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 Treepr; use Treepr;
50 with Uintp; use Uintp;
52 package body Sem_Type is
58 -- The following data structures establish a mapping between nodes and
59 -- their interpretations. An overloaded node has an entry in Interp_Map,
60 -- which in turn contains a pointer into the All_Interp array. The
61 -- interpretations of a given node are contiguous in All_Interp. Each set
62 -- of interpretations is terminated with the marker No_Interp. In order to
63 -- speed up the retrieval of the interpretations of an overloaded node, the
64 -- Interp_Map table is accessed by means of a simple hashing scheme, and
65 -- the entries in Interp_Map are chained. The heads of clash lists are
66 -- stored in array Headers.
68 -- Headers Interp_Map All_Interp
70 -- _ +-----+ +--------+
71 -- |_| |_____| --->|interp1 |
72 -- |_|---------->|node | | |interp2 |
73 -- |_| |index|---------| |nointerp|
78 -- This scheme does not currently reclaim interpretations. In principle,
79 -- after a unit is compiled, all overloadings have been resolved, and the
80 -- candidate interpretations should be deleted. This should be easier
81 -- now than with the previous scheme???
83 package All_Interp is new Table.Table (
84 Table_Component_Type => Interp,
85 Table_Index_Type => Interp_Index,
87 Table_Initial => Alloc.All_Interp_Initial,
88 Table_Increment => Alloc.All_Interp_Increment,
89 Table_Name => "All_Interp");
91 type Interp_Ref is record
97 Header_Size : constant Int := 2 ** 12;
98 No_Entry : constant Int := -1;
99 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
101 package Interp_Map is new Table.Table (
102 Table_Component_Type => Interp_Ref,
103 Table_Index_Type => Int,
104 Table_Low_Bound => 0,
105 Table_Initial => Alloc.Interp_Map_Initial,
106 Table_Increment => Alloc.Interp_Map_Increment,
107 Table_Name => "Interp_Map");
109 function Hash (N : Node_Id) return Int;
110 -- A trivial hashing function for nodes, used to insert an overloaded
111 -- node into the Interp_Map table.
113 -------------------------------------
114 -- Handling of Overload Resolution --
115 -------------------------------------
117 -- Overload resolution uses two passes over the syntax tree of a complete
118 -- context. In the first, bottom-up pass, the types of actuals in calls
119 -- are used to resolve possibly overloaded subprogram and operator names.
120 -- In the second top-down pass, the type of the context (for example the
121 -- condition in a while statement) is used to resolve a possibly ambiguous
122 -- call, and the unique subprogram name in turn imposes a specific context
123 -- on each of its actuals.
125 -- Most expressions are in fact unambiguous, and the bottom-up pass is
126 -- sufficient to resolve most everything. To simplify the common case,
127 -- names and expressions carry a flag Is_Overloaded to indicate whether
128 -- they have more than one interpretation. If the flag is off, then each
129 -- name has already a unique meaning and type, and the bottom-up pass is
130 -- sufficient (and much simpler).
132 --------------------------
133 -- Operator Overloading --
134 --------------------------
136 -- The visibility of operators is handled differently from that of other
137 -- entities. We do not introduce explicit versions of primitive operators
138 -- for each type definition. As a result, there is only one entity
139 -- corresponding to predefined addition on all numeric types, etc. The
140 -- back-end resolves predefined operators according to their type. The
141 -- visibility of primitive operations then reduces to the visibility of the
142 -- resulting type: (a + b) is a legal interpretation of some primitive
143 -- operator + if the type of the result (which must also be the type of a
144 -- and b) is directly visible (either immediately visible or use-visible).
146 -- User-defined operators are treated like other functions, but the
147 -- visibility of these user-defined operations must be special-cased
148 -- to determine whether they hide or are hidden by predefined operators.
149 -- The form P."+" (x, y) requires additional handling.
151 -- Concatenation is treated more conventionally: for every one-dimensional
152 -- array type we introduce a explicit concatenation operator. This is
153 -- necessary to handle the case of (element & element => array) which
154 -- cannot be handled conveniently if there is no explicit instance of
155 -- resulting type of the operation.
157 -----------------------
158 -- Local Subprograms --
159 -----------------------
161 procedure All_Overloads;
162 pragma Warnings (Off, All_Overloads);
163 -- Debugging procedure: list full contents of Overloads table
165 function Binary_Op_Interp_Has_Abstract_Op
167 E : Entity_Id) return Entity_Id;
168 -- Given the node and entity of a binary operator, determine whether the
169 -- actuals of E contain an abstract interpretation with regards to the
170 -- types of their corresponding formals. Return the abstract operation or
173 function Function_Interp_Has_Abstract_Op
175 E : Entity_Id) return Entity_Id;
176 -- Given the node and entity of a function call, determine whether the
177 -- actuals of E contain an abstract interpretation with regards to the
178 -- types of their corresponding formals. Return the abstract operation or
181 function Has_Abstract_Op
183 Typ : Entity_Id) return Entity_Id;
184 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
185 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
186 -- abstract interpretation which yields type Typ.
188 procedure New_Interps (N : Node_Id);
189 -- Initialize collection of interpretations for the given node, which is
190 -- either an overloaded entity, or an operation whose arguments have
191 -- multiple interpretations. Interpretations can be added to only one
194 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id;
195 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
196 -- or is not a "class" type (any_character, etc).
202 procedure Add_One_Interp
206 Opnd_Type : Entity_Id := Empty)
208 Vis_Type : Entity_Id;
210 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
211 -- Add one interpretation to an overloaded node. Add a new entry if
212 -- not hidden by previous one, and remove previous one if hidden by
215 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
216 -- True if the entity is a predefined operator and the operands have
217 -- a universal Interpretation.
223 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
224 Abstr_Op : Entity_Id := Empty;
228 -- Start of processing for Add_Entry
231 -- Find out whether the new entry references interpretations that
232 -- are abstract or disabled by abstract operators.
234 if Ada_Version >= Ada_2005 then
235 if Nkind (N) in N_Binary_Op then
236 Abstr_Op := Binary_Op_Interp_Has_Abstract_Op (N, Name);
237 elsif Nkind (N) = N_Function_Call then
238 Abstr_Op := Function_Interp_Has_Abstract_Op (N, Name);
242 Get_First_Interp (N, I, It);
243 while Present (It.Nam) loop
245 -- A user-defined subprogram hides another declared at an outer
246 -- level, or one that is use-visible. So return if previous
247 -- definition hides new one (which is either in an outer
248 -- scope, or use-visible). Note that for functions use-visible
249 -- is the same as potentially use-visible. If new one hides
250 -- previous one, replace entry in table of interpretations.
251 -- If this is a universal operation, retain the operator in case
252 -- preference rule applies.
254 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
255 and then Ekind (Name) = Ekind (It.Nam))
256 or else (Ekind (Name) = E_Operator
257 and then Ekind (It.Nam) = E_Function))
259 and then Is_Immediately_Visible (It.Nam)
260 and then Type_Conformant (Name, It.Nam)
261 and then Base_Type (It.Typ) = Base_Type (T)
263 if Is_Universal_Operation (Name) then
266 -- If node is an operator symbol, we have no actuals with
267 -- which to check hiding, and this is done in full in the
268 -- caller (Analyze_Subprogram_Renaming) so we include the
269 -- predefined operator in any case.
271 elsif Nkind (N) = N_Operator_Symbol
272 or else (Nkind (N) = N_Expanded_Name
274 Nkind (Selector_Name (N)) = N_Operator_Symbol)
278 elsif not In_Open_Scopes (Scope (Name))
279 or else Scope_Depth (Scope (Name)) <=
280 Scope_Depth (Scope (It.Nam))
282 -- If ambiguity within instance, and entity is not an
283 -- implicit operation, save for later disambiguation.
285 if Scope (Name) = Scope (It.Nam)
286 and then not Is_Inherited_Operation (Name)
295 All_Interp.Table (I).Nam := Name;
299 -- Avoid making duplicate entries in overloads
302 and then Base_Type (It.Typ) = Base_Type (T)
306 -- Otherwise keep going
309 Get_Next_Interp (I, It);
314 All_Interp.Table (All_Interp.Last) := (Name, Typ, Abstr_Op);
315 All_Interp.Append (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
366 if Present (Opnd_Type) then
367 Vis_Type := Opnd_Type;
369 Vis_Type := Base_Type (T);
372 if In_Open_Scopes (Scope (Vis_Type))
373 or else Is_Potentially_Use_Visible (Vis_Type)
374 or else In_Use (Vis_Type)
375 or else (In_Use (Scope (Vis_Type))
376 and then not Is_Hidden (Vis_Type))
377 or else Nkind (N) = N_Expanded_Name
378 or else (Nkind (N) in N_Op and then E = Entity (N))
380 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
384 -- If the node is given in functional notation and the prefix
385 -- is an expanded name, then the operator is visible if the
386 -- prefix is the scope of the result type as well. If the
387 -- operator is (implicitly) defined in an extension of system,
388 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
390 elsif Nkind (N) = N_Function_Call
391 and then Nkind (Name (N)) = N_Expanded_Name
392 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
393 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
394 or else Scope (Vis_Type) = System_Aux_Id)
398 -- Save type for subsequent error message, in case no other
399 -- interpretation is found.
402 Candidate_Type := Vis_Type;
406 -- In an instance, an abstract non-dispatching operation cannot be a
407 -- candidate interpretation, because it could not have been one in the
408 -- generic (it may be a spurious overloading in the instance).
411 and then Is_Overloadable (E)
412 and then Is_Abstract_Subprogram (E)
413 and then not Is_Dispatching_Operation (E)
417 -- An inherited interface operation that is implemented by some derived
418 -- type does not participate in overload resolution, only the
419 -- implementation operation does.
422 and then Is_Subprogram (E)
423 and then Present (Interface_Alias (E))
425 -- Ada 2005 (AI-251): If this primitive operation corresponds with
426 -- an immediate ancestor interface there is no need to add it to the
427 -- list of interpretations. The corresponding aliased primitive is
428 -- also in this list of primitive operations and will be used instead
429 -- because otherwise we have a dummy ambiguity between the two
430 -- subprograms which are in fact the same.
433 (Find_Dispatching_Type (Interface_Alias (E)),
434 Find_Dispatching_Type (E))
436 Add_One_Interp (N, Interface_Alias (E), T);
441 -- Calling stubs for an RACW operation never participate in resolution,
442 -- they are executed only through dispatching calls.
444 elsif Is_RACW_Stub_Type_Operation (E) then
448 -- If this is the first interpretation of N, N has type Any_Type.
