component ActionIsIllegal
{
  provides IA pp;
  requires IB rp;

  behaviour
  {
    on pp.ia(): rp.ia();
    on rp.oa(): illegal;
  }

  // Simulate ActionIsIllegal =>
  //   Action is illegal
  // if following trace is performed:
  //   pp.ia
  //   rp.ia
}

interface IA
{
  in void ia();

  behaviour
  {
    on ia: {}
  }
}

interface IB
{
  in void ia();
  out void oa();

  behaviour
  {
    on ia: illegal;
    on ia: {}
  }
}