard
2585 and then Scope (It.Typ) /= Standard_Standard
2587 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2588 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2591 Error_Msg_Sloc := Sloc (It.Nam);
2592 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2595 Get_Next_Interp (Index, It);
2603 procedure New_Interps (N : Node_Id) is
2607 All_Interp.Increment_Last;
2608 All_Interp.Table (All_Interp.Last) := No_Interp;
2610 Map_Ptr := Headers (Hash (N));
2612 if Map_Ptr = No_Entry then
2614 -- Place new node at end of table
2616 Interp_Map.Increment_Last;
2617 Headers (Hash (N)) := Interp_Map.Last;
2620 -- Place node at end of chain, or locate its previous entry
2623 if Interp_Map.Table (Map_Ptr).Node = N then
2625 -- Node is already in the table, and is being rewritten.
2626 -- Start a new interp section, retain hash link.
2628 Interp_Map.Table (Map_Ptr).Node := N;
2629 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2630 Set_Is_Overloaded (N, True);
2634 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2635 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2639 -- Chain the new node
2641 Interp_Map.Increment_Last;
2642 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2645 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2646 Set_Is_Overloaded (N, True);
2649 ---------------------------
2650 -- Operator_Matches_Spec --
2651 ---------------------------
2653 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2654 Op_Name : constant Name_Id := Chars (Op);
2655 T : constant Entity_Id := Etype (New_S);
2663 -- To verify that a predefined operator matches a given signature,
2664 -- do a case analysis of the operator classes. Function can have one
2665 -- or two formals and must have the proper result type.
2667 New_F := First_Formal (New_S);
2668 Old_F := First_Formal (Op);
2670 while Present (New_F) and then Present (Old_F) loop
2672 Next_Formal (New_F);
2673 Next_Formal (Old_F);
2676 -- Definite mismatch if different number of parameters
2678 if Present (Old_F) or else Present (New_F) then
2684 T1 := Etype (First_Formal (New_S));
2686 if Op_Name = Name_Op_Subtract
2687 or else Op_Name = Name_Op_Add
2688 or else Op_Name = Name_Op_Abs
2690 return Base_Type (T1) = Base_Type (T)
2691 and then Is_Numeric_Type (T);
2693 elsif Op_Name = Name_Op_Not then
2694 return Base_Type (T1) = Base_Type (T)
2695 and then Valid_Boolean_Arg (Base_Type (T));
2704 T1 := Etype (First_Formal (New_S));
2705 T2 := Etype (Next_Formal (First_Formal (New_S)));
2707 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2708 or else Op_Name = Name_Op_Xor
2710 return Base_Type (T1) = Base_Type (T2)
2711 and then Base_Type (T1) = Base_Type (T)
2712 and then Valid_Boolean_Arg (Base_Type (T));
2714 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2715 return Base_Type (T1) = Base_Type (T2)
2716 and then not Is_Limited_Type (T1)
2717 and then Is_Boolean_Type (T);
2719 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2720 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2722 return Base_Type (T1) = Base_Type (T2)
2723 and then Valid_Comparison_Arg (T1)
2724 and then Is_Boolean_Type (T);
2726 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2727 return Base_Type (T1) = Base_Type (T2)
2728 and then Base_Type (T1) = Base_Type (T)
2729 and then Is_Numeric_Type (T);
2731 -- for division and multiplication, a user-defined function does
2732 -- not match the predefined universal_fixed operation, except in
2735 elsif Op_Name = Name_Op_Divide then
2736 return (Base_Type (T1) = Base_Type (T2)
2737 and then Base_Type (T1) = Base_Type (T)
2738 and then Is_Numeric_Type (T)
2739 and then (not Is_Fixed_Point_Type (T)
2740 or else Ada_Version = Ada_83))
2742 -- Mixed_Mode operations on fixed-point types
2744 or else (Base_Type (T1) = Base_Type (T)
2745 and then Base_Type (T2) = Base_Type (Standard_Integer)
2746 and then Is_Fixed_Point_Type (T))
2748 -- A user defined operator can also match (and hide) a mixed
2749 -- operation on universal literals.
