Long[] suffix = {86L, 99L};
      Long[] all = concat(concat(prefix, elements), suffix);
      return makeArray(all).subArray(2, elements.length + 2).asList();
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  @AndroidIncompatible
  private static Long[] concat(Long[] a, Long[] b) {
    return ObjectArrays.concat(a, b, Long.class);
  }

  @J2ktIncompatible

   * @param second the second array of elements to concatenate
   * @param type the component type of the returned array
   */
  @GwtIncompatible // Array.newInstance(Class, int)
  public static <T extends @Nullable Object> T[] concat(
      T[] first, T[] second, Class<@NonNull T> type) {
    T[] result = newArray(type, first.length + second.length);
    arraycopy(first, 0, result, 0, first.length);

      Long[] suffix = {86L, 99L};
      Long[] all = concat(concat(prefix, elements), suffix);
      return makeArray(all).subArray(2, elements.length + 2).asList();
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  @AndroidIncompatible
  private static Long[] concat(Long[] a, Long[] b) {
    return ObjectArrays.concat(a, b, Long.class);
  }

  @J2ktIncompatible

   * stream may perform better.
   *
   * @see Stream#concat(Stream, Stream)
   */
  @SuppressWarnings("unchecked") // could probably be avoided with a forwarding Spliterator
  @SafeVarargs
  public static <T extends @Nullable Object> Stream<T> concat(Stream<? extends T>... streams) {
    // TODO(lowasser): consider an implementation that can support SUBSIZED

   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code CharSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}
   * @since 15.0
   */
  public static CharSource concat(Iterator<? extends CharSource> sources) {

   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code CharSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}
   * @since 15.0
   */
  public static CharSource concat(Iterator<? extends CharSource> sources) {

    assertEquals(
        1391975640 /*C(34,14)*/,
        Collections2.orderedPermutations(concat(nCopies(20, 1), nCopies(14, 2))).size());
    // Do force an overflow in the binomial coefficient calculation
    assertEquals(
        Integer.MAX_VALUE,
        Collections2.orderedPermutations(concat(nCopies(21, 1), nCopies(14, 2))).size());
  }

  public void testOrderedPermutationSetContains() {

   * load data through their streams). Prefer using the {@link #concat(Iterable)} overload if
   * possible.
   *
   * @param sources the sources to concatenate
   * @return a {@code ByteSource} containing the concatenated data
   * @throws NullPointerException if any of {@code sources} is {@code null}
   * @since 15.0
   */
  public static ByteSource concat(Iterator<? extends ByteSource> sources) {

     *
     * @return a stream containing this node and its descendants
     */
    @Nonnull
    default Stream<Node> stream() {
        return Stream.concat(Stream.of(this), getChildren().stream().flatMap(Node::stream));
    }

   * @param second the second array of elements to concatenate
   * @param type the component type of the returned array
   */
  @GwtIncompatible // Array.newInstance(Class, int)
  public static <T extends @Nullable Object> T[] concat(
      T[] first, T[] second, Class<@NonNull T> type) {
    T[] result = newArray(type, first.length + second.length);
    arraycopy(first, 0, result, 0, first.length);