named break used incorrectly?

named_break.dart

enum Thing {
  one,
  two,
}

void main() {
  var thing = Thing.one;
  goback:
  switch (thing) {
    case Thing.one:
      print("one");
      thing = Thing.two;
      break goback;
    case Thing.two:
      print("two");
      break;
  }
}