1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Atree; use Atree;
29 with Debug; use Debug;
30 with Einfo; use Einfo;
31 with Elists; use Elists;
32 with Nlists; use Nlists;
33 with Errout; use Errout;
35 with Namet; use Namet;
37 with Output; use Output;
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_Util; use Sem_Util;
44 with Stand; use Stand;
45 with Sinfo; use Sinfo;
46 with Snames; use Snames;
48 with Uintp; use Uintp;
50 package body Sem_Type is
56 -- The following data structures establish a mapping between nodes and
57 -- their interpretations. An overloaded node has an entry in Interp_Map,
58 -- which in turn contains a pointer into the All_Interp array. The
59 -- interpretations of a given node are contiguous in All_Interp. Each
60 -- set of interpretations is terminated with the marker No_Interp.
61 -- In order to speed up the retrieval of the interpretations of an
62 -- overloaded node, the Interp_Map table is accessed by means of a simple
63 -- hashing scheme, and the entries in Interp_Map are chained. The heads
64 -- of clash lists are stored in array Headers.
66 -- Headers Interp_Map All_Interp
68 -- _ +-----+ +--------+
69 -- |_| |_____| --->|interp1 |
70 -- |_|---------->|node | | |interp2 |
71 -- |_| |index|---------| |nointerp|
76 -- This scheme does not currently reclaim interpretations. In principle,
77 -- after a unit is compiled, all overloadings have been resolved, and the
78 -- candidate interpretations should be deleted. This should be easier
79 -- now than with the previous scheme???
81 package All_Interp is new Table.Table (
82 Table_Component_Type => Interp,
83 Table_Index_Type => Int,
85 Table_Initial => Alloc.All_Interp_Initial,
86 Table_Increment => Alloc.All_Interp_Increment,
87 Table_Name => "All_Interp");
89 type Interp_Ref is record
95 Header_Size : constant Int := 2 ** 12;
96 No_Entry : constant Int := -1;
97 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
99 package Interp_Map is new Table.Table (
100 Table_Component_Type => Interp_Ref,
101 Table_Index_Type => Int,
102 Table_Low_Bound => 0,
103 Table_Initial => Alloc.Interp_Map_Initial,
104 Table_Increment => Alloc.Interp_Map_Increment,
105 Table_Name => "Interp_Map");
107 function Hash (N : Node_Id) return Int;
108 -- A trivial hashing function for nodes, used to insert an overloaded
109 -- node into the Interp_Map table.
111 -------------------------------------
112 -- Handling of Overload Resolution --
113 -------------------------------------
115 -- Overload resolution uses two passes over the syntax tree of a complete
116 -- context. In the first, bottom-up pass, the types of actuals in calls
117 -- are used to resolve possibly overloaded subprogram and operator names.
118 -- In the second top-down pass, the type of the context (for example the
119 -- condition in a while statement) is used to resolve a possibly ambiguous
120 -- call, and the unique subprogram name in turn imposes a specific context
121 -- on each of its actuals.
123 -- Most expressions are in fact unambiguous, and the bottom-up pass is
124 -- sufficient to resolve most everything. To simplify the common case,
125 -- names and expressions carry a flag Is_Overloaded to indicate whether
126 -- they have more than one interpretation. If the flag is off, then each
127 -- name has already a unique meaning and type, and the bottom-up pass is
128 -- sufficient (and much simpler).
130 --------------------------
131 -- Operator Overloading --
132 --------------------------
134 -- The visibility of operators is handled differently from that of
135 -- other entities. We do not introduce explicit versions of primitive
136 -- operators for each type definition. As a result, there is only one
137 -- entity corresponding to predefined addition on all numeric types, etc.
138 -- The back-end resolves predefined operators according to their type.
139 -- The visibility of primitive operations then reduces to the visibility
140 -- of the resulting type: (a + b) is a legal interpretation of some
141 -- primitive operator + if the type of the result (which must also be
142 -- the type of a and b) is directly visible (i.e. either immediately
143 -- 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.Increment_Last;
315 All_Interp.Table (All_Interp.Last) := No_Interp;
318 ----------------------------
319 -- Is_Universal_Operation --
320 ----------------------------
322 function Is_Universal_Operation (Op : Entity_Id) return Boolean is
326 if Ekind (Op) /= E_Operator then
329 elsif Nkind (N) in N_Binary_Op then
330 return Present (Universal_Interpretation (Left_Opnd (N)))
331 and then Present (Universal_Interpretation (Right_Opnd (N)));
333 elsif Nkind (N) in N_Unary_Op then
334 return Present (Universal_Interpretation (Right_Opnd (N)));
336 elsif Nkind (N) = N_Function_Call then
337 Arg := First_Actual (N);
338 while Present (Arg) loop
339 if No (Universal_Interpretation (Arg)) then
351 end Is_Universal_Operation;
353 -- Start of processing for Add_One_Interp
356 -- If the interpretation is a predefined operator, verify that the
357 -- result type is visible, or that the entity has already been
358 -- resolved (case of an instantiation node that refers to a predefined
359 -- operation, or an internally generated operator node, or an operator
360 -- given as an expanded name). If the operator is a comparison or
361 -- equality, it is the type of the operand that matters to determine
362 -- whether the operator is visible. In an instance, the check is not
363 -- performed, given that the operator was visible in the generic.
365 if Ekind (E) = E_Operator then
367 if Present (Opnd_Type) then
368 Vis_Type := Opnd_Type;
370 Vis_Type := Base_Type (T);
373 if In_Open_Scopes (Scope (Vis_Type))
374 or else Is_Potentially_Use_Visible (Vis_Type)
375 or else In_Use (Vis_Type)
376 or else (In_Use (Scope (Vis_Type))
377 and then not Is_Hidden (Vis_Type))
378 or else Nkind (N) = N_Expanded_Name
379 or else (Nkind (N) in N_Op and then E = Entity (N))
381 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
385 -- If the node is given in functional notation and the prefix
386 -- is an expanded name, then the operator is visible if the
387 -- prefix is the scope of the result type as well. If the
388 -- operator is (implicitly) defined in an extension of system,
389 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
391 elsif Nkind (N) = N_Function_Call
392 and then Nkind (Name (N)) = N_Expanded_Name
393 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
394 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
395 or else Scope (Vis_Type) = System_Aux_Id)
399 -- Save type for subsequent error message, in case no other
400 -- interpretation is found.
403 Candidate_Type := Vis_Type;
407 -- In an instance, an abstract non-dispatching operation cannot
408 -- be a candidate interpretation, because it could not have been
409 -- one in the generic (it may be a spurious overloading in the
413 and then Is_Overloadable (E)
414 and then Is_Abstract_Subprogram (E)
415 and then not Is_Dispatching_Operation (E)
419 -- An inherited interface operation that is implemented by some
420 -- derived type does not participate in overload resolution, only
421 -- the implementation operation does.
424 and then Is_Subprogram (E)
425 and then Present (Abstract_Interface_Alias (E))
427 -- Ada 2005 (AI-251): If this primitive operation corresponds with
428 -- an inmediate ancestor interface there is no need to add it to the
429 -- list of interpretations; the corresponding aliased primitive is
430 -- also in this list of primitive operations and will be used instead
431 -- because otherwise we have a dummy between the two subprograms that
432 -- are in fact the same.
435 (Find_Dispatching_Type (Abstract_Interface_Alias (E)),
436 Find_Dispatching_Type (E))
438 Add_One_Interp (N, Abstract_Interface_Alias (E), T);
444 -- If this is the first interpretation of N, N has type Any_Type.
445 -- In that case place the new type on the node. If one interpretation
446 -- already exists, indicate that the node is overloaded, and store
447 -- both the previous and the new interpretation in All_Interp. If
448 -- this is a later interpretation, just add it to the set.
450 if Etype (N) = Any_Type then
455 -- Record both the operator or subprogram name, and its type
457 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
464 -- Either there is no current interpretation in the table for any
465 -- node or the interpretation that is present is for a different
466 -- node. In both cases add a new interpretation to the table.
468 elsif Interp_Map.Last < 0
470 (Interp_Map.Table (Interp_Map.Last).Node /= N
471 and then not Is_Overloaded (N))
475 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
476 and then Present (Entity (N))
478 Add_Entry (Entity (N), Etype (N));
480 elsif (Nkind (N) = N_Function_Call
481 or else Nkind (N) = N_Procedure_Call_Statement)
482 and then (Nkind (Name (N)) = N_Operator_Symbol
483 or else Is_Entity_Name (Name (N)))
485 Add_Entry (Entity (Name (N)), Etype (N));
487 -- If this is an indirect call there will be no name associated
488 -- with the previous entry. To make diagnostics clearer, save
489 -- Subprogram_Type of first interpretation, so that the error will
490 -- point to the anonymous access to subprogram, not to the result
491 -- type of the call itself.
