* sure there's any performance hit from our failure to override subListUnchecked under GWT
   */
  @Override
  ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
    ImmutableList<E> parentSubList = super.subListUnchecked(fromIndex, toIndex);
    return new RegularImmutableSortedSet<E>(parentSubList, comparator()).asList();
  }

  @Override
  public Spliterator<E> spliterator() {

  }

  /**
   * Sorts the array between {@code fromIndex} inclusive and {@code toIndex} exclusive, treating its
   * elements as unsigned 64-bit integers.
   *
   * @since 23.1
   */
  public static void sort(long[] array, int fromIndex, int toIndex) {
    checkNotNull(array);
    checkPositionIndexes(fromIndex, toIndex, array.length);
    for (int i = fromIndex; i < toIndex; i++) {
      array[i] = flip(array[i]);
    }

   */
  @Override
  public ImmutableList<E> subList(int fromIndex, int toIndex) {
    checkPositionIndexes(fromIndex, toIndex, size());
    int length = toIndex - fromIndex;
    if (length == size()) {
      return this;
    } else if (length == 0) {
      return of();
    } else {
      return subListUnchecked(fromIndex, toIndex);
    }
  }

  /**

  @Override
  public ImmutableList<E> subList(int fromIndex, int toIndex) {
    checkPositionIndexes(fromIndex, toIndex, size());
    int length = toIndex - fromIndex;
    if (length == size()) {
      return this;
    } else if (length == 0) {
      return of();
    } else if (length == 1) {
      return of(get(fromIndex));
    } else {
      return subListUnchecked(fromIndex, toIndex);
    }
  }

  /**

  @ParametricNullness
  public E set(int index, @ParametricNullness E element) {
    return delegate().set(index, element);
  }

  @Override
  public List<E> subList(int fromIndex, int toIndex) {
    return delegate().subList(fromIndex, toIndex);
  }

  @Override
  public boolean equals(@CheckForNull Object object) {
    return object == this || delegate().equals(object);
  }

  @Override

    }

    @Override
    public ImmutableList<Character> subList(int fromIndex, int toIndex) {
      checkPositionIndexes(fromIndex, toIndex, size()); // for GWT
      return charactersOf(string.substring(fromIndex, toIndex));
    }

    @Override
    boolean isPartialView() {
      return false;
    }

    @Override

    return delegateList().lastIndexOf(object);
  }

  public E get(int index) {
    return delegateList().get(index);
  }

  public ImmutableList<E> subList(int fromIndex, int toIndex) {
    return unsafeDelegateList(delegateList().subList(fromIndex, toIndex));
  }

  @Override
  public Object[] toArray() {
    // Note that ArrayList.toArray() doesn't work here because it returns E[]
    // instead of Object[].

    }

    @Override
    public int size() {
        return parent.size();
    }

    @Override
    public List<Map<String, Object>> subList(final int fromIndex, final int toIndex) {
        return parent.subList(fromIndex, toIndex);
    }

    @Override
    public Object[] toArray() {
        return parent.toArray();
    }

    @Override
    public <T> T[] toArray(final T[] a) {

        if (size == 0) {
            return docs; // empty
        }
        int fromIndex = startPosition;
        if (fromIndex >= size) {
            fromIndex = size - 1;
        }
        int toIndex = startPosition + pageSize;
        if (toIndex >= size) {
            toIndex = size;
        }
        return docs.subList(fromIndex, toIndex);
    }

    Chars.reverse(input);
    assertThat(input).isEqualTo(expectedOutput);
  }

  private static void testReverse(char[] input, int fromIndex, int toIndex, char[] expectedOutput) {
    input = Arrays.copyOf(input, input.length);
    Chars.reverse(input, fromIndex, toIndex);
    assertThat(input).isEqualTo(expectedOutput);
  }

  public void testReverseIndexed() {