1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2009, 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 set
61 -- of interpretations is terminated with the marker No_Interp. In order to
62 -- speed up the retrieval of the interpretations of an overloaded node, the
63 -- Interp_Map table is accessed by means of a simple hashing scheme, and
64 -- the entries in Interp_Map are chained. The heads of clash lists are
65 -- 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 other
136 -- entities. We do not introduce explicit versions of primitive operators
137 -- for each type definition. As a result, there is only one entity
138 -- corresponding to predefined addition on all numeric types, etc. The
139 -- back-end resolves predefined operators according to their type. The
140 -- visibility of primitive operations then reduces to the visibility of the
141 -- resulting type: (a + b) is a legal interpretation of some primitive
142 -- operator + if the type of the result (which must also be the type of a
143 -- and b) is directly visible (either immediately visible or use-visible).
145 -- User-defined operators are treated like other functions, but the
146 -- visibility of these user-defined operations must be special-cased
147 -- to determine whether they hide or are hidden by predefined operators.
148 -- The form P."+" (x, y) requires additional handling.
150 -- Concatenation is treated more conventionally: for every one-dimensional
151 -- array type we introduce a explicit concatenation operator. This is
152 -- necessary to handle the case of (element & element => array) which
153 -- cannot be handled conveniently if there is no explicit instance of
154 -- resulting type of the operation.
156 -----------------------
157 -- Local Subprograms --
158 -----------------------
160 procedure All_Overloads;
161 pragma Warnings (Off, All_Overloads);
162 -- Debugging procedure: list full contents of Overloads table
164 function Binary_Op_Interp_Has_Abstract_Op
166 E : Entity_Id) return Entity_Id;
167 -- Given the node and entity of a binary operator, determine whether the
168 -- actuals of E contain an abstract interpretation with regards to the
169 -- types of their corresponding formals. Return the abstract operation or
172 function Function_Interp_Has_Abstract_Op
174 E : Entity_Id) return Entity_Id;
175 -- Given the node and entity of a function call, determine whether the
176 -- actuals of E contain an abstract interpretation with regards to the
177 -- types of their corresponding formals. Return the abstract operation or
180 function Has_Abstract_Op
182 Typ : Entity_Id) return Entity_Id;
183 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
184 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
185 -- abstract interpretation which yields type Typ.
187 procedure New_Interps (N : Node_Id);
188 -- Initialize collection of interpretations for the given node, which is
189 -- either an overloaded entity, or an operation whose arguments have
190 -- multiple interpretations. Interpretations can be added to only one
193 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id;
194 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
195 -- or is not a "class" type (any_character, etc).
201 procedure Add_One_Interp
205 Opnd_Type : Entity_Id := Empty)
207 Vis_Type : Entity_Id;
209 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
210 -- Add one interpretation to an overloaded node. Add a new entry if
211 -- not hidden by previous one, and remove previous one if hidden by
214 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
215 -- True if the entity is a predefined operator and the operands have
216 -- a universal Interpretation.
222 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
223 Abstr_Op : Entity_Id := Empty;
227 -- Start of processing for Add_Entry
230 -- Find out whether the new entry references interpretations that
231 -- are abstract or disabled by abstract operators.
233 if Ada_Version >= Ada_05 then
234 if Nkind (N) in N_Binary_Op then
235 Abstr_Op := Binary_Op_Interp_Has_Abstract_Op (N, Name);
236 elsif Nkind (N) = N_Function_Call then
237 Abstr_Op := Function_Interp_Has_Abstract_Op (N, Name);
241 Get_First_Interp (N, I, It);
242 while Present (It.Nam) loop
244 -- A user-defined subprogram hides another declared at an outer
245 -- level, or one that is use-visible. So return if previous
246 -- definition hides new one (which is either in an outer
247 -- scope, or use-visible). Note that for functions use-visible
248 -- is the same as potentially use-visible. If new one hides
249 -- previous one, replace entry in table of interpretations.
250 -- If this is a universal operation, retain the operator in case
251 -- preference rule applies.
253 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
254 and then Ekind (Name) = Ekind (It.Nam))
255 or else (Ekind (Name) = E_Operator
256 and then Ekind (It.Nam) = E_Function))
258 and then Is_Immediately_Visible (It.Nam)
259 and then Type_Conformant (Name, It.Nam)
260 and then Base_Type (It.Typ) = Base_Type (T)
262 if Is_Universal_Operation (Name) then
265 -- If node is an operator symbol, we have no actuals with
266 -- which to check hiding, and this is done in full in the
267 -- caller (Analyze_Subprogram_Renaming) so we include the
268 -- predefined operator in any case.
270 elsif Nkind (N) = N_Operator_Symbol
271 or else (Nkind (N) = N_Expanded_Name
273 Nkind (Selector_Name (N)) = N_Operator_Symbol)
277 elsif not In_Open_Scopes (Scope (Name))
278 or else Scope_Depth (Scope (Name)) <=
279 Scope_Depth (Scope (It.Nam))
281 -- If ambiguity within instance, and entity is not an
282 -- implicit operation, save for later disambiguation.
284 if Scope (Name) = Scope (It.Nam)
285 and then not Is_Inherited_Operation (Name)
294 All_Interp.Table (I).Nam := Name;
298 -- Avoid making duplicate entries in overloads
301 and then Base_Type (It.Typ) = Base_Type (T)
305 -- Otherwise keep going
308 Get_Next_Interp (I, It);
313 All_Interp.Table (All_Interp.Last) := (Name, Typ, Abstr_Op);
314 All_Interp.Append (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 be a
407 -- candidate interpretation, because it could not have been one in the
408 -- generic (it may be a spurious overloading in the instance).
411 and then Is_Overloadable (E)
412 and then Is_Abstract_Subprogram (E)
413 and then not Is_Dispatching_Operation (E)
417 -- An inherited interface operation that is implemented by some derived
418 -- type does not participate in overload resolution, only the
419 -- implementation operation does.
422 and then Is_Subprogram (E)
423 and then Present (Interface_Alias (E))
425 -- Ada 2005 (AI-251): If this primitive operation corresponds with
426 -- an immediate ancestor interface there is no need to add it to the
427 -- list of interpretations. The corresponding aliased primitive is
428 -- also in this list of primitive operations and will be used instead
429 -- because otherwise we have a dummy ambiguity between the two
430 -- subprograms which are in fact the same.
433 (Find_Dispatching_Type (Interface_Alias (E)),
434 Find_Dispatching_Type (E))
436 Add_One_Interp (N, Interface_Alias (E), T);
441 -- Calling stubs for an RACW operation never participate in resolution,
442 -- they are executed only through dispatching calls.
444 elsif Is_RACW_Stub_Type_Operation (E) then
448 -- If this is the first interpretation of N, N has type Any_Type.
449 -- In that case place the new type on the node. If one interpretation
450 -- already exists, indicate that the node is overloaded, and store
451 -- both the previous and the new interpretation in All_Interp. If
452 -- this is a later interpretation, just add it to the set.
454 if Etype (N) = Any_Type then
459 -- Record both the operator or subprogram name, and its type
461 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
468 -- Either there is no current interpretation in the table for any
469 -- node or the interpretation that is present is for a different
470 -- node. In both cases add a new interpretation to the table.
472 elsif Interp_Map.Last < 0
474 (Interp_Map.Table (Interp_Map.Last).Node /= N
475 and then not Is_Overloaded (N))
479 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
480 and then Present (Entity (N))
482 Add_Entry (Entity (N), Etype (N));
484 elsif (Nkind (N) = N_Function_Call
485 or else Nkind (N) = N_Procedure_Call_Statement)
486 and then (Nkind (Name (N)) = N_Operator_Symbol
487 or else Is_Entity_Name (Name (N)))
489 Add_Entry (Entity (Name (N)), Etype (N));
491 -- If this is an indirect call there will be no name associated
492 -- with the previous entry. To make diagnostics clearer, save
493 -- Subprogram_Type of first interpretation, so that the error will
494 -- point to the anonymous access to subprogram, not to the result
495 -- type of the call itself.
497 elsif (Nkind (N)) = N_Function_Call
498 and then Nkind (Name (N)) = N_Explicit_Dereference
499 and then Is_Overloaded (Name (N))
505 pragma Warnings (Off, Itn);
508 Get_First_Interp (Name (N), Itn, It);
509 Add_Entry (It.Nam, Etype (N));
513 -- Overloaded prefix in indexed or selected component, or call
514 -- whose name is an expression or another call.
