interface I
{
  in void e();
  out void f();
  out void g();

  behaviour
  {
    subint Count {0..2};
    Count count = 0;

    [count != 0] on e: illegal;
    [count == 0] on e: count = 1;
    [count == 1] on inevitable: {count = 2; f;}
    [count == 2] on inevitable: {count = 0; g;}
  }
}

component C
{
  provides I p;
  requires I r;

  behaviour
  {
    requires dzn.async i;

    on p.e(): {r.e(); i.req();}
    on i.ack(): p.f();
    on r.f(): p.g();
    on r.g(): {}
  }
}

component async_rank
{
  provides I p;
  requires I r;

  system
  {
    C c2;
    C c1;

    p <=> c1.p;
    c1.r <=> c2.p;
    c2.r <=> r;
  }
}