493 elsif (Nkind (N)) = N_Function_Call
494 and then Nkind (Name (N)) = N_Explicit_Dereference
495 and then Is_Overloaded (Name (N))
501 Get_First_Interp (Name (N), I, It);
502 Add_Entry (It.Nam, Etype (N));
506 -- Overloaded prefix in indexed or selected component,
507 -- or call whose name is an expression or another call.
509 Add_Entry (Etype (N), Etype (N));
523 procedure All_Overloads is
525 for J in All_Interp.First .. All_Interp.Last loop
527 if Present (All_Interp.Table (J).Nam) then
528 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
530 Write_Str ("No Interp");
533 Write_Str ("=================");
538 --------------------------------------
539 -- Binary_Op_Interp_Has_Abstract_Op --
540 --------------------------------------
542 function Binary_Op_Interp_Has_Abstract_Op
544 E : Entity_Id) return Entity_Id
546 Abstr_Op : Entity_Id;
547 E_Left : constant Node_Id := First_Formal (E);
548 E_Right : constant Node_Id := Next_Formal (E_Left);
551 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
552 if Present (Abstr_Op) then
556 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
557 end Binary_Op_Interp_Has_Abstract_Op;
559 ---------------------
560 -- Collect_Interps --
561 ---------------------
563 procedure Collect_Interps (N : Node_Id) is
564 Ent : constant Entity_Id := Entity (N);
566 First_Interp : Interp_Index;
571 -- Unconditionally add the entity that was initially matched
573 First_Interp := All_Interp.Last;
574 Add_One_Interp (N, Ent, Etype (N));
576 -- For expanded name, pick up all additional entities from the
577 -- same scope, since these are obviously also visible. Note that
578 -- these are not necessarily contiguous on the homonym chain.
580 if Nkind (N) = N_Expanded_Name then
582 while Present (H) loop
583 if Scope (H) = Scope (Entity (N)) then
584 Add_One_Interp (N, H, Etype (H));
590 -- Case of direct name
593 -- First, search the homonym chain for directly visible entities
595 H := Current_Entity (Ent);
596 while Present (H) loop
597 exit when (not Is_Overloadable (H))
598 and then Is_Immediately_Visible (H);
600 if Is_Immediately_Visible (H)
603 -- Only add interpretation if not hidden by an inner
604 -- immediately visible one.
606 for J in First_Interp .. All_Interp.Last - 1 loop
608 -- Current homograph is not hidden. Add to overloads
610 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
613 -- Homograph is hidden, unless it is a predefined operator
615 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
617 -- A homograph in the same scope can occur within an
618 -- instantiation, the resulting ambiguity has to be
621 if Scope (H) = Scope (Ent)
623 and then not Is_Inherited_Operation (H)
625 All_Interp.Table (All_Interp.Last) :=
626 (H, Etype (H), Empty);
627 All_Interp.Increment_Last;
628 All_Interp.Table (All_Interp.Last) := No_Interp;
631 elsif Scope (H) /= Standard_Standard then
637 -- On exit, we know that current homograph is not hidden
639 Add_One_Interp (N, H, Etype (H));
642 Write_Str ("Add overloaded Interpretation ");
652 -- Scan list of homographs for use-visible entities only
654 H := Current_Entity (Ent);
656 while Present (H) loop
657 if Is_Potentially_Use_Visible (H)
659 and then Is_Overloadable (H)
661 for J in First_Interp .. All_Interp.Last - 1 loop
663 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
666 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
667 goto Next_Use_Homograph;
671 Add_One_Interp (N, H, Etype (H));
674 <<Next_Use_Homograph>>
679 if All_Interp.Last = First_Interp + 1 then
681 -- The original interpretation is in fact not overloaded
683 Set_Is_Overloaded (N, False);
691 function Covers (T1, T2 : Entity_Id) return Boolean is
696 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
697 -- In an instance the proper view may not always be correct for
698 -- private types, but private and full view are compatible. This
699 -- removes spurious errors from nested instantiations that involve,
700 -- among other things, types derived from private types.
702 ----------------------
703 -- Full_View_Covers --
704 ----------------------
706 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
709 Is_Private_Type (Typ1)
711 ((Present (Full_View (Typ1))
712 and then Covers (Full_View (Typ1), Typ2))
713 or else Base_Type (Typ1) = Typ2
714 or else Base_Type (Typ2) = Typ1);
715 end Full_View_Covers;
717 -- Start of processing for Covers
720 -- If either operand missing, then this is an error, but ignore it (and
721 -- pretend we have a cover) if errors already detected, since this may
722 -- simply mean we have malformed trees.
724 if No (T1) or else No (T2) then
725 if Total_Errors_Detected /= 0 then
732 BT1 := Base_Type (T1);
733 BT2 := Base_Type (T2);
736 -- Simplest case: same types are compatible, and types that have the
737 -- same base type and are not generic actuals are compatible. Generic
738 -- actuals belong to their class but are not compatible with other
739 -- types of their class, and in particular with other generic actuals.
740 -- They are however compatible with their own subtypes, and itypes
741 -- with the same base are compatible as well. Similarly, constrained
742 -- subtypes obtained from expressions of an unconstrained nominal type
743 -- are compatible with the base type (may lead to spurious ambiguities
744 -- in obscure cases ???)
746 -- Generic actuals require special treatment to avoid spurious ambi-
747 -- guities in an instance, when two formal types are instantiated with
748 -- the same actual, so that different subprograms end up with the same
749 -- signature in the instance.
758 if not Is_Generic_Actual_Type (T1) then
761 return (not Is_Generic_Actual_Type (T2)
762 or else Is_Itype (T1)
763 or else Is_Itype (T2)
764 or else Is_Constr_Subt_For_U_Nominal (T1)
765 or else Is_Constr_Subt_For_U_Nominal (T2)
766 or else Scope (T1) /= Scope (T2));
769 -- Literals are compatible with types in a given "class"
771 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
772 or else (T2 = Universal_Real and then Is_Real_Type (T1))
773 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
774 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
775 or else (T2 = Any_String and then Is_String_Type (T1))
776 or else (T2 = Any_Character and then Is_Character_Type (T1))
777 or else (T2 = Any_Access and then Is_Access_Type (T1))
781 -- The context may be class wide
783 elsif Is_Class_Wide_Type (T1)
784 and then Is_Ancestor (Root_Type (T1), T2)
788 elsif Is_Class_Wide_Type (T1)
789 and then Is_Class_Wide_Type (T2)
790 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
794 -- Ada 2005 (AI-345): A class-wide abstract interface type T1 covers a
795 -- task_type or protected_type implementing T1
797 elsif Ada_Version >= Ada_05
798 and then Is_Class_Wide_Type (T1)
799 and then Is_Interface (Etype (T1))
800 and then Is_Concurrent_Type (T2)
801 and then Interface_Present_In_Ancestor
802 (Typ => Base_Type (T2),
807 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
808 -- object T2 implementing T1
810 elsif Ada_Version >= Ada_05
811 and then Is_Class_Wide_Type (T1)
812 and then Is_Interface (Etype (T1))
813 and then Is_Tagged_Type (T2)
815 if Interface_Present_In_Ancestor (Typ => T2,
826 if Is_Concurrent_Type (BT2) then
827 E := Corresponding_Record_Type (BT2);
832 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
833 -- covers an object T2 that implements a direct derivation of T1.
834 -- Note: test for presence of E is defense against previous error.
837 and then Present (Abstract_Interfaces (E))
839 Elmt := First_Elmt (Abstract_Interfaces (E));
840 while Present (Elmt) loop
841 if Is_Ancestor (Etype (T1), Node (Elmt)) then
849 -- We should also check the case in which T1 is an ancestor of
850 -- some implemented interface???
855 -- In a dispatching call the actual may be class-wide
857 elsif Is_Class_Wide_Type (T2)
858 and then Base_Type (Root_Type (T2)) = Base_Type (T1)
862 -- Some contexts require a class of types rather than a specific type
864 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
865 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
866 or else (T1 = Any_Real and then Is_Real_Type (T2))
867 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
868 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
872 -- An aggregate is compatible with an array or record type
874 elsif T2 = Any_Composite
875 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
879 -- If the expected type is an anonymous access, the designated type must
880 -- cover that of the expression. Use the base type for this check: even
881 -- though access subtypes are rare in sources, they are generated for
882 -- actuals in instantiations.
884 elsif Ekind (BT1) = E_Anonymous_Access_Type
885 and then Is_Access_Type (T2)
886 and then Covers (Designated_Type (T1), Designated_Type (T2))
890 -- An Access_To_Subprogram is compatible with itself, or with an
891 -- anonymous type created for an attribute reference Access.
