}

    @Override
    protected T computeNext(T previous) {
      throw new AssertionFailedError();
    }
  }

  private static class BrokenAbstractSequentialIterator extends AbstractSequentialIterator<Object> {

    BrokenAbstractSequentialIterator() {
      super("UNUSED");
    }

    @Override
    protected Object computeNext(Object previous) {
      throw new SomeUncheckedException();
    }