516 Add_Entry (Etype (N), Etype (N));
530 procedure All_Overloads is
532 for J in All_Interp.First .. All_Interp.Last loop
534 if Present (All_Interp.Table (J).Nam) then
535 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
537 Write_Str ("No Interp");
541 Write_Str ("=================");
546 --------------------------------------
547 -- Binary_Op_Interp_Has_Abstract_Op --
548 --------------------------------------
550 function Binary_Op_Interp_Has_Abstract_Op
552 E : Entity_Id) return Entity_Id
554 Abstr_Op : Entity_Id;
555 E_Left : constant Node_Id := First_Formal (E);
556 E_Right : constant Node_Id := Next_Formal (E_Left);
559 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
560 if Present (Abstr_Op) then
564 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
565 end Binary_Op_Interp_Has_Abstract_Op;
567 ---------------------
568 -- Collect_Interps --
569 ---------------------
571 procedure Collect_Interps (N : Node_Id) is
572 Ent : constant Entity_Id := Entity (N);
574 First_Interp : Interp_Index;
579 -- Unconditionally add the entity that was initially matched
581 First_Interp := All_Interp.Last;
582 Add_One_Interp (N, Ent, Etype (N));
584 -- For expanded name, pick up all additional entities from the
585 -- same scope, since these are obviously also visible. Note that
586 -- these are not necessarily contiguous on the homonym chain.
588 if Nkind (N) = N_Expanded_Name then
590 while Present (H) loop
591 if Scope (H) = Scope (Entity (N)) then
592 Add_One_Interp (N, H, Etype (H));
598 -- Case of direct name
601 -- First, search the homonym chain for directly visible entities
603 H := Current_Entity (Ent);
604 while Present (H) loop
605 exit when (not Is_Overloadable (H))
606 and then Is_Immediately_Visible (H);
608 if Is_Immediately_Visible (H)
611 -- Only add interpretation if not hidden by an inner
612 -- immediately visible one.
614 for J in First_Interp .. All_Interp.Last - 1 loop
616 -- Current homograph is not hidden. Add to overloads
618 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
621 -- Homograph is hidden, unless it is a predefined operator
623 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
625 -- A homograph in the same scope can occur within an
626 -- instantiation, the resulting ambiguity has to be
629 if Scope (H) = Scope (Ent)
631 and then not Is_Inherited_Operation (H)
633 All_Interp.Table (All_Interp.Last) :=
634 (H, Etype (H), Empty);
635 All_Interp.Append (No_Interp);
638 elsif Scope (H) /= Standard_Standard then
644 -- On exit, we know that current homograph is not hidden
646 Add_One_Interp (N, H, Etype (H));
649 Write_Str ("Add overloaded interpretation ");
659 -- Scan list of homographs for use-visible entities only
661 H := Current_Entity (Ent);
663 while Present (H) loop
664 if Is_Potentially_Use_Visible (H)
666 and then Is_Overloadable (H)
668 for J in First_Interp .. All_Interp.Last - 1 loop
670 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
673 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
674 goto Next_Use_Homograph;
678 Add_One_Interp (N, H, Etype (H));
681 <<Next_Use_Homograph>>
686 if All_Interp.Last = First_Interp + 1 then
688 -- The final interpretation is in fact not overloaded. Note that the
689 -- unique legal interpretation may or may not be the original one,
690 -- so we need to update N's entity and etype now, because once N
691 -- is marked as not overloaded it is also expected to carry the
692 -- proper interpretation.
694 Set_Is_Overloaded (N, False);
695 Set_Entity (N, All_Interp.Table (First_Interp).Nam);
696 Set_Etype (N, All_Interp.Table (First_Interp).Typ);
704 function Covers (T1, T2 : Entity_Id) return Boolean is
709 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
710 -- In an instance the proper view may not always be correct for
711 -- private types, but private and full view are compatible. This
712 -- removes spurious errors from nested instantiations that involve,
713 -- among other things, types derived from private types.
715 ----------------------
716 -- Full_View_Covers --
717 ----------------------
719 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
722 Is_Private_Type (Typ1)
724 ((Present (Full_View (Typ1))
725 and then Covers (Full_View (Typ1), Typ2))
726 or else Base_Type (Typ1) = Typ2
727 or else Base_Type (Typ2) = Typ1);
728 end Full_View_Covers;
730 -- Start of processing for Covers
733 -- If either operand missing, then this is an error, but ignore it (and
734 -- pretend we have a cover) if errors already detected, since this may
735 -- simply mean we have malformed trees.
737 if No (T1) or else No (T2) then
738 if Total_Errors_Detected /= 0 then
745 BT1 := Base_Type (T1);
746 BT2 := Base_Type (T2);
748 -- Handle underlying view of records with unknown discriminants
749 -- using the original entity that motivated the construction of
750 -- this underlying record view (see Build_Derived_Private_Type).
752 if Is_Underlying_Record_View (BT1) then
753 BT1 := Underlying_Record_View (BT1);
756 if Is_Underlying_Record_View (BT2) then
757 BT2 := Underlying_Record_View (BT2);
761 -- Simplest case: same types are compatible, and types that have the
762 -- same base type and are not generic actuals are compatible. Generic
763 -- actuals belong to their class but are not compatible with other
764 -- types of their class, and in particular with other generic actuals.
765 -- They are however compatible with their own subtypes, and itypes
766 -- with the same base are compatible as well. Similarly, constrained
767 -- subtypes obtained from expressions of an unconstrained nominal type
768 -- are compatible with the base type (may lead to spurious ambiguities
769 -- in obscure cases ???)
771 -- Generic actuals require special treatment to avoid spurious ambi-
772 -- guities in an instance, when two formal types are instantiated with
773 -- the same actual, so that different subprograms end up with the same
774 -- signature in the instance.
783 if not Is_Generic_Actual_Type (T1) then
786 return (not Is_Generic_Actual_Type (T2)
787 or else Is_Itype (T1)
788 or else Is_Itype (T2)
789 or else Is_Constr_Subt_For_U_Nominal (T1)
790 or else Is_Constr_Subt_For_U_Nominal (T2)
791 or else Scope (T1) /= Scope (T2));
794 -- Literals are compatible with types in a given "class"
796 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
797 or else (T2 = Universal_Real and then Is_Real_Type (T1))
798 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
799 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
800 or else (T2 = Any_String and then Is_String_Type (T1))
801 or else (T2 = Any_Character and then Is_Character_Type (T1))
802 or else (T2 = Any_Access and then Is_Access_Type (T1))
806 -- The context may be class wide
808 elsif Is_Class_Wide_Type (T1)
809 and then Is_Ancestor (Root_Type (T1), T2)
813 elsif Is_Class_Wide_Type (T1)
814 and then Is_Class_Wide_Type (T2)
815 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
819 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
820 -- task_type or protected_type implementing T1
822 elsif Ada_Version >= Ada_05
823 and then Is_Class_Wide_Type (T1)
824 and then Is_Interface (Etype (T1))
825 and then Is_Concurrent_Type (T2)
826 and then Interface_Present_In_Ancestor
827 (Typ => Base_Type (T2),
832 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
833 -- object T2 implementing T1
835 elsif Ada_Version >= Ada_05
836 and then Is_Class_Wide_Type (T1)
837 and then Is_Interface (Etype (T1))
838 and then Is_Tagged_Type (T2)
840 if Interface_Present_In_Ancestor (Typ => T2,
851 if Is_Concurrent_Type (BT2) then
852 E := Corresponding_Record_Type (BT2);
857 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
858 -- covers an object T2 that implements a direct derivation of T1.
859 -- Note: test for presence of E is defense against previous error.
862 and then Present (Interfaces (E))
864 Elmt := First_Elmt (Interfaces (E));
865 while Present (Elmt) loop
866 if Is_Ancestor (Etype (T1), Node (Elmt)) then
874 -- We should also check the case in which T1 is an ancestor of
875 -- some implemented interface???
880 -- In a dispatching call the actual may be class-wide
882 elsif Is_Class_Wide_Type (T2)
883 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
887 -- Some contexts require a class of types rather than a specific type
889 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
890 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
891 or else (T1 = Any_Real and then Is_Real_Type (T2))
892 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
893 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
897 -- An aggregate is compatible with an array or record type
899 elsif T2 = Any_Composite
900 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
904 -- If the expected type is an anonymous access, the designated type must
905 -- cover that of the expression. Use the base type for this check: even
906 -- though access subtypes are rare in sources, they are generated for
907 -- actuals in instantiations.
909 elsif Ekind (BT1) = E_Anonymous_Access_Type
910 and then Is_Access_Type (T2)
911 and then Covers (Designated_Type (T1), Designated_Type (T2))
915 -- An Access_To_Subprogram is compatible with itself, or with an
916 -- anonymous type created for an attribute reference Access.
