interface range
{
  in void e();
  out void a();

  behaviour
  {
    subint State {0..3};

    State state = 3; //4; // TODO: static resolver/wfc check

    State f ()
    {
      return 5;
    }

    on e:
    {
      state = 4;
      state = f();
      State x = 6;
      State y = f();
      a;
    }
  }
}