interface irequires_twice
{
  in void e();
  out void a();
  behaviour
    {
      on e: a;
    }
}

component requires_twice
{
  provides irequires_twice p;
  requires irequires_twice once;
  requires irequires_twice twice;
  behaviour
    { on p.e():
      {
        once.e();
        twice.e();
      }
      on once.a(): {}
      on twice.a(): {p.a();}
    }
}