918 elsif (Ekind (BT1) = E_Access_Subprogram_Type
920 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
921 and then Is_Access_Type (T2)
922 and then (not Comes_From_Source (T1)
923 or else not Comes_From_Source (T2))
924 and then (Is_Overloadable (Designated_Type (T2))
926 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
928 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
930 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
934 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
935 -- with itself, or with an anonymous type created for an attribute
938 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
941 = E_Anonymous_Access_Protected_Subprogram_Type)
942 and then Is_Access_Type (T2)
943 and then (not Comes_From_Source (T1)
944 or else not Comes_From_Source (T2))
945 and then (Is_Overloadable (Designated_Type (T2))
947 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
949 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
951 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
955 -- The context can be a remote access type, and the expression the
956 -- corresponding source type declared in a categorized package, or
959 elsif Is_Record_Type (T1)
960 and then (Is_Remote_Call_Interface (T1)
961 or else Is_Remote_Types (T1))
962 and then Present (Corresponding_Remote_Type (T1))
964 return Covers (Corresponding_Remote_Type (T1), T2);
966 elsif Is_Record_Type (T2)
967 and then (Is_Remote_Call_Interface (T2)
968 or else Is_Remote_Types (T2))
969 and then Present (Corresponding_Remote_Type (T2))
971 return Covers (Corresponding_Remote_Type (T2), T1);
973 elsif Ekind (T2) = E_Access_Attribute_Type
974 and then (Ekind (BT1) = E_General_Access_Type
975 or else Ekind (BT1) = E_Access_Type)
976 and then Covers (Designated_Type (T1), Designated_Type (T2))
978 -- If the target type is a RACW type while the source is an access
979 -- attribute type, we are building a RACW that may be exported.
981 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
982 Set_Has_RACW (Current_Sem_Unit);
987 elsif Ekind (T2) = E_Allocator_Type
988 and then Is_Access_Type (T1)
990 return Covers (Designated_Type (T1), Designated_Type (T2))
992 (From_With_Type (Designated_Type (T1))
993 and then Covers (Designated_Type (T2), Designated_Type (T1)));
995 -- A boolean operation on integer literals is compatible with modular
998 elsif T2 = Any_Modular
999 and then Is_Modular_Integer_Type (T1)
1003 -- The actual type may be the result of a previous error
1005 elsif Base_Type (T2) = Any_Type then
1008 -- A packed array type covers its corresponding non-packed type. This is
1009 -- not legitimate Ada, but allows the omission of a number of otherwise
1010 -- useless unchecked conversions, and since this can only arise in
1011 -- (known correct) expanded code, no harm is done
1013 elsif Is_Array_Type (T2)
1014 and then Is_Packed (T2)
1015 and then T1 = Packed_Array_Type (T2)
1019 -- Similarly an array type covers its corresponding packed array type
1021 elsif Is_Array_Type (T1)
1022 and then Is_Packed (T1)
1023 and then T2 = Packed_Array_Type (T1)
1027 -- In instances, or with types exported from instantiations, check
1028 -- whether a partial and a full view match. Verify that types are
1029 -- legal, to prevent cascaded errors.
1033 (Full_View_Covers (T1, T2)
1034 or else Full_View_Covers (T2, T1))
1039 and then Is_Generic_Actual_Type (T2)
1040 and then Full_View_Covers (T1, T2)
1045 and then Is_Generic_Actual_Type (T1)
1046 and then Full_View_Covers (T2, T1)
1050 -- In the expansion of inlined bodies, types are compatible if they
1051 -- are structurally equivalent.
1053 elsif In_Inlined_Body
1054 and then (Underlying_Type (T1) = Underlying_Type (T2)
1055 or else (Is_Access_Type (T1)
1056 and then Is_Access_Type (T2)
1058 Designated_Type (T1) = Designated_Type (T2))
1059 or else (T1 = Any_Access
1060 and then Is_Access_Type (Underlying_Type (T2)))
1061 or else (T2 = Any_Composite
1063 Is_Composite_Type (Underlying_Type (T1))))
1067 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1068 -- compatible with its real entity.
1070 elsif From_With_Type (T1) then
1072 -- If the expected type is the non-limited view of a type, the
1073 -- expression may have the limited view. If that one in turn is
1074 -- incomplete, get full view if available.
1076 if Is_Incomplete_Type (T1) then
1077 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1079 elsif Ekind (T1) = E_Class_Wide_Type then
1081 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1086 elsif From_With_Type (T2) then
1088 -- If units in the context have Limited_With clauses on each other,
1089 -- either type might have a limited view. Checks performed elsewhere
1090 -- verify that the context type is the non-limited view.
1092 if Is_Incomplete_Type (T2) then
1093 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1095 elsif Ekind (T2) = E_Class_Wide_Type then
1097 Present (Non_Limited_View (Etype (T2)))
1099 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1104 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1106 elsif Ekind (T1) = E_Incomplete_Subtype then
1107 return Covers (Full_View (Etype (T1)), T2);
1109 elsif Ekind (T2) = E_Incomplete_Subtype then
1110 return Covers (T1, Full_View (Etype (T2)));
1112 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1113 -- and actual anonymous access types in the context of generic
1114 -- instantiation. We have the following situation:
1117 -- type Formal is private;
1118 -- Formal_Obj : access Formal; -- T1
1122 -- type Actual is ...
1123 -- Actual_Obj : access Actual; -- T2
1124 -- package Instance is new G (Formal => Actual,
1125 -- Formal_Obj => Actual_Obj);
1127 elsif Ada_Version >= Ada_05
1128 and then Ekind (T1) = E_Anonymous_Access_Type
1129 and then Ekind (T2) = E_Anonymous_Access_Type
1130 and then Is_Generic_Type (Directly_Designated_Type (T1))
1131 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1132 Directly_Designated_Type (T2)
1136 -- Otherwise it doesn't cover!
1147 function Disambiguate
1149 I1, I2 : Interp_Index;
1150 Typ : Entity_Id) return Interp
1155 Nam1, Nam2 : Entity_Id;
1156 Predef_Subp : Entity_Id;
1157 User_Subp : Entity_Id;
1159 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1160 -- Determine whether one of the candidates is an operation inherited by
1161 -- a type that is derived from an actual in an instantiation.
1163 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1164 -- Determine whether a subprogram is an actual in an enclosing instance.
1165 -- An overloading between such a subprogram and one declared outside the
1166 -- instance is resolved in favor of the first, because it resolved in
1169 function Matches (Actual, Formal : Node_Id) return Boolean;
1170 -- Look for exact type match in an instance, to remove spurious
1171 -- ambiguities when two formal types have the same actual.
1173 function Standard_Operator return Boolean;
1174 -- Check whether subprogram is predefined operator declared in Standard.
1175 -- It may given by an operator name, or by an expanded name whose prefix
1178 function Remove_Conversions return Interp;
1179 -- Last chance for pathological cases involving comparisons on literals,
1180 -- and user overloadings of the same operator. Such pathologies have
1181 -- been removed from the ACVC, but still appear in two DEC tests, with
1182 -- the following notable quote from Ben Brosgol:
1184 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1185 -- this example; Robert Dewar brought it to our attention, since it is
1186 -- apparently found in the ACVC 1.5. I did not attempt to find the
1187 -- reason in the Reference Manual that makes the example legal, since I
1188 -- was too nauseated by it to want to pursue it further.]
1190 -- Accordingly, this is not a fully recursive solution, but it handles
1191 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1192 -- pathology in the other direction with calls whose multiple overloaded
1193 -- actuals make them truly unresolvable.
1195 -- The new rules concerning abstract operations create additional need
1196 -- for special handling of expressions with universal operands, see
1197 -- comments to Has_Abstract_Interpretation below.
1199 ---------------------------
1200 -- Inherited_From_Actual --
1201 ---------------------------
1203 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1204 Par : constant Node_Id := Parent (S);
1206 if Nkind (Par) /= N_Full_Type_Declaration
1207 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1211 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1213 Is_Generic_Actual_Type (
1214 Entity (Subtype_Indication (Type_Definition (Par))));
1216 end Inherited_From_Actual;
1218 --------------------------
1219 -- Is_Actual_Subprogram --
1220 --------------------------
1222 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1224 return In_Open_Scopes (Scope (S))
1226 (Is_Generic_Instance (Scope (S))
1227 or else Is_Wrapper_Package (Scope (S)));
1228 end Is_Actual_Subprogram;
1234 function Matches (Actual, Formal : Node_Id) return Boolean is
1235 T1 : constant Entity_Id := Etype (Actual);
1236 T2 : constant Entity_Id := Etype (Formal);
1240 (Is_Numeric_Type (T2)
1241 and then (T1 = Universal_Real or else T1 = Universal_Integer));
1244 ------------------------
1245 -- Remove_Conversions --
1246 ------------------------
1248 function Remove_Conversions return Interp is
1256 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1257 -- If an operation has universal operands the universal operation
1258 -- is present among its interpretations. If there is an abstract
1259 -- interpretation for the operator, with a numeric result, this
1260 -- interpretation was already removed in sem_ch4, but the universal
1261 -- one is still visible. We must rescan the list of operators and
1262 -- remove the universal interpretation to resolve the ambiguity.
