@Override
  public int lastIndexOf(@CheckForNull Object target) {
    return indexOf(target);
  }

  @Override
  public boolean contains(@CheckForNull Object target) {
    // Necessary for ISS's with comparators inconsistent with equals.
    return indexOf(target) >= 0;
  }

  @GwtIncompatible // super.subListUnchecked does not exist; inherited subList is valid if slow
  /*