gcc/testsuite/algol68/execute/slice-indexing-1.a68

# { dg-options "-fstropping=upper" }  #
BEGIN STRING foo = "foo";
      ASSERT (foo[1] = "f");
      ASSERT (foo[2] = "o");
      ASSERT (foo[3] = "o");
      STRING bar := "foo";
      ASSERT (bar[1] = "f");
      ASSERT (bar[2] = "o");
      ASSERT (bar[3] = "o")
END