449 -- In that case place the new type on the node. If one interpretation
450 -- already exists, indicate that the node is overloaded, and store
451 -- both the previous and the new interpretation in All_Interp. If
452 -- this is a later interpretation, just add it to the set.
454 if Etype (N) = Any_Type then
459 -- Record both the operator or subprogram name, and its type
461 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
468 -- Either there is no current interpretation in the table for any
469 -- node or the interpretation that is present is for a different
470 -- node. In both cases add a new interpretation to the table.
472 elsif Interp_Map.Last < 0
474 (Interp_Map.Table (Interp_Map.Last).Node /= N
475 and then not Is_Overloaded (N))
479 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
480 and then Present (Entity (N))
482 Add_Entry (Entity (N), Etype (N));
484 elsif Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement)
485 and then Is_Entity_Name (Name (N))
487 Add_Entry (Entity (Name (N)), Etype (N));
489 -- If this is an indirect call there will be no name associated
490 -- with the previous entry. To make diagnostics clearer, save
491 -- Subprogram_Type of first interpretation, so that the error will
492 -- point to the anonymous access to subprogram, not to the result
493 -- type of the call itself.
495 elsif (Nkind (N)) = N_Function_Call
496 and then Nkind (Name (N)) = N_Explicit_Dereference
497 and then Is_Overloaded (Name (N))
503 pragma Warnings (Off, Itn);
506 Get_First_Interp (Name (N), Itn, It);
507 Add_Entry (It.Nam, Etype (N));
511 -- Overloaded prefix in indexed or selected component, or call
512 -- whose name is an expression or another call.
514 Add_Entry (Etype (N), Etype (N));
528 procedure All_Overloads is
530 for J in All_Interp.First .. All_Interp.Last loop
532 if Present (All_Interp.Table (J).Nam) then
533 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
535 Write_Str ("No Interp");
539 Write_Str ("=================");
544 --------------------------------------
545 -- Binary_Op_Interp_Has_Abstract_Op --
546 --------------------------------------
548 function Binary_Op_Interp_Has_Abstract_Op
550 E : Entity_Id) return Entity_Id
552 Abstr_Op : Entity_Id;
553 E_Left : constant Node_Id := First_Formal (E);
554 E_Right : constant Node_Id := Next_Formal (E_Left);
557 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
558 if Present (Abstr_Op) then
562 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
563 end Binary_Op_Interp_Has_Abstract_Op;
565 ---------------------
566 -- Collect_Interps --
567 ---------------------
569 procedure Collect_Interps (N : Node_Id) is
570 Ent : constant Entity_Id := Entity (N);
572 First_Interp : Interp_Index;
574 function Within_Instance (E : Entity_Id) return Boolean;
575 -- Within an instance there can be spurious ambiguities between a local
576 -- entity and one declared outside of the instance. This can only happen
577 -- for subprograms, because otherwise the local entity hides the outer
578 -- one. For an overloadable entity, this predicate determines whether it
579 -- is a candidate within the instance, or must be ignored.
581 ---------------------
582 -- Within_Instance --
583 ---------------------
585 function Within_Instance (E : Entity_Id) return Boolean is
590 if not In_Instance then
594 Inst := Current_Scope;
595 while Present (Inst) and then not Is_Generic_Instance (Inst) loop
596 Inst := Scope (Inst);
600 while Present (Scop) and then Scop /= Standard_Standard loop
604 Scop := Scope (Scop);
610 -- Start of processing for Collect_Interps
615 -- Unconditionally add the entity that was initially matched
617 First_Interp := All_Interp.Last;
618 Add_One_Interp (N, Ent, Etype (N));
620 -- For expanded name, pick up all additional entities from the
621 -- same scope, since these are obviously also visible. Note that
622 -- these are not necessarily contiguous on the homonym chain.
624 if Nkind (N) = N_Expanded_Name then
626 while Present (H) loop
627 if Scope (H) = Scope (Entity (N)) then
628 Add_One_Interp (N, H, Etype (H));
634 -- Case of direct name
637 -- First, search the homonym chain for directly visible entities
639 H := Current_Entity (Ent);
640 while Present (H) loop
641 exit when (not Is_Overloadable (H))
642 and then Is_Immediately_Visible (H);
644 if Is_Immediately_Visible (H)
647 -- Only add interpretation if not hidden by an inner
648 -- immediately visible one.
650 for J in First_Interp .. All_Interp.Last - 1 loop
652 -- Current homograph is not hidden. Add to overloads
654 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
657 -- Homograph is hidden, unless it is a predefined operator
659 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
661 -- A homograph in the same scope can occur within an
662 -- instantiation, the resulting ambiguity has to be
663 -- resolved later. The homographs may both be local
664 -- functions or actuals, or may be declared at different
665 -- levels within the instance. The renaming of an actual
666 -- within the instance must not be included.
668 if Within_Instance (H)
669 and then H /= Renamed_Entity (Ent)
670 and then not Is_Inherited_Operation (H)
672 All_Interp.Table (All_Interp.Last) :=
673 (H, Etype (H), Empty);
674 All_Interp.Append (No_Interp);
677 elsif Scope (H) /= Standard_Standard then
683 -- On exit, we know that current homograph is not hidden
685 Add_One_Interp (N, H, Etype (H));
688 Write_Str ("Add overloaded interpretation ");
698 -- Scan list of homographs for use-visible entities only
700 H := Current_Entity (Ent);
702 while Present (H) loop
703 if Is_Potentially_Use_Visible (H)
705 and then Is_Overloadable (H)
707 for J in First_Interp .. All_Interp.Last - 1 loop
709 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
712 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
713 goto Next_Use_Homograph;
717 Add_One_Interp (N, H, Etype (H));
720 <<Next_Use_Homograph>>
725 if All_Interp.Last = First_Interp + 1 then
727 -- The final interpretation is in fact not overloaded. Note that the
728 -- unique legal interpretation may or may not be the original one,
729 -- so we need to update N's entity and etype now, because once N
730 -- is marked as not overloaded it is also expected to carry the
731 -- proper interpretation.
733 Set_Is_Overloaded (N, False);
734 Set_Entity (N, All_Interp.Table (First_Interp).Nam);
735 Set_Etype (N, All_Interp.Table (First_Interp).Typ);
743 function Covers (T1, T2 : Entity_Id) return Boolean is
748 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
749 -- In an instance the proper view may not always be correct for
750 -- private types, but private and full view are compatible. This
751 -- removes spurious errors from nested instantiations that involve,
752 -- among other things, types derived from private types.
754 ----------------------
755 -- Full_View_Covers --
756 ----------------------
758 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
761 Is_Private_Type (Typ1)
763 ((Present (Full_View (Typ1))
764 and then Covers (Full_View (Typ1), Typ2))
765 or else Base_Type (Typ1) = Typ2
766 or else Base_Type (Typ2) = Typ1);
767 end Full_View_Covers;
769 -- Start of processing for Covers
772 -- If either operand missing, then this is an error, but ignore it (and
773 -- pretend we have a cover) if errors already detected, since this may
774 -- simply mean we have malformed trees or a semantic error upstream.
776 if No (T1) or else No (T2) then
777 if Total_Errors_Detected /= 0 then
784 -- Trivial case: same types are always compatible
790 -- First check for Standard_Void_Type, which is special. Subsequent
791 -- processing in this routine assumes T1 and T2 are bona fide types;
792 -- Standard_Void_Type is a special entity that has some, but not all,
793 -- properties of types.
795 if (T1 = Standard_Void_Type) /= (T2 = Standard_Void_Type) then
799 BT1 := Base_Type (T1);
800 BT2 := Base_Type (T2);
802 -- Handle underlying view of records with unknown discriminants
803 -- using the original entity that motivated the construction of
804 -- this underlying record view (see Build_Derived_Private_Type).
806 if Is_Underlying_Record_View (BT1) then
807 BT1 := Underlying_Record_View (BT1);
810 if Is_Underlying_Record_View (BT2) then
811 BT2 := Underlying_Record_View (BT2);
814 -- Simplest case: types that have the same base type and are not generic
815 -- actuals are compatible. Generic actuals belong to their class but are
816 -- not compatible with other types of their class, and in particular
817 -- with other generic actuals. They are however compatible with their
818 -- own subtypes, and itypes with the same base are compatible as well.
819 -- Similarly, constrained subtypes obtained from expressions of an
820 -- unconstrained nominal type are compatible with the base type (may
821 -- lead to spurious ambiguities in obscure cases ???)
823 -- Generic actuals require special treatment to avoid spurious ambi-
824 -- guities in an instance, when two formal types are instantiated with
825 -- the same actual, so that different subprograms end up with the same
826 -- signature in the instance.
832 if not Is_Generic_Actual_Type (T1) then
835 return (not Is_Generic_Actual_Type (T2)
836 or else Is_Itype (T1)
837 or else Is_Itype (T2)
838 or else Is_Constr_Subt_For_U_Nominal (T1)
839 or else Is_Constr_Subt_For_U_Nominal (T2)
840 or else Scope (T1) /= Scope (T2));
843 -- Literals are compatible with types in a given "class"
845 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
846 or else (T2 = Universal_Real and then Is_Real_Type (T1))
847 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
848 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
849 or else (T2 = Any_String and then Is_String_Type (T1))
850 or else (T2 = Any_Character and then Is_Character_Type (T1))
851 or else (T2 = Any_Access and then Is_Access_Type (T1))
855 -- The context may be class wide, and a class-wide type is compatible
856 -- with any member of the class.
858 elsif Is_Class_Wide_Type (T1)
859 and then Is_Ancestor (Root_Type (T1), T2)
863 elsif Is_Class_Wide_Type (T1)
864 and then Is_Class_Wide_Type (T2)
865 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
869 -- Ada 2005 (AI-345): A class-wide abstract interface type covers a
870 -- task_type or protected_type that implements the interface.
872 elsif Ada_Version >= Ada_2005
873 and then Is_Class_Wide_Type (T1)
874 and then Is_Interface (Etype (T1))
875 and then Is_Concurrent_Type (T2)
876 and then Interface_Present_In_Ancestor
877 (Typ => BT2, Iface => Etype (T1))
881 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
882 -- object T2 implementing T1.
884 elsif Ada_Version >= Ada_2005
885 and then Is_Class_Wide_Type (T1)
886 and then Is_Interface (Etype (T1))
887 and then Is_Tagged_Type (T2)
889 if Interface_Present_In_Ancestor (Typ => T2,
900 if Is_Concurrent_Type (BT2) then
901 E := Corresponding_Record_Type (BT2);
906 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
907 -- covers an object T2 that implements a direct derivation of T1.
908 -- Note: test for presence of E is defense against previous error.
