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;
1156 Nam1, Nam2 : Entity_Id;
1157 Predef_Subp : Entity_Id;
1158 User_Subp : Entity_Id;
1160 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1161 -- Determine whether one of the candidates is an operation inherited by
1162 -- a type that is derived from an actual in an instantiation.
1164 function In_Generic_Actual (Exp : Node_Id) return Boolean;
1165 -- Determine whether the expression is part of a generic actual. At
1166 -- the time the actual is resolved the scope is already that of the
1167 -- instance, but conceptually the resolution of the actual takes place
1168 -- in the enclosing context, and no special disambiguation rules should
1171 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1172 -- Determine whether a subprogram is an actual in an enclosing instance.
1173 -- An overloading between such a subprogram and one declared outside the
1174 -- instance is resolved in favor of the first, because it resolved in
1177 function Matches (Actual, Formal : Node_Id) return Boolean;
1178 -- Look for exact type match in an instance, to remove spurious
1179 -- ambiguities when two formal types have the same actual.
1181 function Standard_Operator return Boolean;
1182 -- Check whether subprogram is predefined operator declared in Standard.
1183 -- It may given by an operator name, or by an expanded name whose prefix
1186 function Remove_Conversions return Interp;
1187 -- Last chance for pathological cases involving comparisons on literals,
1188 -- and user overloadings of the same operator. Such pathologies have
1189 -- been removed from the ACVC, but still appear in two DEC tests, with
1190 -- the following notable quote from Ben Brosgol:
1192 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1193 -- this example; Robert Dewar brought it to our attention, since it is
1194 -- apparently found in the ACVC 1.5. I did not attempt to find the
1195 -- reason in the Reference Manual that makes the example legal, since I
1196 -- was too nauseated by it to want to pursue it further.]
1198 -- Accordingly, this is not a fully recursive solution, but it handles
1199 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1200 -- pathology in the other direction with calls whose multiple overloaded
1201 -- actuals make them truly unresolvable.
1203 -- The new rules concerning abstract operations create additional need
1204 -- for special handling of expressions with universal operands, see
1205 -- comments to Has_Abstract_Interpretation below.
1207 -----------------------
1208 -- In_Generic_Actual --
1209 -----------------------
1211 function In_Generic_Actual (Exp : Node_Id) return Boolean is
1212 Par : constant Node_Id := Parent (Exp);
1218 elsif Nkind (Par) in N_Declaration then
1219 if Nkind (Par) = N_Object_Declaration
1220 or else Nkind (Par) = N_Object_Renaming_Declaration
1222 return Present (Corresponding_Generic_Association (Par));
1227 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
1231 return In_Generic_Actual (Parent (Par));
1233 end In_Generic_Actual;
1235 ---------------------------
1236 -- Inherited_From_Actual --
1237 ---------------------------
1239 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1240 Par : constant Node_Id := Parent (S);
1242 if Nkind (Par) /= N_Full_Type_Declaration
1243 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1247 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1249 Is_Generic_Actual_Type (
1250 Entity (Subtype_Indication (Type_Definition (Par))));
1252 end Inherited_From_Actual;
1254 --------------------------
1255 -- Is_Actual_Subprogram --
1256 --------------------------
1258 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1260 return In_Open_Scopes (Scope (S))
1262 (Is_Generic_Instance (Scope (S))
1263 or else Is_Wrapper_Package (Scope (S)));
1264 end Is_Actual_Subprogram;
1270 function Matches (Actual, Formal : Node_Id) return Boolean is
1271 T1 : constant Entity_Id := Etype (Actual);
1272 T2 : constant Entity_Id := Etype (Formal);
1276 (Is_Numeric_Type (T2)
1278 (T1 = Universal_Real or else T1 = Universal_Integer));
1281 ------------------------
1282 -- Remove_Conversions --
1283 ------------------------
1285 function Remove_Conversions return Interp is
1293 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1294 -- If an operation has universal operands the universal operation
1295 -- is present among its interpretations. If there is an abstract
1296 -- interpretation for the operator, with a numeric result, this
1297 -- interpretation was already removed in sem_ch4, but the universal
1298 -- one is still visible. We must rescan the list of operators and
1299 -- remove the universal interpretation to resolve the ambiguity.
1301 ---------------------------------
1302 -- Has_Abstract_Interpretation --
1303 ---------------------------------
1305 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1309 if Nkind (N) not in N_Op
1310 or else Ada_Version < Ada_05
1311 or else not Is_Overloaded (N)
1312 or else No (Universal_Interpretation (N))
1317 E := Get_Name_Entity_Id (Chars (N));
1318 while Present (E) loop
1319 if Is_Overloadable (E)
1320 and then Is_Abstract_Subprogram (E)
1321 and then Is_Numeric_Type (Etype (E))
1329 -- Finally, if an operand of the binary operator is itself
1330 -- an operator, recurse to see whether its own abstract
1331 -- interpretation is responsible for the spurious ambiguity.
1333 if Nkind (N) in N_Binary_Op then
1334 return Has_Abstract_Interpretation (Left_Opnd (N))
1335 or else Has_Abstract_Interpretation (Right_Opnd (N));
1337 elsif Nkind (N) in N_Unary_Op then
1338 return Has_Abstract_Interpretation (Right_Opnd (N));
1344 end Has_Abstract_Interpretation;
1346 -- Start of processing for Remove_Conversions
1351 Get_First_Interp (N, I, It);
1352 while Present (It.Typ) loop
1353 if not Is_Overloadable (It.Nam) then
1357 F1 := First_Formal (It.Nam);
1363 if Nkind (N) = N_Function_Call
1364 or else Nkind (N) = N_Procedure_Call_Statement
1366 Act1 := First_Actual (N);
1368 if Present (Act1) then
1369 Act2 := Next_Actual (Act1);
1374 elsif Nkind (N) in N_Unary_Op then
1375 Act1 := Right_Opnd (N);
1378 elsif Nkind (N) in N_Binary_Op then
1379 Act1 := Left_Opnd (N);
1380 Act2 := Right_Opnd (N);
1382 -- Use type of second formal, so as to include
1383 -- exponentiation, where the exponent may be
1384 -- ambiguous and the result non-universal.
