-- RM95 3.7(14)
-- If the parent type is not a tagged type, then each
-- discriminant of the derived type shall be used in
-- the constraint defining the parent subtype;
generic
   type T1 is private;
package Test_247013 is
   type T2 (x: integer) is new T1;  -- ERROR: x not used
end Test_247013;


I expect an error message like this:
test_247013.ads:8:11: Discriminant "x" is not used to constrain the parent
subtype "T1" (RM 3.7(14))

But the compiler says nothing