gcc/testsuite/gnat.dg/interface7.adb

   1 --  { dg-do compile }
   2
   3 procedure Interface7 is
   4    type I_Type is interface;
   5
   6    type A1_Type is tagged null record;
   7    type A2_Type is new A1_Type and I_Type with null record;
   8
   9    procedure Test (X : I_Type'Class) is
  10    begin
  11       if X in A2_Type then   --  Test
  12          null;
  13       end if;
  14    end Test;
  15
  16 begin null; end;