1264 ---------------------------------
1265 -- Has_Abstract_Interpretation --
1266 ---------------------------------
1268 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1272 if Nkind (N) not in N_Op
1273 or else Ada_Version < Ada_05
1274 or else not Is_Overloaded (N)
1275 or else No (Universal_Interpretation (N))
1280 E := Get_Name_Entity_Id (Chars (N));
1281 while Present (E) loop
1282 if Is_Overloadable (E)
1283 and then Is_Abstract_Subprogram (E)
1284 and then Is_Numeric_Type (Etype (E))
1292 -- Finally, if an operand of the binary operator is itself
1293 -- an operator, recurse to see whether its own abstract
1294 -- interpretation is responsible for the spurious ambiguity.
1296 if Nkind (N) in N_Binary_Op then
1297 return Has_Abstract_Interpretation (Left_Opnd (N))
1298 or else Has_Abstract_Interpretation (Right_Opnd (N));
1300 elsif Nkind (N) in N_Unary_Op then
1301 return Has_Abstract_Interpretation (Right_Opnd (N));
1307 end Has_Abstract_Interpretation;
1309 -- Start of processing for Remove_Conversions
1314 Get_First_Interp (N, I, It);
1315 while Present (It.Typ) loop
1316 if not Is_Overloadable (It.Nam) then
1320 F1 := First_Formal (It.Nam);
1326 if Nkind (N) = N_Function_Call
1327 or else Nkind (N) = N_Procedure_Call_Statement
1329 Act1 := First_Actual (N);
1331 if Present (Act1) then
1332 Act2 := Next_Actual (Act1);
1337 elsif Nkind (N) in N_Unary_Op then
1338 Act1 := Right_Opnd (N);
1341 elsif Nkind (N) in N_Binary_Op then
1342 Act1 := Left_Opnd (N);
1343 Act2 := Right_Opnd (N);
1345 -- Use type of second formal, so as to include
1346 -- exponentiation, where the exponent may be
1347 -- ambiguous and the result non-universal.
1355 if Nkind (Act1) in N_Op
1356 and then Is_Overloaded (Act1)
1357 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1358 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1359 and then Has_Compatible_Type (Act1, Standard_Boolean)
1360 and then Etype (F1) = Standard_Boolean
1362 -- If the two candidates are the original ones, the
1363 -- ambiguity is real. Otherwise keep the original, further
1364 -- calls to Disambiguate will take care of others in the
1365 -- list of candidates.
1367 if It1 /= No_Interp then
1368 if It = Disambiguate.It1
1369 or else It = Disambiguate.It2
1371 if It1 = Disambiguate.It1
1372 or else It1 = Disambiguate.It2
1380 elsif Present (Act2)
1381 and then Nkind (Act2) in N_Op
1382 and then Is_Overloaded (Act2)
1383 and then Nkind_In (Right_Opnd (Act2), N_Integer_Literal,
1385 and then Has_Compatible_Type (Act2, Standard_Boolean)
1387 -- The preference rule on the first actual is not
1388 -- sufficient to disambiguate.
1396 elsif Is_Numeric_Type (Etype (F1))
1397 and then Has_Abstract_Interpretation (Act1)
1399 -- Current interpretation is not the right one because it
1400 -- expects a numeric operand. Examine all the other ones.
1407 Get_First_Interp (N, I, It);
1408 while Present (It.Typ) loop
1410 not Is_Numeric_Type (Etype (First_Formal (It.Nam)))
1413 or else not Has_Abstract_Interpretation (Act2)
1416 (Etype (Next_Formal (First_Formal (It.Nam))))
1422 Get_Next_Interp (I, It);
1431 Get_Next_Interp (I, It);
1434 -- After some error, a formal may have Any_Type and yield a spurious
1435 -- match. To avoid cascaded errors if possible, check for such a
1436 -- formal in either candidate.
1438 if Serious_Errors_Detected > 0 then
1443 Formal := First_Formal (Nam1);
1444 while Present (Formal) loop
1445 if Etype (Formal) = Any_Type then
1446 return Disambiguate.It2;
1449 Next_Formal (Formal);
1452 Formal := First_Formal (Nam2);
1453 while Present (Formal) loop
1454 if Etype (Formal) = Any_Type then
1455 return Disambiguate.It1;
1458 Next_Formal (Formal);
1464 end Remove_Conversions;
1466 -----------------------
1467 -- Standard_Operator --
1468 -----------------------
1470 function Standard_Operator return Boolean is
1474 if Nkind (N) in N_Op then
1477 elsif Nkind (N) = N_Function_Call then
1480 if Nkind (Nam) /= N_Expanded_Name then
1483 return Entity (Prefix (Nam)) = Standard_Standard;
1488 end Standard_Operator;
1490 -- Start of processing for Disambiguate
1493 -- Recover the two legal interpretations
1495 Get_First_Interp (N, I, It);
1497 Get_Next_Interp (I, It);
1503 Get_Next_Interp (I, It);
1509 if Ada_Version < Ada_05 then
1511 -- Check whether one of the entities is an Ada 2005 entity and we are
1512 -- operating in an earlier mode, in which case we discard the Ada
1513 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1515 if Is_Ada_2005_Only (Nam1) then
1517 elsif Is_Ada_2005_Only (Nam2) then
1522 -- Check for overloaded CIL convention stuff because the CIL libraries
1523 -- do sick things like Console.Write_Line where it matches two different
1524 -- overloads, so just pick the first ???
1526 if Convention (Nam1) = Convention_CIL
1527 and then Convention (Nam2) = Convention_CIL
1528 and then Ekind (Nam1) = Ekind (Nam2)
1529 and then (Ekind (Nam1) = E_Procedure
1530 or else Ekind (Nam1) = E_Function)
1535 -- If the context is universal, the predefined operator is preferred.
1536 -- This includes bounds in numeric type declarations, and expressions
1537 -- in type conversions. If no interpretation yields a universal type,
1538 -- then we must check whether the user-defined entity hides the prede-
1541 if Chars (Nam1) in Any_Operator_Name
1542 and then Standard_Operator
1544 if Typ = Universal_Integer
1545 or else Typ = Universal_Real
1546 or else Typ = Any_Integer
1547 or else Typ = Any_Discrete
1548 or else Typ = Any_Real
1549 or else Typ = Any_Type
1551 -- Find an interpretation that yields the universal type, or else
1552 -- a predefined operator that yields a predefined numeric type.
1555 Candidate : Interp := No_Interp;
1558 Get_First_Interp (N, I, It);
1559 while Present (It.Typ) loop
1560 if (Covers (Typ, It.Typ)
1561 or else Typ = Any_Type)
1563 (It.Typ = Universal_Integer
1564 or else It.Typ = Universal_Real)
1568 elsif Covers (Typ, It.Typ)
1569 and then Scope (It.Typ) = Standard_Standard
1570 and then Scope (It.Nam) = Standard_Standard
1571 and then Is_Numeric_Type (It.Typ)
1576 Get_Next_Interp (I, It);
1579 if Candidate /= No_Interp then
1584 elsif Chars (Nam1) /= Name_Op_Not
1585 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1587 -- Equality or comparison operation. Choose predefined operator if
1588 -- arguments are universal. The node may be an operator, name, or
1589 -- a function call, so unpack arguments accordingly.
1592 Arg1, Arg2 : Node_Id;
1595 if Nkind (N) in N_Op then
1596 Arg1 := Left_Opnd (N);
1597 Arg2 := Right_Opnd (N);
1599 elsif Is_Entity_Name (N)
1600 or else Nkind (N) = N_Operator_Symbol
1602 Arg1 := First_Entity (Entity (N));
1603 Arg2 := Next_Entity (Arg1);
1606 Arg1 := First_Actual (N);
1607 Arg2 := Next_Actual (Arg1);
1611 and then Present (Universal_Interpretation (Arg1))
1612 and then Universal_Interpretation (Arg2) =
1613 Universal_Interpretation (Arg1)
1615 Get_First_Interp (N, I, It);
1616 while Scope (It.Nam) /= Standard_Standard loop
1617 Get_Next_Interp (I, It);
1626 -- If no universal interpretation, check whether user-defined operator
1627 -- hides predefined one, as well as other special cases. If the node
1628 -- is a range, then one or both bounds are ambiguous. Each will have
1629 -- to be disambiguated w.r.t. the context type. The type of the range
1630 -- itself is imposed by the context, so we can return either legal
1633 if Ekind (Nam1) = E_Operator then
1634 Predef_Subp := Nam1;
1637 elsif Ekind (Nam2) = E_Operator then
1638 Predef_Subp := Nam2;
1641 elsif Nkind (N) = N_Range then
1644 -- Implement AI05-105: A renaming declaration with an access
1645 -- definition must resolve to an anonymous access type. This
1646 -- is a resolution rule and can be used to disambiguate.