1392 if Nkind (Act1) in N_Op
1393 and then Is_Overloaded (Act1)
1394 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1395 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1396 and then Has_Compatible_Type (Act1, Standard_Boolean)
1397 and then Etype (F1) = Standard_Boolean
1399 -- If the two candidates are the original ones, the
1400 -- ambiguity is real. Otherwise keep the original, further
1401 -- calls to Disambiguate will take care of others in the
1402 -- list of candidates.
1404 if It1 /= No_Interp then
1405 if It = Disambiguate.It1
1406 or else It = Disambiguate.It2
1408 if It1 = Disambiguate.It1
1409 or else It1 = Disambiguate.It2
1417 elsif Present (Act2)
1418 and then Nkind (Act2) in N_Op
1419 and then Is_Overloaded (Act2)
1420 and then (Nkind (Right_Opnd (Act2)) = N_Integer_Literal
1422 Nkind (Right_Opnd (Act2)) = N_Real_Literal)
1423 and then Has_Compatible_Type (Act2, Standard_Boolean)
1425 -- The preference rule on the first actual is not
1426 -- sufficient to disambiguate.
1434 elsif Is_Numeric_Type (Etype (F1))
1435 and then Has_Abstract_Interpretation (Act1)
1437 -- Current interpretation is not the right one because it
1438 -- expects a numeric operand. Examine all the other ones.
1445 Get_First_Interp (N, I, It);
1446 while Present (It.Typ) loop
1448 not Is_Numeric_Type (Etype (First_Formal (It.Nam)))
1451 or else not Has_Abstract_Interpretation (Act2)
1454 (Etype (Next_Formal (First_Formal (It.Nam))))
1460 Get_Next_Interp (I, It);
1469 Get_Next_Interp (I, It);
1472 -- After some error, a formal may have Any_Type and yield a spurious
1473 -- match. To avoid cascaded errors if possible, check for such a
1474 -- formal in either candidate.
1476 if Serious_Errors_Detected > 0 then
1481 Formal := First_Formal (Nam1);
1482 while Present (Formal) loop
1483 if Etype (Formal) = Any_Type then
1484 return Disambiguate.It2;
1487 Next_Formal (Formal);
1490 Formal := First_Formal (Nam2);
1491 while Present (Formal) loop
1492 if Etype (Formal) = Any_Type then
1493 return Disambiguate.It1;
1496 Next_Formal (Formal);
1502 end Remove_Conversions;
1504 -----------------------
1505 -- Standard_Operator --
1506 -----------------------
1508 function Standard_Operator return Boolean is
1512 if Nkind (N) in N_Op then
1515 elsif Nkind (N) = N_Function_Call then
1518 if Nkind (Nam) /= N_Expanded_Name then
1521 return Entity (Prefix (Nam)) = Standard_Standard;
1526 end Standard_Operator;
1528 -- Start of processing for Disambiguate
1531 -- Recover the two legal interpretations
1533 Get_First_Interp (N, I, It);
1535 Get_Next_Interp (I, It);
1541 Get_Next_Interp (I, It);
1547 if Ada_Version < Ada_05 then
1549 -- Check whether one of the entities is an Ada 2005 entity and we are
1550 -- operating in an earlier mode, in which case we discard the Ada
1551 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1553 if Is_Ada_2005_Only (Nam1) then
1555 elsif Is_Ada_2005_Only (Nam2) then
1560 -- Check for overloaded CIL convention stuff because the CIL libraries
1561 -- do sick things like Console.Write_Line where it matches two different
1562 -- overloads, so just pick the first ???
1564 if Convention (Nam1) = Convention_CIL
1565 and then Convention (Nam2) = Convention_CIL
1566 and then Ekind (Nam1) = Ekind (Nam2)
1567 and then (Ekind (Nam1) = E_Procedure
1568 or else Ekind (Nam1) = E_Function)
1573 -- If the context is universal, the predefined operator is preferred.
1574 -- This includes bounds in numeric type declarations, and expressions
1575 -- in type conversions. If no interpretation yields a universal type,
1576 -- then we must check whether the user-defined entity hides the prede-
1579 if Chars (Nam1) in Any_Operator_Name
1580 and then Standard_Operator
1582 if Typ = Universal_Integer
1583 or else Typ = Universal_Real
1584 or else Typ = Any_Integer
1585 or else Typ = Any_Discrete
1586 or else Typ = Any_Real
1587 or else Typ = Any_Type
1589 -- Find an interpretation that yields the universal type, or else
1590 -- a predefined operator that yields a predefined numeric type.
1593 Candidate : Interp := No_Interp;
1596 Get_First_Interp (N, I, It);
1597 while Present (It.Typ) loop
1598 if (Covers (Typ, It.Typ)
1599 or else Typ = Any_Type)
1601 (It.Typ = Universal_Integer
1602 or else It.Typ = Universal_Real)
1606 elsif Covers (Typ, It.Typ)
1607 and then Scope (It.Typ) = Standard_Standard
1608 and then Scope (It.Nam) = Standard_Standard
1609 and then Is_Numeric_Type (It.Typ)
1614 Get_Next_Interp (I, It);
1617 if Candidate /= No_Interp then
1622 elsif Chars (Nam1) /= Name_Op_Not
1623 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1625 -- Equality or comparison operation. Choose predefined operator if
1626 -- arguments are universal. The node may be an operator, name, or
1627 -- a function call, so unpack arguments accordingly.
