[Ada] Fix implementation issues with equality for untagged record types

This moves the implementation of AI12-0101 + AI05-0123 from the expander
to the semantic analyzer and completes the implementation of AI12-0413,
which are both binding interpretations in Ada 2012, fixing a few bugs in
the process and removing a fair amount of duplicated code throughout.

gcc/ada/

	* einfo-utils.adb (Remove_Entity): Fix couple of oversights.
	* exp_ch3.adb (Is_User_Defined_Equality): Delete.
	(User_Defined_Eq): Call Get_User_Defined_Equality.
	(Make_Eq_Body): Likewise.
	(Predefined_Primitive_Eq_Body): Call Is_User_Defined_Equality.
	* exp_ch4.adb (Build_Eq_Call): Call Get_User_Defined_Equality.
	(Is_Equality): Delete.
	(User_Defined_Primitive_Equality_Op): Likewise.
	(Find_Aliased_Equality): Call Is_User_Defined_Equality.
	(Expand_N_Op_Eq): Call Underlying_Type unconditionally.
	Do not implement AI12-0101 + AI05-0123 here.
	(Expand_Set_Membership): Call Resolve_Membership_Equality.
	* exp_ch6.adb (Expand_Call_Helper): Remove obsolete code.
	* sem_aux.ads (Is_Record_Or_Limited_Type): Delete.
	* sem_aux.adb (Is_Record_Or_Limited_Type): Likewise.
	* sem_ch4.ads (Nondispatching_Call_To_Abstract_Operation): Declare.
	* sem_ch4.adb (Analyze_Call): Call Call_Abstract_Operation.
	(Analyze_Membership_Op): Call Resolve_Membership_Equality.
	(Nondispatching_Call_To_Abstract_Operation): New procedure.
	(Remove_Abstract_Operations): Call it.
	* sem_ch6.adb (Check_Untagged_Equality): Remove obsolete error and
	call Is_User_Defined_Equality.
	* sem_ch7.adb (Inspect_Untagged_Record_Completion): New procedure
	implementing AI12-0101 + AI05-0123.
	(Analyze_Package_Specification): Call it.
	(Declare_Inherited_Private_Subprograms): Minor tweak.
	(Uninstall_Declarations): Likewise.
	* sem_disp.adb (Check_Direct_Call): Adjust to new implementation
	of Is_User_Defined_Equality.
	* sem_res.ads (Resolve_Membership_Equality): Declare.
	* sem_res.adb (Resolve): Replace direct error handling with call to
	Nondispatching_Call_To_Abstract_Operation
	(Resolve_Call): Likewise.
	(Resolve_Equality_Op): Likewise.  mplement AI12-0413.
	(Resolve_Membership_Equality): New procedure.
	(Resolve_Membership_Op): Call Get_User_Defined_Equality.
	* sem_util.ads (Get_User_Defined_Eq): Rename into...
	(Get_User_Defined_Equality): ...this.
	* sem_util.adb (Get_User_Defined_Eq): Rename into...
	(Get_User_Defined_Equality): ...this. Call Is_User_Defined_Equality.
	(Is_User_Defined_Equality): Also check the profile but remove tests
	on Comes_From_Source and Parent.
	* sinfo.ads (Generic_Parent_Type): Adjust field description.
	* uintp.ads (Ubool): Invoke user-defined equality in predicate.

1 files changed, 9 insertions, 26 deletions

diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index be093d6863f..dbcb2556fe3 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -190,14 +190,12 @@ package body Sem_Ch6 is
    --  in posting the warning message.
 
    procedure Check_Untagged_Equality (Eq_Op : Entity_Id);
-   --  In Ada 2012, a primitive equality operator on an untagged record type
-   --  must appear before the type is frozen, and have the same visibility as
-   --  that of the type. This procedure checks that this rule is met, and
-   --  otherwise emits an error on the subprogram declaration and a warning
-   --  on the earlier freeze point if it is easy to locate. In Ada 2012 mode,
-   --  this routine outputs errors (or warnings if -gnatd.E is set). In earlier
-   --  versions of Ada, warnings are output if Warn_On_Ada_2012_Incompatibility
-   --  is set, otherwise the call has no effect.
+   --  In Ada 2012, a primitive equality operator for an untagged record type
+   --  must appear before the type is frozen. This procedure checks that this
+   --  rule is met, and otherwise gives an error on the subprogram declaration
+   --  and a warning on the earlier freeze point if it is easy to pinpoint. In
+   --  earlier versions of Ada, the call has not effect, unless compatibility
+   --  warnings are requested by means of Warn_On_Ada_2012_Incompatibility.
 
    procedure Enter_Overloaded_Entity (S : Entity_Id);
    --  This procedure makes S, a new overloaded entity, into the first visible
@@ -9511,12 +9509,12 @@ package body Sem_Ch6 is
 
    begin
       --  This check applies only if we have a subprogram declaration with an
-      --  untagged record type that is conformant to the predefined op.
+      --  untagged record type that is conformant to the predefined operator.
 
       if Nkind (Decl) /= N_Subprogram_Declaration
         or else not Is_Record_Type (Typ)
         or else Is_Tagged_Type (Typ)
-        or else Etype (Next_Formal (First_Formal (Eq_Op))) /= Typ
+        or else not Is_User_Defined_Equality (Eq_Op)
       then
          return;
       end if;
@@ -9628,22 +9626,7 @@ package body Sem_Ch6 is
             end if;
          end if;
 
-      --  Here if type is not frozen yet. It is illegal to have a primitive
-      --  equality declared in the private part if the type is visible
-      --  (RM 4.5.2(9.8)).
-
-      elsif not In_Same_List (Parent (Typ), Decl)
-        and then not Is_Limited_Type (Typ)
-      then
-         if Ada_Version >= Ada_2012 then
-            Error_Msg_N
-              ("equality operator appears too late<<", Eq_Op);
-         else
-            Error_Msg_N
-              ("equality operator appears too late (Ada 2012)?y?", Eq_Op);
-         end if;
-
-      --  Finally check for AI12-0352: declaration of a user-defined primitive
+      --  Now check for AI12-0352: the declaration of a user-defined primitive
       --  equality operation for a record type T is illegal if it occurs after
       --  a type has been derived from T.