893 elsif (Ekind (BT1) = E_Access_Subprogram_Type
895 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
896 and then Is_Access_Type (T2)
897 and then (not Comes_From_Source (T1)
898 or else not Comes_From_Source (T2))
899 and then (Is_Overloadable (Designated_Type (T2))
901 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
903 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
905 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
909 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
910 -- with itself, or with an anonymous type created for an attribute
913 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
916 = E_Anonymous_Access_Protected_Subprogram_Type)
917 and then Is_Access_Type (T2)
918 and then (not Comes_From_Source (T1)
919 or else not Comes_From_Source (T2))
920 and then (Is_Overloadable (Designated_Type (T2))
922 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
924 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
926 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
930 -- The context can be a remote access type, and the expression the
931 -- corresponding source type declared in a categorized package, or
934 elsif Is_Record_Type (T1)
935 and then (Is_Remote_Call_Interface (T1)
936 or else Is_Remote_Types (T1))
937 and then Present (Corresponding_Remote_Type (T1))
939 return Covers (Corresponding_Remote_Type (T1), T2);
941 elsif Is_Record_Type (T2)
942 and then (Is_Remote_Call_Interface (T2)
943 or else Is_Remote_Types (T2))
944 and then Present (Corresponding_Remote_Type (T2))
946 return Covers (Corresponding_Remote_Type (T2), T1);
948 elsif Ekind (T2) = E_Access_Attribute_Type
949 and then (Ekind (BT1) = E_General_Access_Type
950 or else Ekind (BT1) = E_Access_Type)
951 and then Covers (Designated_Type (T1), Designated_Type (T2))
953 -- If the target type is a RACW type while the source is an access
954 -- attribute type, we are building a RACW that may be exported.
956 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
957 Set_Has_RACW (Current_Sem_Unit);
962 elsif Ekind (T2) = E_Allocator_Type
963 and then Is_Access_Type (T1)
965 return Covers (Designated_Type (T1), Designated_Type (T2))
967 (From_With_Type (Designated_Type (T1))
968 and then Covers (Designated_Type (T2), Designated_Type (T1)));
970 -- A boolean operation on integer literals is compatible with modular
973 elsif T2 = Any_Modular
974 and then Is_Modular_Integer_Type (T1)
978 -- The actual type may be the result of a previous error
980 elsif Base_Type (T2) = Any_Type then
983 -- A packed array type covers its corresponding non-packed type. This is
984 -- not legitimate Ada, but allows the omission of a number of otherwise
985 -- useless unchecked conversions, and since this can only arise in
986 -- (known correct) expanded code, no harm is done
988 elsif Is_Array_Type (T2)
989 and then Is_Packed (T2)
990 and then T1 = Packed_Array_Type (T2)
994 -- Similarly an array type covers its corresponding packed array type
996 elsif Is_Array_Type (T1)
997 and then Is_Packed (T1)
998 and then T2 = Packed_Array_Type (T1)
1002 -- In instances, or with types exported from instantiations, check
1003 -- whether a partial and a full view match. Verify that types are
1004 -- legal, to prevent cascaded errors.
1008 (Full_View_Covers (T1, T2)
1009 or else Full_View_Covers (T2, T1))
1014 and then Is_Generic_Actual_Type (T2)
1015 and then Full_View_Covers (T1, T2)
1020 and then Is_Generic_Actual_Type (T1)
1021 and then Full_View_Covers (T2, T1)
1025 -- In the expansion of inlined bodies, types are compatible if they
1026 -- are structurally equivalent.
1028 elsif In_Inlined_Body
1029 and then (Underlying_Type (T1) = Underlying_Type (T2)
1030 or else (Is_Access_Type (T1)
1031 and then Is_Access_Type (T2)
1033 Designated_Type (T1) = Designated_Type (T2))
1034 or else (T1 = Any_Access
1035 and then Is_Access_Type (Underlying_Type (T2)))
1036 or else (T2 = Any_Composite
1038 Is_Composite_Type (Underlying_Type (T1))))
1042 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1043 -- compatible with its real entity.
1045 elsif From_With_Type (T1) then
1047 -- If the expected type is the non-limited view of a type, the
1048 -- expression may have the limited view. If that one in turn is
1049 -- incomplete, get full view if available.
1051 if Is_Incomplete_Type (T1) then
1052 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1054 elsif Ekind (T1) = E_Class_Wide_Type then
1056 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1061 elsif From_With_Type (T2) then
1063 -- If units in the context have Limited_With clauses on each other,
1064 -- either type might have a limited view. Checks performed elsewhere
1065 -- verify that the context type is the non-limited view.
1067 if Is_Incomplete_Type (T2) then
1068 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1070 elsif Ekind (T2) = E_Class_Wide_Type then
1072 Present (Non_Limited_View (Etype (T2)))
1074 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1079 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1081 elsif Ekind (T1) = E_Incomplete_Subtype then
1082 return Covers (Full_View (Etype (T1)), T2);
1084 elsif Ekind (T2) = E_Incomplete_Subtype then
1085 return Covers (T1, Full_View (Etype (T2)));
1087 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1088 -- and actual anonymous access types in the context of generic
1089 -- instantiation. We have the following situation:
1092 -- type Formal is private;
1093 -- Formal_Obj : access Formal; -- T1
1097 -- type Actual is ...
1098 -- Actual_Obj : access Actual; -- T2
1099 -- package Instance is new G (Formal => Actual,
1100 -- Formal_Obj => Actual_Obj);
1102 elsif Ada_Version >= Ada_05
1103 and then Ekind (T1) = E_Anonymous_Access_Type
1104 and then Ekind (T2) = E_Anonymous_Access_Type
1105 and then Is_Generic_Type (Directly_Designated_Type (T1))
1106 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1107 Directly_Designated_Type (T2)
1111 -- Otherwise it doesn't cover!
1122 function Disambiguate
1124 I1, I2 : Interp_Index;
1131 Nam1, Nam2 : Entity_Id;
1132 Predef_Subp : Entity_Id;
1133 User_Subp : Entity_Id;
1135 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1136 -- Determine whether one of the candidates is an operation inherited by
1137 -- a type that is derived from an actual in an instantiation.
1139 function In_Generic_Actual (Exp : Node_Id) return Boolean;
1140 -- Determine whether the expression is part of a generic actual. At
1141 -- the time the actual is resolved the scope is already that of the
1142 -- instance, but conceptually the resolution of the actual takes place
1143 -- in the enclosing context, and no special disambiguation rules should
1146 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1147 -- Determine whether a subprogram is an actual in an enclosing instance.
1148 -- An overloading between such a subprogram and one declared outside the
1149 -- instance is resolved in favor of the first, because it resolved in
1152 function Matches (Actual, Formal : Node_Id) return Boolean;
1153 -- Look for exact type match in an instance, to remove spurious
1154 -- ambiguities when two formal types have the same actual.
1156 function Standard_Operator return Boolean;
1157 -- Check whether subprogram is predefined operator declared in Standard.
1158 -- It may given by an operator name, or by an expanded name whose prefix
1161 function Remove_Conversions return Interp;
1162 -- Last chance for pathological cases involving comparisons on literals,
1163 -- and user overloadings of the same operator. Such pathologies have
1164 -- been removed from the ACVC, but still appear in two DEC tests, with
1165 -- the following notable quote from Ben Brosgol:
1167 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1168 -- this example; Robert Dewar brought it to our attention, since it is
1169 -- apparently found in the ACVC 1.5. I did not attempt to find the
1170 -- reason in the Reference Manual that makes the example legal, since I
1171 -- was too nauseated by it to want to pursue it further.]
1173 -- Accordingly, this is not a fully recursive solution, but it handles
1174 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1175 -- pathology in the other direction with calls whose multiple overloaded
1176 -- actuals make them truly unresolvable.
1178 -- The new rules concerning abstract operations create additional need
1179 -- for special handling of expressions with universal operands, see
1180 -- comments to Has_Abstract_Interpretation below.