1630 Arg1, Arg2 : Node_Id;
1633 if Nkind (N) in N_Op then
1634 Arg1 := Left_Opnd (N);
1635 Arg2 := Right_Opnd (N);
1637 elsif Is_Entity_Name (N)
1638 or else Nkind (N) = N_Operator_Symbol
1640 Arg1 := First_Entity (Entity (N));
1641 Arg2 := Next_Entity (Arg1);
1644 Arg1 := First_Actual (N);
1645 Arg2 := Next_Actual (Arg1);
1649 and then Present (Universal_Interpretation (Arg1))
1650 and then Universal_Interpretation (Arg2) =
1651 Universal_Interpretation (Arg1)
1653 Get_First_Interp (N, I, It);
1654 while Scope (It.Nam) /= Standard_Standard loop
1655 Get_Next_Interp (I, It);
1664 -- If no universal interpretation, check whether user-defined operator
1665 -- hides predefined one, as well as other special cases. If the node
1666 -- is a range, then one or both bounds are ambiguous. Each will have
1667 -- to be disambiguated w.r.t. the context type. The type of the range
1668 -- itself is imposed by the context, so we can return either legal
1671 if Ekind (Nam1) = E_Operator then
1672 Predef_Subp := Nam1;
1675 elsif Ekind (Nam2) = E_Operator then
1676 Predef_Subp := Nam2;
1679 elsif Nkind (N) = N_Range then
1682 -- Implement AI05-105: A renaming declaration with an access
1683 -- definition must resolve to an anonymous access type. This
1684 -- is a resolution rule and can be used to disambiguate.
1686 elsif Nkind (Parent (N)) = N_Object_Renaming_Declaration
1687 and then Present (Access_Definition (Parent (N)))
1689 if Ekind (It1.Typ) = E_Anonymous_Access_Type
1691 Ekind (It1.Typ) = E_Anonymous_Access_Subprogram_Type
1693 if Ekind (It2.Typ) = Ekind (It1.Typ) then
1703 elsif Ekind (It2.Typ) = E_Anonymous_Access_Type
1705 Ekind (It2.Typ) = E_Anonymous_Access_Subprogram_Type
1709 -- No legal interpretation
1715 -- If two user defined-subprograms are visible, it is a true ambiguity,
1716 -- unless one of them is an entry and the context is a conditional or
1717 -- timed entry call, or unless we are within an instance and this is
1718 -- results from two formals types with the same actual.
1721 if Nkind (N) = N_Procedure_Call_Statement
1722 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1723 and then N = Entry_Call_Statement (Parent (N))
1725 if Ekind (Nam2) = E_Entry then
1727 elsif Ekind (Nam1) = E_Entry then
1733 -- If the ambiguity occurs within an instance, it is due to several
1734 -- formal types with the same actual. Look for an exact match between
1735 -- the types of the formals of the overloadable entities, and the
1736 -- actuals in the call, to recover the unambiguous match in the
1737 -- original generic.
1739 -- The ambiguity can also be due to an overloading between a formal
1740 -- subprogram and a subprogram declared outside the generic. If the
1741 -- node is overloaded, it did not resolve to the global entity in
1742 -- the generic, and we choose the formal subprogram.
1744 -- Finally, the ambiguity can be between an explicit subprogram and
1745 -- one inherited (with different defaults) from an actual. In this
1746 -- case the resolution was to the explicit declaration in the
1747 -- generic, and remains so in the instance.
1750 and then not In_Generic_Actual (N)
1752 if Nkind (N) = N_Function_Call
1753 or else Nkind (N) = N_Procedure_Call_Statement
1758 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1759 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1762 if Is_Act1 and then not Is_Act2 then
1765 elsif Is_Act2 and then not Is_Act1 then
1768 elsif Inherited_From_Actual (Nam1)
1769 and then Comes_From_Source (Nam2)
1773 elsif Inherited_From_Actual (Nam2)
1774 and then Comes_From_Source (Nam1)
1779 Actual := First_Actual (N);
1780 Formal := First_Formal (Nam1);
1781 while Present (Actual) loop
1782 if Etype (Actual) /= Etype (Formal) then
1786 Next_Actual (Actual);
1787 Next_Formal (Formal);
1793 elsif Nkind (N) in N_Binary_Op then
1794 if Matches (Left_Opnd (N), First_Formal (Nam1))
1796 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1803 elsif Nkind (N) in N_Unary_Op then
1804 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1811 return Remove_Conversions;
1814 return Remove_Conversions;
1818 -- An implicit concatenation operator on a string type cannot be
1819 -- disambiguated from the predefined concatenation. This can only
1820 -- happen with concatenation of string literals.
1822 if Chars (User_Subp) = Name_Op_Concat
1823 and then Ekind (User_Subp) = E_Operator
1824 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1828 -- If the user-defined operator is in an open scope, or in the scope
1829 -- of the resulting type, or given by an expanded name that names its
1830 -- scope, it hides the predefined operator for the type. Exponentiation
1831 -- has to be special-cased because the implicit operator does not have
1832 -- a symmetric signature, and may not be hidden by the explicit one.
1834 elsif (Nkind (N) = N_Function_Call
1835 and then Nkind (Name (N)) = N_Expanded_Name
1836 and then (Chars (Predef_Subp) /= Name_Op_Expon
1837 or else Hides_Op (User_Subp, Predef_Subp))
1838 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1839 or else Hides_Op (User_Subp, Predef_Subp)
1841 if It1.Nam = User_Subp then
1847 -- Otherwise, the predefined operator has precedence, or if the user-
1848 -- defined operation is directly visible we have a true ambiguity. If
1849 -- this is a fixed-point multiplication and division in Ada83 mode,
1850 -- exclude the universal_fixed operator, which often causes ambiguities
1854 if (In_Open_Scopes (Scope (User_Subp))
1855 or else Is_Potentially_Use_Visible (User_Subp))
1856 and then not In_Instance
1858 if Is_Fixed_Point_Type (Typ)
1859 and then (Chars (Nam1) = Name_Op_Multiply
1860 or else Chars (Nam1) = Name_Op_Divide)
1861 and then Ada_Version = Ada_83
1863 if It2.Nam = Predef_Subp then
1869 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1870 -- states that the operator defined in Standard is not available
1871 -- if there is a user-defined equality with the proper signature,
1872 -- declared in the same declarative list as the type. The node
1873 -- may be an operator or a function call.
