[Ada] Ada 2022: Class-wide types and formal abstract subprograms

[Pierre-Marie de Rodat via Gcc-patches]

Ada 2022 specifies that when the controlling type of a formal abstract
subprogram declaration is a formal type, and the actual type is a
class-wide type T'Class, the actual subprogram can be an implicitly
declared subprogram corresponding to a primitive operation of type T
(AI12-0165-1/05).

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * sem_ch8.adb (Build_Class_Wide_Wrapper): Previous version split
        in two subprograms to factorize its functionality:
        Find_Suitable_Candidate, and Build_Class_Wide_Wrapper. These
        routines are also placed in the new subprogram
        Handle_Instance_With_Class_Wide_Type.
        (Handle_Instance_With_Class_Wide_Type): New subprogram that
        encapsulates all the code that handles instantiations with
        class-wide types.
        (Analyze_Subprogram_Renaming): Adjust code to invoke the new
        nested subprogram Handle_Instance_With_Class_Wide_Type; adjust
        documentation.

patch.diff.gz
Description: application/gzip