1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, 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_2005 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
365 if Present (Opnd_Type) then
366 Vis_Type := Opnd_Type;
368 Vis_Type := Base_Type (T);
371 if In_Open_Scopes (Scope (Vis_Type))
372 or else Is_Potentially_Use_Visible (Vis_Type)
373 or else In_Use (Vis_Type)
374 or else (In_Use (Scope (Vis_Type))
375 and then not Is_Hidden (Vis_Type))
376 or else Nkind (N) = N_Expanded_Name
377 or else (Nkind (N) in N_Op and then E = Entity (N))
379 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
383 -- If the node is given in functional notation and the prefix
384 -- is an expanded name, then the operator is visible if the
385 -- prefix is the scope of the result type as well. If the
386 -- operator is (implicitly) defined in an extension of system,
387 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
389 elsif Nkind (N) = N_Function_Call
390 and then Nkind (Name (N)) = N_Expanded_Name
391 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
392 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
393 or else Scope (Vis_Type) = System_Aux_Id)
397 -- Save type for subsequent error message, in case no other
398 -- interpretation is found.
401 Candidate_Type := Vis_Type;
405 -- In an instance, an abstract non-dispatching operation cannot be a
406 -- candidate interpretation, because it could not have been one in the
407 -- generic (it may be a spurious overloading in the instance).
410 and then Is_Overloadable (E)
411 and then Is_Abstract_Subprogram (E)
412 and then not Is_Dispatching_Operation (E)
416 -- An inherited interface operation that is implemented by some derived
417 -- type does not participate in overload resolution, only the
418 -- implementation operation does.
421 and then Is_Subprogram (E)
422 and then Present (Interface_Alias (E))
424 -- Ada 2005 (AI-251): If this primitive operation corresponds with
425 -- an immediate ancestor interface there is no need to add it to the
426 -- list of interpretations. The corresponding aliased primitive is
427 -- also in this list of primitive operations and will be used instead
428 -- because otherwise we have a dummy ambiguity between the two
429 -- subprograms which are in fact the same.
432 (Find_Dispatching_Type (Interface_Alias (E)),
433 Find_Dispatching_Type (E))
435 Add_One_Interp (N, Interface_Alias (E), T);
440 -- Calling stubs for an RACW operation never participate in resolution,
441 -- they are executed only through dispatching calls.
443 elsif Is_RACW_Stub_Type_Operation (E) then
447 -- If this is the first interpretation of N, N has type Any_Type.
448 -- In that case place the new type on the node. If one interpretation
449 -- already exists, indicate that the node is overloaded, and store
450 -- both the previous and the new interpretation in All_Interp. If
451 -- this is a later interpretation, just add it to the set.
453 if Etype (N) = Any_Type then
458 -- Record both the operator or subprogram name, and its type
460 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
467 -- Either there is no current interpretation in the table for any
468 -- node or the interpretation that is present is for a different
469 -- node. In both cases add a new interpretation to the table.
471 elsif Interp_Map.Last < 0
473 (Interp_Map.Table (Interp_Map.Last).Node /= N
474 and then not Is_Overloaded (N))
478 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
479 and then Present (Entity (N))
481 Add_Entry (Entity (N), Etype (N));
483 elsif Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement)
484 and then Is_Entity_Name (Name (N))
486 Add_Entry (Entity (Name (N)), Etype (N));
488 -- If this is an indirect call there will be no name associated
489 -- with the previous entry. To make diagnostics clearer, save
490 -- Subprogram_Type of first interpretation, so that the error will
491 -- point to the anonymous access to subprogram, not to the result
492 -- type of the call itself.
494 elsif (Nkind (N)) = N_Function_Call
495 and then Nkind (Name (N)) = N_Explicit_Dereference
496 and then Is_Overloaded (Name (N))
502 pragma Warnings (Off, Itn);
505 Get_First_Interp (Name (N), Itn, It);
506 Add_Entry (It.Nam, Etype (N));
510 -- Overloaded prefix in indexed or selected component, or call
511 -- whose name is an expression or another call.
513 Add_Entry (Etype (N), Etype (N));
527 procedure All_Overloads is
529 for J in All_Interp.First .. All_Interp.Last loop
531 if Present (All_Interp.Table (J).Nam) then
532 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
534 Write_Str ("No Interp");
538 Write_Str ("=================");
543 --------------------------------------
544 -- Binary_Op_Interp_Has_Abstract_Op --
545 --------------------------------------
547 function Binary_Op_Interp_Has_Abstract_Op
549 E : Entity_Id) return Entity_Id
551 Abstr_Op : Entity_Id;
552 E_Left : constant Node_Id := First_Formal (E);
553 E_Right : constant Node_Id := Next_Formal (E_Left);
556 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
557 if Present (Abstr_Op) then
561 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
562 end Binary_Op_Interp_Has_Abstract_Op;
564 ---------------------
565 -- Collect_Interps --
566 ---------------------
568 procedure Collect_Interps (N : Node_Id) is
569 Ent : constant Entity_Id := Entity (N);
571 First_Interp : Interp_Index;
573 function Within_Instance (E : Entity_Id) return Boolean;
574 -- Within an instance there can be spurious ambiguities between a local
575 -- entity and one declared outside of the instance. This can only happen
576 -- for subprograms, because otherwise the local entity hides the outer
577 -- one. For an overloadable entity, this predicate determines whether it
578 -- is a candidate within the instance, or must be ignored.
580 ---------------------
581 -- Within_Instance --
582 ---------------------
584 function Within_Instance (E : Entity_Id) return Boolean is
589 if not In_Instance then
593 Inst := Current_Scope;
594 while Present (Inst) and then not Is_Generic_Instance (Inst) loop
595 Inst := Scope (Inst);
599 while Present (Scop) and then Scop /= Standard_Standard loop
603 Scop := Scope (Scop);
609 -- Start of processing for Collect_Interps
614 -- Unconditionally add the entity that was initially matched
616 First_Interp := All_Interp.Last;
617 Add_One_Interp (N, Ent, Etype (N));
619 -- For expanded name, pick up all additional entities from the
620 -- same scope, since these are obviously also visible. Note that
621 -- these are not necessarily contiguous on the homonym chain.
623 if Nkind (N) = N_Expanded_Name then
625 while Present (H) loop
626 if Scope (H) = Scope (Entity (N)) then
627 Add_One_Interp (N, H, Etype (H));
633 -- Case of direct name
636 -- First, search the homonym chain for directly visible entities
638 H := Current_Entity (Ent);
639 while Present (H) loop
640 exit when (not Is_Overloadable (H))
641 and then Is_Immediately_Visible (H);
643 if Is_Immediately_Visible (H)
646 -- Only add interpretation if not hidden by an inner
647 -- immediately visible one.
649 for J in First_Interp .. All_Interp.Last - 1 loop
651 -- Current homograph is not hidden. Add to overloads
653 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
656 -- Homograph is hidden, unless it is a predefined operator
658 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
660 -- A homograph in the same scope can occur within an
661 -- instantiation, the resulting ambiguity has to be
662 -- resolved later. The homographs may both be local
663 -- functions or actuals, or may be declared at different
664 -- levels within the instance. The renaming of an actual
665 -- within the instance must not be included.
667 if Within_Instance (H)
668 and then H /= Renamed_Entity (Ent)
669 and then not Is_Inherited_Operation (H)
671 All_Interp.Table (All_Interp.Last) :=
672 (H, Etype (H), Empty);
673 All_Interp.Append (No_Interp);
676 elsif Scope (H) /= Standard_Standard then
682 -- On exit, we know that current homograph is not hidden
684 Add_One_Interp (N, H, Etype (H));
687 Write_Str ("Add overloaded interpretation ");
697 -- Scan list of homographs for use-visible entities only
699 H := Current_Entity (Ent);
701 while Present (H) loop
702 if Is_Potentially_Use_Visible (H)
704 and then Is_Overloadable (H)
706 for J in First_Interp .. All_Interp.Last - 1 loop
708 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
711 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
712 goto Next_Use_Homograph;
716 Add_One_Interp (N, H, Etype (H));
719 <<Next_Use_Homograph>>
724 if All_Interp.Last = First_Interp + 1 then
726 -- The final interpretation is in fact not overloaded. Note that the
727 -- unique legal interpretation may or may not be the original one,
728 -- so we need to update N's entity and etype now, because once N
729 -- is marked as not overloaded it is also expected to carry the
730 -- proper interpretation.
732 Set_Is_Overloaded (N, False);
733 Set_Entity (N, All_Interp.Table (First_Interp).Nam);
734 Set_Etype (N, All_Interp.Table (First_Interp).Typ);
742 function Covers (T1, T2 : Entity_Id) return Boolean is
747 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
748 -- In an instance the proper view may not always be correct for
749 -- private types, but private and full view are compatible. This
750 -- removes spurious errors from nested instantiations that involve,
751 -- among other things, types derived from private types.
753 ----------------------
754 -- Full_View_Covers --
755 ----------------------
757 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
760 Is_Private_Type (Typ1)
762 ((Present (Full_View (Typ1))
763 and then Covers (Full_View (Typ1), Typ2))
764 or else Base_Type (Typ1) = Typ2
765 or else Base_Type (Typ2) = Typ1);
766 end Full_View_Covers;
768 -- Start of processing for Covers
771 -- If either operand missing, then this is an error, but ignore it (and
772 -- pretend we have a cover) if errors already detected, since this may
773 -- simply mean we have malformed trees or a semantic error upstream.
