class Forwarding {
  Forwarding(int? arg) : this.initialize(arg);
  Forwarding.initialize(this.x);
  int? x;
}

class Initialized {
  Initialized(this.x);
  int? x;
}

class PartiallyInitialized {
  PartiallyInitialized(this.x);
  PartiallyInitialized.noInitializer();
  int? x;
}

class Uninitialized {
  int? x;
}

int? initializedTopLevel = 4;
int? uninitializedTopLevel;
main() {}