1648 elsif Nkind (Parent (N)) = N_Object_Renaming_Declaration
1649 and then Present (Access_Definition (Parent (N)))
1651 if Ekind (It1.Typ) = E_Anonymous_Access_Type
1653 Ekind (It1.Typ) = E_Anonymous_Access_Subprogram_Type
1655 if Ekind (It2.Typ) = Ekind (It1.Typ) then
1665 elsif Ekind (It2.Typ) = E_Anonymous_Access_Type
1667 Ekind (It2.Typ) = E_Anonymous_Access_Subprogram_Type
1671 -- No legal interpretation
1677 -- If two user defined-subprograms are visible, it is a true ambiguity,
1678 -- unless one of them is an entry and the context is a conditional or
1679 -- timed entry call, or unless we are within an instance and this is
1680 -- results from two formals types with the same actual.
1683 if Nkind (N) = N_Procedure_Call_Statement
1684 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1685 and then N = Entry_Call_Statement (Parent (N))
1687 if Ekind (Nam2) = E_Entry then
1689 elsif Ekind (Nam1) = E_Entry then
1695 -- If the ambiguity occurs within an instance, it is due to several
1696 -- formal types with the same actual. Look for an exact match between
1697 -- the types of the formals of the overloadable entities, and the
1698 -- actuals in the call, to recover the unambiguous match in the
1699 -- original generic.
1701 -- The ambiguity can also be due to an overloading between a formal
1702 -- subprogram and a subprogram declared outside the generic. If the
1703 -- node is overloaded, it did not resolve to the global entity in
1704 -- the generic, and we choose the formal subprogram.
1706 -- Finally, the ambiguity can be between an explicit subprogram and
1707 -- one inherited (with different defaults) from an actual. In this
1708 -- case the resolution was to the explicit declaration in the
1709 -- generic, and remains so in the instance.
1712 and then not In_Generic_Actual (N)
1714 if Nkind (N) = N_Function_Call
1715 or else Nkind (N) = N_Procedure_Call_Statement
1720 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1721 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1724 if Is_Act1 and then not Is_Act2 then
1727 elsif Is_Act2 and then not Is_Act1 then
1730 elsif Inherited_From_Actual (Nam1)
1731 and then Comes_From_Source (Nam2)
1735 elsif Inherited_From_Actual (Nam2)
1736 and then Comes_From_Source (Nam1)
1741 Actual := First_Actual (N);
1742 Formal := First_Formal (Nam1);
1743 while Present (Actual) loop
1744 if Etype (Actual) /= Etype (Formal) then
1748 Next_Actual (Actual);
1749 Next_Formal (Formal);
1755 elsif Nkind (N) in N_Binary_Op then
1756 if Matches (Left_Opnd (N), First_Formal (Nam1))
1758 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1765 elsif Nkind (N) in N_Unary_Op then
1766 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1773 return Remove_Conversions;
1776 return Remove_Conversions;
1780 -- An implicit concatenation operator on a string type cannot be
1781 -- disambiguated from the predefined concatenation. This can only
1782 -- happen with concatenation of string literals.
1784 if Chars (User_Subp) = Name_Op_Concat
1785 and then Ekind (User_Subp) = E_Operator
1786 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1790 -- If the user-defined operator is in an open scope, or in the scope
1791 -- of the resulting type, or given by an expanded name that names its
1792 -- scope, it hides the predefined operator for the type. Exponentiation
1793 -- has to be special-cased because the implicit operator does not have
1794 -- a symmetric signature, and may not be hidden by the explicit one.
1796 elsif (Nkind (N) = N_Function_Call
1797 and then Nkind (Name (N)) = N_Expanded_Name
1798 and then (Chars (Predef_Subp) /= Name_Op_Expon
1799 or else Hides_Op (User_Subp, Predef_Subp))
1800 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1801 or else Hides_Op (User_Subp, Predef_Subp)
1803 if It1.Nam = User_Subp then
1809 -- Otherwise, the predefined operator has precedence, or if the user-
1810 -- defined operation is directly visible we have a true ambiguity. If
1811 -- this is a fixed-point multiplication and division in Ada83 mode,
1812 -- exclude the universal_fixed operator, which often causes ambiguities
1816 if (In_Open_Scopes (Scope (User_Subp))
1817 or else Is_Potentially_Use_Visible (User_Subp))
1818 and then not In_Instance
1820 if Is_Fixed_Point_Type (Typ)
1821 and then (Chars (Nam1) = Name_Op_Multiply
1822 or else Chars (Nam1) = Name_Op_Divide)
1823 and then Ada_Version = Ada_83
1825 if It2.Nam = Predef_Subp then
1831 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1832 -- states that the operator defined in Standard is not available
1833 -- if there is a user-defined equality with the proper signature,
1834 -- declared in the same declarative list as the type. The node
1835 -- may be an operator or a function call.
1837 elsif (Chars (Nam1) = Name_Op_Eq
1839 Chars (Nam1) = Name_Op_Ne)
1840 and then Ada_Version >= Ada_05
1841 and then Etype (User_Subp) = Standard_Boolean
1846 if Nkind (N) = N_Function_Call then
1847 Opnd := First_Actual (N);
1849 Opnd := Left_Opnd (N);
1852 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1854 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1855 = List_Containing (Unit_Declaration_Node (User_Subp))
1857 if It2.Nam = Predef_Subp then
1863 return Remove_Conversions;
1871 elsif It1.Nam = Predef_Subp then
1880 ---------------------
1881 -- End_Interp_List --
1882 ---------------------
1884 procedure End_Interp_List is
1886 All_Interp.Table (All_Interp.Last) := No_Interp;
1887 All_Interp.Increment_Last;
1888 end End_Interp_List;
1890 -------------------------
1891 -- Entity_Matches_Spec --
1892 -------------------------
1894 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1896 -- Simple case: same entity kinds, type conformance is required. A
1897 -- parameterless function can also rename a literal.
1899 if Ekind (Old_S) = Ekind (New_S)
1900 or else (Ekind (New_S) = E_Function
1901 and then Ekind (Old_S) = E_Enumeration_Literal)
1903 return Type_Conformant (New_S, Old_S);
1905 elsif Ekind (New_S) = E_Function
1906 and then Ekind (Old_S) = E_Operator
1908 return Operator_Matches_Spec (Old_S, New_S);
1910 elsif Ekind (New_S) = E_Procedure
1911 and then Is_Entry (Old_S)
1913 return Type_Conformant (New_S, Old_S);
1918 end Entity_Matches_Spec;
1920 ----------------------
1921 -- Find_Unique_Type --
1922 ----------------------
1924 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1925 T : constant Entity_Id := Etype (L);
1928 TR : Entity_Id := Any_Type;
1931 if Is_Overloaded (R) then
1932 Get_First_Interp (R, I, It);
1933 while Present (It.Typ) loop
1934 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1936 -- If several interpretations are possible and L is universal,
1937 -- apply preference rule.
1939 if TR /= Any_Type then
1941 if (T = Universal_Integer or else T = Universal_Real)
1952 Get_Next_Interp (I, It);
1957 -- In the non-overloaded case, the Etype of R is already set correctly
1963 -- If one of the operands is Universal_Fixed, the type of the other
1964 -- operand provides the context.
1966 if Etype (R) = Universal_Fixed then
1969 elsif T = Universal_Fixed then
1972 -- Ada 2005 (AI-230): Support the following operators:
1974 -- function "=" (L, R : universal_access) return Boolean;
1975 -- function "/=" (L, R : universal_access) return Boolean;
1977 -- Pool specific access types (E_Access_Type) are not covered by these
1978 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1979 -- of the equality operators for universal_access shall be convertible
1980 -- to one another (see 4.6)". For example, considering the type decla-
1981 -- ration "type P is access Integer" and an anonymous access to Integer,
1982 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1983 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1985 elsif Ada_Version >= Ada_05
1987 (Ekind (Etype (L)) = E_Anonymous_Access_Type
1989 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
1990 and then Is_Access_Type (Etype (R))
1991 and then Ekind (Etype (R)) /= E_Access_Type
1995 elsif Ada_Version >= Ada_05
1997 (Ekind (Etype (R)) = E_Anonymous_Access_Type
1998 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
1999 and then Is_Access_Type (Etype (L))
2000 and then Ekind (Etype (L)) /= E_Access_Type
2005 return Specific_Type (T, Etype (R));
2007 end Find_Unique_Type;
2009 -------------------------------------
2010 -- Function_Interp_Has_Abstract_Op --
2011 -------------------------------------
2013 function Function_Interp_Has_Abstract_Op
2015 E : Entity_Id) return Entity_Id
2017 Abstr_Op : Entity_Id;
2020 Form_Parm : Node_Id;
2023 -- Why is check on E needed below ???