775 if No (T1) or else No (T2) then
776 if Total_Errors_Detected /= 0 then
783 -- Trivial case: same types are always compatible
789 -- First check for Standard_Void_Type, which is special. Subsequent
790 -- processing in this routine assumes T1 and T2 are bona fide types;
791 -- Standard_Void_Type is a special entity that has some, but not all,
792 -- properties of types.
794 if (T1 = Standard_Void_Type) /= (T2 = Standard_Void_Type) then
798 BT1 := Base_Type (T1);
799 BT2 := Base_Type (T2);
801 -- Handle underlying view of records with unknown discriminants
802 -- using the original entity that motivated the construction of
803 -- this underlying record view (see Build_Derived_Private_Type).
805 if Is_Underlying_Record_View (BT1) then
806 BT1 := Underlying_Record_View (BT1);
809 if Is_Underlying_Record_View (BT2) then
810 BT2 := Underlying_Record_View (BT2);
813 -- Simplest case: types that have the same base type and are not generic
814 -- actuals are compatible. Generic actuals belong to their class but are
815 -- not compatible with other types of their class, and in particular
816 -- with other generic actuals. They are however compatible with their
817 -- own subtypes, and itypes with the same base are compatible as well.
818 -- Similarly, constrained subtypes obtained from expressions of an
819 -- unconstrained nominal type are compatible with the base type (may
820 -- lead to spurious ambiguities in obscure cases ???)
822 -- Generic actuals require special treatment to avoid spurious ambi-
823 -- guities in an instance, when two formal types are instantiated with
824 -- the same actual, so that different subprograms end up with the same
825 -- signature in the instance.
831 if not Is_Generic_Actual_Type (T1) then
834 return (not Is_Generic_Actual_Type (T2)
835 or else Is_Itype (T1)
836 or else Is_Itype (T2)
837 or else Is_Constr_Subt_For_U_Nominal (T1)
838 or else Is_Constr_Subt_For_U_Nominal (T2)
839 or else Scope (T1) /= Scope (T2));
842 -- Literals are compatible with types in a given "class"
844 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
845 or else (T2 = Universal_Real and then Is_Real_Type (T1))
846 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
847 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
848 or else (T2 = Any_String and then Is_String_Type (T1))
849 or else (T2 = Any_Character and then Is_Character_Type (T1))
850 or else (T2 = Any_Access and then Is_Access_Type (T1))
854 -- The context may be class wide, and a class-wide type is compatible
855 -- with any member of the class.
857 elsif Is_Class_Wide_Type (T1)
858 and then Is_Ancestor (Root_Type (T1), T2)
862 elsif Is_Class_Wide_Type (T1)
863 and then Is_Class_Wide_Type (T2)
864 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
868 -- Ada 2005 (AI-345): A class-wide abstract interface type covers a
869 -- task_type or protected_type that implements the interface.
871 elsif Ada_Version >= Ada_2005
872 and then Is_Class_Wide_Type (T1)
873 and then Is_Interface (Etype (T1))
874 and then Is_Concurrent_Type (T2)
875 and then Interface_Present_In_Ancestor
876 (Typ => BT2, Iface => Etype (T1))
880 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
881 -- object T2 implementing T1.
883 elsif Ada_Version >= Ada_2005
884 and then Is_Class_Wide_Type (T1)
885 and then Is_Interface (Etype (T1))
886 and then Is_Tagged_Type (T2)
888 if Interface_Present_In_Ancestor (Typ => T2,
899 if Is_Concurrent_Type (BT2) then
900 E := Corresponding_Record_Type (BT2);
905 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
906 -- covers an object T2 that implements a direct derivation of T1.
907 -- Note: test for presence of E is defense against previous error.
910 and then Present (Interfaces (E))
912 Elmt := First_Elmt (Interfaces (E));
913 while Present (Elmt) loop
914 if Is_Ancestor (Etype (T1), Node (Elmt)) then
922 -- We should also check the case in which T1 is an ancestor of
923 -- some implemented interface???
928 -- In a dispatching call, the formal is of some specific type, and the
929 -- actual is of the corresponding class-wide type, including a subtype
930 -- of the class-wide type.
932 elsif Is_Class_Wide_Type (T2)
934 (Class_Wide_Type (T1) = Class_Wide_Type (T2)
935 or else Base_Type (Root_Type (T2)) = BT1)
939 -- Some contexts require a class of types rather than a specific type.
940 -- For example, conditions require any boolean type, fixed point
941 -- attributes require some real type, etc. The built-in types Any_XXX
942 -- represent these classes.
944 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
945 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
946 or else (T1 = Any_Real and then Is_Real_Type (T2))
947 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
948 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
952 -- An aggregate is compatible with an array or record type
954 elsif T2 = Any_Composite
955 and then Is_Aggregate_Type (T1)
959 -- If the expected type is an anonymous access, the designated type must
960 -- cover that of the expression. Use the base type for this check: even
961 -- though access subtypes are rare in sources, they are generated for
962 -- actuals in instantiations.
964 elsif Ekind (BT1) = E_Anonymous_Access_Type
965 and then Is_Access_Type (T2)
966 and then Covers (Designated_Type (T1), Designated_Type (T2))
970 -- Ada 2012 (AI05-0149): Allow an anonymous access type in the context
971 -- of a named general access type. An implicit conversion will be
972 -- applied. For the resolution, one designated type must cover the
975 elsif Ada_Version >= Ada_2012
976 and then Ekind (BT1) = E_General_Access_Type
977 and then Ekind (BT2) = E_Anonymous_Access_Type
978 and then (Covers (Designated_Type (T1), Designated_Type (T2))
979 or else Covers (Designated_Type (T2), Designated_Type (T1)))
983 -- An Access_To_Subprogram is compatible with itself, or with an
984 -- anonymous type created for an attribute reference Access.
986 elsif (Ekind (BT1) = E_Access_Subprogram_Type
988 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
989 and then Is_Access_Type (T2)
990 and then (not Comes_From_Source (T1)
991 or else not Comes_From_Source (T2))
992 and then (Is_Overloadable (Designated_Type (T2))
994 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
996 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
998 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1002 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
1003 -- with itself, or with an anonymous type created for an attribute
1004 -- reference Access.
1006 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
1009 = E_Anonymous_Access_Protected_Subprogram_Type)
1010 and then Is_Access_Type (T2)
1011 and then (not Comes_From_Source (T1)
1012 or else not Comes_From_Source (T2))
1013 and then (Is_Overloadable (Designated_Type (T2))
1015 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
1017 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
1019 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1023 -- The context can be a remote access type, and the expression the
1024 -- corresponding source type declared in a categorized package, or
1027 elsif Is_Record_Type (T1)
1028 and then (Is_Remote_Call_Interface (T1)
1029 or else Is_Remote_Types (T1))
1030 and then Present (Corresponding_Remote_Type (T1))
1032 return Covers (Corresponding_Remote_Type (T1), T2);
1036 elsif Is_Record_Type (T2)
1037 and then (Is_Remote_Call_Interface (T2)
1038 or else Is_Remote_Types (T2))
1039 and then Present (Corresponding_Remote_Type (T2))
1041 return Covers (Corresponding_Remote_Type (T2), T1);
1043 -- Synchronized types are represented at run time by their corresponding
1044 -- record type. During expansion one is replaced with the other, but
1045 -- they are compatible views of the same type.
1047 elsif Is_Record_Type (T1)
1048 and then Is_Concurrent_Type (T2)
1049 and then Present (Corresponding_Record_Type (T2))
1051 return Covers (T1, Corresponding_Record_Type (T2));
1053 elsif Is_Concurrent_Type (T1)
1054 and then Present (Corresponding_Record_Type (T1))
1055 and then Is_Record_Type (T2)
1057 return Covers (Corresponding_Record_Type (T1), T2);
1059 -- During analysis, an attribute reference 'Access has a special type
1060 -- kind: Access_Attribute_Type, to be replaced eventually with the type
1061 -- imposed by context.
1063 elsif Ekind (T2) = E_Access_Attribute_Type
1064 and then Ekind_In (BT1, E_General_Access_Type, E_Access_Type)
1065 and then Covers (Designated_Type (T1), Designated_Type (T2))
1067 -- If the target type is a RACW type while the source is an access
1068 -- attribute type, we are building a RACW that may be exported.
1070 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
1071 Set_Has_RACW (Current_Sem_Unit);
1076 -- Ditto for allocators, which eventually resolve to the context type
1078 elsif Ekind (T2) = E_Allocator_Type
1079 and then Is_Access_Type (T1)
1081 return Covers (Designated_Type (T1), Designated_Type (T2))
1083 (From_With_Type (Designated_Type (T1))
1084 and then Covers (Designated_Type (T2), Designated_Type (T1)));
1086 -- A boolean operation on integer literals is compatible with modular
1089 elsif T2 = Any_Modular
1090 and then Is_Modular_Integer_Type (T1)
1094 -- The actual type may be the result of a previous error
1096 elsif BT2 = Any_Type then
1099 -- A packed array type covers its corresponding non-packed type. This is
1100 -- not legitimate Ada, but allows the omission of a number of otherwise
1101 -- useless unchecked conversions, and since this can only arise in
1102 -- (known correct) expanded code, no harm is done.