1182 ------------------------
1183 -- In_Generic_Actual --
1184 ------------------------
1186 function In_Generic_Actual (Exp : Node_Id) return Boolean is
1187 Par : constant Node_Id := Parent (Exp);
1193 elsif Nkind (Par) in N_Declaration then
1194 if Nkind (Par) = N_Object_Declaration
1195 or else Nkind (Par) = N_Object_Renaming_Declaration
1197 return Present (Corresponding_Generic_Association (Par));
1202 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
1206 return In_Generic_Actual (Parent (Par));
1208 end In_Generic_Actual;
1210 ---------------------------
1211 -- Inherited_From_Actual --
1212 ---------------------------
1214 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1215 Par : constant Node_Id := Parent (S);
1217 if Nkind (Par) /= N_Full_Type_Declaration
1218 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1222 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1224 Is_Generic_Actual_Type (
1225 Entity (Subtype_Indication (Type_Definition (Par))));
1227 end Inherited_From_Actual;
1229 --------------------------
1230 -- Is_Actual_Subprogram --
1231 --------------------------
1233 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1235 return In_Open_Scopes (Scope (S))
1237 (Is_Generic_Instance (Scope (S))
1238 or else Is_Wrapper_Package (Scope (S)));
1239 end Is_Actual_Subprogram;
1245 function Matches (Actual, Formal : Node_Id) return Boolean is
1246 T1 : constant Entity_Id := Etype (Actual);
1247 T2 : constant Entity_Id := Etype (Formal);
1251 (Is_Numeric_Type (T2)
1253 (T1 = Universal_Real or else T1 = Universal_Integer));
1256 ------------------------
1257 -- Remove_Conversions --
1258 ------------------------
1260 function Remove_Conversions return Interp is
1268 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1269 -- If an operation has universal operands the universal operation
1270 -- is present among its interpretations. If there is an abstract
1271 -- interpretation for the operator, with a numeric result, this
1272 -- interpretation was already removed in sem_ch4, but the universal
1273 -- one is still visible. We must rescan the list of operators and
1274 -- remove the universal interpretation to resolve the ambiguity.
1276 ---------------------------------
1277 -- Has_Abstract_Interpretation --
1278 ---------------------------------
1280 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1284 if Nkind (N) not in N_Op
1285 or else Ada_Version < Ada_05
1286 or else not Is_Overloaded (N)
1287 or else No (Universal_Interpretation (N))
1292 E := Get_Name_Entity_Id (Chars (N));
1293 while Present (E) loop
1294 if Is_Overloadable (E)
1295 and then Is_Abstract_Subprogram (E)
1296 and then Is_Numeric_Type (Etype (E))
1304 -- Finally, if an operand of the binary operator is itself
1305 -- an operator, recurse to see whether its own abstract
1306 -- interpretation is responsible for the spurious ambiguity.
1308 if Nkind (N) in N_Binary_Op then
1309 return Has_Abstract_Interpretation (Left_Opnd (N))
1310 or else Has_Abstract_Interpretation (Right_Opnd (N));
1312 elsif Nkind (N) in N_Unary_Op then
1313 return Has_Abstract_Interpretation (Right_Opnd (N));
1319 end Has_Abstract_Interpretation;
1321 -- Start of processing for Remove_Conversions
1326 Get_First_Interp (N, I, It);
1327 while Present (It.Typ) loop
1328 if not Is_Overloadable (It.Nam) then
1332 F1 := First_Formal (It.Nam);
1338 if Nkind (N) = N_Function_Call
1339 or else Nkind (N) = N_Procedure_Call_Statement
1341 Act1 := First_Actual (N);
1343 if Present (Act1) then
1344 Act2 := Next_Actual (Act1);
1349 elsif Nkind (N) in N_Unary_Op then
1350 Act1 := Right_Opnd (N);
1353 elsif Nkind (N) in N_Binary_Op then
1354 Act1 := Left_Opnd (N);
1355 Act2 := Right_Opnd (N);
1357 -- Use type of second formal, so as to include
1358 -- exponentiation, where the exponent may be
1359 -- ambiguous and the result non-universal.
1367 if Nkind (Act1) in N_Op
1368 and then Is_Overloaded (Act1)
1369 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1370 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1371 and then Has_Compatible_Type (Act1, Standard_Boolean)
1372 and then Etype (F1) = Standard_Boolean
1374 -- If the two candidates are the original ones, the
1375 -- ambiguity is real. Otherwise keep the original, further
1376 -- calls to Disambiguate will take care of others in the
1377 -- list of candidates.
1379 if It1 /= No_Interp then
1380 if It = Disambiguate.It1
1381 or else It = Disambiguate.It2
1383 if It1 = Disambiguate.It1
1384 or else It1 = Disambiguate.It2
1392 elsif Present (Act2)
1393 and then Nkind (Act2) in N_Op
1394 and then Is_Overloaded (Act2)
1395 and then (Nkind (Right_Opnd (Act2)) = N_Integer_Literal
1397 Nkind (Right_Opnd (Act2)) = N_Real_Literal)
1398 and then Has_Compatible_Type (Act2, Standard_Boolean)
1400 -- The preference rule on the first actual is not
1401 -- sufficient to disambiguate.
1409 elsif Is_Numeric_Type (Etype (F1))
1411 (Has_Abstract_Interpretation (Act1)
1412 or else Has_Abstract_Interpretation (Act2))
1414 if It = Disambiguate.It1 then
1415 return Disambiguate.It2;
1416 elsif It = Disambiguate.It2 then
1417 return Disambiguate.It1;
1423 Get_Next_Interp (I, It);
1426 -- After some error, a formal may have Any_Type and yield a spurious
1427 -- match. To avoid cascaded errors if possible, check for such a
1428 -- formal in either candidate.
1430 if Serious_Errors_Detected > 0 then
1435 Formal := First_Formal (Nam1);
1436 while Present (Formal) loop
1437 if Etype (Formal) = Any_Type then
1438 return Disambiguate.It2;
1441 Next_Formal (Formal);
1444 Formal := First_Formal (Nam2);
1445 while Present (Formal) loop
1446 if Etype (Formal) = Any_Type then
1447 return Disambiguate.It1;
1450 Next_Formal (Formal);
1456 end Remove_Conversions;
1458 -----------------------
1459 -- Standard_Operator --
1460 -----------------------
1462 function Standard_Operator return Boolean is
1466 if Nkind (N) in N_Op then
1469 elsif Nkind (N) = N_Function_Call then
1472 if Nkind (Nam) /= N_Expanded_Name then
1475 return Entity (Prefix (Nam)) = Standard_Standard;
1480 end Standard_Operator;
1482 -- Start of processing for Disambiguate
1485 -- Recover the two legal interpretations
1487 Get_First_Interp (N, I, It);
1489 Get_Next_Interp (I, It);
1495 Get_Next_Interp (I, It);
1501 if Ada_Version < Ada_05 then
1503 -- Check whether one of the entities is an Ada 2005 entity and we are
1504 -- operating in an earlier mode, in which case we discard the Ada
1505 -- 2005 entity, so that we get proper Ada 95 overload resolution.
1507 if Is_Ada_2005_Only (Nam1) then
1509 elsif Is_Ada_2005_Only (Nam2) then
1514 -- Check for overloaded CIL convention stuff because the CIL libraries
1515 -- do sick things like Console.WriteLine where it matches
1516 -- two different overloads, so just pick the first ???
1518 if Convention (Nam1) = Convention_CIL
1519 and then Convention (Nam2) = Convention_CIL
1520 and then Ekind (Nam1) = Ekind (Nam2)
1521 and then (Ekind (Nam1) = E_Procedure
1522 or else Ekind (Nam1) = E_Function)
1527 -- If the context is universal, the predefined operator is preferred.
1528 -- This includes bounds in numeric type declarations, and expressions
1529 -- in type conversions. If no interpretation yields a universal type,
1530 -- then we must check whether the user-defined entity hides the prede-
1533 if Chars (Nam1) in Any_Operator_Name
1534 and then Standard_Operator
1536 if Typ = Universal_Integer
1537 or else Typ = Universal_Real
1538 or else Typ = Any_Integer
1539 or else Typ = Any_Discrete
1540 or else Typ = Any_Real
1541 or else Typ = Any_Type
1543 -- Find an interpretation that yields the universal type, or else
1544 -- a predefined operator that yields a predefined numeric type.
1547 Candidate : Interp := No_Interp;
1550 Get_First_Interp (N, I, It);
1551 while Present (It.Typ) loop
1552 if (Covers (Typ, It.Typ)
1553 or else Typ = Any_Type)
1555 (It.Typ = Universal_Integer
1556 or else It.Typ = Universal_Real)
1560 elsif Covers (Typ, It.Typ)
1561 and then Scope (It.Typ) = Standard_Standard
1562 and then Scope (It.Nam) = Standard_Standard
1563 and then Is_Numeric_Type (It.Typ)
1568 Get_Next_Interp (I, It);
1571 if Candidate /= No_Interp then
1576 elsif Chars (Nam1) /= Name_Op_Not
1577 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1579 -- Equality or comparison operation. Choose predefined operator if
1580 -- arguments are universal. The node may be an operator, name, or
1581 -- a function call, so unpack arguments accordingly.