911 and then Present (Interfaces (E))
913 Elmt := First_Elmt (Interfaces (E));
914 while Present (Elmt) loop
915 if Is_Ancestor (Etype (T1), Node (Elmt)) then
923 -- We should also check the case in which T1 is an ancestor of
924 -- some implemented interface???
929 -- In a dispatching call, the formal is of some specific type, and the
930 -- actual is of the corresponding class-wide type, including a subtype
931 -- of the class-wide type.
933 elsif Is_Class_Wide_Type (T2)
935 (Class_Wide_Type (T1) = Class_Wide_Type (T2)
936 or else Base_Type (Root_Type (T2)) = BT1)
940 -- Some contexts require a class of types rather than a specific type.
941 -- For example, conditions require any boolean type, fixed point
942 -- attributes require some real type, etc. The built-in types Any_XXX
943 -- represent these classes.
945 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
946 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
947 or else (T1 = Any_Real and then Is_Real_Type (T2))
948 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
949 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
953 -- An aggregate is compatible with an array or record type
955 elsif T2 = Any_Composite
956 and then Is_Aggregate_Type (T1)
960 -- If the expected type is an anonymous access, the designated type must
961 -- cover that of the expression. Use the base type for this check: even
962 -- though access subtypes are rare in sources, they are generated for
963 -- actuals in instantiations.
965 elsif Ekind (BT1) = E_Anonymous_Access_Type
966 and then Is_Access_Type (T2)
967 and then Covers (Designated_Type (T1), Designated_Type (T2))
971 -- Ada 2012 (AI05-0149): Allow an anonymous access type in the context
972 -- of a named general access type. An implicit conversion will be
973 -- applied. For the resolution, one designated type must cover the
976 elsif Ada_Version >= Ada_2012
977 and then Ekind (BT1) = E_General_Access_Type
978 and then Ekind (BT2) = E_Anonymous_Access_Type
979 and then (Covers (Designated_Type (T1), Designated_Type (T2))
980 or else Covers (Designated_Type (T2), Designated_Type (T1)))
984 -- An Access_To_Subprogram is compatible with itself, or with an
985 -- anonymous type created for an attribute reference Access.
987 elsif (Ekind (BT1) = E_Access_Subprogram_Type
989 Ekind (BT1) = E_Access_Protected_Subprogram_Type)
990 and then Is_Access_Type (T2)
991 and then (not Comes_From_Source (T1)
992 or else not Comes_From_Source (T2))
993 and then (Is_Overloadable (Designated_Type (T2))
995 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
997 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
999 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1003 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
1004 -- with itself, or with an anonymous type created for an attribute
1005 -- reference Access.
1007 elsif (Ekind (BT1) = E_Anonymous_Access_Subprogram_Type
1010 = E_Anonymous_Access_Protected_Subprogram_Type)
1011 and then Is_Access_Type (T2)
1012 and then (not Comes_From_Source (T1)
1013 or else not Comes_From_Source (T2))
1014 and then (Is_Overloadable (Designated_Type (T2))
1016 Ekind (Designated_Type (T2)) = E_Subprogram_Type)
1018 Type_Conformant (Designated_Type (T1), Designated_Type (T2))
1020 Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1024 -- The context can be a remote access type, and the expression the
1025 -- corresponding source type declared in a categorized package, or
1028 elsif Is_Record_Type (T1)
1029 and then (Is_Remote_Call_Interface (T1)
1030 or else Is_Remote_Types (T1))
1031 and then Present (Corresponding_Remote_Type (T1))
1033 return Covers (Corresponding_Remote_Type (T1), T2);
1037 elsif Is_Record_Type (T2)
1038 and then (Is_Remote_Call_Interface (T2)
1039 or else Is_Remote_Types (T2))
1040 and then Present (Corresponding_Remote_Type (T2))
1042 return Covers (Corresponding_Remote_Type (T2), T1);
1044 -- Synchronized types are represented at run time by their corresponding
1045 -- record type. During expansion one is replaced with the other, but
1046 -- they are compatible views of the same type.
1048 elsif Is_Record_Type (T1)
1049 and then Is_Concurrent_Type (T2)
1050 and then Present (Corresponding_Record_Type (T2))
1052 return Covers (T1, Corresponding_Record_Type (T2));
1054 elsif Is_Concurrent_Type (T1)
1055 and then Present (Corresponding_Record_Type (T1))
1056 and then Is_Record_Type (T2)
1058 return Covers (Corresponding_Record_Type (T1), T2);
1060 -- During analysis, an attribute reference 'Access has a special type
1061 -- kind: Access_Attribute_Type, to be replaced eventually with the type
1062 -- imposed by context.
1064 elsif Ekind (T2) = E_Access_Attribute_Type
1065 and then Ekind_In (BT1, E_General_Access_Type, E_Access_Type)
1066 and then Covers (Designated_Type (T1), Designated_Type (T2))
1068 -- If the target type is a RACW type while the source is an access
1069 -- attribute type, we are building a RACW that may be exported.
1071 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
1072 Set_Has_RACW (Current_Sem_Unit);
1077 -- Ditto for allocators, which eventually resolve to the context type
1079 elsif Ekind (T2) = E_Allocator_Type
1080 and then Is_Access_Type (T1)
1082 return Covers (Designated_Type (T1), Designated_Type (T2))
1084 (From_With_Type (Designated_Type (T1))
1085 and then Covers (Designated_Type (T2), Designated_Type (T1)));
1087 -- A boolean operation on integer literals is compatible with modular
1090 elsif T2 = Any_Modular
1091 and then Is_Modular_Integer_Type (T1)
1095 -- The actual type may be the result of a previous error
1097 elsif BT2 = Any_Type then
1100 -- A packed array type covers its corresponding non-packed type. This is
1101 -- not legitimate Ada, but allows the omission of a number of otherwise
1102 -- useless unchecked conversions, and since this can only arise in
1103 -- (known correct) expanded code, no harm is done.
1105 elsif Is_Array_Type (T2)
1106 and then Is_Packed (T2)
1107 and then T1 = Packed_Array_Type (T2)
1111 -- Similarly an array type covers its corresponding packed array type
1113 elsif Is_Array_Type (T1)
1114 and then Is_Packed (T1)
1115 and then T2 = Packed_Array_Type (T1)
1119 -- In instances, or with types exported from instantiations, check
1120 -- whether a partial and a full view match. Verify that types are
1121 -- legal, to prevent cascaded errors.
1125 (Full_View_Covers (T1, T2)
1126 or else Full_View_Covers (T2, T1))
1131 and then Is_Generic_Actual_Type (T2)
1132 and then Full_View_Covers (T1, T2)
1137 and then Is_Generic_Actual_Type (T1)
1138 and then Full_View_Covers (T2, T1)
1142 -- In the expansion of inlined bodies, types are compatible if they
1143 -- are structurally equivalent.
1145 elsif In_Inlined_Body
1146 and then (Underlying_Type (T1) = Underlying_Type (T2)
1147 or else (Is_Access_Type (T1)
1148 and then Is_Access_Type (T2)
1150 Designated_Type (T1) = Designated_Type (T2))
1151 or else (T1 = Any_Access
1152 and then Is_Access_Type (Underlying_Type (T2)))
1153 or else (T2 = Any_Composite
1155 Is_Composite_Type (Underlying_Type (T1))))
1159 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1160 -- obtained through a limited_with compatible with its real entity.
1162 elsif From_With_Type (T1) then
1164 -- If the expected type is the non-limited view of a type, the
1165 -- expression may have the limited view. If that one in turn is
1166 -- incomplete, get full view if available.
1168 if Is_Incomplete_Type (T1) then
1169 return Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1171 elsif Ekind (T1) = E_Class_Wide_Type then
1173 Covers (Class_Wide_Type (Non_Limited_View (Etype (T1))), T2);
1178 elsif From_With_Type (T2) then
1180 -- If units in the context have Limited_With clauses on each other,
1181 -- either type might have a limited view. Checks performed elsewhere
1182 -- verify that the context type is the nonlimited view.
1184 if Is_Incomplete_Type (T2) then
1185 return Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1187 elsif Ekind (T2) = E_Class_Wide_Type then
1189 Present (Non_Limited_View (Etype (T2)))
1191 Covers (T1, Class_Wide_Type (Non_Limited_View (Etype (T2))));
1196 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1198 elsif Ekind (T1) = E_Incomplete_Subtype then
1199 return Covers (Full_View (Etype (T1)), T2);
1201 elsif Ekind (T2) = E_Incomplete_Subtype then
1202 return Covers (T1, Full_View (Etype (T2)));
1204 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1205 -- and actual anonymous access types in the context of generic
1206 -- instantiations. We have the following situation:
1209 -- type Formal is private;
1210 -- Formal_Obj : access Formal; -- T1
1214 -- type Actual is ...
1215 -- Actual_Obj : access Actual; -- T2
1216 -- package Instance is new G (Formal => Actual,
1217 -- Formal_Obj => Actual_Obj);
1219 elsif Ada_Version >= Ada_2005
1220 and then Ekind (T1) = E_Anonymous_Access_Type
1221 and then Ekind (T2) = E_Anonymous_Access_Type
1222 and then Is_Generic_Type (Directly_Designated_Type (T1))
1223 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1224 Directly_Designated_Type (T2)
1228 -- Otherwise, types are not compatible!
1239 function Disambiguate
1241 I1, I2 : Interp_Index;
1242 Typ : Entity_Id) return Interp
1247 Nam1, Nam2 : Entity_Id;
1248 Predef_Subp : Entity_Id;
1249 User_Subp : Entity_Id;
1251 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1252 -- Determine whether one of the candidates is an operation inherited by
1253 -- a type that is derived from an actual in an instantiation.
1255 function In_Same_Declaration_List
1257 Op_Decl : Entity_Id) return Boolean;
1258 -- AI05-0020: a spurious ambiguity may arise when equality on anonymous
1259 -- access types is declared on the partial view of a designated type, so
1260 -- that the type declaration and equality are not in the same list of
1261 -- declarations. This AI gives a preference rule for the user-defined
1262 -- operation. Same rule applies for arithmetic operations on private
1263 -- types completed with fixed-point types: the predefined operation is
1264 -- hidden; this is already handled properly in GNAT.
1266 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1267 -- Determine whether a subprogram is an actual in an enclosing instance.
1268 -- An overloading between such a subprogram and one declared outside the
1269 -- instance is resolved in favor of the first, because it resolved in
1272 function Matches (Actual, Formal : Node_Id) return Boolean;
1273 -- Look for exact type match in an instance, to remove spurious
1274 -- ambiguities when two formal types have the same actual.