1104 elsif Is_Array_Type (T2)
1105 and then Is_Packed (T2)
1106 and then T1 = Packed_Array_Type (T2)
1110 -- Similarly an array type covers its corresponding packed array type
1112 elsif Is_Array_Type (T1)
1113 and then Is_Packed (T1)
1114 and then T2 = Packed_Array_Type (T1)
1118 -- In instances, or with types exported from instantiations, check
1119 -- whether a partial and a full view match. Verify that types are
1120 -- legal, to prevent cascaded errors.
1124 (Full_View_Covers (T1, T2)
1125 or else Full_View_Covers (T2, T1))
1130 and then Is_Generic_Actual_Type (T2)
1131 and then Full_View_Covers (T1, T2)
1136 and then Is_Generic_Actual_Type (T1)
1137 and then Full_View_Covers (T2, T1)
1141 -- In the expansion of inlined bodies, types are compatible if they
1142 -- are structurally equivalent.
1144 elsif In_Inlined_Body
1145 and then (Underlying_Type (T1) = Underlying_Type (T2)
1146 or else (Is_Access_Type (T1)
1147 and then Is_Access_Type (T2)
1149 Designated_Type (T1) = Designated_Type (T2))
1150 or else (T1 = Any_Access
1151 and then Is_Access_Type (Underlying_Type (T2)))
1152 or else (T2 = Any_Composite
1154 Is_Composite_Type (Underlying_Type (T1))))
1158 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1159 -- obtained through a limited_with compatible with its real entity.
1161 elsif From_With_Type (T1) then
1163 -- If the expected type is the non-limited view of a type, the
1164 -- expression may have the limited view. If that one in turn is
1165 -- incomplete, get full view if available.
1167 if Is_Incomplete_Type (T1) then
1168 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1170 elsif Ekind (T1) = E_Class_Wide_Type then
1172 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1177 elsif From_With_Type (T2) then
1179 -- If units in the context have Limited_With clauses on each other,
1180 -- either type might have a limited view. Checks performed elsewhere
1181 -- verify that the context type is the nonlimited view.
1183 if Is_Incomplete_Type (T2) then
1184 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1186 elsif Ekind (T2) = E_Class_Wide_Type then
1188 Present (Non_Limited_View (Etype (T2)))
1190 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1195 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1197 elsif Ekind (T1) = E_Incomplete_Subtype then
1198 return Covers (Full_View (Etype (T1)), T2);
1200 elsif Ekind (T2) = E_Incomplete_Subtype then
1201 return Covers (T1, Full_View (Etype (T2)));
1203 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1204 -- and actual anonymous access types in the context of generic
1205 -- instantiations. We have the following situation:
1208 -- type Formal is private;
1209 -- Formal_Obj : access Formal; -- T1
1213 -- type Actual is ...
1214 -- Actual_Obj : access Actual; -- T2
1215 -- package Instance is new G (Formal => Actual,
1216 -- Formal_Obj => Actual_Obj);
1218 elsif Ada_Version >= Ada_2005
1219 and then Ekind (T1) = E_Anonymous_Access_Type
1220 and then Ekind (T2) = E_Anonymous_Access_Type
1221 and then Is_Generic_Type (Directly_Designated_Type (T1))
1222 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1223 Directly_Designated_Type (T2)
1227 -- Otherwise, types are not compatible!
1238 function Disambiguate
1240 I1, I2 : Interp_Index;
1241 Typ : Entity_Id) return Interp
1246 Nam1, Nam2 : Entity_Id;
1247 Predef_Subp : Entity_Id;
1248 User_Subp : Entity_Id;
1250 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1251 -- Determine whether one of the candidates is an operation inherited by
1252 -- a type that is derived from an actual in an instantiation.
1254 function In_Same_Declaration_List
1256 Op_Decl : Entity_Id) return Boolean;
1257 -- AI05-0020: a spurious ambiguity may arise when equality on anonymous
1258 -- access types is declared on the partial view of a designated type, so
1259 -- that the type declaration and equality are not in the same list of
1260 -- declarations. This AI gives a preference rule for the user-defined
1261 -- operation. Same rule applies for arithmetic operations on private
1262 -- types completed with fixed-point types: the predefined operation is
1263 -- hidden; this is already handled properly in GNAT.
1265 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1266 -- Determine whether a subprogram is an actual in an enclosing instance.
1267 -- An overloading between such a subprogram and one declared outside the
1268 -- instance is resolved in favor of the first, because it resolved in
1271 function Matches (Actual, Formal : Node_Id) return Boolean;
1272 -- Look for exact type match in an instance, to remove spurious
1273 -- ambiguities when two formal types have the same actual.
1275 function Operand_Type return Entity_Id;
1276 -- Determine type of operand for an equality operation, to apply
1277 -- Ada 2005 rules to equality on anonymous access types.
1279 function Standard_Operator return Boolean;
1280 -- Check whether subprogram is predefined operator declared in Standard.
1281 -- It may given by an operator name, or by an expanded name whose prefix
1284 function Remove_Conversions return Interp;
1285 -- Last chance for pathological cases involving comparisons on literals,
1286 -- and user overloadings of the same operator. Such pathologies have
1287 -- been removed from the ACVC, but still appear in two DEC tests, with
1288 -- the following notable quote from Ben Brosgol:
1290 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1291 -- this example; Robert Dewar brought it to our attention, since it is
1292 -- apparently found in the ACVC 1.5. I did not attempt to find the
1293 -- reason in the Reference Manual that makes the example legal, since I
1294 -- was too nauseated by it to want to pursue it further.]
1296 -- Accordingly, this is not a fully recursive solution, but it handles
1297 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1298 -- pathology in the other direction with calls whose multiple overloaded
1299 -- actuals make them truly unresolvable.
1301 -- The new rules concerning abstract operations create additional need
1302 -- for special handling of expressions with universal operands, see
1303 -- comments to Has_Abstract_Interpretation below.
1305 ---------------------------
1306 -- Inherited_From_Actual --
1307 ---------------------------
1309 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1310 Par : constant Node_Id := Parent (S);
1312 if Nkind (Par) /= N_Full_Type_Declaration
1313 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1317 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1319 Is_Generic_Actual_Type (
1320 Entity (Subtype_Indication (Type_Definition (Par))));
1322 end Inherited_From_Actual;
1324 ------------------------------
1325 -- In_Same_Declaration_List --
1326 ------------------------------
1328 function In_Same_Declaration_List
1330 Op_Decl : Entity_Id) return Boolean
1332 Scop : constant Entity_Id := Scope (Typ);
1335 return In_Same_List (Parent (Typ), Op_Decl)
1337 (Ekind_In (Scop, E_Package, E_Generic_Package)
1338 and then List_Containing (Op_Decl) =
1339 Visible_Declarations (Parent (Scop))
1340 and then List_Containing (Parent (Typ)) =
1341 Private_Declarations (Parent (Scop)));
1342 end In_Same_Declaration_List;
1344 --------------------------
1345 -- Is_Actual_Subprogram --
1346 --------------------------
1348 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1350 return In_Open_Scopes (Scope (S))
1352 (Is_Generic_Instance (Scope (S))
1353 or else Is_Wrapper_Package (Scope (S)));
1354 end Is_Actual_Subprogram;
1360 function Matches (Actual, Formal : Node_Id) return Boolean is
1361 T1 : constant Entity_Id := Etype (Actual);
1362 T2 : constant Entity_Id := Etype (Formal);
1366 (Is_Numeric_Type (T2)
1367 and then (T1 = Universal_Real or else T1 = Universal_Integer));
1374 function Operand_Type return Entity_Id is
1378 if Nkind (N) = N_Function_Call then
1379 Opnd := First_Actual (N);
1381 Opnd := Left_Opnd (N);
1384 return Etype (Opnd);
1387 ------------------------
1388 -- Remove_Conversions --
1389 ------------------------
1391 function Remove_Conversions return Interp is
1399 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1400 -- If an operation has universal operands the universal operation
1401 -- is present among its interpretations. If there is an abstract
1402 -- interpretation for the operator, with a numeric result, this
1403 -- interpretation was already removed in sem_ch4, but the universal
1404 -- one is still visible. We must rescan the list of operators and
1405 -- remove the universal interpretation to resolve the ambiguity.
1407 ---------------------------------
1408 -- Has_Abstract_Interpretation --
1409 ---------------------------------
1411 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1415 if Nkind (N) not in N_Op
1416 or else Ada_Version < Ada_2005
1417 or else not Is_Overloaded (N)
1418 or else No (Universal_Interpretation (N))
1423 E := Get_Name_Entity_Id (Chars (N));
1424 while Present (E) loop
1425 if Is_Overloadable (E)
1426 and then Is_Abstract_Subprogram (E)
1427 and then Is_Numeric_Type (Etype (E))
1435 -- Finally, if an operand of the binary operator is itself
1436 -- an operator, recurse to see whether its own abstract
1437 -- interpretation is responsible for the spurious ambiguity.
