}
  }

  /** A singleton implementation of iterator() for the empty ImmutableList. */
  // TODO(b/345814817): Move this to RegularImmutableList?
  @SuppressWarnings("ClassInitializationDeadlock")
  private static final UnmodifiableListIterator<Object> EMPTY_ITR =
      new Itr<Object>(RegularImmutableList.EMPTY, 0);

  static class Itr<E> extends AbstractIndexedListIterator<E> {