1276 function Operand_Type return Entity_Id;
1277 -- Determine type of operand for an equality operation, to apply
1278 -- Ada 2005 rules to equality on anonymous access types.
1280 function Standard_Operator return Boolean;
1281 -- Check whether subprogram is predefined operator declared in Standard.
1282 -- It may given by an operator name, or by an expanded name whose prefix
1285 function Remove_Conversions return Interp;
1286 -- Last chance for pathological cases involving comparisons on literals,
1287 -- and user overloadings of the same operator. Such pathologies have
1288 -- been removed from the ACVC, but still appear in two DEC tests, with
1289 -- the following notable quote from Ben Brosgol:
1291 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1292 -- this example; Robert Dewar brought it to our attention, since it is
1293 -- apparently found in the ACVC 1.5. I did not attempt to find the
1294 -- reason in the Reference Manual that makes the example legal, since I
1295 -- was too nauseated by it to want to pursue it further.]
1297 -- Accordingly, this is not a fully recursive solution, but it handles
1298 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1299 -- pathology in the other direction with calls whose multiple overloaded
1300 -- actuals make them truly unresolvable.
1302 -- The new rules concerning abstract operations create additional need
1303 -- for special handling of expressions with universal operands, see
1304 -- comments to Has_Abstract_Interpretation below.
1306 ---------------------------
1307 -- Inherited_From_Actual --
1308 ---------------------------
1310 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1311 Par : constant Node_Id := Parent (S);
1313 if Nkind (Par) /= N_Full_Type_Declaration
1314 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1318 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1320 Is_Generic_Actual_Type (
1321 Entity (Subtype_Indication (Type_Definition (Par))));
1323 end Inherited_From_Actual;
1325 ------------------------------
1326 -- In_Same_Declaration_List --
1327 ------------------------------
1329 function In_Same_Declaration_List
1331 Op_Decl : Entity_Id) return Boolean
1333 Scop : constant Entity_Id := Scope (Typ);
1336 return In_Same_List (Parent (Typ), Op_Decl)
1338 (Ekind_In (Scop, E_Package, E_Generic_Package)
1339 and then List_Containing (Op_Decl) =
1340 Visible_Declarations (Parent (Scop))
1341 and then List_Containing (Parent (Typ)) =
1342 Private_Declarations (Parent (Scop)));
1343 end In_Same_Declaration_List;
1345 --------------------------
1346 -- Is_Actual_Subprogram --
1347 --------------------------
1349 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1351 return In_Open_Scopes (Scope (S))
1353 (Is_Generic_Instance (Scope (S))
1354 or else Is_Wrapper_Package (Scope (S)));
1355 end Is_Actual_Subprogram;
1361 function Matches (Actual, Formal : Node_Id) return Boolean is
1362 T1 : constant Entity_Id := Etype (Actual);
1363 T2 : constant Entity_Id := Etype (Formal);
1367 (Is_Numeric_Type (T2)
1368 and then (T1 = Universal_Real or else T1 = Universal_Integer));
1375 function Operand_Type return Entity_Id is
1379 if Nkind (N) = N_Function_Call then
1380 Opnd := First_Actual (N);
1382 Opnd := Left_Opnd (N);
1385 return Etype (Opnd);
1388 ------------------------
1389 -- Remove_Conversions --
1390 ------------------------
1392 function Remove_Conversions return Interp is
1400 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1401 -- If an operation has universal operands the universal operation
1402 -- is present among its interpretations. If there is an abstract
1403 -- interpretation for the operator, with a numeric result, this
1404 -- interpretation was already removed in sem_ch4, but the universal
1405 -- one is still visible. We must rescan the list of operators and
1406 -- remove the universal interpretation to resolve the ambiguity.
1408 ---------------------------------
1409 -- Has_Abstract_Interpretation --
1410 ---------------------------------
1412 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1416 if Nkind (N) not in N_Op
1417 or else Ada_Version < Ada_2005
1418 or else not Is_Overloaded (N)
1419 or else No (Universal_Interpretation (N))
1424 E := Get_Name_Entity_Id (Chars (N));
1425 while Present (E) loop
1426 if Is_Overloadable (E)
1427 and then Is_Abstract_Subprogram (E)
1428 and then Is_Numeric_Type (Etype (E))
1436 -- Finally, if an operand of the binary operator is itself
1437 -- an operator, recurse to see whether its own abstract
1438 -- interpretation is responsible for the spurious ambiguity.
1440 if Nkind (N) in N_Binary_Op then
1441 return Has_Abstract_Interpretation (Left_Opnd (N))
1442 or else Has_Abstract_Interpretation (Right_Opnd (N));
1444 elsif Nkind (N) in N_Unary_Op then
1445 return Has_Abstract_Interpretation (Right_Opnd (N));
1451 end Has_Abstract_Interpretation;
1453 -- Start of processing for Remove_Conversions
1458 Get_First_Interp (N, I, It);
1459 while Present (It.Typ) loop
1460 if not Is_Overloadable (It.Nam) then
1464 F1 := First_Formal (It.Nam);
1470 if Nkind (N) = N_Function_Call
1471 or else Nkind (N) = N_Procedure_Call_Statement
1473 Act1 := First_Actual (N);
1475 if Present (Act1) then
1476 Act2 := Next_Actual (Act1);
1481 elsif Nkind (N) in N_Unary_Op then
1482 Act1 := Right_Opnd (N);
1485 elsif Nkind (N) in N_Binary_Op then
1486 Act1 := Left_Opnd (N);
1487 Act2 := Right_Opnd (N);
1489 -- Use type of second formal, so as to include
1490 -- exponentiation, where the exponent may be
1491 -- ambiguous and the result non-universal.
1499 if Nkind (Act1) in N_Op
1500 and then Is_Overloaded (Act1)
1501 and then (Nkind (Right_Opnd (Act1)) = N_Integer_Literal
1502 or else Nkind (Right_Opnd (Act1)) = N_Real_Literal)
1503 and then Has_Compatible_Type (Act1, Standard_Boolean)
1504 and then Etype (F1) = Standard_Boolean
1506 -- If the two candidates are the original ones, the
1507 -- ambiguity is real. Otherwise keep the original, further
1508 -- calls to Disambiguate will take care of others in the
1509 -- list of candidates.
1511 if It1 /= No_Interp then
1512 if It = Disambiguate.It1
1513 or else It = Disambiguate.It2
1515 if It1 = Disambiguate.It1
1516 or else It1 = Disambiguate.It2
1524 elsif Present (Act2)
1525 and then Nkind (Act2) in N_Op
1526 and then Is_Overloaded (Act2)
1527 and then Nkind_In (Right_Opnd (Act2), N_Integer_Literal,
1529 and then Has_Compatible_Type (Act2, Standard_Boolean)
1531 -- The preference rule on the first actual is not
1532 -- sufficient to disambiguate.
1540 elsif Is_Numeric_Type (Etype (F1))
1541 and then Has_Abstract_Interpretation (Act1)
1543 -- Current interpretation is not the right one because it
1544 -- expects a numeric operand. Examine all the other ones.
1551 Get_First_Interp (N, I, It);
1552 while Present (It.Typ) loop
1554 not Is_Numeric_Type (Etype (First_Formal (It.Nam)))
1557 or else not Has_Abstract_Interpretation (Act2)
1560 (Etype (Next_Formal (First_Formal (It.Nam))))
1566 Get_Next_Interp (I, It);
1575 Get_Next_Interp (I, It);
1578 -- After some error, a formal may have Any_Type and yield a spurious
1579 -- match. To avoid cascaded errors if possible, check for such a
1580 -- formal in either candidate.
1582 if Serious_Errors_Detected > 0 then
1587 Formal := First_Formal (Nam1);
1588 while Present (Formal) loop
1589 if Etype (Formal) = Any_Type then
1590 return Disambiguate.It2;
1593 Next_Formal (Formal);
1596 Formal := First_Formal (Nam2);
1597 while Present (Formal) loop
1598 if Etype (Formal) = Any_Type then
1599 return Disambiguate.It1;
1602 Next_Formal (Formal);
1608 end Remove_Conversions;
1610 -----------------------
1611 -- Standard_Operator --
1612 -----------------------
1614 function Standard_Operator return Boolean is
1618 if Nkind (N) in N_Op then
1621 elsif Nkind (N) = N_Function_Call then
1624 if Nkind (Nam) /= N_Expanded_Name then
1627 return Entity (Prefix (Nam)) = Standard_Standard;
1632 end Standard_Operator;
1634 -- Start of processing for Disambiguate
1637 -- Recover the two legal interpretations
1639 Get_First_Interp (N, I, It);
1641 Get_Next_Interp (I, It);
1647 Get_Next_Interp (I, It);
1653 -- Check whether one of the entities is an Ada 2005/2012 and we are
1654 -- operating in an earlier mode, in which case we discard the Ada
1655 -- 2005/2012 entity, so that we get proper Ada 95 overload resolution.
1657 if Ada_Version < Ada_2005 then
1658 if Is_Ada_2005_Only (Nam1) or else Is_Ada_2012_Only (Nam1) then
1660 elsif Is_Ada_2005_Only (Nam2) or else Is_Ada_2012_Only (Nam1) then
1665 -- Check whether one of the entities is an Ada 2012 entity and we are
1666 -- operating in Ada 2005 mode, in which case we discard the Ada 2012
1667 -- entity, so that we get proper Ada 2005 overload resolution.
1669 if Ada_Version = Ada_2005 then
1670 if Is_Ada_2012_Only (Nam1) then
1672 elsif Is_Ada_2012_Only (Nam2) then
1677 -- Check for overloaded CIL convention stuff because the CIL libraries
1678 -- do sick things like Console.Write_Line where it matches two different
1679 -- overloads, so just pick the first ???
1681 if Convention (Nam1) = Convention_CIL
1682 and then Convention (Nam2) = Convention_CIL
1683 and then Ekind (Nam1) = Ekind (Nam2)
1684 and then (Ekind (Nam1) = E_Procedure
1685 or else Ekind (Nam1) = E_Function)
1690 -- If the context is universal, the predefined operator is preferred.
1691 -- This includes bounds in numeric type declarations, and expressions
1692 -- in type conversions. If no interpretation yields a universal type,
1693 -- then we must check whether the user-defined entity hides the prede-
1696 if Chars (Nam1) in Any_Operator_Name
1697 and then Standard_Operator
1699 if Typ = Universal_Integer
1700 or else Typ = Universal_Real
1701 or else Typ = Any_Integer
1702 or else Typ = Any_Discrete
1703 or else Typ = Any_Real
1704 or else Typ = Any_Type
1706 -- Find an interpretation that yields the universal type, or else
1707 -- a predefined operator that yields a predefined numeric type.