2024 -- In any case this para needs comments ???
2026 if Is_Overloaded (N) and then Is_Overloadable (E) then
2027 Act_Parm := First_Actual (N);
2028 Form_Parm := First_Formal (E);
2029 while Present (Act_Parm)
2030 and then Present (Form_Parm)
2034 if Nkind (Act) = N_Parameter_Association then
2035 Act := Explicit_Actual_Parameter (Act);
2038 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2040 if Present (Abstr_Op) then
2044 Next_Actual (Act_Parm);
2045 Next_Formal (Form_Parm);
2050 end Function_Interp_Has_Abstract_Op;
2052 ----------------------
2053 -- Get_First_Interp --
2054 ----------------------
2056 procedure Get_First_Interp
2058 I : out Interp_Index;
2061 Int_Ind : Interp_Index;
2066 -- If a selected component is overloaded because the selector has
2067 -- multiple interpretations, the node is a call to a protected
2068 -- operation or an indirect call. Retrieve the interpretation from
2069 -- the selector name. The selected component may be overloaded as well
2070 -- if the prefix is overloaded. That case is unchanged.
2072 if Nkind (N) = N_Selected_Component
2073 and then Is_Overloaded (Selector_Name (N))
2075 O_N := Selector_Name (N);
2080 Map_Ptr := Headers (Hash (O_N));
2081 while Map_Ptr /= No_Entry loop
2082 if Interp_Map.Table (Map_Ptr).Node = O_N then
2083 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2084 It := All_Interp.Table (Int_Ind);
2088 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2092 -- Procedure should never be called if the node has no interpretations
2094 raise Program_Error;
2095 end Get_First_Interp;
2097 ---------------------
2098 -- Get_Next_Interp --
2099 ---------------------
2101 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2104 It := All_Interp.Table (I);
2105 end Get_Next_Interp;
2107 -------------------------
2108 -- Has_Compatible_Type --
2109 -------------------------
2111 function Has_Compatible_Type
2113 Typ : Entity_Id) return Boolean
2123 if Nkind (N) = N_Subtype_Indication
2124 or else not Is_Overloaded (N)
2127 Covers (Typ, Etype (N))
2129 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2130 -- If the type is already frozen use the corresponding_record
2131 -- to check whether it is a proper descendant.
2134 (Is_Record_Type (Typ)
2135 and then Is_Concurrent_Type (Etype (N))
2136 and then Present (Corresponding_Record_Type (Etype (N)))
2137 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2140 (Is_Concurrent_Type (Typ)
2141 and then Is_Record_Type (Etype (N))
2142 and then Present (Corresponding_Record_Type (Typ))
2143 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2146 (not Is_Tagged_Type (Typ)
2147 and then Ekind (Typ) /= E_Anonymous_Access_Type
2148 and then Covers (Etype (N), Typ));
2151 Get_First_Interp (N, I, It);
2152 while Present (It.Typ) loop
2153 if (Covers (Typ, It.Typ)
2155 (Scope (It.Nam) /= Standard_Standard
2156 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2158 -- Ada 2005 (AI-345)
2161 (Is_Concurrent_Type (It.Typ)
2162 and then Present (Corresponding_Record_Type
2164 and then Covers (Typ, Corresponding_Record_Type
2167 or else (not Is_Tagged_Type (Typ)
2168 and then Ekind (Typ) /= E_Anonymous_Access_Type
2169 and then Covers (It.Typ, Typ))
2174 Get_Next_Interp (I, It);
2179 end Has_Compatible_Type;
2181 ---------------------
2182 -- Has_Abstract_Op --
2183 ---------------------
2185 function Has_Abstract_Op
2187 Typ : Entity_Id) return Entity_Id
2193 if Is_Overloaded (N) then
2194 Get_First_Interp (N, I, It);
2195 while Present (It.Nam) loop
2196 if Present (It.Abstract_Op)
2197 and then Etype (It.Abstract_Op) = Typ
2199 return It.Abstract_Op;
2202 Get_Next_Interp (I, It);
2207 end Has_Abstract_Op;
2213 function Hash (N : Node_Id) return Int is
2215 -- Nodes have a size that is power of two, so to select significant
2216 -- bits only we remove the low-order bits.
2218 return ((Int (N) / 2 ** 5) mod Header_Size);
2225 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2226 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2228 return Operator_Matches_Spec (Op, F)
2229 and then (In_Open_Scopes (Scope (F))
2230 or else Scope (F) = Scope (Btyp)
2231 or else (not In_Open_Scopes (Scope (Btyp))
2232 and then not In_Use (Btyp)
2233 and then not In_Use (Scope (Btyp))));
2236 ------------------------
2237 -- Init_Interp_Tables --
2238 ------------------------
2240 procedure Init_Interp_Tables is
2244 Headers := (others => No_Entry);
2245 end Init_Interp_Tables;
2247 -----------------------------------
2248 -- Interface_Present_In_Ancestor --
2249 -----------------------------------
2251 function Interface_Present_In_Ancestor
2253 Iface : Entity_Id) return Boolean
2255 Target_Typ : Entity_Id;
2256 Iface_Typ : Entity_Id;
2258 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2259 -- Returns True if Typ or some ancestor of Typ implements Iface
2261 -------------------------------
2262 -- Iface_Present_In_Ancestor --
2263 -------------------------------
2265 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2271 if Typ = Iface_Typ then
2275 -- Handle private types
2277 if Present (Full_View (Typ))
2278 and then not Is_Concurrent_Type (Full_View (Typ))
2280 E := Full_View (Typ);
2286 if Present (Interfaces (E))
2287 and then Present (Interfaces (E))
2288 and then not Is_Empty_Elmt_List (Interfaces (E))
2290 Elmt := First_Elmt (Interfaces (E));
2291 while Present (Elmt) loop
2294 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2302 exit when Etype (E) = E
2304 -- Handle private types
2306 or else (Present (Full_View (Etype (E)))
2307 and then Full_View (Etype (E)) = E);
2309 -- Check if the current type is a direct derivation of the
2312 if Etype (E) = Iface_Typ then
2316 -- Climb to the immediate ancestor handling private types
2318 if Present (Full_View (Etype (E))) then
2319 E := Full_View (Etype (E));
2326 end Iface_Present_In_Ancestor;
2328 -- Start of processing for Interface_Present_In_Ancestor
2331 -- Iface might be a class-wide subtype, so we have to apply Base_Type
2333 if Is_Class_Wide_Type (Iface) then
2334 Iface_Typ := Etype (Base_Type (Iface));
2341 Iface_Typ := Base_Type (Iface_Typ);
2343 if Is_Access_Type (Typ) then
2344 Target_Typ := Etype (Directly_Designated_Type (Typ));
2349 if Is_Concurrent_Record_Type (Target_Typ) then
2350 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2353 Target_Typ := Base_Type (Target_Typ);
2355 -- In case of concurrent types we can't use the Corresponding Record_Typ
2356 -- to look for the interface because it is built by the expander (and
2357 -- hence it is not always available). For this reason we traverse the
2358 -- list of interfaces (available in the parent of the concurrent type)
2360 if Is_Concurrent_Type (Target_Typ) then
2361 if Present (Interface_List (Parent (Target_Typ))) then
2366 AI := First (Interface_List (Parent (Target_Typ)));
2367 while Present (AI) loop
2368 if Etype (AI) = Iface_Typ then
2371 elsif Present (Interfaces (Etype (AI)))
2372 and then Iface_Present_In_Ancestor (Etype (AI))
2385 if Is_Class_Wide_Type (Target_Typ) then
2386 Target_Typ := Etype (Target_Typ);
2389 if Ekind (Target_Typ) = E_Incomplete_Type then
2390 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2391 Target_Typ := Non_Limited_View (Target_Typ);
2393 -- Protect the frontend against previously detected errors
2395 if Ekind (Target_Typ) = E_Incomplete_Type then
2400 return Iface_Present_In_Ancestor (Target_Typ);
2401 end Interface_Present_In_Ancestor;
2403 ---------------------
2404 -- Intersect_Types --
2405 ---------------------
2407 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2408 Index : Interp_Index;
2412 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2413 -- Find interpretation of right arg that has type compatible with T
2415 --------------------------
2416 -- Check_Right_Argument --
2417 --------------------------
2419 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2420 Index : Interp_Index;
2425 if not Is_Overloaded (R) then
2426 return Specific_Type (T, Etype (R));
2429 Get_First_Interp (R, Index, It);
2431 T2 := Specific_Type (T, It.Typ);
2433 if T2 /= Any_Type then
2437 Get_Next_Interp (Index, It);
2438 exit when No (It.Typ);
2443 end Check_Right_Argument;
2445 -- Start of processing for Intersect_Types
2448 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2452 if not Is_Overloaded (L) then
2453 Typ := Check_Right_Argument (Etype (L));
2457 Get_First_Interp (L, Index, It);
2458 while Present (It.Typ) loop
2459 Typ := Check_Right_Argument (It.Typ);
2460 exit when Typ /= Any_Type;
2461 Get_Next_Interp (Index, It);
2466 -- If Typ is Any_Type, it means no compatible pair of types was found
2468 if Typ = Any_Type then
2469 if Nkind (Parent (L)) in N_Op then
2470 Error_Msg_N ("incompatible types for operator", Parent (L));
2472 elsif Nkind (Parent (L)) = N_Range then
2473 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2475 -- Ada 2005 (AI-251): Complete the error notification
2477 elsif Is_Class_Wide_Type (Etype (R))
2478 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2480 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2481 L, Etype (Class_Wide_Type (Etype (R))));
2484 Error_Msg_N ("incompatible types", Parent (L));
2489 end Intersect_Types;
2491 -----------------------
2492 -- In_Generic_Actual --
2493 -----------------------
2495 function In_Generic_Actual (Exp : Node_Id) return Boolean is
2496 Par : constant Node_Id := Parent (Exp);
2502 elsif Nkind (Par) in N_Declaration then
2503 if Nkind (Par) = N_Object_Declaration then
2504 return Present (Corresponding_Generic_Association (Par));
2509 elsif Nkind (Par) = N_Object_Renaming_Declaration then
2510 return Present (Corresponding_Generic_Association (Par));
2512 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
2516 return In_Generic_Actual (Parent (Par));
2518 end In_Generic_Actual;
2524 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2530 BT1 := Base_Type (T1);
2531 BT2 := Base_Type (T2);
2533 -- Handle underlying view of records with unknown discriminants
2534 -- using the original entity that motivated the construction of
2535 -- this underlying record view (see Build_Derived_Private_Type).
