gcc/testsuite/algol68/execute/string-4.a68

# { dg-options "-fstropping=upper" }  #
BEGIN STRING s;
      ASSERT (LWB s = 1 AND UPB s = 0 AND ELEMS s = 0);
      s +:= "foo";
      ASSERT (LWB s = 1 AND UPB s = 3 AND ELEMS s = 3)
END