1710 Candidate : Interp := No_Interp;
1713 Get_First_Interp (N, I, It);
1714 while Present (It.Typ) loop
1715 if (Covers (Typ, It.Typ)
1716 or else Typ = Any_Type)
1718 (It.Typ = Universal_Integer
1719 or else It.Typ = Universal_Real)
1723 elsif Covers (Typ, It.Typ)
1724 and then Scope (It.Typ) = Standard_Standard
1725 and then Scope (It.Nam) = Standard_Standard
1726 and then Is_Numeric_Type (It.Typ)
1731 Get_Next_Interp (I, It);
1734 if Candidate /= No_Interp then
1739 elsif Chars (Nam1) /= Name_Op_Not
1740 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1742 -- Equality or comparison operation. Choose predefined operator if
1743 -- arguments are universal. The node may be an operator, name, or
1744 -- a function call, so unpack arguments accordingly.
1747 Arg1, Arg2 : Node_Id;
1750 if Nkind (N) in N_Op then
1751 Arg1 := Left_Opnd (N);
1752 Arg2 := Right_Opnd (N);
1754 elsif Is_Entity_Name (N) then
1755 Arg1 := First_Entity (Entity (N));
1756 Arg2 := Next_Entity (Arg1);
1759 Arg1 := First_Actual (N);
1760 Arg2 := Next_Actual (Arg1);
1764 and then Present (Universal_Interpretation (Arg1))
1765 and then Universal_Interpretation (Arg2) =
1766 Universal_Interpretation (Arg1)
1768 Get_First_Interp (N, I, It);
1769 while Scope (It.Nam) /= Standard_Standard loop
1770 Get_Next_Interp (I, It);
1779 -- If no universal interpretation, check whether user-defined operator
1780 -- hides predefined one, as well as other special cases. If the node
1781 -- is a range, then one or both bounds are ambiguous. Each will have
1782 -- to be disambiguated w.r.t. the context type. The type of the range
1783 -- itself is imposed by the context, so we can return either legal
1786 if Ekind (Nam1) = E_Operator then
1787 Predef_Subp := Nam1;
1790 elsif Ekind (Nam2) = E_Operator then
1791 Predef_Subp := Nam2;
1794 elsif Nkind (N) = N_Range then
1797 -- Implement AI05-105: A renaming declaration with an access
1798 -- definition must resolve to an anonymous access type. This
1799 -- is a resolution rule and can be used to disambiguate.
1801 elsif Nkind (Parent (N)) = N_Object_Renaming_Declaration
1802 and then Present (Access_Definition (Parent (N)))
1804 if Ekind_In (It1.Typ, E_Anonymous_Access_Type,
1805 E_Anonymous_Access_Subprogram_Type)
1807 if Ekind (It2.Typ) = Ekind (It1.Typ) then
1817 elsif Ekind_In (It2.Typ, E_Anonymous_Access_Type,
1818 E_Anonymous_Access_Subprogram_Type)
1822 -- No legal interpretation
1828 -- If two user defined-subprograms are visible, it is a true ambiguity,
1829 -- unless one of them is an entry and the context is a conditional or
1830 -- timed entry call, or unless we are within an instance and this is
1831 -- results from two formals types with the same actual.
1834 if Nkind (N) = N_Procedure_Call_Statement
1835 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1836 and then N = Entry_Call_Statement (Parent (N))
1838 if Ekind (Nam2) = E_Entry then
1840 elsif Ekind (Nam1) = E_Entry then
1846 -- If the ambiguity occurs within an instance, it is due to several
1847 -- formal types with the same actual. Look for an exact match between
1848 -- the types of the formals of the overloadable entities, and the
1849 -- actuals in the call, to recover the unambiguous match in the
1850 -- original generic.
1852 -- The ambiguity can also be due to an overloading between a formal
1853 -- subprogram and a subprogram declared outside the generic. If the
1854 -- node is overloaded, it did not resolve to the global entity in
1855 -- the generic, and we choose the formal subprogram.
1857 -- Finally, the ambiguity can be between an explicit subprogram and
1858 -- one inherited (with different defaults) from an actual. In this
1859 -- case the resolution was to the explicit declaration in the
1860 -- generic, and remains so in the instance.
1862 -- The same sort of disambiguation needed for calls is also required
1863 -- for the name given in a subprogram renaming, and that case is
1864 -- handled here as well. We test Comes_From_Source to exclude this
1865 -- treatment for implicit renamings created for formal subprograms.
1868 and then not In_Generic_Actual (N)
1870 if Nkind (N) = N_Function_Call
1871 or else Nkind (N) = N_Procedure_Call_Statement
1873 (Nkind (N) in N_Has_Entity
1875 Nkind (Parent (N)) = N_Subprogram_Renaming_Declaration
1876 and then Comes_From_Source (Parent (N)))
1881 Renam : Entity_Id := Empty;
1882 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1883 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1886 if Is_Act1 and then not Is_Act2 then
1889 elsif Is_Act2 and then not Is_Act1 then
1892 elsif Inherited_From_Actual (Nam1)
1893 and then Comes_From_Source (Nam2)
1897 elsif Inherited_From_Actual (Nam2)
1898 and then Comes_From_Source (Nam1)
1903 -- In the case of a renamed subprogram, pick up the entity
1904 -- of the renaming declaration so we can traverse its
1905 -- formal parameters.
1907 if Nkind (N) in N_Has_Entity then
1908 Renam := Defining_Unit_Name (Specification (Parent (N)));
1911 if Present (Renam) then
1912 Actual := First_Formal (Renam);
1914 Actual := First_Actual (N);
1917 Formal := First_Formal (Nam1);
1918 while Present (Actual) loop
1919 if Etype (Actual) /= Etype (Formal) then
1923 if Present (Renam) then
1924 Next_Formal (Actual);
1926 Next_Actual (Actual);
1929 Next_Formal (Formal);
1935 elsif Nkind (N) in N_Binary_Op then
1936 if Matches (Left_Opnd (N), First_Formal (Nam1))
1938 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1945 elsif Nkind (N) in N_Unary_Op then
1946 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
1953 return Remove_Conversions;
1956 return Remove_Conversions;
1960 -- An implicit concatenation operator on a string type cannot be
1961 -- disambiguated from the predefined concatenation. This can only
1962 -- happen with concatenation of string literals.
1964 if Chars (User_Subp) = Name_Op_Concat
1965 and then Ekind (User_Subp) = E_Operator
1966 and then Is_String_Type (Etype (First_Formal (User_Subp)))
1970 -- If the user-defined operator is in an open scope, or in the scope
1971 -- of the resulting type, or given by an expanded name that names its
1972 -- scope, it hides the predefined operator for the type. Exponentiation
1973 -- has to be special-cased because the implicit operator does not have
1974 -- a symmetric signature, and may not be hidden by the explicit one.
1976 elsif (Nkind (N) = N_Function_Call
1977 and then Nkind (Name (N)) = N_Expanded_Name
1978 and then (Chars (Predef_Subp) /= Name_Op_Expon
1979 or else Hides_Op (User_Subp, Predef_Subp))
1980 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
1981 or else Hides_Op (User_Subp, Predef_Subp)
1983 if It1.Nam = User_Subp then
1989 -- Otherwise, the predefined operator has precedence, or if the user-
1990 -- defined operation is directly visible we have a true ambiguity.
1992 -- If this is a fixed-point multiplication and division in Ada 83 mode,
1993 -- exclude the universal_fixed operator, which often causes ambiguities
1996 -- Ditto in Ada 2012, where an ambiguity may arise for an operation
1997 -- on a partial view that is completed with a fixed point type. See
1998 -- AI05-0020 and AI05-0209. The ambiguity is resolved in favor of the
1999 -- user-defined subprogram so that a client of the package has the
2000 -- same resulution as the body of the package.
2003 if (In_Open_Scopes (Scope (User_Subp))
2004 or else Is_Potentially_Use_Visible (User_Subp))
2005 and then not In_Instance
2007 if Is_Fixed_Point_Type (Typ)
2008 and then (Chars (Nam1) = Name_Op_Multiply
2009 or else Chars (Nam1) = Name_Op_Divide)
2011 (Ada_Version = Ada_83
2013 (Ada_Version >= Ada_2012
2015 In_Same_Declaration_List
2016 (Typ, Unit_Declaration_Node (User_Subp))))
2018 if It2.Nam = Predef_Subp then
2024 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
2025 -- states that the operator defined in Standard is not available
2026 -- if there is a user-defined equality with the proper signature,
2027 -- declared in the same declarative list as the type. The node
2028 -- may be an operator or a function call.
2030 elsif (Chars (Nam1) = Name_Op_Eq
2032 Chars (Nam1) = Name_Op_Ne)
2033 and then Ada_Version >= Ada_2005
2034 and then Etype (User_Subp) = Standard_Boolean
2035 and then Ekind (Operand_Type) = E_Anonymous_Access_Type
2037 In_Same_Declaration_List
2038 (Designated_Type (Operand_Type),
2039 Unit_Declaration_Node (User_Subp))
2041 if It2.Nam = Predef_Subp then
2047 -- An immediately visible operator hides a use-visible user-
2048 -- defined operation. This disambiguation cannot take place
2049 -- earlier because the visibility of the predefined operator
2050 -- can only be established when operand types are known.
2052 elsif Ekind (User_Subp) = E_Function
2053 and then Ekind (Predef_Subp) = E_Operator
2054 and then Nkind (N) in N_Op
2055 and then not Is_Overloaded (Right_Opnd (N))
2057 Is_Immediately_Visible (Base_Type (Etype (Right_Opnd (N))))
2058 and then Is_Potentially_Use_Visible (User_Subp)
2060 if It2.Nam = Predef_Subp then
2070 elsif It1.Nam = Predef_Subp then
2079 ---------------------
2080 -- End_Interp_List --
2081 ---------------------
2083 procedure End_Interp_List is
2085 All_Interp.Table (All_Interp.Last) := No_Interp;
2086 All_Interp.Increment_Last;
2087 end End_Interp_List;
2089 -------------------------
2090 -- Entity_Matches_Spec --
2091 -------------------------
2093 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
2095 -- Simple case: same entity kinds, type conformance is required. A
2096 -- parameterless function can also rename a literal.