2751 or else (Is_Integer_Type (T2)
2752 and then Is_Floating_Point_Type (T1)
2753 and then Base_Type (T1) = Base_Type (T));
2755 elsif Op_Name = Name_Op_Multiply then
2756 return (Base_Type (T1) = Base_Type (T2)
2757 and then Base_Type (T1) = Base_Type (T)
2758 and then Is_Numeric_Type (T)
2759 and then (not Is_Fixed_Point_Type (T)
2760 or else Ada_Version = Ada_83))
2762 -- Mixed_Mode operations on fixed-point types
2764 or else (Base_Type (T1) = Base_Type (T)
2765 and then Base_Type (T2) = Base_Type (Standard_Integer)
2766 and then Is_Fixed_Point_Type (T))
2768 or else (Base_Type (T2) = Base_Type (T)
2769 and then Base_Type (T1) = Base_Type (Standard_Integer)
2770 and then Is_Fixed_Point_Type (T))
2772 or else (Is_Integer_Type (T2)
2773 and then Is_Floating_Point_Type (T1)
2774 and then Base_Type (T1) = Base_Type (T))
2776 or else (Is_Integer_Type (T1)
2777 and then Is_Floating_Point_Type (T2)
2778 and then Base_Type (T2) = Base_Type (T));
2780 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2781 return Base_Type (T1) = Base_Type (T2)
2782 and then Base_Type (T1) = Base_Type (T)
2783 and then Is_Integer_Type (T);
2785 elsif Op_Name = Name_Op_Expon then
2786 return Base_Type (T1) = Base_Type (T)
2787 and then Is_Numeric_Type (T)
2788 and then Base_Type (T2) = Base_Type (Standard_Integer);
2790 elsif Op_Name = Name_Op_Concat then
2791 return Is_Array_Type (T)
2792 and then (Base_Type (T) = Base_Type (Etype (Op)))
2793 and then (Base_Type (T1) = Base_Type (T)
2795 Base_Type (T1) = Base_Type (Component_Type (T)))
2796 and then (Base_Type (T2) = Base_Type (T)
2798 Base_Type (T2) = Base_Type (Component_Type (T)));
2804 end Operator_Matches_Spec;
2810 procedure Remove_Interp (I : in out Interp_Index) is
2814 -- Find end of Interp list and copy downward to erase the discarded one
2817 while Present (All_Interp.Table (II).Typ) loop
2821 for J in I + 1 .. II loop
2822 All_Interp.Table (J - 1) := All_Interp.Table (J);
2825 -- Back up interp. index to insure that iterator will pick up next
2826 -- available interpretation.
2835 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2837 O_N : Node_Id := Old_N;
2840 if Is_Overloaded (Old_N) then
2841 if Nkind (Old_N) = N_Selected_Component
2842 and then Is_Overloaded (Selector_Name (Old_N))
2844 O_N := Selector_Name (Old_N);
2847 Map_Ptr := Headers (Hash (O_N));
2849 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2850 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2851 pragma Assert (Map_Ptr /= No_Entry);
2854 New_Interps (New_N);
2855 Interp_Map.Table (Interp_Map.Last).Index :=
2856 Interp_Map.Table (Map_Ptr).Index;
2864 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2865 T1 : constant Entity_Id := Available_View (Typ_1);
2866 T2 : constant Entity_Id := Available_View (Typ_2);
2867 B1 : constant Entity_Id := Base_Type (T1);
2868 B2 : constant Entity_Id := Base_Type (T2);
2870 function Is_Remote_Access (T : Entity_Id) return Boolean;
2871 -- Check whether T is the equivalent type of a remote access type.
2872 -- If distribution is enabled, T is a legal context for Null.
2874 ----------------------
2875 -- Is_Remote_Access --
2876 ----------------------
2878 function Is_Remote_Access (T : Entity_Id) return Boolean is
2880 return Is_Record_Type (T)
2881 and then (Is_Remote_Call_Interface (T)
2882 or else Is_Remote_Types (T))
2883 and then Present (Corresponding_Remote_Type (T))
2884 and then Is_Access_Type (Corresponding_Remote_Type (T));
2885 end Is_Remote_Access;
2887 -- Start of processing for Specific_Type
2890 if T1 = Any_Type or else T2 = Any_Type then
2897 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2898 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2899 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2900 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2904 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2905 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2906 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2907 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2911 elsif T2 = Any_String and then Is_String_Type (T1) then
2914 elsif T1 = Any_String and then Is_String_Type (T2) then
2917 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2920 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2923 elsif T1 = Any_Access
2924 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2928 elsif T2 = Any_Access
2929 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
2933 elsif T2 = Any_Composite
2934 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
2938 elsif T1 = Any_Composite
2939 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