1439 if Nkind (N) in N_Binary_Op then
1440 return Has_Abstract_Interpretation (Left_Opnd (N))
1441 or else Has_Abstract_Interpretation (Right_Opnd (N));
1443 elsif Nkind (N) in N_Unary_Op then
1444 return Has_Abstract_Interpretation (Right_Opnd (N));
1450 end Has_Abstract_Interpretation;
1452 -- Start of processing for Remove_Conversions
1457 Get_First_Interp (N, I, It);
1458 while Present (It.Typ) loop
1459 if not Is_Overloadable (It.Nam) then
1463 F1 := First_Formal (It.Nam);
1469 if Nkind (N) = N_Function_Call
1470 or else Nkind (N) = N_Procedure_Call_Statement
1472 Act1 := First_Actual (N);
1474 if Present (Act1) then
1475 Act2 := Next_Actual (Act1);
1480 elsif Nkind (N) in N_Unary_Op then
1481 Act1 := Right_Opnd (N);
1484 elsif Nkind (N) in N_Binary_Op then
1485 Act1 := Left_Opnd (N);
1486 Act2 := Right_Opnd (N);
1488 -- Use type of second formal, so as to include
1489 -- exponentiation, where the exponent may be
1490 -- ambiguous and the result non-universal.
1498 if Nkind (Act1) in N_Op
1499 and then Is_Overloaded (Act1)
1500 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1501 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1502 and then Has_Compatible_Type (Act1, Standard_Boolean)
1503 and then Etype (F1) = Standard_Boolean
1505 -- If the two candidates are the original ones, the
1506 -- ambiguity is real. Otherwise keep the original, further
1507 -- calls to Disambiguate will take care of others in the
1508 -- list of candidates.
1510 if It1 /= No_Interp then
1511 if It = Disambiguate.It1
1512 or else It = Disambiguate.It2
1514 if It1 = Disambiguate.It1
1515 or else It1 = Disambiguate.It2
1523 elsif Present (Act2)
1524 and then Nkind (Act2) in N_Op
1525 and then Is_Overloaded (Act2)
1526 and then Nkind_In (Right_Opnd (Act2), N_Integer_Literal,
1528 and then Has_Compatible_Type (Act2, Standard_Boolean)
1530 -- The preference rule on the first actual is not
1531 -- sufficient to disambiguate.
1539 elsif Is_Numeric_Type (Etype (F1))
1540 and then Has_Abstract_Interpretation (Act1)
1542 -- Current interpretation is not the right one because it
1543 -- expects a numeric operand. Examine all the other ones.
1550 Get_First_Interp (N, I, It);
1551 while Present (It.Typ) loop
1553 not Is_Numeric_Type (Etype (First_Formal (It.Nam)))
1556 or else not Has_Abstract_Interpretation (Act2)
1559 (Etype (Next_Formal (First_Formal (It.Nam))))
1565 Get_Next_Interp (I, It);
1574 Get_Next_Interp (I, It);
1577 -- After some error, a formal may have Any_Type and yield a spurious
1578 -- match. To avoid cascaded errors if possible, check for such a
1579 -- formal in either candidate.
1581 if Serious_Errors_Detected > 0 then
1586 Formal := First_Formal (Nam1);
1587 while Present (Formal) loop
1588 if Etype (Formal) = Any_Type then
1589 return Disambiguate.It2;
1592 Next_Formal (Formal);
1595 Formal := First_Formal (Nam2);
1596 while Present (Formal) loop
1597 if Etype (Formal) = Any_Type then
1598 return Disambiguate.It1;
1601 Next_Formal (Formal);
1607 end Remove_Conversions;
1609 -----------------------
1610 -- Standard_Operator --
1611 -----------------------
1613 function Standard_Operator return Boolean is
1617 if Nkind (N) in N_Op then
1620 elsif Nkind (N) = N_Function_Call then
1623 if Nkind (Nam) /= N_Expanded_Name then
1626 return Entity (Prefix (Nam)) = Standard_Standard;
1631 end Standard_Operator;
1633 -- Start of processing for Disambiguate
1636 -- Recover the two legal interpretations
1638 Get_First_Interp (N, I, It);
1640 Get_Next_Interp (I, It);
1646 Get_Next_Interp (I, It);
1652 -- Check whether one of the entities is an Ada 2005/2012 and we are
1653 -- operating in an earlier mode, in which case we discard the Ada
1654 -- 2005/2012 entity, so that we get proper Ada 95 overload resolution.
1656 if Ada_Version < Ada_2005 then
1657 if Is_Ada_2005_Only (Nam1) or else Is_Ada_2012_Only (Nam1) then
1659 elsif Is_Ada_2005_Only (Nam2) or else Is_Ada_2012_Only (Nam1) then
1664 -- Check whether one of the entities is an Ada 2012 entity and we are
1665 -- operating in Ada 2005 mode, in which case we discard the Ada 2012
1666 -- entity, so that we get proper Ada 2005 overload resolution.
1668 if Ada_Version = Ada_2005 then
1669 if Is_Ada_2012_Only (Nam1) then
1671 elsif Is_Ada_2012_Only (Nam2) then
1676 -- Check for overloaded CIL convention stuff because the CIL libraries
1677 -- do sick things like Console.Write_Line where it matches two different
1678 -- overloads, so just pick the first ???
1680 if Convention (Nam1) = Convention_CIL
1681 and then Convention (Nam2) = Convention_CIL
1682 and then Ekind (Nam1) = Ekind (Nam2)
1683 and then (Ekind (Nam1) = E_Procedure
1684 or else Ekind (Nam1) = E_Function)
1689 -- If the context is universal, the predefined operator is preferred.
1690 -- This includes bounds in numeric type declarations, and expressions
1691 -- in type conversions. If no interpretation yields a universal type,
1692 -- then we must check whether the user-defined entity hides the prede-
1695 if Chars (Nam1) in Any_Operator_Name
1696 and then Standard_Operator
1698 if Typ = Universal_Integer
1699 or else Typ = Universal_Real
1700 or else Typ = Any_Integer
1701 or else Typ = Any_Discrete
1702 or else Typ = Any_Real
1703 or else Typ = Any_Type
1705 -- Find an interpretation that yields the universal type, or else
1706 -- a predefined operator that yields a predefined numeric type.
1709 Candidate : Interp := No_Interp;
1712 Get_First_Interp (N, I, It);
1713 while Present (It.Typ) loop
1714 if (Covers (Typ, It.Typ)
1715 or else Typ = Any_Type)
1717 (It.Typ = Universal_Integer
1718 or else It.Typ = Universal_Real)
1722 elsif Covers (Typ, It.Typ)
1723 and then Scope (It.Typ) = Standard_Standard
1724 and then Scope (It.Nam) = Standard_Standard
1725 and then Is_Numeric_Type (It.Typ)
1730 Get_Next_Interp (I, It);
1733 if Candidate /= No_Interp then
1738 elsif Chars (Nam1) /= Name_Op_Not
1739 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1741 -- Equality or comparison operation. Choose predefined operator if
1742 -- arguments are universal. The node may be an operator, name, or
1743 -- a function call, so unpack arguments accordingly.
1746 Arg1, Arg2 : Node_Id;
1749 if Nkind (N) in N_Op then
1750 Arg1 := Left_Opnd (N);
1751 Arg2 := Right_Opnd (N);
1753 elsif Is_Entity_Name (N) then
1754 Arg1 := First_Entity (Entity (N));
1755 Arg2 := Next_Entity (Arg1);
1758 Arg1 := First_Actual (N);
1759 Arg2 := Next_Actual (Arg1);
1763 and then Present (Universal_Interpretation (Arg1))
1764 and then Universal_Interpretation (Arg2) =
1765 Universal_Interpretation (Arg1)
1767 Get_First_Interp (N, I, It);
1768 while Scope (It.Nam) /= Standard_Standard loop
1769 Get_Next_Interp (I, It);
1778 -- If no universal interpretation, check whether user-defined operator
1779 -- hides predefined one, as well as other special cases. If the node
1780 -- is a range, then one or both bounds are ambiguous. Each will have
1781 -- to be disambiguated w.r.t. the context type. The type of the range
1782 -- itself is imposed by the context, so we can return either legal
1785 if Ekind (Nam1) = E_Operator then
1786 Predef_Subp := Nam1;
1789 elsif Ekind (Nam2) = E_Operator then
1790 Predef_Subp := Nam2;
1793 elsif Nkind (N) = N_Range then
1796 -- Implement AI05-105: A renaming declaration with an access
1797 -- definition must resolve to an anonymous access type. This
1798 -- is a resolution rule and can be used to disambiguate.
1800 elsif Nkind (Parent (N)) = N_Object_Renaming_Declaration
1801 and then Present (Access_Definition (Parent (N)))
1803 if Ekind_In (It1.Typ, E_Anonymous_Access_Type,
1804 E_Anonymous_Access_Subprogram_Type)
1806 if Ekind (It2.Typ) = Ekind (It1.Typ) then
1816 elsif Ekind_In (It2.Typ, E_Anonymous_Access_Type,
1817 E_Anonymous_Access_Subprogram_Type)
1821 -- No legal interpretation
1827 -- If two user defined-subprograms are visible, it is a true ambiguity,
1828 -- unless one of them is an entry and the context is a conditional or
1829 -- timed entry call, or unless we are within an instance and this is
1830 -- results from two formals types with the same actual.
1833 if Nkind (N) = N_Procedure_Call_Statement
1834 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1835 and then N = Entry_Call_Statement (Parent (N))
1837 if Ekind (Nam2) = E_Entry then
1839 elsif Ekind (Nam1) = E_Entry then
1845 -- If the ambiguity occurs within an instance, it is due to several
1846 -- formal types with the same actual. Look for an exact match between
1847 -- the types of the formals of the overloadable entities, and the
1848 -- actuals in the call, to recover the unambiguous match in the
1849 -- original generic.
