gcc/testsuite/gnat.dg/warn2.adb

   1 --  { dg-do compile }
   2
   3 with Unchecked_Conversion;
   4 procedure warn2 is
   5    type R1 is record X : Integer; end record;
   6    type R2 is record X, Y : Integer; end record;
   7    pragma Warnings
   8      (Off, "types for unchecked conversion have different sizes");
   9    function F is new Unchecked_Conversion (R1, R2);
  10    pragma Warnings
  11      (On, "types for unchecked conversion have different sizes");
  12 begin
  13    null;
  14 end warn2;