===================================================================
@@ -12601,6 +12601,9 @@ package body Sem_Ch3 is
if Ekind (Parent_Subp) = E_Procedure then
Set_Is_Valued_Procedure
(New_Subp, Is_Valued_Procedure (Parent_Subp));
+ else
+ Set_Has_Controlling_Result
+ (New_Subp, Has_Controlling_Result (Parent_Subp));
end if;
-- No_Return must be inherited properly. If this is overridden in the
@@ -12654,6 +12657,15 @@ package body Sem_Ch3 is
then
Set_Is_Abstract_Subprogram (New_Subp);
+ -- AI05-0097 : an inherited operation that dispatches on result is
+ -- abstract if the derived type is abstract, even if the parent type
+ -- is concrete and the derived type is a null extension.
+
+ elsif Has_Controlling_Result (Alias (New_Subp))
+ and then Is_Abstract_Type (Etype (New_Subp))
+ then
+ Set_Is_Abstract_Subprogram (New_Subp);
+
-- Finally, if the parent type is abstract we must verify that all
-- inherited operations are either non-abstract or overridden, or that
-- the derived type itself is abstract (this check is performed at the
AI05-0097 fixes a gap in the RM, that allowed an abstract null extension to inherit a concrete constructor. The following must be rejected in any Ada mode: --- package P is type Generator is tagged record Value : Integer := 17; end record; function Create return Generator; end P; --- with P; package Q is type Windmill is abstract new P.Generator with null record; -- Inherits a concrete Create here(!!) end Q; --- with P, Q; procedure Main is Obj : P.Generator'Class := Q.Create; begin null; end; Tested on x86_64-pc-linux-gnu, committed on trunk 2010-10-08 Ed Schonberg <schonberg@adacore.com> * sem_ch3.adb (Derive_Subprogram): If an abstract extension has a concrete parent with a concrete constructor, the inherited constructor is abstract even if the derived type is a null extension.