1584 Arg1, Arg2 : Node_Id;
1587 if Nkind (N) in N_Op then
1588 Arg1 := Left_Opnd (N);
1589 Arg2 := Right_Opnd (N);
1591 elsif Is_Entity_Name (N)
1592 or else Nkind (N) = N_Operator_Symbol
1594 Arg1 := First_Entity (Entity (N));
1595 Arg2 := Next_Entity (Arg1);
1598 Arg1 := First_Actual (N);
1599 Arg2 := Next_Actual (Arg1);
1603 and then Present (Universal_Interpretation (Arg1))
1604 and then Universal_Interpretation (Arg2) =
1605 Universal_Interpretation (Arg1)
1607 Get_First_Interp (N, I, It);
1608 while Scope (It.Nam) /= Standard_Standard loop
1609 Get_Next_Interp (I, It);
1618 -- If no universal interpretation, check whether user-defined operator
1619 -- hides predefined one, as well as other special cases. If the node
1620 -- is a range, then one or both bounds are ambiguous. Each will have
1621 -- to be disambiguated w.r.t. the context type. The type of the range
1622 -- itself is imposed by the context, so we can return either legal
1625 if Ekind (Nam1) = E_Operator then
1626 Predef_Subp := Nam1;
1629 elsif Ekind (Nam2) = E_Operator then
1630 Predef_Subp := Nam2;
1633 elsif Nkind (N) = N_Range then
1636 -- If two user defined-subprograms are visible, it is a true ambiguity,
1637 -- unless one of them is an entry and the context is a conditional or
1638 -- timed entry call, or unless we are within an instance and this is
1639 -- results from two formals types with the same actual.
1642 if Nkind (N) = N_Procedure_Call_Statement
1643 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1644 and then N = Entry_Call_Statement (Parent (N))
1646 if Ekind (Nam2) = E_Entry then
1648 elsif Ekind (Nam1) = E_Entry then
1654 -- If the ambiguity occurs within an instance, it is due to several
1655 -- formal types with the same actual. Look for an exact match between
1656 -- the types of the formals of the overloadable entities, and the
1657 -- actuals in the call, to recover the unambiguous match in the
1658 -- original generic.
1660 -- The ambiguity can also be due to an overloading between a formal
1661 -- subprogram and a subprogram declared outside the generic. If the
1662 -- node is overloaded, it did not resolve to the global entity in
1663 -- the generic, and we choose the formal subprogram.
1665 -- Finally, the ambiguity can be between an explicit subprogram and
1666 -- one inherited (with different defaults) from an actual. In this
1667 -- case the resolution was to the explicit declaration in the
1668 -- generic, and remains so in the instance.
1671 and then not In_Generic_Actual (N)
1673 if Nkind (N) = N_Function_Call
1674 or else Nkind (N) = N_Procedure_Call_Statement
1679 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1680 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1683 if Is_Act1 and then not Is_Act2 then
1686 elsif Is_Act2 and then not Is_Act1 then
1689 elsif Inherited_From_Actual (Nam1)
1690 and then Comes_From_Source (Nam2)
1694 elsif Inherited_From_Actual (Nam2)
1695 and then Comes_From_Source (Nam1)
1700 Actual := First_Actual (N);
1701 Formal := First_Formal (Nam1);
1702 while Present (Actual) loop
1703 if Etype (Actual) /= Etype (Formal) then
1707 Next_Actual (Actual);
1708 Next_Formal (Formal);
1714 elsif Nkind (N) in N_Binary_Op then
1715 if Matches (Left_Opnd (N), First_Formal (Nam1))
1717 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1724 elsif Nkind (N) in N_Unary_Op then
1725 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1732 return Remove_Conversions;
1735 return Remove_Conversions;
1739 -- An implicit concatenation operator on a string type cannot be
1740 -- disambiguated from the predefined concatenation. This can only
1741 -- happen with concatenation of string literals.
1743 if Chars (User_Subp) = Name_Op_Concat
1744 and then Ekind (User_Subp) = E_Operator
1745 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1749 -- If the user-defined operator is in an open scope, or in the scope
1750 -- of the resulting type, or given by an expanded name that names its
1751 -- scope, it hides the predefined operator for the type. Exponentiation
1752 -- has to be special-cased because the implicit operator does not have
1753 -- a symmetric signature, and may not be hidden by the explicit one.
1755 elsif (Nkind (N) = N_Function_Call
1756 and then Nkind (Name (N)) = N_Expanded_Name
1757 and then (Chars (Predef_Subp) /= Name_Op_Expon
1758 or else Hides_Op (User_Subp, Predef_Subp))
1759 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1760 or else Hides_Op (User_Subp, Predef_Subp)
1762 if It1.Nam = User_Subp then
1768 -- Otherwise, the predefined operator has precedence, or if the user-
1769 -- defined operation is directly visible we have a true ambiguity. If
1770 -- this is a fixed-point multiplication and division in Ada83 mode,
1771 -- exclude the universal_fixed operator, which often causes ambiguities
1775 if (In_Open_Scopes (Scope (User_Subp))
1776 or else Is_Potentially_Use_Visible (User_Subp))
1777 and then not In_Instance
1779 if Is_Fixed_Point_Type (Typ)
1780 and then (Chars (Nam1) = Name_Op_Multiply
1781 or else Chars (Nam1) = Name_Op_Divide)
1782 and then Ada_Version = Ada_83
1784 if It2.Nam = Predef_Subp then
1790 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
1791 -- states that the operator defined in Standard is not available
1792 -- if there is a user-defined equality with the proper signature,
1793 -- declared in the same declarative list as the type. The node
1794 -- may be an operator or a function call.
1796 elsif (Chars (Nam1) = Name_Op_Eq
1798 Chars (Nam1) = Name_Op_Ne)
1799 and then Ada_Version >= Ada_05
1800 and then Etype (User_Subp) = Standard_Boolean
1805 if Nkind (N) = N_Function_Call then
1806 Opnd := First_Actual (N);
1808 Opnd := Left_Opnd (N);
1811 if Ekind (Etype (Opnd)) = E_Anonymous_Access_Type
1813 List_Containing (Parent (Designated_Type (Etype (Opnd))))
1814 = List_Containing (Unit_Declaration_Node (User_Subp))
1816 if It2.Nam = Predef_Subp then
1822 return Remove_Conversions;
1830 elsif It1.Nam = Predef_Subp then
1839 ---------------------
1840 -- End_Interp_List --
1841 ---------------------
1843 procedure End_Interp_List is
1845 All_Interp.Table (All_Interp.Last) := No_Interp;
1846 All_Interp.Increment_Last;
1847 end End_Interp_List;
1849 -------------------------
1850 -- Entity_Matches_Spec --
1851 -------------------------
1853 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
1855 -- Simple case: same entity kinds, type conformance is required. A
1856 -- parameterless function can also rename a literal.
1858 if Ekind (Old_S) = Ekind (New_S)
1859 or else (Ekind (New_S) = E_Function
1860 and then Ekind (Old_S) = E_Enumeration_Literal)
1862 return Type_Conformant (New_S, Old_S);
1864 elsif Ekind (New_S) = E_Function
1865 and then Ekind (Old_S) = E_Operator
1867 return Operator_Matches_Spec (Old_S, New_S);
1869 elsif Ekind (New_S) = E_Procedure
1870 and then Is_Entry (Old_S)
1872 return Type_Conformant (New_S, Old_S);
1877 end Entity_Matches_Spec;
1879 ----------------------
1880 -- Find_Unique_Type --
1881 ----------------------
1883 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
1884 T : constant Entity_Id := Etype (L);
1887 TR : Entity_Id := Any_Type;
1890 if Is_Overloaded (R) then
1891 Get_First_Interp (R, I, It);
1892 while Present (It.Typ) loop
1893 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
1895 -- If several interpretations are possible and L is universal,
1896 -- apply preference rule.
1898 if TR /= Any_Type then
1900 if (T = Universal_Integer or else T = Universal_Real)
1911 Get_Next_Interp (I, It);
1916 -- In the non-overloaded case, the Etype of R is already set correctly
1922 -- If one of the operands is Universal_Fixed, the type of the other
1923 -- operand provides the context.
