component EventNotAllowedByPort
{
  provides IA pp;
  requires IB rp;
  
  behaviour
  {
    on pp.ia(): {}
    on rp.oa(): pp.oa();
  }
  
  // Simulating EventNotAllowedByPort shall report error
  //   pp.oa not allowed by port pp
  // for trace
  //   rp.oa
  //   pp.oa
}

interface IA
{  
  in void ia();
  out void oa();
  
  behaviour
  {
    bool b = false;
    
    on ia: b = true;
    [b] on optional: {b = false; oa;}
  }
}

interface IB
{
  in void ia();
  out void oa();
  
  behaviour
  {
    on ia: {}
    on optional: oa;
  }
}