2943 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
2946 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
2949 -- ----------------------------------------------------------
2950 -- Special cases for equality operators (all other predefined
2951 -- operators can never apply to tagged types)
2952 -- ----------------------------------------------------------
2954 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
2957 elsif Is_Class_Wide_Type (T1)
2958 and then Is_Class_Wide_Type (T2)
2959 and then Is_Interface (Etype (T2))
2963 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
2964 -- class-wide interface T2
2966 elsif Is_Class_Wide_Type (T2)
2967 and then Is_Interface (Etype (T2))
2968 and then Interface_Present_In_Ancestor (Typ => T1,
2969 Iface => Etype (T2))
2973 elsif Is_Class_Wide_Type (T1)
2974 and then Is_Ancestor (Root_Type (T1), T2)
2978 elsif Is_Class_Wide_Type (T2)
2979 and then Is_Ancestor (Root_Type (T2), T1)
2983 elsif (Ekind (B1) = E_Access_Subprogram_Type
2985 Ekind (B1) = E_Access_Protected_Subprogram_Type)
2986 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
2987 and then Is_Access_Type (T2)
2991 elsif (Ekind (B2) = E_Access_Subprogram_Type
2993 Ekind (B2) = E_Access_Protected_Subprogram_Type)
2994 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
2995 and then Is_Access_Type (T1)
2999 elsif (Ekind (T1) = E_Allocator_Type
3000 or else Ekind (T1) = E_Access_Attribute_Type
3001 or else Ekind (T1) = E_Anonymous_Access_Type)
3002 and then Is_Access_Type (T2)
3006 elsif (Ekind (T2) = E_Allocator_Type
3007 or else Ekind (T2) = E_Access_Attribute_Type
3008 or else Ekind (T2) = E_Anonymous_Access_Type)
3009 and then Is_Access_Type (T1)
3013 -- If none of the above cases applies, types are not compatible
3020 ---------------------
3021 -- Set_Abstract_Op --
3022 ---------------------
3024 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3026 All_Interp.Table (I).Abstract_Op := V;
3027 end Set_Abstract_Op;
3029 -----------------------
3030 -- Valid_Boolean_Arg --
3031 -----------------------
3033 -- In addition to booleans and arrays of booleans, we must include
3034 -- aggregates as valid boolean arguments, because in the first pass of
3035 -- resolution their components are not examined. If it turns out not to be
3036 -- an aggregate of booleans, this will be diagnosed in Resolve.
3037 -- Any_Composite must be checked for prior to the array type checks because
3038 -- Any_Composite does not have any associated indexes.
3040 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3042 return Is_Boolean_Type (T)
3043 or else T = Any_Composite
3044 or else (Is_Array_Type (T)
3045 and then T /= Any_String
3046 and then Number_Dimensions (T) = 1
3047 and then Is_Boolean_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))
3052 or else Is_Modular_Integer_Type (T)
3053 or else T = Universal_Integer;
3054 end Valid_Boolean_Arg;
3056 --------------------------
3057 -- Valid_Comparison_Arg --
3058 --------------------------
3060 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3063 if T = Any_Composite then
3065 elsif Is_Discrete_Type (T)
3066 or else Is_Real_Type (T)
3069 elsif Is_Array_Type (T)
3070 and then Number_Dimensions (T) = 1
3071 and then Is_Discrete_Type (Component_Type (T))
3072 and then (not Is_Private_Composite (T)
3073 or else In_Instance)
3074 and then (not Is_Limited_Composite (T)
3075 or else In_Instance)
3078 elsif Is_String_Type (T) then
3083 end Valid_Comparison_Arg;
3085 ----------------------
3086 -- Write_Interp_Ref --
3087 ----------------------
3089 procedure Write_Interp_Ref (Map_Ptr : Int) is
3091 Write_Str (" Node: ");
3092 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3093 Write_Str (" Index: ");
3094 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3095 Write_Str (" Next: ");
3096 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3098 end Write_Interp_Ref;
3100 ---------------------
3101 -- Write_Overloads --
3102 ---------------------
3104 procedure Write_Overloads (N : Node_Id) is
3110 if not Is_Overloaded (N) then
3111 Write_Str ("Non-overloaded entity ");
3113 Write_Entity_Info (Entity (N), " ");
3116 Get_First_Interp (N, I, It);
3117 Write_Str ("Overloaded entity ");
3119 Write_Str (" Name Type Abstract Op");
3121 Write_Str ("===============================================");
3125 while Present (Nam) loop
3126 Write_Int (Int (Nam));
3128 Write_Name (Chars (Nam));
3130 Write_Int (Int (It.Typ));
3132 Write_Name (Chars (It.Typ));
3134 if Present (It.Abstract_Op) then
3136 Write_Int (Int (It.Abstract_Op));
3138 Write_Name (Chars (It.Abstract_Op));
3142 Get_Next_Interp (I, It);
3146 end Write_Overloads;