1875 elsif (Chars (Nam1) = Name_Op_Eq
1877 Chars (Nam1) = Name_Op_Ne)
1878 and then Ada_Version >= Ada_05
1879 and then Etype (User_Subp) = Standard_Boolean
1884 if Nkind (N) = N_Function_Call then
1885 Opnd := First_Actual (N);
1887 Opnd := Left_Opnd (N);
1890 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1892 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1893 = List_Containing (Unit_Declaration_Node (User_Subp))
1895 if It2.Nam = Predef_Subp then
1901 return Remove_Conversions;
1909 elsif It1.Nam = Predef_Subp then
1918 ---------------------
1919 -- End_Interp_List --
1920 ---------------------
1922 procedure End_Interp_List is
1924 All_Interp.Table (All_Interp.Last) := No_Interp;
1925 All_Interp.Increment_Last;
1926 end End_Interp_List;
1928 -------------------------
1929 -- Entity_Matches_Spec --
1930 -------------------------
1932 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1934 -- Simple case: same entity kinds, type conformance is required. A
1935 -- parameterless function can also rename a literal.
1937 if Ekind (Old_S) = Ekind (New_S)
1938 or else (Ekind (New_S) = E_Function
1939 and then Ekind (Old_S) = E_Enumeration_Literal)
1941 return Type_Conformant (New_S, Old_S);
1943 elsif Ekind (New_S) = E_Function
1944 and then Ekind (Old_S) = E_Operator
1946 return Operator_Matches_Spec (Old_S, New_S);
1948 elsif Ekind (New_S) = E_Procedure
1949 and then Is_Entry (Old_S)
1951 return Type_Conformant (New_S, Old_S);
1956 end Entity_Matches_Spec;
1958 ----------------------
1959 -- Find_Unique_Type --
1960 ----------------------
1962 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1963 T : constant Entity_Id := Etype (L);
1966 TR : Entity_Id := Any_Type;
1969 if Is_Overloaded (R) then
1970 Get_First_Interp (R, I, It);
1971 while Present (It.Typ) loop
1972 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1974 -- If several interpretations are possible and L is universal,
1975 -- apply preference rule.
1977 if TR /= Any_Type then
1979 if (T = Universal_Integer or else T = Universal_Real)
1990 Get_Next_Interp (I, It);
1995 -- In the non-overloaded case, the Etype of R is already set correctly
2001 -- If one of the operands is Universal_Fixed, the type of the other
2002 -- operand provides the context.
2004 if Etype (R) = Universal_Fixed then
2007 elsif T = Universal_Fixed then
2010 -- Ada 2005 (AI-230): Support the following operators:
2012 -- function "=" (L, R : universal_access) return Boolean;
2013 -- function "/=" (L, R : universal_access) return Boolean;
2015 -- Pool specific access types (E_Access_Type) are not covered by these
2016 -- operators because of the legality rule of 4.5.2(9.2): "The operands
2017 -- of the equality operators for universal_access shall be convertible
2018 -- to one another (see 4.6)". For example, considering the type decla-
2019 -- ration "type P is access Integer" and an anonymous access to Integer,
2020 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
2021 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
2023 elsif Ada_Version >= Ada_05
2025 (Ekind (Etype (L)) = E_Anonymous_Access_Type
2027 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
2028 and then Is_Access_Type (Etype (R))
2029 and then Ekind (Etype (R)) /= E_Access_Type
2033 elsif Ada_Version >= Ada_05
2035 (Ekind (Etype (R)) = E_Anonymous_Access_Type
2036 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
2037 and then Is_Access_Type (Etype (L))
2038 and then Ekind (Etype (L)) /= E_Access_Type
2043 return Specific_Type (T, Etype (R));
2045 end Find_Unique_Type;
2047 -------------------------------------
2048 -- Function_Interp_Has_Abstract_Op --
2049 -------------------------------------
2051 function Function_Interp_Has_Abstract_Op
2053 E : Entity_Id) return Entity_Id
2055 Abstr_Op : Entity_Id;
2058 Form_Parm : Node_Id;
2061 -- Why is check on E needed below ???
2062 -- In any case this para needs comments ???
2064 if Is_Overloaded (N) and then Is_Overloadable (E) then
2065 Act_Parm := First_Actual (N);
2066 Form_Parm := First_Formal (E);
2067 while Present (Act_Parm)
2068 and then Present (Form_Parm)
2072 if Nkind (Act) = N_Parameter_Association then
2073 Act := Explicit_Actual_Parameter (Act);
2076 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2078 if Present (Abstr_Op) then
2082 Next_Actual (Act_Parm);
2083 Next_Formal (Form_Parm);
2088 end Function_Interp_Has_Abstract_Op;
2090 ----------------------
2091 -- Get_First_Interp --
2092 ----------------------
2094 procedure Get_First_Interp
2096 I : out Interp_Index;
2099 Int_Ind : Interp_Index;
2104 -- If a selected component is overloaded because the selector has
2105 -- multiple interpretations, the node is a call to a protected
2106 -- operation or an indirect call. Retrieve the interpretation from
2107 -- the selector name. The selected component may be overloaded as well
2108 -- if the prefix is overloaded. That case is unchanged.
2110 if Nkind (N) = N_Selected_Component
2111 and then Is_Overloaded (Selector_Name (N))
2113 O_N := Selector_Name (N);
2118 Map_Ptr := Headers (Hash (O_N));
2119 while Map_Ptr /= No_Entry loop
2120 if Interp_Map.Table (Map_Ptr).Node = O_N then
2121 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2122 It := All_Interp.Table (Int_Ind);
2126 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2130 -- Procedure should never be called if the node has no interpretations
2132 raise Program_Error;
2133 end Get_First_Interp;
2135 ---------------------
2136 -- Get_Next_Interp --
2137 ---------------------
2139 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2142 It := All_Interp.Table (I);
2143 end Get_Next_Interp;
2145 -------------------------
2146 -- Has_Compatible_Type --
2147 -------------------------
2149 function Has_Compatible_Type
2151 Typ : Entity_Id) return Boolean
2161 if Nkind (N) = N_Subtype_Indication
2162 or else not Is_Overloaded (N)
2165 Covers (Typ, Etype (N))
2167 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2168 -- If the type is already frozen use the corresponding_record
2169 -- to check whether it is a proper descendant.
