!7

p {
  Thread t = startThread("Whoopsie", r {
    while licensed {
      print("sleeping");
      sleep(1000);
      print("done sleeping");
    }
  });
    
  assertEmpty(cancelledThreads());
  print("cancelling");
  cancelThread(t);
  assertNempty(cancelledThreads());
  t = null;

  while licensed {
    gc();
    L<Thread> threads = cancelledThreads();
    
    // use System.err to clear reference to Whoopsie thread in x30.pout3
    System.err.println(threads);
    
    if (empty(threads)) break;
    threads = null;
    sleep(100);
  }
  
  assertEmpty(cancelledThreads());
  print("OK");
}