2098 if Ekind (Old_S) = Ekind (New_S)
2099 or else (Ekind (New_S) = E_Function
2100 and then Ekind (Old_S) = E_Enumeration_Literal)
2102 return Type_Conformant (New_S, Old_S);
2104 elsif Ekind (New_S) = E_Function
2105 and then Ekind (Old_S) = E_Operator
2107 return Operator_Matches_Spec (Old_S, New_S);
2109 elsif Ekind (New_S) = E_Procedure
2110 and then Is_Entry (Old_S)
2112 return Type_Conformant (New_S, Old_S);
2117 end Entity_Matches_Spec;
2119 ----------------------
2120 -- Find_Unique_Type --
2121 ----------------------
2123 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
2124 T : constant Entity_Id := Etype (L);
2127 TR : Entity_Id := Any_Type;
2130 if Is_Overloaded (R) then
2131 Get_First_Interp (R, I, It);
2132 while Present (It.Typ) loop
2133 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
2135 -- If several interpretations are possible and L is universal,
2136 -- apply preference rule.
2138 if TR /= Any_Type then
2140 if (T = Universal_Integer or else T = Universal_Real)
2151 Get_Next_Interp (I, It);
2156 -- In the non-overloaded case, the Etype of R is already set correctly
2162 -- If one of the operands is Universal_Fixed, the type of the other
2163 -- operand provides the context.
2165 if Etype (R) = Universal_Fixed then
2168 elsif T = Universal_Fixed then
2171 -- Ada 2005 (AI-230): Support the following operators:
2173 -- function "=" (L, R : universal_access) return Boolean;
2174 -- function "/=" (L, R : universal_access) return Boolean;
2176 -- Pool specific access types (E_Access_Type) are not covered by these
2177 -- operators because of the legality rule of 4.5.2(9.2): "The operands
2178 -- of the equality operators for universal_access shall be convertible
2179 -- to one another (see 4.6)". For example, considering the type decla-
2180 -- ration "type P is access Integer" and an anonymous access to Integer,
2181 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
2182 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
2184 elsif Ada_Version >= Ada_2005
2186 (Ekind (Etype (L)) = E_Anonymous_Access_Type
2188 Ekind (Etype (L)) = E_Anonymous_Access_Subprogram_Type)
2189 and then Is_Access_Type (Etype (R))
2190 and then Ekind (Etype (R)) /= E_Access_Type
2194 elsif Ada_Version >= Ada_2005
2196 (Ekind (Etype (R)) = E_Anonymous_Access_Type
2197 or else Ekind (Etype (R)) = E_Anonymous_Access_Subprogram_Type)
2198 and then Is_Access_Type (Etype (L))
2199 and then Ekind (Etype (L)) /= E_Access_Type
2204 return Specific_Type (T, Etype (R));
2206 end Find_Unique_Type;
2208 -------------------------------------
2209 -- Function_Interp_Has_Abstract_Op --
2210 -------------------------------------
2212 function Function_Interp_Has_Abstract_Op
2214 E : Entity_Id) return Entity_Id
2216 Abstr_Op : Entity_Id;
2219 Form_Parm : Node_Id;
2222 -- Why is check on E needed below ???
2223 -- In any case this para needs comments ???
2225 if Is_Overloaded (N) and then Is_Overloadable (E) then
2226 Act_Parm := First_Actual (N);
2227 Form_Parm := First_Formal (E);
2228 while Present (Act_Parm)
2229 and then Present (Form_Parm)
2233 if Nkind (Act) = N_Parameter_Association then
2234 Act := Explicit_Actual_Parameter (Act);
2237 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2239 if Present (Abstr_Op) then
2243 Next_Actual (Act_Parm);
2244 Next_Formal (Form_Parm);
2249 end Function_Interp_Has_Abstract_Op;
2251 ----------------------
2252 -- Get_First_Interp --
2253 ----------------------
2255 procedure Get_First_Interp
2257 I : out Interp_Index;
2260 Int_Ind : Interp_Index;
2265 -- If a selected component is overloaded because the selector has
2266 -- multiple interpretations, the node is a call to a protected
2267 -- operation or an indirect call. Retrieve the interpretation from
2268 -- the selector name. The selected component may be overloaded as well
2269 -- if the prefix is overloaded. That case is unchanged.
2271 if Nkind (N) = N_Selected_Component
2272 and then Is_Overloaded (Selector_Name (N))
2274 O_N := Selector_Name (N);
2279 Map_Ptr := Headers (Hash (O_N));
2280 while Map_Ptr /= No_Entry loop
2281 if Interp_Map.Table (Map_Ptr).Node = O_N then
2282 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2283 It := All_Interp.Table (Int_Ind);
2287 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2291 -- Procedure should never be called if the node has no interpretations
2293 raise Program_Error;
2294 end Get_First_Interp;
2296 ---------------------
2297 -- Get_Next_Interp --
2298 ---------------------
2300 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2303 It := All_Interp.Table (I);
2304 end Get_Next_Interp;
2306 -------------------------
2307 -- Has_Compatible_Type --
2308 -------------------------
2310 function Has_Compatible_Type
2312 Typ : Entity_Id) return Boolean
2322 if Nkind (N) = N_Subtype_Indication
2323 or else not Is_Overloaded (N)
2326 Covers (Typ, Etype (N))
2328 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2329 -- If the type is already frozen use the corresponding_record
2330 -- to check whether it is a proper descendant.
2333 (Is_Record_Type (Typ)
2334 and then Is_Concurrent_Type (Etype (N))
2335 and then Present (Corresponding_Record_Type (Etype (N)))
2336 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2339 (Is_Concurrent_Type (Typ)
2340 and then Is_Record_Type (Etype (N))
2341 and then Present (Corresponding_Record_Type (Typ))
2342 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2345 (not Is_Tagged_Type (Typ)
2346 and then Ekind (Typ) /= E_Anonymous_Access_Type
2347 and then Covers (Etype (N), Typ));
2350 Get_First_Interp (N, I, It);
2351 while Present (It.Typ) loop
2352 if (Covers (Typ, It.Typ)
2354 (Scope (It.Nam) /= Standard_Standard
2355 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2357 -- Ada 2005 (AI-345)
2360 (Is_Concurrent_Type (It.Typ)
2361 and then Present (Corresponding_Record_Type
2363 and then Covers (Typ, Corresponding_Record_Type
2366 or else (not Is_Tagged_Type (Typ)
2367 and then Ekind (Typ) /= E_Anonymous_Access_Type
2368 and then Covers (It.Typ, Typ))
2373 Get_Next_Interp (I, It);
2378 end Has_Compatible_Type;
2380 ---------------------
2381 -- Has_Abstract_Op --
2382 ---------------------
2384 function Has_Abstract_Op
2386 Typ : Entity_Id) return Entity_Id
2392 if Is_Overloaded (N) then
2393 Get_First_Interp (N, I, It);
2394 while Present (It.Nam) loop
2395 if Present (It.Abstract_Op)
2396 and then Etype (It.Abstract_Op) = Typ
2398 return It.Abstract_Op;
2401 Get_Next_Interp (I, It);
2406 end Has_Abstract_Op;
2412 function Hash (N : Node_Id) return Int is
2414 -- Nodes have a size that is power of two, so to select significant
2415 -- bits only we remove the low-order bits.
2417 return ((Int (N) / 2 ** 5) mod Header_Size);
2424 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2425 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2427 return Operator_Matches_Spec (Op, F)
2428 and then (In_Open_Scopes (Scope (F))
2429 or else Scope (F) = Scope (Btyp)
2430 or else (not In_Open_Scopes (Scope (Btyp))
2431 and then not In_Use (Btyp)
2432 and then not In_Use (Scope (Btyp))));
2435 ------------------------
2436 -- Init_Interp_Tables --
2437 ------------------------
2439 procedure Init_Interp_Tables is
2443 Headers := (others => No_Entry);
2444 end Init_Interp_Tables;
2446 -----------------------------------
2447 -- Interface_Present_In_Ancestor --
2448 -----------------------------------
2450 function Interface_Present_In_Ancestor
2452 Iface : Entity_Id) return Boolean
2454 Target_Typ : Entity_Id;
2455 Iface_Typ : Entity_Id;
2457 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2458 -- Returns True if Typ or some ancestor of Typ implements Iface
2460 -------------------------------
2461 -- Iface_Present_In_Ancestor --
2462 -------------------------------
2464 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2470 if Typ = Iface_Typ then
2474 -- Handle private types
2476 if Present (Full_View (Typ))
2477 and then not Is_Concurrent_Type (Full_View (Typ))
2479 E := Full_View (Typ);
2485 if Present (Interfaces (E))
2486 and then Present (Interfaces (E))
2487 and then not Is_Empty_Elmt_List (Interfaces (E))
2489 Elmt := First_Elmt (Interfaces (E));
2490 while Present (Elmt) loop
2493 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2501 exit when Etype (E) = E
2503 -- Handle private types
2505 or else (Present (Full_View (Etype (E)))
2506 and then Full_View (Etype (E)) = E);
2508 -- Check if the current type is a direct derivation of the
2511 if Etype (E) = Iface_Typ then
2515 -- Climb to the immediate ancestor handling private types
2517 if Present (Full_View (Etype (E))) then
2518 E := Full_View (Etype (E));
2525 end Iface_Present_In_Ancestor;
2527 -- Start of processing for Interface_Present_In_Ancestor
2530 -- Iface might be a class-wide subtype, so we have to apply Base_Type
2532 if Is_Class_Wide_Type (Iface) then
2533 Iface_Typ := Etype (Base_Type (Iface));
2540 Iface_Typ := Base_Type (Iface_Typ);
2542 if Is_Access_Type (Typ) then
2543 Target_Typ := Etype (Directly_Designated_Type (Typ));
2548 if Is_Concurrent_Record_Type (Target_Typ) then
2549 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2552 Target_Typ := Base_Type (Target_Typ);
2554 -- In case of concurrent types we can't use the Corresponding Record_Typ
2555 -- to look for the interface because it is built by the expander (and
2556 -- hence it is not always available). For this reason we traverse the
2557 -- list of interfaces (available in the parent of the concurrent type)
2559 if Is_Concurrent_Type (Target_Typ) then
2560 if Present (Interface_List (Parent (Target_Typ))) then
2565 AI := First (Interface_List (Parent (Target_Typ)));
2566 while Present (AI) loop
2567 if Etype (AI) = Iface_Typ then
2570 elsif Present (Interfaces (Etype (AI)))
2571 and then Iface_Present_In_Ancestor (Etype (AI))
2584 if Is_Class_Wide_Type (Target_Typ) then
2585 Target_Typ := Etype (Target_Typ);
2588 if Ekind (Target_Typ) = E_Incomplete_Type then
2589 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2590 Target_Typ := Non_Limited_View (Target_Typ);
2592 -- Protect the frontend against previously detected errors
2594 if Ekind (Target_Typ) = E_Incomplete_Type then
2599 return Iface_Present_In_Ancestor (Target_Typ);
2600 end Interface_Present_In_Ancestor;
2602 ---------------------
2603 -- Intersect_Types --
2604 ---------------------
2606 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2607 Index : Interp_Index;
2611 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2612 -- Find interpretation of right arg that has type compatible with T
2614 --------------------------
2615 -- Check_Right_Argument --
2616 --------------------------
2618 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2619 Index : Interp_Index;
2624 if not Is_Overloaded (R) then
2625 return Specific_Type (T, Etype (R));
2628 Get_First_Interp (R, Index, It);
2630 T2 := Specific_Type (T, It.Typ);
2632 if T2 /= Any_Type then
2636 Get_Next_Interp (Index, It);
2637 exit when No (It.Typ);
2642 end Check_Right_Argument;
2644 -- Start of processing for Intersect_Types
2647 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2651 if not Is_Overloaded (L) then
2652 Typ := Check_Right_Argument (Etype (L));
2656 Get_First_Interp (L, Index, It);
2657 while Present (It.Typ) loop
2658 Typ := Check_Right_Argument (It.Typ);
2659 exit when Typ /= Any_Type;
2660 Get_Next_Interp (Index, It);
2665 -- If Typ is Any_Type, it means no compatible pair of types was found
2667 if Typ = Any_Type then
2668 if Nkind (Parent (L)) in N_Op then
2669 Error_Msg_N ("incompatible types for operator", Parent (L));
2671 elsif Nkind (Parent (L)) = N_Range then
2672 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2674 -- Ada 2005 (AI-251): Complete the error notification
2676 elsif Is_Class_Wide_Type (Etype (R))
2677 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2679 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2680 L, Etype (Class_Wide_Type (Etype (R))));
2683 Error_Msg_N ("incompatible types", Parent (L));
2688 end Intersect_Types;
2690 -----------------------
2691 -- In_Generic_Actual --
2692 -----------------------
2694 function In_Generic_Actual (Exp : Node_Id) return Boolean is
2695 Par : constant Node_Id := Parent (Exp);
2701 elsif Nkind (Par) in N_Declaration then
2702 if Nkind (Par) = N_Object_Declaration then
2703 return Present (Corresponding_Generic_Association (Par));
2708 elsif Nkind (Par) = N_Object_Renaming_Declaration then
2709 return Present (Corresponding_Generic_Association (Par));
2711 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
2715 return In_Generic_Actual (Parent (Par));
2717 end In_Generic_Actual;
2723 function Is_Ancestor
2726 Use_Full_View : Boolean := False) return Boolean
2733 BT1 := Base_Type (T1);
2734 BT2 := Base_Type (T2);
2736 -- Handle underlying view of records with unknown discriminants using
2737 -- the original entity that motivated the construction of this
2738 -- underlying record view (see Build_Derived_Private_Type).