2172 (Is_Record_Type (Typ)
2173 and then Is_Concurrent_Type (Etype (N))
2174 and then Present (Corresponding_Record_Type (Etype (N)))
2175 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2178 (Is_Concurrent_Type (Typ)
2179 and then Is_Record_Type (Etype (N))
2180 and then Present (Corresponding_Record_Type (Typ))
2181 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2184 (not Is_Tagged_Type (Typ)
2185 and then Ekind (Typ) /= E_Anonymous_Access_Type
2186 and then Covers (Etype (N), Typ));
2189 Get_First_Interp (N, I, It);
2190 while Present (It.Typ) loop
2191 if (Covers (Typ, It.Typ)
2193 (Scope (It.Nam) /= Standard_Standard
2194 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2196 -- Ada 2005 (AI-345)
2199 (Is_Concurrent_Type (It.Typ)
2200 and then Present (Corresponding_Record_Type
2202 and then Covers (Typ, Corresponding_Record_Type
2205 or else (not Is_Tagged_Type (Typ)
2206 and then Ekind (Typ) /= E_Anonymous_Access_Type
2207 and then Covers (It.Typ, Typ))
2212 Get_Next_Interp (I, It);
2217 end Has_Compatible_Type;
2219 ---------------------
2220 -- Has_Abstract_Op --
2221 ---------------------
2223 function Has_Abstract_Op
2225 Typ : Entity_Id) return Entity_Id
2231 if Is_Overloaded (N) then
2232 Get_First_Interp (N, I, It);
2233 while Present (It.Nam) loop
2234 if Present (It.Abstract_Op)
2235 and then Etype (It.Abstract_Op) = Typ
2237 return It.Abstract_Op;
2240 Get_Next_Interp (I, It);
2245 end Has_Abstract_Op;
2251 function Hash (N : Node_Id) return Int is
2253 -- Nodes have a size that is power of two, so to select significant
2254 -- bits only we remove the low-order bits.
2256 return ((Int (N) / 2 ** 5) mod Header_Size);
2263 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2264 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2266 return Operator_Matches_Spec (Op, F)
2267 and then (In_Open_Scopes (Scope (F))
2268 or else Scope (F) = Scope (Btyp)
2269 or else (not In_Open_Scopes (Scope (Btyp))
2270 and then not In_Use (Btyp)
2271 and then not In_Use (Scope (Btyp))));
2274 ------------------------
2275 -- Init_Interp_Tables --
2276 ------------------------
2278 procedure Init_Interp_Tables is
2282 Headers := (others => No_Entry);
2283 end Init_Interp_Tables;
2285 -----------------------------------
2286 -- Interface_Present_In_Ancestor --
2287 -----------------------------------
2289 function Interface_Present_In_Ancestor
2291 Iface : Entity_Id) return Boolean
2293 Target_Typ : Entity_Id;
2294 Iface_Typ : Entity_Id;
2296 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2297 -- Returns True if Typ or some ancestor of Typ implements Iface
2299 -------------------------------
2300 -- Iface_Present_In_Ancestor --
2301 -------------------------------
2303 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2309 if Typ = Iface_Typ then
2313 -- Handle private types
2315 if Present (Full_View (Typ))
2316 and then not Is_Concurrent_Type (Full_View (Typ))
2318 E := Full_View (Typ);
2324 if Present (Interfaces (E))
2325 and then Present (Interfaces (E))
2326 and then not Is_Empty_Elmt_List (Interfaces (E))
2328 Elmt := First_Elmt (Interfaces (E));
2329 while Present (Elmt) loop
2332 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2340 exit when Etype (E) = E
2342 -- Handle private types
2344 or else (Present (Full_View (Etype (E)))
2345 and then Full_View (Etype (E)) = E);
2347 -- Check if the current type is a direct derivation of the
2350 if Etype (E) = Iface_Typ then
2354 -- Climb to the immediate ancestor handling private types
2356 if Present (Full_View (Etype (E))) then
2357 E := Full_View (Etype (E));
2364 end Iface_Present_In_Ancestor;
2366 -- Start of processing for Interface_Present_In_Ancestor
2369 -- Iface might be a class-wide subtype, so we have to apply Base_Type
2371 if Is_Class_Wide_Type (Iface) then
2372 Iface_Typ := Etype (Base_Type (Iface));
2379 Iface_Typ := Base_Type (Iface_Typ);
2381 if Is_Access_Type (Typ) then
2382 Target_Typ := Etype (Directly_Designated_Type (Typ));
2387 if Is_Concurrent_Record_Type (Target_Typ) then
2388 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2391 Target_Typ := Base_Type (Target_Typ);
2393 -- In case of concurrent types we can't use the Corresponding Record_Typ
2394 -- to look for the interface because it is built by the expander (and
2395 -- hence it is not always available). For this reason we traverse the
2396 -- list of interfaces (available in the parent of the concurrent type)
2398 if Is_Concurrent_Type (Target_Typ) then
2399 if Present (Interface_List (Parent (Target_Typ))) then
2404 AI := First (Interface_List (Parent (Target_Typ)));
2405 while Present (AI) loop
2406 if Etype (AI) = Iface_Typ then
2409 elsif Present (Interfaces (Etype (AI)))
2410 and then Iface_Present_In_Ancestor (Etype (AI))
2423 if Is_Class_Wide_Type (Target_Typ) then
2424 Target_Typ := Etype (Target_Typ);
2427 if Ekind (Target_Typ) = E_Incomplete_Type then
2428 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2429 Target_Typ := Non_Limited_View (Target_Typ);
2431 -- Protect the frontend against previously detected errors
2433 if Ekind (Target_Typ) = E_Incomplete_Type then
2438 return Iface_Present_In_Ancestor (Target_Typ);
2439 end Interface_Present_In_Ancestor;
2441 ---------------------
2442 -- Intersect_Types --
2443 ---------------------
2445 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2446 Index : Interp_Index;
2450 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2451 -- Find interpretation of right arg that has type compatible with T