1851 -- The ambiguity can also be due to an overloading between a formal
1852 -- subprogram and a subprogram declared outside the generic. If the
1853 -- node is overloaded, it did not resolve to the global entity in
1854 -- the generic, and we choose the formal subprogram.
1856 -- Finally, the ambiguity can be between an explicit subprogram and
1857 -- one inherited (with different defaults) from an actual. In this
1858 -- case the resolution was to the explicit declaration in the
1859 -- generic, and remains so in the instance.
1861 -- The same sort of disambiguation needed for calls is also required
1862 -- for the name given in a subprogram renaming, and that case is
1863 -- handled here as well. We test Comes_From_Source to exclude this
1864 -- treatment for implicit renamings created for formal subprograms.
1867 and then not In_Generic_Actual (N)
1869 if Nkind (N) = N_Function_Call
1870 or else Nkind (N) = N_Procedure_Call_Statement
1872 (Nkind (N) in N_Has_Entity
1874 Nkind (Parent (N)) = N_Subprogram_Renaming_Declaration
1875 and then Comes_From_Source (Parent (N)))
1880 Renam : Entity_Id := Empty;
1881 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1882 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1885 if Is_Act1 and then not Is_Act2 then
1888 elsif Is_Act2 and then not Is_Act1 then
1891 elsif Inherited_From_Actual (Nam1)
1892 and then Comes_From_Source (Nam2)
1896 elsif Inherited_From_Actual (Nam2)
1897 and then Comes_From_Source (Nam1)
1902 -- In the case of a renamed subprogram, pick up the entity
1903 -- of the renaming declaration so we can traverse its
1904 -- formal parameters.
1906 if Nkind (N) in N_Has_Entity then
1907 Renam := Defining_Unit_Name (Specification (Parent (N)));
1910 if Present (Renam) then
1911 Actual := First_Formal (Renam);
1913 Actual := First_Actual (N);
1916 Formal := First_Formal (Nam1);
1917 while Present (Actual) loop
1918 if Etype (Actual) /= Etype (Formal) then
1922 if Present (Renam) then
1923 Next_Formal (Actual);
1925 Next_Actual (Actual);
1928 Next_Formal (Formal);
1934 elsif Nkind (N) in N_Binary_Op then
1935 if Matches (Left_Opnd (N), First_Formal (Nam1))
1937 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1944 elsif Nkind (N) in N_Unary_Op then
1945 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1952 return Remove_Conversions;
1955 return Remove_Conversions;
1959 -- An implicit concatenation operator on a string type cannot be
1960 -- disambiguated from the predefined concatenation. This can only
1961 -- happen with concatenation of string literals.
1963 if Chars (User_Subp) = Name_Op_Concat
1964 and then Ekind (User_Subp) = E_Operator
1965 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1969 -- If the user-defined operator is in an open scope, or in the scope
1970 -- of the resulting type, or given by an expanded name that names its
1971 -- scope, it hides the predefined operator for the type. Exponentiation
1972 -- has to be special-cased because the implicit operator does not have
1973 -- a symmetric signature, and may not be hidden by the explicit one.
1975 elsif (Nkind (N) = N_Function_Call
1976 and then Nkind (Name (N)) = N_Expanded_Name
1977 and then (Chars (Predef_Subp) /= Name_Op_Expon
1978 or else Hides_Op (User_Subp, Predef_Subp))
1979 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1980 or else Hides_Op (User_Subp, Predef_Subp)
1982 if It1.Nam = User_Subp then
1988 -- Otherwise, the predefined operator has precedence, or if the user-
1989 -- defined operation is directly visible we have a true ambiguity.
1991 -- If this is a fixed-point multiplication and division in Ada 83 mode,
1992 -- exclude the universal_fixed operator, which often causes ambiguities
1995 -- Ditto in Ada 2012, where an ambiguity may arise for an operation
1996 -- on a partial view that is completed with a fixed point type. See
1997 -- AI05-0020 and AI05-0209. The ambiguity is resolved in favor of the
1998 -- user-defined subprogram so that a client of the package has the
1999 -- same resulution as the body of the package.
2002 if (In_Open_Scopes (Scope (User_Subp))
2003 or else Is_Potentially_Use_Visible (User_Subp))
2004 and then not In_Instance
2006 if Is_Fixed_Point_Type (Typ)
2007 and then (Chars (Nam1) = Name_Op_Multiply
2008 or else Chars (Nam1) = Name_Op_Divide)
2010 (Ada_Version = Ada_83
2012 (Ada_Version >= Ada_2012
2014 In_Same_Declaration_List
2015 (Typ, Unit_Declaration_Node (User_Subp))))
2017 if It2.Nam = Predef_Subp then
2023 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
2024 -- states that the operator defined in Standard is not available
2025 -- if there is a user-defined equality with the proper signature,
2026 -- declared in the same declarative list as the type. The node
2027 -- may be an operator or a function call.
2029 elsif (Chars (Nam1) = Name_Op_Eq
2031 Chars (Nam1) = Name_Op_Ne)
2032 and then Ada_Version >= Ada_2005
2033 and then Etype (User_Subp) = Standard_Boolean
2034 and then Ekind (Operand_Type) = E_Anonymous_Access_Type
2036 In_Same_Declaration_List
2037 (Designated_Type (Operand_Type),
2038 Unit_Declaration_Node (User_Subp))
2040 if It2.Nam = Predef_Subp then
2046 -- An immediately visible operator hides a use-visible user-
2047 -- defined operation. This disambiguation cannot take place
2048 -- earlier because the visibility of the predefined operator
2049 -- can only be established when operand types are known.
2051 elsif Ekind (User_Subp) = E_Function
2052 and then Ekind (Predef_Subp) = E_Operator
2053 and then Nkind (N) in N_Op
2054 and then not Is_Overloaded (Right_Opnd (N))
2056 Is_Immediately_Visible (Base_Type (Etype (Right_Opnd (N))))
2057 and then Is_Potentially_Use_Visible (User_Subp)
2059 if It2.Nam = Predef_Subp then
2069 elsif It1.Nam = Predef_Subp then
2078 ---------------------
2079 -- End_Interp_List --
2080 ---------------------
2082 procedure End_Interp_List is
2084 All_Interp.Table (All_Interp.Last) := No_Interp;
2085 All_Interp.Increment_Last;
2086 end End_Interp_List;
2088 -------------------------
2089 -- Entity_Matches_Spec --
2090 -------------------------
2092 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
2094 -- Simple case: same entity kinds, type conformance is required. A
2095 -- parameterless function can also rename a literal.
2097 if Ekind (Old_S) = Ekind (New_S)
2098 or else (Ekind (New_S) = E_Function
2099 and then Ekind (Old_S) = E_Enumeration_Literal)
2101 return Type_Conformant (New_S, Old_S);
2103 elsif Ekind (New_S) = E_Function
2104 and then Ekind (Old_S) = E_Operator
2106 return Operator_Matches_Spec (Old_S, New_S);
2108 elsif Ekind (New_S) = E_Procedure
2109 and then Is_Entry (Old_S)
2111 return Type_Conformant (New_S, Old_S);
2116 end Entity_Matches_Spec;
2118 ----------------------
2119 -- Find_Unique_Type --
2120 ----------------------
2122 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
2123 T : constant Entity_Id := Etype (L);
2126 TR : Entity_Id := Any_Type;
2129 if Is_Overloaded (R) then
2130 Get_First_Interp (R, I, It);
2131 while Present (It.Typ) loop
2132 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
2134 -- If several interpretations are possible and L is universal,
2135 -- apply preference rule.
2137 if TR /= Any_Type then
2139 if (T = Universal_Integer or else T = Universal_Real)
2150 Get_Next_Interp (I, It);
2155 -- In the non-overloaded case, the Etype of R is already set correctly
2161 -- If one of the operands is Universal_Fixed, the type of the other
2162 -- operand provides the context.
2164 if Etype (R) = Universal_Fixed then
2167 elsif T = Universal_Fixed then
2170 -- Ada 2005 (AI-230): Support the following operators:
2172 -- function "=" (L, R : universal_access) return Boolean;
2173 -- function "/=" (L, R : universal_access) return Boolean;
2175 -- Pool specific access types (E_Access_Type) are not covered by these
2176 -- operators because of the legality rule of 4.5.2(9.2): "The operands
2177 -- of the equality operators for universal_access shall be convertible
2178 -- to one another (see 4.6)". For example, considering the type decla-
2179 -- ration "type P is access Integer" and an anonymous access to Integer,
2180 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
2181 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
2183 elsif Ada_Version >= Ada_2005
2185 (Ekind (Etype (L)) = E_Anonymous_Access_Type
2187 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
2188 and then Is_Access_Type (Etype (R))
2189 and then Ekind (Etype (R)) /= E_Access_Type
2193 elsif Ada_Version >= Ada_2005
2195 (Ekind (Etype (R)) = E_Anonymous_Access_Type
2196 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
2197 and then Is_Access_Type (Etype (L))
2198 and then Ekind (Etype (L)) /= E_Access_Type
2203 return Specific_Type (T, Etype (R));
2205 end Find_Unique_Type;
2207 -------------------------------------
2208 -- Function_Interp_Has_Abstract_Op --
2209 -------------------------------------
2211 function Function_Interp_Has_Abstract_Op
2213 E : Entity_Id) return Entity_Id
2215 Abstr_Op : Entity_Id;
2218 Form_Parm : Node_Id;
2221 -- Why is check on E needed below ???
