Aggregates of Unchecked_Unions using named notation

Given that it is generally regarded as good practice to use named notation rather than positional notation, it was somewhat bizarre that Unchecked_Unions only allowed the latter. Both are now allowed by Aggregates of Unchecked_Unions using named notation (AI12-0174) (see RM B.3.3). For example:

type Data_Kind is (C_int, C_char);
type C_Variant (Format : Data_Kind := C_int) is record
      case Format is
         when C_int =>
            int_Val : C.int;
         when C_char =>
            char_Val : C.char;
      end case;
end record
   with Unchecked_Union, Convention => C;
Int1 : C_Variant := (C_int, 12); -- Always OK
Int2 : C_Variant := (Format => C_int, int_Val => 12);
                  -- Was illegal, now OK

7.8 Aggregates of Unchecked_Unions using named notation