2453 --------------------------
2454 -- Check_Right_Argument --
2455 --------------------------
2457 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2458 Index : Interp_Index;
2463 if not Is_Overloaded (R) then
2464 return Specific_Type (T, Etype (R));
2467 Get_First_Interp (R, Index, It);
2469 T2 := Specific_Type (T, It.Typ);
2471 if T2 /= Any_Type then
2475 Get_Next_Interp (Index, It);
2476 exit when No (It.Typ);
2481 end Check_Right_Argument;
2483 -- Start of processing for Intersect_Types
2486 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2490 if not Is_Overloaded (L) then
2491 Typ := Check_Right_Argument (Etype (L));
2495 Get_First_Interp (L, Index, It);
2496 while Present (It.Typ) loop
2497 Typ := Check_Right_Argument (It.Typ);
2498 exit when Typ /= Any_Type;
2499 Get_Next_Interp (Index, It);
2504 -- If Typ is Any_Type, it means no compatible pair of types was found
2506 if Typ = Any_Type then
2507 if Nkind (Parent (L)) in N_Op then
2508 Error_Msg_N ("incompatible types for operator", Parent (L));
2510 elsif Nkind (Parent (L)) = N_Range then
2511 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2513 -- Ada 2005 (AI-251): Complete the error notification
2515 elsif Is_Class_Wide_Type (Etype (R))
2516 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2518 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2519 L, Etype (Class_Wide_Type (Etype (R))));
2522 Error_Msg_N ("incompatible types", Parent (L));
2527 end Intersect_Types;
2533 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2539 BT1 := Base_Type (T1);
2540 BT2 := Base_Type (T2);
2542 -- Handle underlying view of records with unknown discriminants
2543 -- using the original entity that motivated the construction of
2544 -- this underlying record view (see Build_Derived_Private_Type).
2546 if Is_Underlying_Record_View (BT1) then
2547 BT1 := Underlying_Record_View (BT1);
2550 if Is_Underlying_Record_View (BT2) then
2551 BT2 := Underlying_Record_View (BT2);
2557 elsif Is_Private_Type (T1)
2558 and then Present (Full_View (T1))
2559 and then BT2 = Base_Type (Full_View (T1))
2567 -- If there was a error on the type declaration, do not recurse
2569 if Error_Posted (Par) then
2572 elsif BT1 = Base_Type (Par)
2573 or else (Is_Private_Type (T1)
2574 and then Present (Full_View (T1))
2575 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2579 elsif Is_Private_Type (Par)
2580 and then Present (Full_View (Par))
2581 and then Full_View (Par) = BT1
2585 elsif Etype (Par) /= Par then
2594 ---------------------------
2595 -- Is_Invisible_Operator --
2596 ---------------------------
2598 function Is_Invisible_Operator
2600 T : Entity_Id) return Boolean
2602 Orig_Node : constant Node_Id := Original_Node (N);
2605 if Nkind (N) not in N_Op then
2608 elsif not Comes_From_Source (N) then
2611 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2614 elsif Nkind (N) in N_Binary_Op
2615 and then No (Universal_Interpretation (Left_Opnd (N)))
2620 return Is_Numeric_Type (T)
2621 and then not In_Open_Scopes (Scope (T))
2622 and then not Is_Potentially_Use_Visible (T)
2623 and then not In_Use (T)
2624 and then not In_Use (Scope (T))
2626 (Nkind (Orig_Node) /= N_Function_Call
2627 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2628 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2629 and then not In_Instance;
2631 end Is_Invisible_Operator;
2637 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2641 S := Ancestor_Subtype (T1);
2642 while Present (S) loop
2646 S := Ancestor_Subtype (S);
2657 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2658 Index : Interp_Index;
2662 Get_First_Interp (Nam, Index, It);
2663 while Present (It.Nam) loop
2664 if Scope (It.Nam) = Standard_Standard
2665 and then Scope (It.Typ) /= Standard_Standard
2667 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2668 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2671 Error_Msg_Sloc := Sloc (It.Nam);
2672 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2675 Get_Next_Interp (Index, It);
2683 procedure New_Interps (N : Node_Id) is
2687 All_Interp.Append (No_Interp);
2689 Map_Ptr := Headers (Hash (N));
2691 if Map_Ptr = No_Entry then
2693 -- Place new node at end of table
2695 Interp_Map.Increment_Last;
2696 Headers (Hash (N)) := Interp_Map.Last;
2699 -- Place node at end of chain, or locate its previous entry
2702 if Interp_Map.Table (Map_Ptr).Node = N then
2704 -- Node is already in the table, and is being rewritten.
2705 -- Start a new interp section, retain hash link.
2707 Interp_Map.Table (Map_Ptr).Node := N;
2708 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2709 Set_Is_Overloaded (N, True);
2713 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2714 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2718 -- Chain the new node
2720 Interp_Map.Increment_Last;
2721 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2724 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2725 Set_Is_Overloaded (N, True);
2728 ---------------------------
2729 -- Operator_Matches_Spec --
2730 ---------------------------
2732 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2733 Op_Name : constant Name_Id := Chars (Op);
2734 T : constant Entity_Id := Etype (New_S);
2742 -- To verify that a predefined operator matches a given signature,
2743 -- do a case analysis of the operator classes. Function can have one
2744 -- or two formals and must have the proper result type.