2740 if Is_Underlying_Record_View (BT1) then
2741 BT1 := Underlying_Record_View (BT1);
2744 if Is_Underlying_Record_View (BT2) then
2745 BT2 := Underlying_Record_View (BT2);
2751 -- The predicate must look past privacy
2753 elsif Is_Private_Type (T1)
2754 and then Present (Full_View (T1))
2755 and then BT2 = Base_Type (Full_View (T1))
2759 elsif Is_Private_Type (T2)
2760 and then Present (Full_View (T2))
2761 and then BT1 = Base_Type (Full_View (T2))
2766 -- Obtain the parent of the base type of T2 (use the full view if
2770 and then Is_Private_Type (BT2)
2771 and then Present (Full_View (BT2))
2773 -- No climbing needed if its full view is the root type
2775 if Full_View (BT2) = Root_Type (Full_View (BT2)) then
2779 Par := Etype (Full_View (BT2));
2786 -- If there was a error on the type declaration, do not recurse
2788 if Error_Posted (Par) then
2791 elsif BT1 = Base_Type (Par)
2792 or else (Is_Private_Type (T1)
2793 and then Present (Full_View (T1))
2794 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2798 elsif Is_Private_Type (Par)
2799 and then Present (Full_View (Par))
2800 and then Full_View (Par) = BT1
2806 elsif Par = Root_Type (Par) then
2809 -- Continue climbing
2812 -- Use the full-view of private types (if allowed)
2815 and then Is_Private_Type (Par)
2816 and then Present (Full_View (Par))
2818 Par := Etype (Full_View (Par));
2827 ---------------------------
2828 -- Is_Invisible_Operator --
2829 ---------------------------
2831 function Is_Invisible_Operator
2833 T : Entity_Id) return Boolean
2835 Orig_Node : constant Node_Id := Original_Node (N);
2838 if Nkind (N) not in N_Op then
2841 elsif not Comes_From_Source (N) then
2844 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2847 elsif Nkind (N) in N_Binary_Op
2848 and then No (Universal_Interpretation (Left_Opnd (N)))
2853 return Is_Numeric_Type (T)
2854 and then not In_Open_Scopes (Scope (T))
2855 and then not Is_Potentially_Use_Visible (T)
2856 and then not In_Use (T)
2857 and then not In_Use (Scope (T))
2859 (Nkind (Orig_Node) /= N_Function_Call
2860 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2861 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2862 and then not In_Instance;
2864 end Is_Invisible_Operator;
2866 --------------------
2868 --------------------
2870 function Is_Progenitor
2872 Typ : Entity_Id) return Boolean
2875 return Implements_Interface (Typ, Iface, Exclude_Parents => True);
2882 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2886 S := Ancestor_Subtype (T1);
2887 while Present (S) loop
2891 S := Ancestor_Subtype (S);
2902 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2903 Index : Interp_Index;
2907 Get_First_Interp (Nam, Index, It);
2908 while Present (It.Nam) loop
2909 if Scope (It.Nam) = Standard_Standard
2910 and then Scope (It.Typ) /= Standard_Standard
2912 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2913 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2916 Error_Msg_Sloc := Sloc (It.Nam);
2917 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2920 Get_Next_Interp (Index, It);
2928 procedure New_Interps (N : Node_Id) is
2932 All_Interp.Append (No_Interp);
2934 Map_Ptr := Headers (Hash (N));
2936 if Map_Ptr = No_Entry then
2938 -- Place new node at end of table
2940 Interp_Map.Increment_Last;
2941 Headers (Hash (N)) := Interp_Map.Last;
2944 -- Place node at end of chain, or locate its previous entry
2947 if Interp_Map.Table (Map_Ptr).Node = N then
2949 -- Node is already in the table, and is being rewritten.
2950 -- Start a new interp section, retain hash link.
2952 Interp_Map.Table (Map_Ptr).Node := N;
2953 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2954 Set_Is_Overloaded (N, True);
2958 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
2959 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2963 -- Chain the new node
2965 Interp_Map.Increment_Last;
2966 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
2969 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
2970 Set_Is_Overloaded (N, True);
2973 ---------------------------
2974 -- Operator_Matches_Spec --
2975 ---------------------------
2977 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
2978 Op_Name : constant Name_Id := Chars (Op);
2979 T : constant Entity_Id := Etype (New_S);
2987 -- To verify that a predefined operator matches a given signature,
2988 -- do a case analysis of the operator classes. Function can have one
2989 -- or two formals and must have the proper result type.
2991 New_F := First_Formal (New_S);
2992 Old_F := First_Formal (Op);
2994 while Present (New_F) and then Present (Old_F) loop
2996 Next_Formal (New_F);
2997 Next_Formal (Old_F);
3000 -- Definite mismatch if different number of parameters
3002 if Present (Old_F) or else Present (New_F) then
3008 T1 := Etype (First_Formal (New_S));
3010 if Op_Name = Name_Op_Subtract
3011 or else Op_Name = Name_Op_Add
3012 or else Op_Name = Name_Op_Abs
3014 return Base_Type (T1) = Base_Type (T)
3015 and then Is_Numeric_Type (T);
3017 elsif Op_Name = Name_Op_Not then
3018 return Base_Type (T1) = Base_Type (T)
3019 and then Valid_Boolean_Arg (Base_Type (T));
3028 T1 := Etype (First_Formal (New_S));
3029 T2 := Etype (Next_Formal (First_Formal (New_S)));
3031 if Op_Name = Name_Op_And or else Op_Name = Name_Op_Or
3032 or else Op_Name = Name_Op_Xor
3034 return Base_Type (T1) = Base_Type (T2)
3035 and then Base_Type (T1) = Base_Type (T)
3036 and then Valid_Boolean_Arg (Base_Type (T));
3038 elsif Op_Name = Name_Op_Eq or else Op_Name = Name_Op_Ne then
3039 return Base_Type (T1) = Base_Type (T2)
3040 and then not Is_Limited_Type (T1)
3041 and then Is_Boolean_Type (T);
3043 elsif Op_Name = Name_Op_Lt or else Op_Name = Name_Op_Le
3044 or else Op_Name = Name_Op_Gt or else Op_Name = Name_Op_Ge
3046 return Base_Type (T1) = Base_Type (T2)
3047 and then Valid_Comparison_Arg (T1)
3048 and then Is_Boolean_Type (T);
3050 elsif Op_Name = Name_Op_Add or else Op_Name = Name_Op_Subtract then
3051 return Base_Type (T1) = Base_Type (T2)
3052 and then Base_Type (T1) = Base_Type (T)
3053 and then Is_Numeric_Type (T);
3055 -- For division and multiplication, a user-defined function does not
3056 -- match the predefined universal_fixed operation, except in Ada 83.
3058 elsif Op_Name = Name_Op_Divide then
3059 return (Base_Type (T1) = Base_Type (T2)
3060 and then Base_Type (T1) = Base_Type (T)
3061 and then Is_Numeric_Type (T)
3062 and then (not Is_Fixed_Point_Type (T)
3063 or else Ada_Version = Ada_83))
3065 -- Mixed_Mode operations on fixed-point types
3067 or else (Base_Type (T1) = Base_Type (T)
3068 and then Base_Type (T2) = Base_Type (Standard_Integer)
3069 and then Is_Fixed_Point_Type (T))
3071 -- A user defined operator can also match (and hide) a mixed
3072 -- operation on universal literals.