1925 if Etype (R) = Universal_Fixed then
1928 elsif T = Universal_Fixed then
1931 -- Ada 2005 (AI-230): Support the following operators:
1933 -- function "=" (L, R : universal_access) return Boolean;
1934 -- function "/=" (L, R : universal_access) return Boolean;
1936 -- Pool specific access types (E_Access_Type) are not covered by these
1937 -- operators because of the legality rule of 4.5.2(9.2): "The operands
1938 -- of the equality operators for universal_access shall be convertible
1939 -- to one another (see 4.6)". For example, considering the type decla-
1940 -- ration "type P is access Integer" and an anonymous access to Integer,
1941 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
1942 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
1944 elsif Ada_Version >= Ada_05
1946 (Ekind (Etype (L)) = E_Anonymous_Access_Type
1948 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
1949 and then Is_Access_Type (Etype (R))
1950 and then Ekind (Etype (R)) /= E_Access_Type
1954 elsif Ada_Version >= Ada_05
1956 (Ekind (Etype (R)) = E_Anonymous_Access_Type
1957 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
1958 and then Is_Access_Type (Etype (L))
1959 and then Ekind (Etype (L)) /= E_Access_Type
1964 return Specific_Type (T, Etype (R));
1966 end Find_Unique_Type;
1968 -------------------------------------
1969 -- Function_Interp_Has_Abstract_Op --
1970 -------------------------------------
1972 function Function_Interp_Has_Abstract_Op
1974 E : Entity_Id) return Entity_Id
1976 Abstr_Op : Entity_Id;
1979 Form_Parm : Node_Id;
1982 if Is_Overloaded (N) then
1983 Act_Parm := First_Actual (N);
1984 Form_Parm := First_Formal (E);
1985 while Present (Act_Parm)
1986 and then Present (Form_Parm)
1990 if Nkind (Act) = N_Parameter_Association then
1991 Act := Explicit_Actual_Parameter (Act);
1994 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
1996 if Present (Abstr_Op) then
2000 Next_Actual (Act_Parm);
2001 Next_Formal (Form_Parm);
2006 end Function_Interp_Has_Abstract_Op;
2008 ----------------------
2009 -- Get_First_Interp --
2010 ----------------------
2012 procedure Get_First_Interp
2014 I : out Interp_Index;
2017 Int_Ind : Interp_Index;
2022 -- If a selected component is overloaded because the selector has
2023 -- multiple interpretations, the node is a call to a protected
2024 -- operation or an indirect call. Retrieve the interpretation from
2025 -- the selector name. The selected component may be overloaded as well
2026 -- if the prefix is overloaded. That case is unchanged.
2028 if Nkind (N) = N_Selected_Component
2029 and then Is_Overloaded (Selector_Name (N))
2031 O_N := Selector_Name (N);
2036 Map_Ptr := Headers (Hash (O_N));
2037 while Present (Interp_Map.Table (Map_Ptr).Node) loop
2038 if Interp_Map.Table (Map_Ptr).Node = O_N then
2039 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2040 It := All_Interp.Table (Int_Ind);
2044 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2048 -- Procedure should never be called if the node has no interpretations
2050 raise Program_Error;
2051 end Get_First_Interp;
2053 ---------------------
2054 -- Get_Next_Interp --
2055 ---------------------
2057 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2060 It := All_Interp.Table (I);
2061 end Get_Next_Interp;
2063 -------------------------
2064 -- Has_Compatible_Type --
2065 -------------------------
2067 function Has_Compatible_Type
2080 if Nkind (N) = N_Subtype_Indication
2081 or else not Is_Overloaded (N)
2084 Covers (Typ, Etype (N))
2086 -- Ada 2005 (AI-345) The context may be a synchronized interface.
2087 -- If the type is already frozen use the corresponding_record
2088 -- to check whether it is a proper descendant.
2091 (Is_Concurrent_Type (Etype (N))
2092 and then Present (Corresponding_Record_Type (Etype (N)))
2093 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2096 (not Is_Tagged_Type (Typ)
2097 and then Ekind (Typ) /= E_Anonymous_Access_Type
2098 and then Covers (Etype (N), Typ));
2101 Get_First_Interp (N, I, It);
2102 while Present (It.Typ) loop
2103 if (Covers (Typ, It.Typ)
2105 (Scope (It.Nam) /= Standard_Standard
2106 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2108 -- Ada 2005 (AI-345)
2111 (Is_Concurrent_Type (It.Typ)
2112 and then Present (Corresponding_Record_Type
2114 and then Covers (Typ, Corresponding_Record_Type
2117 or else (not Is_Tagged_Type (Typ)
2118 and then Ekind (Typ) /= E_Anonymous_Access_Type
2119 and then Covers (It.Typ, Typ))
2124 Get_Next_Interp (I, It);
2129 end Has_Compatible_Type;
2131 ---------------------
2132 -- Has_Abstract_Op --
2133 ---------------------
2135 function Has_Abstract_Op
2137 Typ : Entity_Id) return Entity_Id
2143 if Is_Overloaded (N) then
2144 Get_First_Interp (N, I, It);
2145 while Present (It.Nam) loop
2146 if Present (It.Abstract_Op)
2147 and then Etype (It.Abstract_Op) = Typ
2149 return It.Abstract_Op;
2152 Get_Next_Interp (I, It);
2157 end Has_Abstract_Op;
2163 function Hash (N : Node_Id) return Int is
2165 -- Nodes have a size that is power of two, so to select significant
2166 -- bits only we remove the low-order bits.
2168 return ((Int (N) / 2 ** 5) mod Header_Size);
2175 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2176 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2178 return Operator_Matches_Spec (Op, F)
2179 and then (In_Open_Scopes (Scope (F))
2180 or else Scope (F) = Scope (Btyp)
2181 or else (not In_Open_Scopes (Scope (Btyp))
2182 and then not In_Use (Btyp)
2183 and then not In_Use (Scope (Btyp))));
2186 ------------------------
2187 -- Init_Interp_Tables --
2188 ------------------------
2190 procedure Init_Interp_Tables is
2194 Headers := (others => No_Entry);
2195 end Init_Interp_Tables;
2197 -----------------------------------
2198 -- Interface_Present_In_Ancestor --
2199 -----------------------------------
2201 function Interface_Present_In_Ancestor
2203 Iface : Entity_Id) return Boolean
2205 Target_Typ : Entity_Id;
2206 Iface_Typ : Entity_Id;
2208 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2209 -- Returns True if Typ or some ancestor of Typ implements Iface
2211 -------------------------------
2212 -- Iface_Present_In_Ancestor --
2213 -------------------------------
2215 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2221 if Typ = Iface_Typ then
2225 -- Handle private types
2227 if Present (Full_View (Typ))
2228 and then not Is_Concurrent_Type (Full_View (Typ))
2230 E := Full_View (Typ);
2236 if Present (Abstract_Interfaces (E))
2237 and then Present (Abstract_Interfaces (E))
2238 and then not Is_Empty_Elmt_List (Abstract_Interfaces (E))
2240 Elmt := First_Elmt (Abstract_Interfaces (E));
2241 while Present (Elmt) loop
2244 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2252 exit when Etype (E) = E
2254 -- Handle private types
2256 or else (Present (Full_View (Etype (E)))
2257 and then Full_View (Etype (E)) = E);
2259 -- Check if the current type is a direct derivation of the
2262 if Etype (E) = Iface_Typ then
2266 -- Climb to the immediate ancestor handling private types
2268 if Present (Full_View (Etype (E))) then
2269 E := Full_View (Etype (E));
2276 end Iface_Present_In_Ancestor;
2278 -- Start of processing for Interface_Present_In_Ancestor
2281 if Is_Class_Wide_Type (Iface) then
2282 Iface_Typ := Etype (Iface);
2289 Iface_Typ := Base_Type (Iface_Typ);
2291 if Is_Access_Type (Typ) then
2292 Target_Typ := Etype (Directly_Designated_Type (Typ));
2297 if Is_Concurrent_Record_Type (Target_Typ) then
2298 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2301 Target_Typ := Base_Type (Target_Typ);
2303 -- In case of concurrent types we can't use the Corresponding Record_Typ
2304 -- to look for the interface because it is built by the expander (and
2305 -- hence it is not always available). For this reason we traverse the
2306 -- list of interfaces (available in the parent of the concurrent type)
2308 if Is_Concurrent_Type (Target_Typ) then
2309 if Present (Interface_List (Parent (Target_Typ))) then
2314 AI := First (Interface_List (Parent (Target_Typ)));
2315 while Present (AI) loop
2316 if Etype (AI) = Iface_Typ then
2319 elsif Present (Abstract_Interfaces (Etype (AI)))
2320 and then Iface_Present_In_Ancestor (Etype (AI))
2333 if Is_Class_Wide_Type (Target_Typ) then
2334 Target_Typ := Etype (Target_Typ);
2337 if Ekind (Target_Typ) = E_Incomplete_Type then
2338 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2339 Target_Typ := Non_Limited_View (Target_Typ);
2341 -- Protect the frontend against previously detected errors
2343 if Ekind (Target_Typ) = E_Incomplete_Type then
2348 return Iface_Present_In_Ancestor (Target_Typ);
2349 end Interface_Present_In_Ancestor;
2351 ---------------------
2352 -- Intersect_Types --
2353 ---------------------
2355 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2356 Index : Interp_Index;
2360 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2361 -- Find interpretation of right arg that has type compatible with T
2363 --------------------------
2364 -- Check_Right_Argument --
2365 --------------------------
2367 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2368 Index : Interp_Index;
2373 if not Is_Overloaded (R) then