2746 New_F := First_Formal (New_S);
2747 Old_F := First_Formal (Op);
2749 while Present (New_F) and then Present (Old_F) loop
2751 Next_Formal (New_F);
2752 Next_Formal (Old_F);
2755 -- Definite mismatch if different number of parameters
2757 if Present (Old_F) or else Present (New_F) then
2763 T1 := Etype (First_Formal (New_S));
2765 if Op_Name = Name_Op_Subtract
2766 or else Op_Name = Name_Op_Add
2767 or else Op_Name = Name_Op_Abs
2769 return Base_Type (T1) = Base_Type (T)
2770 and then Is_Numeric_Type (T);
2772 elsif Op_Name = Name_Op_Not then
2773 return Base_Type (T1) = Base_Type (T)
2774 and then Valid_Boolean_Arg (Base_Type (T));
2783 T1 := Etype (First_Formal (New_S));
2784 T2 := Etype (Next_Formal (First_Formal (New_S)));
2786 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2787 or else Op_Name = Name_Op_Xor
2789 return Base_Type (T1) = Base_Type (T2)
2790 and then Base_Type (T1) = Base_Type (T)
2791 and then Valid_Boolean_Arg (Base_Type (T));
2793 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2794 return Base_Type (T1) = Base_Type (T2)
2795 and then not Is_Limited_Type (T1)
2796 and then Is_Boolean_Type (T);
2798 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2799 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2801 return Base_Type (T1) = Base_Type (T2)
2802 and then Valid_Comparison_Arg (T1)
2803 and then Is_Boolean_Type (T);
2805 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2806 return Base_Type (T1) = Base_Type (T2)
2807 and then Base_Type (T1) = Base_Type (T)
2808 and then Is_Numeric_Type (T);
2810 -- For division and multiplication, a user-defined function does not
2811 -- match the predefined universal_fixed operation, except in Ada 83.
2813 elsif Op_Name = Name_Op_Divide then
2814 return (Base_Type (T1) = Base_Type (T2)
2815 and then Base_Type (T1) = Base_Type (T)
2816 and then Is_Numeric_Type (T)
2817 and then (not Is_Fixed_Point_Type (T)
2818 or else Ada_Version = Ada_83))
2820 -- Mixed_Mode operations on fixed-point types
2822 or else (Base_Type (T1) = Base_Type (T)
2823 and then Base_Type (T2) = Base_Type (Standard_Integer)
2824 and then Is_Fixed_Point_Type (T))
2826 -- A user defined operator can also match (and hide) a mixed
2827 -- operation on universal literals.
2829 or else (Is_Integer_Type (T2)
2830 and then Is_Floating_Point_Type (T1)
2831 and then Base_Type (T1) = Base_Type (T));
2833 elsif Op_Name = Name_Op_Multiply then
2834 return (Base_Type (T1) = Base_Type (T2)
2835 and then Base_Type (T1) = Base_Type (T)
2836 and then Is_Numeric_Type (T)
2837 and then (not Is_Fixed_Point_Type (T)
2838 or else Ada_Version = Ada_83))
2840 -- Mixed_Mode operations on fixed-point types
2842 or else (Base_Type (T1) = Base_Type (T)
2843 and then Base_Type (T2) = Base_Type (Standard_Integer)
2844 and then Is_Fixed_Point_Type (T))
2846 or else (Base_Type (T2) = Base_Type (T)
2847 and then Base_Type (T1) = Base_Type (Standard_Integer)
2848 and then Is_Fixed_Point_Type (T))
2850 or else (Is_Integer_Type (T2)
2851 and then Is_Floating_Point_Type (T1)
2852 and then Base_Type (T1) = Base_Type (T))
2854 or else (Is_Integer_Type (T1)
2855 and then Is_Floating_Point_Type (T2)
2856 and then Base_Type (T2) = Base_Type (T));
2858 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2859 return Base_Type (T1) = Base_Type (T2)
2860 and then Base_Type (T1) = Base_Type (T)
2861 and then Is_Integer_Type (T);
2863 elsif Op_Name = Name_Op_Expon then
2864 return Base_Type (T1) = Base_Type (T)
2865 and then Is_Numeric_Type (T)
2866 and then Base_Type (T2) = Base_Type (Standard_Integer);
2868 elsif Op_Name = Name_Op_Concat then
2869 return Is_Array_Type (T)
2870 and then (Base_Type (T) = Base_Type (Etype (Op)))
2871 and then (Base_Type (T1) = Base_Type (T)
2873 Base_Type (T1) = Base_Type (Component_Type (T)))
2874 and then (Base_Type (T2) = Base_Type (T)
2876 Base_Type (T2) = Base_Type (Component_Type (T)));
2882 end Operator_Matches_Spec;
2888 procedure Remove_Interp (I : in out Interp_Index) is
2892 -- Find end of interp list and copy downward to erase the discarded one
2895 while Present (All_Interp.Table (II).Typ) loop
2899 for J in I + 1 .. II loop
2900 All_Interp.Table (J - 1) := All_Interp.Table (J);
2903 -- Back up interp index to insure that iterator will pick up next
2904 -- available interpretation.
2913 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2915 O_N : Node_Id := Old_N;
2918 if Is_Overloaded (Old_N) then
2919 if Nkind (Old_N) = N_Selected_Component
2920 and then Is_Overloaded (Selector_Name (Old_N))
2922 O_N := Selector_Name (Old_N);
2925 Map_Ptr := Headers (Hash (O_N));
2927 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2928 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2929 pragma Assert (Map_Ptr /= No_Entry);
2932 New_Interps (New_N);
2933 Interp_Map.Table (Interp_Map.Last).Index :=
2934 Interp_Map.Table (Map_Ptr).Index;
2942 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2943 T1 : constant Entity_Id := Available_View (Typ_1);
2944 T2 : constant Entity_Id := Available_View (Typ_2);
2945 B1 : constant Entity_Id := Base_Type (T1);
2946 B2 : constant Entity_Id := Base_Type (T2);
2948 function Is_Remote_Access (T : Entity_Id) return Boolean;
2949 -- Check whether T is the equivalent type of a remote access type.
2950 -- If distribution is enabled, T is a legal context for Null.
