gcc/testsuite/gnat.dg/test_ai254.adb

   1 --  { dg-do compile }
   2
   3 procedure test_ai254 is
   4    function Func
   5       (Obj : not null access protected function (X : Float) return Float)
   6       return not null access protected function (X : Float) return Float is
   7    begin
   8       return null;
   9    end;
  10 begin
  11    null;
  12 end;