2537 if Is_Underlying_Record_View (BT1) then
2538 BT1 := Underlying_Record_View (BT1);
2541 if Is_Underlying_Record_View (BT2) then
2542 BT2 := Underlying_Record_View (BT2);
2548 elsif Is_Private_Type (T1)
2549 and then Present (Full_View (T1))
2550 and then BT2 = Base_Type (Full_View (T1))
2558 -- If there was a error on the type declaration, do not recurse
2560 if Error_Posted (Par) then
2563 elsif BT1 = Base_Type (Par)
2564 or else (Is_Private_Type (T1)
2565 and then Present (Full_View (T1))
2566 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2570 elsif Is_Private_Type (Par)
2571 and then Present (Full_View (Par))
2572 and then Full_View (Par) = BT1
2576 elsif Etype (Par) /= Par then
2585 ---------------------------
2586 -- Is_Invisible_Operator --
2587 ---------------------------
2589 function Is_Invisible_Operator
2591 T : Entity_Id) return Boolean
2593 Orig_Node : constant Node_Id := Original_Node (N);
2596 if Nkind (N) not in N_Op then
2599 elsif not Comes_From_Source (N) then
2602 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2605 elsif Nkind (N) in N_Binary_Op
2606 and then No (Universal_Interpretation (Left_Opnd (N)))
2611 return Is_Numeric_Type (T)
2612 and then not In_Open_Scopes (Scope (T))
2613 and then not Is_Potentially_Use_Visible (T)
2614 and then not In_Use (T)
2615 and then not In_Use (Scope (T))
2617 (Nkind (Orig_Node) /= N_Function_Call
2618 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2619 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2620 and then not In_Instance;
2622 end Is_Invisible_Operator;
2628 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2632 S := Ancestor_Subtype (T1);
2633 while Present (S) loop
2637 S := Ancestor_Subtype (S);
2648 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2649 Index : Interp_Index;
2653 Get_First_Interp (Nam, Index, It);
2654 while Present (It.Nam) loop
2655 if Scope (It.Nam) = Standard_Standard
2656 and then Scope (It.Typ) /= Standard_Standard
2658 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2659 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2662 Error_Msg_Sloc := Sloc (It.Nam);
2663 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2666 Get_Next_Interp (Index, It);
2674 procedure New_Interps (N : Node_Id) is
2678 All_Interp.Append (No_Interp);
2680 Map_Ptr := Headers (Hash (N));
2682 if Map_Ptr = No_Entry then
2684 -- Place new node at end of table
2686 Interp_Map.Increment_Last;
2687 Headers (Hash (N)) := Interp_Map.Last;
2690 -- Place node at end of chain, or locate its previous entry
2693 if Interp_Map.Table (Map_Ptr).Node = N then
2695 -- Node is already in the table, and is being rewritten.
2696 -- Start a new interp section, retain hash link.
2698 Interp_Map.Table (Map_Ptr).Node := N;
2699 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2700 Set_Is_Overloaded (N, True);
2704 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2705 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2709 -- Chain the new node
2711 Interp_Map.Increment_Last;
2712 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2715 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2716 Set_Is_Overloaded (N, True);
2719 ---------------------------
2720 -- Operator_Matches_Spec --
2721 ---------------------------
2723 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2724 Op_Name : constant Name_Id := Chars (Op);
2725 T : constant Entity_Id := Etype (New_S);
2733 -- To verify that a predefined operator matches a given signature,
2734 -- do a case analysis of the operator classes. Function can have one
2735 -- or two formals and must have the proper result type.
2737 New_F := First_Formal (New_S);
2738 Old_F := First_Formal (Op);
2740 while Present (New_F) and then Present (Old_F) loop
2742 Next_Formal (New_F);
2743 Next_Formal (Old_F);
2746 -- Definite mismatch if different number of parameters
2748 if Present (Old_F) or else Present (New_F) then
2754 T1 := Etype (First_Formal (New_S));
2756 if Op_Name = Name_Op_Subtract
2757 or else Op_Name = Name_Op_Add
2758 or else Op_Name = Name_Op_Abs
2760 return Base_Type (T1) = Base_Type (T)
2761 and then Is_Numeric_Type (T);
2763 elsif Op_Name = Name_Op_Not then
2764 return Base_Type (T1) = Base_Type (T)
2765 and then Valid_Boolean_Arg (Base_Type (T));
2774 T1 := Etype (First_Formal (New_S));
2775 T2 := Etype (Next_Formal (First_Formal (New_S)));
2777 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2778 or else Op_Name = Name_Op_Xor
2780 return Base_Type (T1) = Base_Type (T2)
2781 and then Base_Type (T1) = Base_Type (T)
2782 and then Valid_Boolean_Arg (Base_Type (T));
2784 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2785 return Base_Type (T1) = Base_Type (T2)
2786 and then not Is_Limited_Type (T1)
2787 and then Is_Boolean_Type (T);
2789 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2790 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2792 return Base_Type (T1) = Base_Type (T2)
2793 and then Valid_Comparison_Arg (T1)
2794 and then Is_Boolean_Type (T);
2796 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2797 return Base_Type (T1) = Base_Type (T2)
2798 and then Base_Type (T1) = Base_Type (T)
2799 and then Is_Numeric_Type (T);
2801 -- For division and multiplication, a user-defined function does not
2802 -- match the predefined universal_fixed operation, except in Ada 83.
2804 elsif Op_Name = Name_Op_Divide then
2805 return (Base_Type (T1) = Base_Type (T2)
2806 and then Base_Type (T1) = Base_Type (T)
2807 and then Is_Numeric_Type (T)
2808 and then (not Is_Fixed_Point_Type (T)
2809 or else Ada_Version = Ada_83))
2811 -- Mixed_Mode operations on fixed-point types
2813 or else (Base_Type (T1) = Base_Type (T)
2814 and then Base_Type (T2) = Base_Type (Standard_Integer)
2815 and then Is_Fixed_Point_Type (T))
2817 -- A user defined operator can also match (and hide) a mixed
2818 -- operation on universal literals.