2952 ----------------------
2953 -- Is_Remote_Access --
2954 ----------------------
2956 function Is_Remote_Access (T : Entity_Id) return Boolean is
2958 return Is_Record_Type (T)
2959 and then (Is_Remote_Call_Interface (T)
2960 or else Is_Remote_Types (T))
2961 and then Present (Corresponding_Remote_Type (T))
2962 and then Is_Access_Type (Corresponding_Remote_Type (T));
2963 end Is_Remote_Access;
2965 -- Start of processing for Specific_Type
2968 if T1 = Any_Type or else T2 = Any_Type then
2975 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2976 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2977 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2978 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2982 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2983 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2984 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2985 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2989 elsif T2 = Any_String and then Is_String_Type (T1) then
2992 elsif T1 = Any_String and then Is_String_Type (T2) then
2995 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2998 elsif T1 = Any_Character and then Is_Character_Type (T2) then
3001 elsif T1 = Any_Access
3002 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
3006 elsif T2 = Any_Access
3007 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
3011 elsif T2 = Any_Composite
3012 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
3016 elsif T1 = Any_Composite
3017 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
3021 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
3024 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
3027 -- ----------------------------------------------------------
3028 -- Special cases for equality operators (all other predefined
3029 -- operators can never apply to tagged types)
3030 -- ----------------------------------------------------------
3032 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
3035 elsif Is_Class_Wide_Type (T1)
3036 and then Is_Class_Wide_Type (T2)
3037 and then Is_Interface (Etype (T2))
3041 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
3042 -- class-wide interface T2
3044 elsif Is_Class_Wide_Type (T2)
3045 and then Is_Interface (Etype (T2))
3046 and then Interface_Present_In_Ancestor (Typ => T1,
3047 Iface => Etype (T2))
3051 elsif Is_Class_Wide_Type (T1)
3052 and then Is_Ancestor (Root_Type (T1), T2)
3056 elsif Is_Class_Wide_Type (T2)
3057 and then Is_Ancestor (Root_Type (T2), T1)
3061 elsif (Ekind (B1) = E_Access_Subprogram_Type
3063 Ekind (B1) = E_Access_Protected_Subprogram_Type)
3064 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
3065 and then Is_Access_Type (T2)
3069 elsif (Ekind (B2) = E_Access_Subprogram_Type
3071 Ekind (B2) = E_Access_Protected_Subprogram_Type)
3072 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
3073 and then Is_Access_Type (T1)
3077 elsif (Ekind (T1) = E_Allocator_Type
3078 or else Ekind (T1) = E_Access_Attribute_Type
3079 or else Ekind (T1) = E_Anonymous_Access_Type)
3080 and then Is_Access_Type (T2)
3084 elsif (Ekind (T2) = E_Allocator_Type
3085 or else Ekind (T2) = E_Access_Attribute_Type
3086 or else Ekind (T2) = E_Anonymous_Access_Type)
3087 and then Is_Access_Type (T1)
3091 -- If none of the above cases applies, types are not compatible
3098 ---------------------
3099 -- Set_Abstract_Op --
3100 ---------------------
3102 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3104 All_Interp.Table (I).Abstract_Op := V;
3105 end Set_Abstract_Op;
3107 -----------------------
3108 -- Valid_Boolean_Arg --
3109 -----------------------
3111 -- In addition to booleans and arrays of booleans, we must include
3112 -- aggregates as valid boolean arguments, because in the first pass of
3113 -- resolution their components are not examined. If it turns out not to be
3114 -- an aggregate of booleans, this will be diagnosed in Resolve.
3115 -- Any_Composite must be checked for prior to the array type checks because
3116 -- Any_Composite does not have any associated indexes.
3118 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3120 return Is_Boolean_Type (T)
3121 or else T = Any_Composite
3122 or else (Is_Array_Type (T)
3123 and then T /= Any_String
3124 and then Number_Dimensions (T) = 1
3125 and then Is_Boolean_Type (Component_Type (T))
3126 and then (not Is_Private_Composite (T)
3127 or else In_Instance)
3128 and then (not Is_Limited_Composite (T)
3129 or else In_Instance))
3130 or else Is_Modular_Integer_Type (T)
3131 or else T = Universal_Integer;
3132 end Valid_Boolean_Arg;
3134 --------------------------
3135 -- Valid_Comparison_Arg --
3136 --------------------------
3138 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3141 if T = Any_Composite then
3143 elsif Is_Discrete_Type (T)
3144 or else Is_Real_Type (T)
3147 elsif Is_Array_Type (T)
3148 and then Number_Dimensions (T) = 1
3149 and then Is_Discrete_Type (Component_Type (T))
3150 and then (not Is_Private_Composite (T)
3151 or else In_Instance)
3152 and then (not Is_Limited_Composite (T)
3153 or else In_Instance)
3156 elsif Is_String_Type (T) then
3161 end Valid_Comparison_Arg;
3163 ----------------------
3164 -- Write_Interp_Ref --
3165 ----------------------
3167 procedure Write_Interp_Ref (Map_Ptr : Int) is
3169 Write_Str (" Node: ");
3170 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3171 Write_Str (" Index: ");
3172 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3173 Write_Str (" Next: ");
3174 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3176 end Write_Interp_Ref;
3178 ---------------------
3179 -- Write_Overloads --
3180 ---------------------
3182 procedure Write_Overloads (N : Node_Id) is
3188 if not Is_Overloaded (N) then
3189 Write_Str ("Non-overloaded entity ");
3191 Write_Entity_Info (Entity (N), " ");
3194 Get_First_Interp (N, I, It);
3195 Write_Str ("Overloaded entity ");
3197 Write_Str (" Name Type Abstract Op");
3199 Write_Str ("===============================================");
3203 while Present (Nam) loop
3204 Write_Int (Int (Nam));
3206 Write_Name (Chars (Nam));
3208 Write_Int (Int (It.Typ));
3210 Write_Name (Chars (It.Typ));
3212 if Present (It.Abstract_Op) then
3214 Write_Int (Int (It.Abstract_Op));
3216 Write_Name (Chars (It.Abstract_Op));
3220 Get_Next_Interp (I, It);
3224 end Write_Overloads;