2374 return Specific_Type (T, Etype (R));
2377 Get_First_Interp (R, Index, It);
2379 T2 := Specific_Type (T, It.Typ);
2381 if T2 /= Any_Type then
2385 Get_Next_Interp (Index, It);
2386 exit when No (It.Typ);
2391 end Check_Right_Argument;
2393 -- Start processing for Intersect_Types
2396 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2400 if not Is_Overloaded (L) then
2401 Typ := Check_Right_Argument (Etype (L));
2405 Get_First_Interp (L, Index, It);
2406 while Present (It.Typ) loop
2407 Typ := Check_Right_Argument (It.Typ);
2408 exit when Typ /= Any_Type;
2409 Get_Next_Interp (Index, It);
2414 -- If Typ is Any_Type, it means no compatible pair of types was found
2416 if Typ = Any_Type then
2417 if Nkind (Parent (L)) in N_Op then
2418 Error_Msg_N ("incompatible types for operator", Parent (L));
2420 elsif Nkind (Parent (L)) = N_Range then
2421 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2423 -- Ada 2005 (AI-251): Complete the error notification
2425 elsif Is_Class_Wide_Type (Etype (R))
2426 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2428 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2429 L, Etype (Class_Wide_Type (Etype (R))));
2432 Error_Msg_N ("incompatible types", Parent (L));
2437 end Intersect_Types;
2443 function Is_Ancestor (T1, T2 : Entity_Id) return Boolean is
2447 if Base_Type (T1) = Base_Type (T2) then
2450 elsif Is_Private_Type (T1)
2451 and then Present (Full_View (T1))
2452 and then Base_Type (T2) = Base_Type (Full_View (T1))
2460 -- If there was a error on the type declaration, do not recurse
2462 if Error_Posted (Par) then
2465 elsif Base_Type (T1) = Base_Type (Par)
2466 or else (Is_Private_Type (T1)
2467 and then Present (Full_View (T1))
2468 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2472 elsif Is_Private_Type (Par)
2473 and then Present (Full_View (Par))
2474 and then Full_View (Par) = Base_Type (T1)
2478 elsif Etype (Par) /= Par then
2487 ---------------------------
2488 -- Is_Invisible_Operator --
2489 ---------------------------
2491 function Is_Invisible_Operator
2496 Orig_Node : constant Node_Id := Original_Node (N);
2499 if Nkind (N) not in N_Op then
2502 elsif not Comes_From_Source (N) then
2505 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2508 elsif Nkind (N) in N_Binary_Op
2509 and then No (Universal_Interpretation (Left_Opnd (N)))
2514 return Is_Numeric_Type (T)
2515 and then not In_Open_Scopes (Scope (T))
2516 and then not Is_Potentially_Use_Visible (T)
2517 and then not In_Use (T)
2518 and then not In_Use (Scope (T))
2520 (Nkind (Orig_Node) /= N_Function_Call
2521 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2522 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2523 and then not In_Instance;
2525 end Is_Invisible_Operator;
2531 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2535 S := Ancestor_Subtype (T1);
2536 while Present (S) loop
2540 S := Ancestor_Subtype (S);
2551 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2552 Index : Interp_Index;
2556 Get_First_Interp (Nam, Index, It);
2557 while Present (It.Nam) loop
2558 if Scope (It.Nam) = Standard_Standard
2559 and then Scope (It.Typ) /= Standard_Standard
2561 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2562 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2565 Error_Msg_Sloc := Sloc (It.Nam);
2566 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2569 Get_Next_Interp (Index, It);
2577 procedure New_Interps (N : Node_Id) is
2581 All_Interp.Increment_Last;
2582 All_Interp.Table (All_Interp.Last) := No_Interp;
2584 Map_Ptr := Headers (Hash (N));
2586 if Map_Ptr = No_Entry then
2588 -- Place new node at end of table
2590 Interp_Map.Increment_Last;
2591 Headers (Hash (N)) := Interp_Map.Last;
2594 -- Place node at end of chain, or locate its previous entry
2597 if Interp_Map.Table (Map_Ptr).Node = N then
2599 -- Node is already in the table, and is being rewritten.
2600 -- Start a new interp section, retain hash link.
2602 Interp_Map.Table (Map_Ptr).Node := N;
2603 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2604 Set_Is_Overloaded (N, True);
2608 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2609 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2613 -- Chain the new node
2615 Interp_Map.Increment_Last;
2616 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2619 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2620 Set_Is_Overloaded (N, True);
2623 ---------------------------
2624 -- Operator_Matches_Spec --
2625 ---------------------------
2627 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2628 Op_Name : constant Name_Id := Chars (Op);
2629 T : constant Entity_Id := Etype (New_S);
2637 -- To verify that a predefined operator matches a given signature,
2638 -- do a case analysis of the operator classes. Function can have one
2639 -- or two formals and must have the proper result type.
2641 New_F := First_Formal (New_S);
2642 Old_F := First_Formal (Op);
2644 while Present (New_F) and then Present (Old_F) loop
2646 Next_Formal (New_F);
2647 Next_Formal (Old_F);
2650 -- Definite mismatch if different number of parameters
2652 if Present (Old_F) or else Present (New_F) then
2658 T1 := Etype (First_Formal (New_S));
2660 if Op_Name = Name_Op_Subtract
2661 or else Op_Name = Name_Op_Add
2662 or else Op_Name = Name_Op_Abs
2664 return Base_Type (T1) = Base_Type (T)
2665 and then Is_Numeric_Type (T);
2667 elsif Op_Name = Name_Op_Not then
2668 return Base_Type (T1) = Base_Type (T)
2669 and then Valid_Boolean_Arg (Base_Type (T));
2678 T1 := Etype (First_Formal (New_S));
2679 T2 := Etype (Next_Formal (First_Formal (New_S)));
2681 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
2682 or else Op_Name = Name_Op_Xor
2684 return Base_Type (T1) = Base_Type (T2)
2685 and then Base_Type (T1) = Base_Type (T)
2686 and then Valid_Boolean_Arg (Base_Type (T));
2688 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
2689 return Base_Type (T1) = Base_Type (T2)
2690 and then not Is_Limited_Type (T1)
2691 and then Is_Boolean_Type (T);
2693 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
2694 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
2696 return Base_Type (T1) = Base_Type (T2)
2697 and then Valid_Comparison_Arg (T1)
2698 and then Is_Boolean_Type (T);
2700 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
2701 return Base_Type (T1) = Base_Type (T2)
2702 and then Base_Type (T1) = Base_Type (T)
2703 and then Is_Numeric_Type (T);
2705 -- for division and multiplication, a user-defined function does
2706 -- not match the predefined universal_fixed operation, except in
2709 elsif Op_Name = Name_Op_Divide then
2710 return (Base_Type (T1) = Base_Type (T2)
2711 and then Base_Type (T1) = Base_Type (T)
2712 and then Is_Numeric_Type (T)
2713 and then (not Is_Fixed_Point_Type (T)
2714 or else Ada_Version = Ada_83))
2716 -- Mixed_Mode operations on fixed-point types
2718 or else (Base_Type (T1) = Base_Type (T)
2719 and then Base_Type (T2) = Base_Type (Standard_Integer)
2720 and then Is_Fixed_Point_Type (T))
2722 -- A user defined operator can also match (and hide) a mixed
2723 -- operation on universal literals.
2725 or else (Is_Integer_Type (T2)
2726 and then Is_Floating_Point_Type (T1)
2727 and then Base_Type (T1) = Base_Type (T));
2729 elsif Op_Name = Name_Op_Multiply then
2730 return (Base_Type (T1) = Base_Type (T2)
2731 and then Base_Type (T1) = Base_Type (T)
2732 and then Is_Numeric_Type (T)
2733 and then (not Is_Fixed_Point_Type (T)
2734 or else Ada_Version = Ada_83))
2736 -- Mixed_Mode operations on fixed-point types
2738 or else (Base_Type (T1) = Base_Type (T)
2739 and then Base_Type (T2) = Base_Type (Standard_Integer)
2740 and then Is_Fixed_Point_Type (T))
2742 or else (Base_Type (T2) = Base_Type (T)
2743 and then Base_Type (T1) = Base_Type (Standard_Integer)
2744 and then Is_Fixed_Point_Type (T))
2746 or else (Is_Integer_Type (T2)
2747 and then Is_Floating_Point_Type (T1)
2748 and then Base_Type (T1) = Base_Type (T))
2750 or else (Is_Integer_Type (T1)
2751 and then Is_Floating_Point_Type (T2)
2752 and then Base_Type (T2) = Base_Type (T));
2754 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
2755 return Base_Type (T1) = Base_Type (T2)
2756 and then Base_Type (T1) = Base_Type (T)
2757 and then Is_Integer_Type (T);
2759 elsif Op_Name = Name_Op_Expon then
2760 return Base_Type (T1) = Base_Type (T)
2761 and then Is_Numeric_Type (T)
2762 and then Base_Type (T2) = Base_Type (Standard_Integer);
2764 elsif Op_Name = Name_Op_Concat then
2765 return Is_Array_Type (T)
2766 and then (Base_Type (T) = Base_Type (Etype (Op)))
2767 and then (Base_Type (T1) = Base_Type (T)
2769 Base_Type (T1) = Base_Type (Component_Type (T)))
2770 and then (Base_Type (T2) = Base_Type (T)
2772 Base_Type (T2) = Base_Type (Component_Type (T)));
2778 end Operator_Matches_Spec;
2784 procedure Remove_Interp (I : in out Interp_Index) is
2788 -- Find end of Interp list and copy downward to erase the discarded one
2791 while Present (All_Interp.Table (II).Typ) loop
2795 for J in I + 1 .. II loop
2796 All_Interp.Table (J - 1) := All_Interp.Table (J);
2799 -- Back up interp. index to insure that iterator will pick up next
2800 -- available interpretation.