2222 -- In any case this para needs comments ???
2224 if Is_Overloaded (N) and then Is_Overloadable (E) then
2225 Act_Parm := First_Actual (N);
2226 Form_Parm := First_Formal (E);
2227 while Present (Act_Parm)
2228 and then Present (Form_Parm)
2232 if Nkind (Act) = N_Parameter_Association then
2233 Act := Explicit_Actual_Parameter (Act);
2236 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2238 if Present (Abstr_Op) then
2242 Next_Actual (Act_Parm);
2243 Next_Formal (Form_Parm);
2248 end Function_Interp_Has_Abstract_Op;
2250 ----------------------
2251 -- Get_First_Interp --
2252 ----------------------
2254 procedure Get_First_Interp
2256 I : out Interp_Index;
2259 Int_Ind : Interp_Index;
2264 -- If a selected component is overloaded because the selector has
2265 -- multiple interpretations, the node is a call to a protected
2266 -- operation or an indirect call. Retrieve the interpretation from
2267 -- the selector name. The selected component may be overloaded as well
2268 -- if the prefix is overloaded. That case is unchanged.
2270 if Nkind (N) = N_Selected_Component
2271 and then Is_Overloaded (Selector_Name (N))
2273 O_N := Selector_Name (N);
2278 Map_Ptr := Headers (Hash (O_N));
2279 while Map_Ptr /= No_Entry loop
2280 if Interp_Map.Table (Map_Ptr).Node = O_N then
2281 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2282 It := All_Interp.Table (Int_Ind);
2286 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2290 -- Procedure should never be called if the node has no interpretations
2292 raise Program_Error;
2293 end Get_First_Interp;
2295 ---------------------
2296 -- Get_Next_Interp --
2297 ---------------------
2299 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2302 It := All_Interp.Table (I);
2303 end Get_Next_Interp;
2305 -------------------------
2306 -- Has_Compatible_Type --
2307 -------------------------
2309 function Has_Compatible_Type
2311 Typ : Entity_Id) return Boolean
2321 if Nkind (N) = N_Subtype_Indication
2322 or else not Is_Overloaded (N)
2325 Covers (Typ, Etype (N))
2327 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2328 -- If the type is already frozen use the corresponding_record
2329 -- to check whether it is a proper descendant.
2332 (Is_Record_Type (Typ)
2333 and then Is_Concurrent_Type (Etype (N))
2334 and then Present (Corresponding_Record_Type (Etype (N)))
2335 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2338 (Is_Concurrent_Type (Typ)
2339 and then Is_Record_Type (Etype (N))
2340 and then Present (Corresponding_Record_Type (Typ))
2341 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2344 (not Is_Tagged_Type (Typ)
2345 and then Ekind (Typ) /= E_Anonymous_Access_Type
2346 and then Covers (Etype (N), Typ));
2349 Get_First_Interp (N, I, It);
2350 while Present (It.Typ) loop
2351 if (Covers (Typ, It.Typ)
2353 (Scope (It.Nam) /= Standard_Standard
2354 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2356 -- Ada 2005 (AI-345)
2359 (Is_Concurrent_Type (It.Typ)
2360 and then Present (Corresponding_Record_Type
2362 and then Covers (Typ, Corresponding_Record_Type
2365 or else (not Is_Tagged_Type (Typ)
2366 and then Ekind (Typ) /= E_Anonymous_Access_Type
2367 and then Covers (It.Typ, Typ))
2372 Get_Next_Interp (I, It);
2377 end Has_Compatible_Type;
2379 ---------------------
2380 -- Has_Abstract_Op --
2381 ---------------------
2383 function Has_Abstract_Op
2385 Typ : Entity_Id) return Entity_Id
2391 if Is_Overloaded (N) then
2392 Get_First_Interp (N, I, It);
2393 while Present (It.Nam) loop
2394 if Present (It.Abstract_Op)
2395 and then Etype (It.Abstract_Op) = Typ
2397 return It.Abstract_Op;
2400 Get_Next_Interp (I, It);
2405 end Has_Abstract_Op;
2411 function Hash (N : Node_Id) return Int is
2413 -- Nodes have a size that is power of two, so to select significant
2414 -- bits only we remove the low-order bits.
2416 return ((Int (N) / 2 ** 5) mod Header_Size);
2423 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2424 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2426 return Operator_Matches_Spec (Op, F)
2427 and then (In_Open_Scopes (Scope (F))
2428 or else Scope (F) = Scope (Btyp)
2429 or else (not In_Open_Scopes (Scope (Btyp))
2430 and then not In_Use (Btyp)
2431 and then not In_Use (Scope (Btyp))));
2434 ------------------------
2435 -- Init_Interp_Tables --
2436 ------------------------
2438 procedure Init_Interp_Tables is
2442 Headers := (others => No_Entry);
2443 end Init_Interp_Tables;
2445 -----------------------------------
2446 -- Interface_Present_In_Ancestor --
2447 -----------------------------------
2449 function Interface_Present_In_Ancestor
2451 Iface : Entity_Id) return Boolean
2453 Target_Typ : Entity_Id;
2454 Iface_Typ : Entity_Id;
2456 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2457 -- Returns True if Typ or some ancestor of Typ implements Iface
2459 -------------------------------
2460 -- Iface_Present_In_Ancestor --
2461 -------------------------------
2463 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2469 if Typ = Iface_Typ then
2473 -- Handle private types
2475 if Present (Full_View (Typ))
2476 and then not Is_Concurrent_Type (Full_View (Typ))
2478 E := Full_View (Typ);
2484 if Present (Interfaces (E))
2485 and then Present (Interfaces (E))
2486 and then not Is_Empty_Elmt_List (Interfaces (E))
2488 Elmt := First_Elmt (Interfaces (E));
2489 while Present (Elmt) loop
2492 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2500 exit when Etype (E) = E
2502 -- Handle private types
2504 or else (Present (Full_View (Etype (E)))
2505 and then Full_View (Etype (E)) = E);
2507 -- Check if the current type is a direct derivation of the
2510 if Etype (E) = Iface_Typ then
2514 -- Climb to the immediate ancestor handling private types
2516 if Present (Full_View (Etype (E))) then
2517 E := Full_View (Etype (E));
2524 end Iface_Present_In_Ancestor;
2526 -- Start of processing for Interface_Present_In_Ancestor
2529 -- Iface might be a class-wide subtype, so we have to apply Base_Type
2531 if Is_Class_Wide_Type (Iface) then
2532 Iface_Typ := Etype (Base_Type (Iface));
2539 Iface_Typ := Base_Type (Iface_Typ);
2541 if Is_Access_Type (Typ) then
2542 Target_Typ := Etype (Directly_Designated_Type (Typ));
2547 if Is_Concurrent_Record_Type (Target_Typ) then
2548 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2551 Target_Typ := Base_Type (Target_Typ);
2553 -- In case of concurrent types we can't use the Corresponding Record_Typ
2554 -- to look for the interface because it is built by the expander (and
2555 -- hence it is not always available). For this reason we traverse the
2556 -- list of interfaces (available in the parent of the concurrent type)
2558 if Is_Concurrent_Type (Target_Typ) then
2559 if Present (Interface_List (Parent (Target_Typ))) then
2564 AI := First (Interface_List (Parent (Target_Typ)));
2565 while Present (AI) loop
2566 if Etype (AI) = Iface_Typ then
2569 elsif Present (Interfaces (Etype (AI)))
2570 and then Iface_Present_In_Ancestor (Etype (AI))
2583 if Is_Class_Wide_Type (Target_Typ) then
2584 Target_Typ := Etype (Target_Typ);
2587 if Ekind (Target_Typ) = E_Incomplete_Type then
2588 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2589 Target_Typ := Non_Limited_View (Target_Typ);
2591 -- Protect the frontend against previously detected errors
2593 if Ekind (Target_Typ) = E_Incomplete_Type then
2598 return Iface_Present_In_Ancestor (Target_Typ);
2599 end Interface_Present_In_Ancestor;
2601 ---------------------
2602 -- Intersect_Types --
2603 ---------------------
2605 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2606 Index : Interp_Index;
2610 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2611 -- Find interpretation of right arg that has type compatible with T
2613 --------------------------
2614 -- Check_Right_Argument --
2615 --------------------------
2617 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2618 Index : Interp_Index;
2623 if not Is_Overloaded (R) then
2624 return Specific_Type (T, Etype (R));
2627 Get_First_Interp (R, Index, It);
2629 T2 := Specific_Type (T, It.Typ);
2631 if T2 /= Any_Type then
2635 Get_Next_Interp (Index, It);
2636 exit when No (It.Typ);
2641 end Check_Right_Argument;
2643 -- Start of processing for Intersect_Types
2646 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2650 if not Is_Overloaded (L) then
2651 Typ := Check_Right_Argument (Etype (L));
2655 Get_First_Interp (L, Index, It);
2656 while Present (It.Typ) loop
2657 Typ := Check_Right_Argument (It.Typ);
2658 exit when Typ /= Any_Type;
2659 Get_Next_Interp (Index, It);
2664 -- If Typ is Any_Type, it means no compatible pair of types was found
2666 if Typ = Any_Type then
2667 if Nkind (Parent (L)) in N_Op then
2668 Error_Msg_N ("incompatible types for operator", Parent (L));
2670 elsif Nkind (Parent (L)) = N_Range then
2671 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2673 -- Ada 2005 (AI-251): Complete the error notification
2675 elsif Is_Class_Wide_Type (Etype (R))
2676 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2678 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2679 L, Etype (Class_Wide_Type (Etype (R))));
2682 Error_Msg_N ("incompatible types", Parent (L));
2687 end Intersect_Types;
2689 -----------------------
2690 -- In_Generic_Actual --
2691 -----------------------
2693 function In_Generic_Actual (Exp : Node_Id) return Boolean is
2694 Par : constant Node_Id := Parent (Exp);
2700 elsif Nkind (Par) in N_Declaration then
2701 if Nkind (Par) = N_Object_Declaration then
2702 return Present (Corresponding_Generic_Association (Par));
2707 elsif Nkind (Par) = N_Object_Renaming_Declaration then
2708 return Present (Corresponding_Generic_Association (Par));
2710 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
2714 return In_Generic_Actual (Parent (Par));
2716 end In_Generic_Actual;
2722 function Is_Ancestor
2725 Use_Full_View : Boolean := False) return Boolean
2732 BT1 := Base_Type (T1);
2733 BT2 := Base_Type (T2);
2735 -- Handle underlying view of records with unknown discriminants using
2736 -- the original entity that motivated the construction of this
2737 -- underlying record view (see Build_Derived_Private_Type).
