}

  /** An implementation of {@link List#lastIndexOf(Object)}. */
  static int lastIndexOfImpl(List<?> list, @Nullable Object element) {
    if (list instanceof RandomAccess) {
      return lastIndexOfRandomAccess(list, element);
    } else {
      ListIterator<?> listIterator = list.listIterator(list.size());
      while (listIterator.hasPrevious()) {
        if (Objects.equals(element, listIterator.previous())) {