2809 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
2811 O_N : Node_Id := Old_N;
2814 if Is_Overloaded (Old_N) then
2815 if Nkind (Old_N) = N_Selected_Component
2816 and then Is_Overloaded (Selector_Name (Old_N))
2818 O_N := Selector_Name (Old_N);
2821 Map_Ptr := Headers (Hash (O_N));
2823 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
2824 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2825 pragma Assert (Map_Ptr /= No_Entry);
2828 New_Interps (New_N);
2829 Interp_Map.Table (Interp_Map.Last).Index :=
2830 Interp_Map.Table (Map_Ptr).Index;
2838 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
2839 T1 : constant Entity_Id := Available_View (Typ_1);
2840 T2 : constant Entity_Id := Available_View (Typ_2);
2841 B1 : constant Entity_Id := Base_Type (T1);
2842 B2 : constant Entity_Id := Base_Type (T2);
2844 function Is_Remote_Access (T : Entity_Id) return Boolean;
2845 -- Check whether T is the equivalent type of a remote access type.
2846 -- If distribution is enabled, T is a legal context for Null.
2848 ----------------------
2849 -- Is_Remote_Access --
2850 ----------------------
2852 function Is_Remote_Access (T : Entity_Id) return Boolean is
2854 return Is_Record_Type (T)
2855 and then (Is_Remote_Call_Interface (T)
2856 or else Is_Remote_Types (T))
2857 and then Present (Corresponding_Remote_Type (T))
2858 and then Is_Access_Type (Corresponding_Remote_Type (T));
2859 end Is_Remote_Access;
2861 -- Start of processing for Specific_Type
2864 if T1 = Any_Type or else T2 = Any_Type then
2871 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
2872 or else (T1 = Universal_Real and then Is_Real_Type (T2))
2873 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
2874 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
2878 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
2879 or else (T2 = Universal_Real and then Is_Real_Type (T1))
2880 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
2881 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
2885 elsif T2 = Any_String and then Is_String_Type (T1) then
2888 elsif T1 = Any_String and then Is_String_Type (T2) then
2891 elsif T2 = Any_Character and then Is_Character_Type (T1) then
2894 elsif T1 = Any_Character and then Is_Character_Type (T2) then
2897 elsif T1 = Any_Access
2898 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
2902 elsif T2 = Any_Access
2903 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
2907 elsif T2 = Any_Composite
2908 and then Ekind (T1) in E_Array_Type .. E_Record_Subtype
2912 elsif T1 = Any_Composite
2913 and then Ekind (T2) in E_Array_Type .. E_Record_Subtype
2917 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
2920 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
2923 -- ----------------------------------------------------------
2924 -- Special cases for equality operators (all other predefined
2925 -- operators can never apply to tagged types)
2926 -- ----------------------------------------------------------
2928 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
2931 elsif Is_Class_Wide_Type (T1)
2932 and then Is_Class_Wide_Type (T2)
2933 and then Is_Interface (Etype (T2))
2937 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
2938 -- class-wide interface T2
2940 elsif Is_Class_Wide_Type (T2)
2941 and then Is_Interface (Etype (T2))
2942 and then Interface_Present_In_Ancestor (Typ => T1,
2943 Iface => Etype (T2))
2947 elsif Is_Class_Wide_Type (T1)
2948 and then Is_Ancestor (Root_Type (T1), T2)
2952 elsif Is_Class_Wide_Type (T2)
2953 and then Is_Ancestor (Root_Type (T2), T1)
2957 elsif (Ekind (B1) = E_Access_Subprogram_Type
2959 Ekind (B1) = E_Access_Protected_Subprogram_Type)
2960 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
2961 and then Is_Access_Type (T2)
2965 elsif (Ekind (B2) = E_Access_Subprogram_Type
2967 Ekind (B2) = E_Access_Protected_Subprogram_Type)
2968 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
2969 and then Is_Access_Type (T1)
2973 elsif (Ekind (T1) = E_Allocator_Type
2974 or else Ekind (T1) = E_Access_Attribute_Type
2975 or else Ekind (T1) = E_Anonymous_Access_Type)
2976 and then Is_Access_Type (T2)
2980 elsif (Ekind (T2) = E_Allocator_Type
2981 or else Ekind (T2) = E_Access_Attribute_Type
2982 or else Ekind (T2) = E_Anonymous_Access_Type)
2983 and then Is_Access_Type (T1)
2987 -- If none of the above cases applies, types are not compatible
2994 ---------------------
2995 -- Set_Abstract_Op --
2996 ---------------------
2998 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3000 All_Interp.Table (I).Abstract_Op := V;
3001 end Set_Abstract_Op;
3003 -----------------------
3004 -- Valid_Boolean_Arg --
3005 -----------------------
3007 -- In addition to booleans and arrays of booleans, we must include
3008 -- aggregates as valid boolean arguments, because in the first pass of
3009 -- resolution their components are not examined. If it turns out not to be
3010 -- an aggregate of booleans, this will be diagnosed in Resolve.
3011 -- Any_Composite must be checked for prior to the array type checks because
3012 -- Any_Composite does not have any associated indexes.
3014 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3016 return Is_Boolean_Type (T)
3017 or else T = Any_Composite
3018 or else (Is_Array_Type (T)
3019 and then T /= Any_String
3020 and then Number_Dimensions (T) = 1
3021 and then Is_Boolean_Type (Component_Type (T))
3022 and then (not Is_Private_Composite (T)
3023 or else In_Instance)
3024 and then (not Is_Limited_Composite (T)
3025 or else In_Instance))
3026 or else Is_Modular_Integer_Type (T)
3027 or else T = Universal_Integer;
3028 end Valid_Boolean_Arg;
3030 --------------------------
3031 -- Valid_Comparison_Arg --
3032 --------------------------
3034 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3037 if T = Any_Composite then
3039 elsif Is_Discrete_Type (T)
3040 or else Is_Real_Type (T)
3043 elsif Is_Array_Type (T)
3044 and then Number_Dimensions (T) = 1
3045 and then Is_Discrete_Type (Component_Type (T))
3046 and then (not Is_Private_Composite (T)
3047 or else In_Instance)
3048 and then (not Is_Limited_Composite (T)
3049 or else In_Instance)
3052 elsif Is_String_Type (T) then
3057 end Valid_Comparison_Arg;
3059 ----------------------
3060 -- Write_Interp_Ref --
3061 ----------------------
3063 procedure Write_Interp_Ref (Map_Ptr : Int) is
3065 Write_Str (" Node: ");
3066 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3067 Write_Str (" Index: ");
3068 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3069 Write_Str (" Next: ");
3070 Write_Int (Int (Interp_Map.Table (Map_Ptr).Next));
3072 end Write_Interp_Ref;
3074 ---------------------
3075 -- Write_Overloads --
3076 ---------------------
3078 procedure Write_Overloads (N : Node_Id) is
3084 if not Is_Overloaded (N) then
3085 Write_Str ("Non-overloaded entity ");
3087 Write_Entity_Info (Entity (N), " ");
3090 Get_First_Interp (N, I, It);
3091 Write_Str ("Overloaded entity ");
3093 Write_Str (" Name Type Abstract Op");
3095 Write_Str ("===============================================");
3099 while Present (Nam) loop
3100 Write_Int (Int (Nam));
3102 Write_Name (Chars (Nam));
3104 Write_Int (Int (It.Typ));
3106 Write_Name (Chars (It.Typ));
3108 if Present (It.Abstract_Op) then
3110 Write_Int (Int (It.Abstract_Op));
3112 Write_Name (Chars (It.Abstract_Op));
3116 Get_Next_Interp (I, It);
3120 end Write_Overloads;