2739 if Is_Underlying_Record_View (BT1) then
2740 BT1 := Underlying_Record_View (BT1);
2743 if Is_Underlying_Record_View (BT2) then
2744 BT2 := Underlying_Record_View (BT2);
2750 -- The predicate must look past privacy
2752 elsif Is_Private_Type (T1)
2753 and then Present (Full_View (T1))
2754 and then BT2 = Base_Type (Full_View (T1))
2758 elsif Is_Private_Type (T2)
2759 and then Present (Full_View (T2))
2760 and then BT1 = Base_Type (Full_View (T2))
2765 -- Obtain the parent of the base type of T2 (use the full view if
2769 and then Is_Private_Type (BT2)
2770 and then Present (Full_View (BT2))
2772 -- No climbing needed if its full view is the root type
2774 if Full_View (BT2) = Root_Type (Full_View (BT2)) then
2778 Par := Etype (Full_View (BT2));
2785 -- If there was a error on the type declaration, do not recurse
2787 if Error_Posted (Par) then
2790 elsif BT1 = Base_Type (Par)
2791 or else (Is_Private_Type (T1)
2792 and then Present (Full_View (T1))
2793 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2797 elsif Is_Private_Type (Par)
2798 and then Present (Full_View (Par))
2799 and then Full_View (Par) = BT1
2805 elsif Par = Root_Type (Par) then
2808 -- Continue climbing
2811 -- Use the full-view of private types (if allowed)
2814 and then Is_Private_Type (Par)
2815 and then Present (Full_View (Par))
2817 Par := Etype (Full_View (Par));
2826 ---------------------------
2827 -- Is_Invisible_Operator --
2828 ---------------------------
2830 function Is_Invisible_Operator
2832 T : Entity_Id) return Boolean
2834 Orig_Node : constant Node_Id := Original_Node (N);
2837 if Nkind (N) not in N_Op then
2840 elsif not Comes_From_Source (N) then
2843 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2846 elsif Nkind (N) in N_Binary_Op
2847 and then No (Universal_Interpretation (Left_Opnd (N)))
2852 return Is_Numeric_Type (T)
2853 and then not In_Open_Scopes (Scope (T))
2854 and then not Is_Potentially_Use_Visible (T)
2855 and then not In_Use (T)
2856 and then not In_Use (Scope (T))
2858 (Nkind (Orig_Node) /= N_Function_Call
2859 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2860 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2861 and then not In_Instance;
2863 end Is_Invisible_Operator;
2865 --------------------
2867 --------------------
2869 function Is_Progenitor
2871 Typ : Entity_Id) return Boolean
2874 return Implements_Interface (Typ, Iface, Exclude_Parents => True);
2881 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2885 S := Ancestor_Subtype (T1);
2886 while Present (S) loop
2890 S := Ancestor_Subtype (S);
2901 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2902 Index : Interp_Index;
2906 Get_First_Interp (Nam, Index, It);
2907 while Present (It.Nam) loop
2908 if Scope (It.Nam) = Standard_Standard
2909 and then Scope (It.Typ) /= Standard_Standard
2911 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2912 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2915 Error_Msg_Sloc := Sloc (It.Nam);
2916 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2919 Get_Next_Interp (Index, It);
2927 procedure New_Interps (N : Node_Id) is
2931 All_Interp.Append (No_Interp);
2933 Map_Ptr := Headers (Hash (N));
2935 if Map_Ptr = No_Entry then
2937 -- Place new node at end of table
2939 Interp_Map.Increment_Last;
2940 Headers (Hash (N)) := Interp_Map.Last;
2943 -- Place node at end of chain, or locate its previous entry
2946 if Interp_Map.Table (Map_Ptr).Node = N then
2948 -- Node is already in the table, and is being rewritten.
2949 -- Start a new interp section, retain hash link.
2951 Interp_Map.Table (Map_Ptr).Node := N;
2952 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2953 Set_Is_Overloaded (N, True);
2957 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2958 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2962 -- Chain the new node
2964 Interp_Map.Increment_Last;
2965 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2968 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2969 Set_Is_Overloaded (N, True);
2972 ---------------------------
2973 -- Operator_Matches_Spec --
2974 ---------------------------
2976 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2977 Op_Name : constant Name_Id := Chars (Op);
2978 T : constant Entity_Id := Etype (New_S);
2986 -- To verify that a predefined operator matches a given signature,
2987 -- do a case analysis of the operator classes. Function can have one
2988 -- or two formals and must have the proper result type.
2990 New_F := First_Formal (New_S);
2991 Old_F := First_Formal (Op);
2993 while Present (New_F) and then Present (Old_F) loop
2995 Next_Formal (New_F);
2996 Next_Formal (Old_F);
2999 -- Definite mismatch if different number of parameters
3001 if Present (Old_F) or else Present (New_F) then
3007 T1 := Etype (First_Formal (New_S));
3009 if Op_Name = Name_Op_Subtract
3010 or else Op_Name = Name_Op_Add
3011 or else Op_Name = Name_Op_Abs
3013 return Base_Type (T1) = Base_Type (T)
3014 and then Is_Numeric_Type (T);
3016 elsif Op_Name = Name_Op_Not then
3017 return Base_Type (T1) = Base_Type (T)
3018 and then Valid_Boolean_Arg (Base_Type (T));
3027 T1 := Etype (First_Formal (New_S));
3028 T2 := Etype (Next_Formal (First_Formal (New_S)));
3030 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
3031 or else Op_Name = Name_Op_Xor
3033 return Base_Type (T1) = Base_Type (T2)
3034 and then Base_Type (T1) = Base_Type (T)
3035 and then Valid_Boolean_Arg (Base_Type (T));
3037 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
3038 return Base_Type (T1) = Base_Type (T2)
3039 and then not Is_Limited_Type (T1)
3040 and then Is_Boolean_Type (T);
3042 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
3043 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
3045 return Base_Type (T1) = Base_Type (T2)
3046 and then Valid_Comparison_Arg (T1)
3047 and then Is_Boolean_Type (T);
3049 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
3050 return Base_Type (T1) = Base_Type (T2)
3051 and then Base_Type (T1) = Base_Type (T)
3052 and then Is_Numeric_Type (T);
3054 -- For division and multiplication, a user-defined function does not
3055 -- match the predefined universal_fixed operation, except in Ada 83.
3057 elsif Op_Name = Name_Op_Divide then
3058 return (Base_Type (T1) = Base_Type (T2)
3059 and then Base_Type (T1) = Base_Type (T)
3060 and then Is_Numeric_Type (T)
3061 and then (not Is_Fixed_Point_Type (T)
3062 or else Ada_Version = Ada_83))
3064 -- Mixed_Mode operations on fixed-point types
3066 or else (Base_Type (T1) = Base_Type (T)
3067 and then Base_Type (T2) = Base_Type (Standard_Integer)
3068 and then Is_Fixed_Point_Type (T))
3070 -- A user defined operator can also match (and hide) a mixed
3071 -- operation on universal literals.