2820 or else (Is_Integer_Type (T2)
2821 and then Is_Floating_Point_Type (T1)
2822 and then Base_Type (T1) = Base_Type (T));
2824 elsif Op_Name = Name_Op_Multiply then
2825 return (Base_Type (T1) = Base_Type (T2)
2826 and then Base_Type (T1) = Base_Type (T)
2827 and then Is_Numeric_Type (T)
2828 and then (not Is_Fixed_Point_Type (T)
2829 or else Ada_Version = Ada_83))
2831 -- Mixed_Mode operations on fixed-point types
2833 or else (Base_Type (T1) = Base_Type (T)
2834 and then Base_Type (T2) = Base_Type (Standard_Integer)
2835 and then Is_Fixed_Point_Type (T))
2837 or else (Base_Type (T2) = Base_Type (T)
2838 and then Base_Type (T1) = Base_Type (Standard_Integer)
2839 and then Is_Fixed_Point_Type (T))
2841 or else (Is_Integer_Type (T2)
2842 and then Is_Floating_Point_Type (T1)
2843 and then Base_Type (T1) = Base_Type (T))
2845 or else (Is_Integer_Type (T1)
2846 and then Is_Floating_Point_Type (T2)
2847 and then Base_Type (T2) = Base_Type (T));
2849 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2850 return Base_Type (T1) = Base_Type (T2)
2851 and then Base_Type (T1) = Base_Type (T)
2852 and then Is_Integer_Type (T);
2854 elsif Op_Name = Name_Op_Expon then
2855 return Base_Type (T1) = Base_Type (T)
2856 and then Is_Numeric_Type (T)
2857 and then Base_Type (T2) = Base_Type (Standard_Integer);
2859 elsif Op_Name = Name_Op_Concat then
2860 return Is_Array_Type (T)
2861 and then (Base_Type (T) = Base_Type (Etype (Op)))
2862 and then (Base_Type (T1) = Base_Type (T)
2864 Base_Type (T1) = Base_Type (Component_Type (T)))
2865 and then (Base_Type (T2) = Base_Type (T)
2867 Base_Type (T2) = Base_Type (Component_Type (T)));
2873 end Operator_Matches_Spec;
2879 procedure Remove_Interp (I : in out Interp_Index) is
2883 -- Find end of interp list and copy downward to erase the discarded one
2886 while Present (All_Interp.Table (II).Typ) loop
2890 for J in I + 1 .. II loop
2891 All_Interp.Table (J - 1) := All_Interp.Table (J);
2894 -- Back up interp index to insure that iterator will pick up next
2895 -- available interpretation.
2904 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2906 O_N : Node_Id := Old_N;
2909 if Is_Overloaded (Old_N) then
2910 if Nkind (Old_N) = N_Selected_Component
2911 and then Is_Overloaded (Selector_Name (Old_N))
2913 O_N := Selector_Name (Old_N);
2916 Map_Ptr := Headers (Hash (O_N));
2918 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2919 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2920 pragma Assert (Map_Ptr /= No_Entry);
2923 New_Interps (New_N);
2924 Interp_Map.Table (Interp_Map.Last).Index :=
2925 Interp_Map.Table (Map_Ptr).Index;
2933 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2934 T1 : constant Entity_Id := Available_View (Typ_1);
2935 T2 : constant Entity_Id := Available_View (Typ_2);
2936 B1 : constant Entity_Id := Base_Type (T1);
2937 B2 : constant Entity_Id := Base_Type (T2);
2939 function Is_Remote_Access (T : Entity_Id) return Boolean;
2940 -- Check whether T is the equivalent type of a remote access type.
2941 -- If distribution is enabled, T is a legal context for Null.
2943 ----------------------
2944 -- Is_Remote_Access --
2945 ----------------------
2947 function Is_Remote_Access (T : Entity_Id) return Boolean is
2949 return Is_Record_Type (T)
2950 and then (Is_Remote_Call_Interface (T)
2951 or else Is_Remote_Types (T))
2952 and then Present (Corresponding_Remote_Type (T))
2953 and then Is_Access_Type (Corresponding_Remote_Type (T));
2954 end Is_Remote_Access;
2956 -- Start of processing for Specific_Type
2959 if T1 = Any_Type or else T2 = Any_Type then
2966 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2967 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2968 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2969 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2973 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2974 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2975 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2976 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2980 elsif T2 = Any_String and then Is_String_Type (T1) then
2983 elsif T1 = Any_String and then Is_String_Type (T2) then
2986 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2989 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2992 elsif T1 = Any_Access
2993 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2997 elsif T2 = Any_Access
2998 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
3002 elsif T2 = Any_Composite
3003 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
3007 elsif T1 = Any_Composite
3008 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
3012 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
3015 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
3018 -- ----------------------------------------------------------
3019 -- Special cases for equality operators (all other predefined
3020 -- operators can never apply to tagged types)
3021 -- ----------------------------------------------------------
3023 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
3026 elsif Is_Class_Wide_Type (T1)
3027 and then Is_Class_Wide_Type (T2)
3028 and then Is_Interface (Etype (T2))
3032 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
3033 -- class-wide interface T2
3035 elsif Is_Class_Wide_Type (T2)
3036 and then Is_Interface (Etype (T2))
3037 and then Interface_Present_In_Ancestor (Typ => T1,
3038 Iface => Etype (T2))
3042 elsif Is_Class_Wide_Type (T1)
3043 and then Is_Ancestor (Root_Type (T1), T2)
3047 elsif Is_Class_Wide_Type (T2)
3048 and then Is_Ancestor (Root_Type (T2), T1)
3052 elsif (Ekind (B1) = E_Access_Subprogram_Type
3054 Ekind (B1) = E_Access_Protected_Subprogram_Type)
3055 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
3056 and then Is_Access_Type (T2)
3060 elsif (Ekind (B2) = E_Access_Subprogram_Type
3062 Ekind (B2) = E_Access_Protected_Subprogram_Type)
3063 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
3064 and then Is_Access_Type (T1)
3068 elsif (Ekind (T1) = E_Allocator_Type
3069 or else Ekind (T1) = E_Access_Attribute_Type
3070 or else Ekind (T1) = E_Anonymous_Access_Type)
3071 and then Is_Access_Type (T2)
3075 elsif (Ekind (T2) = E_Allocator_Type
3076 or else Ekind (T2) = E_Access_Attribute_Type
3077 or else Ekind (T2) = E_Anonymous_Access_Type)
3078 and then Is_Access_Type (T1)
3082 -- If none of the above cases applies, types are not compatible
3089 ---------------------
3090 -- Set_Abstract_Op --
3091 ---------------------
3093 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3095 All_Interp.Table (I).Abstract_Op := V;
3096 end Set_Abstract_Op;
3098 -----------------------
3099 -- Valid_Boolean_Arg --
3100 -----------------------
3102 -- In addition to booleans and arrays of booleans, we must include
3103 -- aggregates as valid boolean arguments, because in the first pass of
3104 -- resolution their components are not examined. If it turns out not to be
3105 -- an aggregate of booleans, this will be diagnosed in Resolve.
3106 -- Any_Composite must be checked for prior to the array type checks because
3107 -- Any_Composite does not have any associated indexes.
3109 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3111 return Is_Boolean_Type (T)
3112 or else T = Any_Composite
3113 or else (Is_Array_Type (T)
3114 and then T /= Any_String
3115 and then Number_Dimensions (T) = 1
3116 and then Is_Boolean_Type (Component_Type (T))
3117 and then (not Is_Private_Composite (T)
3118 or else In_Instance)
3119 and then (not Is_Limited_Composite (T)
3120 or else In_Instance))
3121 or else Is_Modular_Integer_Type (T)
3122 or else T = Universal_Integer;
3123 end Valid_Boolean_Arg;
3125 --------------------------
3126 -- Valid_Comparison_Arg --
3127 --------------------------
3129 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3132 if T = Any_Composite then
3134 elsif Is_Discrete_Type (T)
3135 or else Is_Real_Type (T)
3138 elsif Is_Array_Type (T)
3139 and then Number_Dimensions (T) = 1
3140 and then Is_Discrete_Type (Component_Type (T))
3141 and then (not Is_Private_Composite (T)
3142 or else In_Instance)
3143 and then (not Is_Limited_Composite (T)
3144 or else In_Instance)
3147 elsif Is_String_Type (T) then
3152 end Valid_Comparison_Arg;
3154 ----------------------
3155 -- Write_Interp_Ref --
3156 ----------------------
3158 procedure Write_Interp_Ref (Map_Ptr : Int) is
3160 Write_Str (" Node: ");
3161 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3162 Write_Str (" Index: ");
3163 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3164 Write_Str (" Next: ");
3165 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3167 end Write_Interp_Ref;
3169 ---------------------
3170 -- Write_Overloads --
3171 ---------------------
3173 procedure Write_Overloads (N : Node_Id) is
3179 if not Is_Overloaded (N) then
3180 Write_Str ("Non-overloaded entity ");
3182 Write_Entity_Info (Entity (N), " ");
3185 Get_First_Interp (N, I, It);
3186 Write_Str ("Overloaded entity ");
3188 Write_Str (" Name Type Abstract Op");
3190 Write_Str ("===============================================");
3194 while Present (Nam) loop
3195 Write_Int (Int (Nam));
3197 Write_Name (Chars (Nam));
3199 Write_Int (Int (It.Typ));
3201 Write_Name (Chars (It.Typ));
3203 if Present (It.Abstract_Op) then
3205 Write_Int (Int (It.Abstract_Op));
3207 Write_Name (Chars (It.Abstract_Op));
3211 Get_Next_Interp (I, It);
3215 end Write_Overloads;