3074 or else (Is_Integer_Type (T2)
3075 and then Is_Floating_Point_Type (T1)
3076 and then Base_Type (T1) = Base_Type (T));
3078 elsif Op_Name = Name_Op_Multiply then
3079 return (Base_Type (T1) = Base_Type (T2)
3080 and then Base_Type (T1) = Base_Type (T)
3081 and then Is_Numeric_Type (T)
3082 and then (not Is_Fixed_Point_Type (T)
3083 or else Ada_Version = Ada_83))
3085 -- Mixed_Mode operations on fixed-point types
3087 or else (Base_Type (T1) = Base_Type (T)
3088 and then Base_Type (T2) = Base_Type (Standard_Integer)
3089 and then Is_Fixed_Point_Type (T))
3091 or else (Base_Type (T2) = Base_Type (T)
3092 and then Base_Type (T1) = Base_Type (Standard_Integer)
3093 and then Is_Fixed_Point_Type (T))
3095 or else (Is_Integer_Type (T2)
3096 and then Is_Floating_Point_Type (T1)
3097 and then Base_Type (T1) = Base_Type (T))
3099 or else (Is_Integer_Type (T1)
3100 and then Is_Floating_Point_Type (T2)
3101 and then Base_Type (T2) = Base_Type (T));
3103 elsif Op_Name = Name_Op_Mod or else Op_Name = Name_Op_Rem then
3104 return Base_Type (T1) = Base_Type (T2)
3105 and then Base_Type (T1) = Base_Type (T)
3106 and then Is_Integer_Type (T);
3108 elsif Op_Name = Name_Op_Expon then
3109 return Base_Type (T1) = Base_Type (T)
3110 and then Is_Numeric_Type (T)
3111 and then Base_Type (T2) = Base_Type (Standard_Integer);
3113 elsif Op_Name = Name_Op_Concat then
3114 return Is_Array_Type (T)
3115 and then (Base_Type (T) = Base_Type (Etype (Op)))
3116 and then (Base_Type (T1) = Base_Type (T)
3118 Base_Type (T1) = Base_Type (Component_Type (T)))
3119 and then (Base_Type (T2) = Base_Type (T)
3121 Base_Type (T2) = Base_Type (Component_Type (T)));
3127 end Operator_Matches_Spec;
3133 procedure Remove_Interp (I : in out Interp_Index) is
3137 -- Find end of interp list and copy downward to erase the discarded one
3140 while Present (All_Interp.Table (II).Typ) loop
3144 for J in I + 1 .. II loop
3145 All_Interp.Table (J - 1) := All_Interp.Table (J);
3148 -- Back up interp index to insure that iterator will pick up next
3149 -- available interpretation.
3158 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
3160 O_N : Node_Id := Old_N;
3163 if Is_Overloaded (Old_N) then
3164 if Nkind (Old_N) = N_Selected_Component
3165 and then Is_Overloaded (Selector_Name (Old_N))
3167 O_N := Selector_Name (Old_N);
3170 Map_Ptr := Headers (Hash (O_N));
3172 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
3173 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
3174 pragma Assert (Map_Ptr /= No_Entry);
3177 New_Interps (New_N);
3178 Interp_Map.Table (Interp_Map.Last).Index :=
3179 Interp_Map.Table (Map_Ptr).Index;
3187 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
3188 T1 : constant Entity_Id := Available_View (Typ_1);
3189 T2 : constant Entity_Id := Available_View (Typ_2);
3190 B1 : constant Entity_Id := Base_Type (T1);
3191 B2 : constant Entity_Id := Base_Type (T2);
3193 function Is_Remote_Access (T : Entity_Id) return Boolean;
3194 -- Check whether T is the equivalent type of a remote access type.
3195 -- If distribution is enabled, T is a legal context for Null.
3197 ----------------------
3198 -- Is_Remote_Access --
3199 ----------------------
3201 function Is_Remote_Access (T : Entity_Id) return Boolean is
3203 return Is_Record_Type (T)
3204 and then (Is_Remote_Call_Interface (T)
3205 or else Is_Remote_Types (T))
3206 and then Present (Corresponding_Remote_Type (T))
3207 and then Is_Access_Type (Corresponding_Remote_Type (T));
3208 end Is_Remote_Access;
3210 -- Start of processing for Specific_Type
3213 if T1 = Any_Type or else T2 = Any_Type then
3220 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
3221 or else (T1 = Universal_Real and then Is_Real_Type (T2))
3222 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
3223 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
3227 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
3228 or else (T2 = Universal_Real and then Is_Real_Type (T1))
3229 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
3230 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
3234 elsif T2 = Any_String and then Is_String_Type (T1) then
3237 elsif T1 = Any_String and then Is_String_Type (T2) then
3240 elsif T2 = Any_Character and then Is_Character_Type (T1) then
3243 elsif T1 = Any_Character and then Is_Character_Type (T2) then
3246 elsif T1 = Any_Access
3247 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
3251 elsif T2 = Any_Access
3252 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
3256 -- In an instance, the specific type may have a private view. Use full
3257 -- view to check legality.
3259 elsif T2 = Any_Access
3260 and then Is_Private_Type (T1)
3261 and then Present (Full_View (T1))
3262 and then Is_Access_Type (Full_View (T1))
3263 and then In_Instance
3267 elsif T2 = Any_Composite
3268 and then Is_Aggregate_Type (T1)
3272 elsif T1 = Any_Composite
3273 and then Is_Aggregate_Type (T2)
3277 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
3280 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
3283 -- ----------------------------------------------------------
3284 -- Special cases for equality operators (all other predefined
3285 -- operators can never apply to tagged types)
3286 -- ----------------------------------------------------------
3288 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
3291 elsif Is_Class_Wide_Type (T1)
3292 and then Is_Class_Wide_Type (T2)
3293 and then Is_Interface (Etype (T2))
3297 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
3298 -- class-wide interface T2
3300 elsif Is_Class_Wide_Type (T2)
3301 and then Is_Interface (Etype (T2))
3302 and then Interface_Present_In_Ancestor (Typ => T1,
3303 Iface => Etype (T2))
3307 elsif Is_Class_Wide_Type (T1)
3308 and then Is_Ancestor (Root_Type (T1), T2)
3312 elsif Is_Class_Wide_Type (T2)
3313 and then Is_Ancestor (Root_Type (T2), T1)
3317 elsif (Ekind (B1) = E_Access_Subprogram_Type
3319 Ekind (B1) = E_Access_Protected_Subprogram_Type)
3320 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
3321 and then Is_Access_Type (T2)
3325 elsif (Ekind (B2) = E_Access_Subprogram_Type
3327 Ekind (B2) = E_Access_Protected_Subprogram_Type)
3328 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
3329 and then Is_Access_Type (T1)
3333 elsif (Ekind (T1) = E_Allocator_Type
3334 or else Ekind (T1) = E_Access_Attribute_Type
3335 or else Ekind (T1) = E_Anonymous_Access_Type)
3336 and then Is_Access_Type (T2)
3340 elsif (Ekind (T2) = E_Allocator_Type
3341 or else Ekind (T2) = E_Access_Attribute_Type
3342 or else Ekind (T2) = E_Anonymous_Access_Type)
3343 and then Is_Access_Type (T1)
3347 -- If none of the above cases applies, types are not compatible
3354 ---------------------
3355 -- Set_Abstract_Op --
3356 ---------------------
3358 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3360 All_Interp.Table (I).Abstract_Op := V;
3361 end Set_Abstract_Op;
3363 -----------------------
3364 -- Valid_Boolean_Arg --
3365 -----------------------
3367 -- In addition to booleans and arrays of booleans, we must include
3368 -- aggregates as valid boolean arguments, because in the first pass of
3369 -- resolution their components are not examined. If it turns out not to be
3370 -- an aggregate of booleans, this will be diagnosed in Resolve.
3371 -- Any_Composite must be checked for prior to the array type checks because
3372 -- Any_Composite does not have any associated indexes.
3374 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3376 if Is_Boolean_Type (T)
3377 or else Is_Modular_Integer_Type (T)
3378 or else T = Universal_Integer
3379 or else T = Any_Composite
3383 elsif Is_Array_Type (T)
3384 and then T /= Any_String
3385 and then Number_Dimensions (T) = 1
3386 and then Is_Boolean_Type (Component_Type (T))
3388 ((not Is_Private_Composite (T)
3389 and then not Is_Limited_Composite (T))
3391 or else Available_Full_View_Of_Component (T))
3398 end Valid_Boolean_Arg;
3400 --------------------------
3401 -- Valid_Comparison_Arg --
3402 --------------------------
3404 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3407 if T = Any_Composite then
3410 elsif Is_Discrete_Type (T)
3411 or else Is_Real_Type (T)
3415 elsif Is_Array_Type (T)
3416 and then Number_Dimensions (T) = 1
3417 and then Is_Discrete_Type (Component_Type (T))
3418 and then (not Is_Private_Composite (T)
3419 or else In_Instance)
3420 and then (not Is_Limited_Composite (T)
3421 or else In_Instance)
3425 elsif Is_Array_Type (T)
3426 and then Number_Dimensions (T) = 1
3427 and then Is_Discrete_Type (Component_Type (T))
3428 and then Available_Full_View_Of_Component (T)
3432 elsif Is_String_Type (T) then
3437 end Valid_Comparison_Arg;
3443 procedure Write_Interp (It : Interp) is
3445 Write_Str ("Nam: ");
3446 Print_Tree_Node (It.Nam);
3447 Write_Str ("Typ: ");
3448 Print_Tree_Node (It.Typ);
3449 Write_Str ("Abstract_Op: ");
3450 Print_Tree_Node (It.Abstract_Op);
3453 ----------------------
3454 -- Write_Interp_Ref --
3455 ----------------------
3457 procedure Write_Interp_Ref (Map_Ptr : Int) is
3459 Write_Str (" Node: ");
3460 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3461 Write_Str (" Index: ");
3462 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3463 Write_Str (" Next: ");
3464 Write_Int (Interp_Map.Table (Map_Ptr).Next);
3466 end Write_Interp_Ref;
3468 ---------------------
3469 -- Write_Overloads --
3470 ---------------------
3472 procedure Write_Overloads (N : Node_Id) is
3478 Write_Str ("Overloads: ");
3479 Print_Node_Briefly (N);
3481 if Nkind (N) not in N_Has_Entity then
3485 if not Is_Overloaded (N) then
3486 Write_Str ("Non-overloaded entity ");
3488 Write_Entity_Info (Entity (N), " ");
3491 Get_First_Interp (N, I, It);
3492 Write_Str ("Overloaded entity ");
3494 Write_Str (" Name Type Abstract Op");
3496 Write_Str ("===============================================");
3500 while Present (Nam) loop
3501 Write_Int (Int (Nam));
3503 Write_Name (Chars (Nam));
3505 Write_Int (Int (It.Typ));
3507 Write_Name (Chars (It.Typ));
3509 if Present (It.Abstract_Op) then
3511 Write_Int (Int (It.Abstract_Op));
3513 Write_Name (Chars (It.Abstract_Op));
3517 Get_Next_Interp (I, It);
3521 end Write_Overloads;