3073 or else (Is_Integer_Type (T2)
3074 and then Is_Floating_Point_Type (T1)
3075 and then Base_Type (T1) = Base_Type (T));
3077 elsif Op_Name = Name_Op_Multiply then
3078 return (Base_Type (T1) = Base_Type (T2)
3079 and then Base_Type (T1) = Base_Type (T)
3080 and then Is_Numeric_Type (T)
3081 and then (not Is_Fixed_Point_Type (T)
3082 or else Ada_Version = Ada_83))
3084 -- Mixed_Mode operations on fixed-point types
3086 or else (Base_Type (T1) = Base_Type (T)
3087 and then Base_Type (T2) = Base_Type (Standard_Integer)
3088 and then Is_Fixed_Point_Type (T))
3090 or else (Base_Type (T2) = Base_Type (T)
3091 and then Base_Type (T1) = Base_Type (Standard_Integer)
3092 and then Is_Fixed_Point_Type (T))
3094 or else (Is_Integer_Type (T2)
3095 and then Is_Floating_Point_Type (T1)
3096 and then Base_Type (T1) = Base_Type (T))
3098 or else (Is_Integer_Type (T1)
3099 and then Is_Floating_Point_Type (T2)
3100 and then Base_Type (T2) = Base_Type (T));
3102 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
3103 return Base_Type (T1) = Base_Type (T2)
3104 and then Base_Type (T1) = Base_Type (T)
3105 and then Is_Integer_Type (T);
3107 elsif Op_Name = Name_Op_Expon then
3108 return Base_Type (T1) = Base_Type (T)
3109 and then Is_Numeric_Type (T)
3110 and then Base_Type (T2) = Base_Type (Standard_Integer);
3112 elsif Op_Name = Name_Op_Concat then
3113 return Is_Array_Type (T)
3114 and then (Base_Type (T) = Base_Type (Etype (Op)))
3115 and then (Base_Type (T1) = Base_Type (T)
3117 Base_Type (T1) = Base_Type (Component_Type (T)))
3118 and then (Base_Type (T2) = Base_Type (T)
3120 Base_Type (T2) = Base_Type (Component_Type (T)));
3126 end Operator_Matches_Spec;
3132 procedure Remove_Interp (I : in out Interp_Index) is
3136 -- Find end of interp list and copy downward to erase the discarded one
3139 while Present (All_Interp.Table (II).Typ) loop
3143 for J in I + 1 .. II loop
3144 All_Interp.Table (J - 1) := All_Interp.Table (J);
3147 -- Back up interp index to insure that iterator will pick up next
3148 -- available interpretation.
3157 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
3159 O_N : Node_Id := Old_N;
3162 if Is_Overloaded (Old_N) then
3163 if Nkind (Old_N) = N_Selected_Component
3164 and then Is_Overloaded (Selector_Name (Old_N))
3166 O_N := Selector_Name (Old_N);
3169 Map_Ptr := Headers (Hash (O_N));
3171 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
3172 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
3173 pragma Assert (Map_Ptr /= No_Entry);
3176 New_Interps (New_N);
3177 Interp_Map.Table (Interp_Map.Last).Index :=
3178 Interp_Map.Table (Map_Ptr).Index;
3186 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
3187 T1 : constant Entity_Id := Available_View (Typ_1);
3188 T2 : constant Entity_Id := Available_View (Typ_2);
3189 B1 : constant Entity_Id := Base_Type (T1);
3190 B2 : constant Entity_Id := Base_Type (T2);
3192 function Is_Remote_Access (T : Entity_Id) return Boolean;
3193 -- Check whether T is the equivalent type of a remote access type.
3194 -- If distribution is enabled, T is a legal context for Null.
3196 ----------------------
3197 -- Is_Remote_Access --
3198 ----------------------
3200 function Is_Remote_Access (T : Entity_Id) return Boolean is
3202 return Is_Record_Type (T)
3203 and then (Is_Remote_Call_Interface (T)
3204 or else Is_Remote_Types (T))
3205 and then Present (Corresponding_Remote_Type (T))
3206 and then Is_Access_Type (Corresponding_Remote_Type (T));
3207 end Is_Remote_Access;
3209 -- Start of processing for Specific_Type
3212 if T1 = Any_Type or else T2 = Any_Type then
3219 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
3220 or else (T1 = Universal_Real and then Is_Real_Type (T2))
3221 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
3222 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
3226 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
3227 or else (T2 = Universal_Real and then Is_Real_Type (T1))
3228 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
3229 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
3233 elsif T2 = Any_String and then Is_String_Type (T1) then
3236 elsif T1 = Any_String and then Is_String_Type (T2) then
3239 elsif T2 = Any_Character and then Is_Character_Type (T1) then
3242 elsif T1 = Any_Character and then Is_Character_Type (T2) then
3245 elsif T1 = Any_Access
3246 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
3250 elsif T2 = Any_Access
3251 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
3255 -- In an instance, the specific type may have a private view. Use full
3256 -- view to check legality.
3258 elsif T2 = Any_Access
3259 and then Is_Private_Type (T1)
3260 and then Present (Full_View (T1))
3261 and then Is_Access_Type (Full_View (T1))
3262 and then In_Instance
3266 elsif T2 = Any_Composite
3267 and then Is_Aggregate_Type (T1)
3271 elsif T1 = Any_Composite
3272 and then Is_Aggregate_Type (T2)
3276 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
3279 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
3282 -- ----------------------------------------------------------
3283 -- Special cases for equality operators (all other predefined
3284 -- operators can never apply to tagged types)
3285 -- ----------------------------------------------------------
3287 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
3290 elsif Is_Class_Wide_Type (T1)
3291 and then Is_Class_Wide_Type (T2)
3292 and then Is_Interface (Etype (T2))
3296 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
3297 -- class-wide interface T2
3299 elsif Is_Class_Wide_Type (T2)
3300 and then Is_Interface (Etype (T2))
3301 and then Interface_Present_In_Ancestor (Typ => T1,
3302 Iface => Etype (T2))
3306 elsif Is_Class_Wide_Type (T1)
3307 and then Is_Ancestor (Root_Type (T1), T2)
3311 elsif Is_Class_Wide_Type (T2)
3312 and then Is_Ancestor (Root_Type (T2), T1)
3316 elsif (Ekind (B1) = E_Access_Subprogram_Type
3318 Ekind (B1) = E_Access_Protected_Subprogram_Type)
3319 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
3320 and then Is_Access_Type (T2)
3324 elsif (Ekind (B2) = E_Access_Subprogram_Type
3326 Ekind (B2) = E_Access_Protected_Subprogram_Type)
3327 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
3328 and then Is_Access_Type (T1)
3332 elsif (Ekind (T1) = E_Allocator_Type
3333 or else Ekind (T1) = E_Access_Attribute_Type
3334 or else Ekind (T1) = E_Anonymous_Access_Type)
3335 and then Is_Access_Type (T2)
3339 elsif (Ekind (T2) = E_Allocator_Type
3340 or else Ekind (T2) = E_Access_Attribute_Type
3341 or else Ekind (T2) = E_Anonymous_Access_Type)
3342 and then Is_Access_Type (T1)
3346 -- If none of the above cases applies, types are not compatible
3353 ---------------------
3354 -- Set_Abstract_Op --
3355 ---------------------
3357 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3359 All_Interp.Table (I).Abstract_Op := V;
3360 end Set_Abstract_Op;
3362 -----------------------
3363 -- Valid_Boolean_Arg --
3364 -----------------------
3366 -- In addition to booleans and arrays of booleans, we must include
3367 -- aggregates as valid boolean arguments, because in the first pass of
3368 -- resolution their components are not examined. If it turns out not to be
3369 -- an aggregate of booleans, this will be diagnosed in Resolve.
3370 -- Any_Composite must be checked for prior to the array type checks because
3371 -- Any_Composite does not have any associated indexes.
3373 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3375 return Is_Boolean_Type (T)
3376 or else T = Any_Composite
3377 or else (Is_Array_Type (T)
3378 and then T /= Any_String
3379 and then Number_Dimensions (T) = 1
3380 and then Is_Boolean_Type (Component_Type (T))
3381 and then (not Is_Private_Composite (T)
3382 or else In_Instance)
3383 and then (not Is_Limited_Composite (T)
3384 or else In_Instance))
3385 or else Is_Modular_Integer_Type (T)
3386 or else T = Universal_Integer;
3387 end Valid_Boolean_Arg;
3389 --------------------------
3390 -- Valid_Comparison_Arg --
3391 --------------------------
3393 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3396 if T = Any_Composite then
3398 elsif Is_Discrete_Type (T)
3399 or else Is_Real_Type (T)
3402 elsif Is_Array_Type (T)
3403 and then Number_Dimensions (T) = 1
3404 and then Is_Discrete_Type (Component_Type (T))
3405 and then (not Is_Private_Composite (T)
3406 or else In_Instance)
3407 and then (not Is_Limited_Composite (T)
3408 or else In_Instance)
3411 elsif Is_String_Type (T) then
3416 end Valid_Comparison_Arg;
3418 ----------------------
3419 -- Write_Interp_Ref --
3420 ----------------------
3422 procedure Write_Interp_Ref (Map_Ptr : Int) is
3424 Write_Str (" Node: ");
3425 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3426 Write_Str (" Index: ");
3427 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3428 Write_Str (" Next: ");
3429 Write_Int (Interp_Map.Table (Map_Ptr).Next);
3431 end Write_Interp_Ref;
3433 ---------------------
3434 -- Write_Overloads --
3435 ---------------------
3437 procedure Write_Overloads (N : Node_Id) is
3443 if not Is_Overloaded (N) then
3444 Write_Str ("Non-overloaded entity ");
3446 Write_Entity_Info (Entity (N), " ");
3449 Get_First_Interp (N, I, It);
3450 Write_Str ("Overloaded entity ");
3452 Write_Str (" Name Type Abstract Op");
3454 Write_Str ("===============================================");
3458 while Present (Nam) loop
3459 Write_Int (Int (Nam));
3461 Write_Name (Chars (Nam));
3463 Write_Int (Int (It.Typ));
3465 Write_Name (Chars (It.Typ));
3467 if Present (It.Abstract_Op) then
3469 Write_Int (Int (It.Abstract_Op));
3471 Write_Name (Chars (It.Abstract_Op));
3475 Get_Next_Interp (I, It);
3479 end Write_Overloads;