assertFalse(Iterators.elementsEqual(a.iterator(), b.iterator()));
    assertFalse(Iterators.elementsEqual(b.iterator(), a.iterator()));

    // Different lengths, one is empty.
    a = Collections.emptySet();
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterators.elementsEqual(a.iterator(), b.iterator()));
    assertFalse(Iterators.elementsEqual(b.iterator(), a.iterator()));
  }

    assertFalse(Iterators.elementsEqual(a.iterator(), b.iterator()));
    assertFalse(Iterators.elementsEqual(b.iterator(), a.iterator()));

    // Different lengths, one is empty.
    a = Collections.emptySet();
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterators.elementsEqual(a.iterator(), b.iterator()));
    assertFalse(Iterators.elementsEqual(b.iterator(), a.iterator()));
  }

    assertTrue(Iterables.elementsEqual(a, b));

    // An element differs.
    a = asList(4, 8, 15, 12, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterables.elementsEqual(a, b));

    // null versus non-null.
    a = Arrays.<@Nullable Integer>asList(4, 8, 15, null, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterables.elementsEqual(a, b));

  @CanIgnoreReturnValue
  @GwtIncompatible // SerializableTester
  static <E> Collection<E> reserializeAndAssertElementsEqual(Collection<E> original) {
    Collection<E> copy = reserialize(original);
    assertTrue(Iterables.elementsEqual(original, copy));
    assertTrue(copy instanceof ImmutableCollection);
    return copy;
  }

  private LenientSerializableTester() {}

  @CanIgnoreReturnValue
  @GwtIncompatible // SerializableTester
  static <E> Collection<E> reserializeAndAssertElementsEqual(Collection<E> original) {
    Collection<E> copy = reserialize(original);
    assertTrue(Iterables.elementsEqual(original, copy));
    assertTrue(copy instanceof ImmutableCollection);
    return copy;
  }

  private LenientSerializableTester() {}

    assertTrue(Iterables.elementsEqual(LegacyComparable.VALUES_FORWARD, set));
  }

  public void testLegacyComparable_copyOf_iterator() {
    ImmutableSortedSet<LegacyComparable> set =
        ImmutableSortedSet.copyOf(LegacyComparable.VALUES_BACKWARD.iterator());
    assertTrue(Iterables.elementsEqual(LegacyComparable.VALUES_FORWARD, set));
  }

    assertTrue(Iterables.elementsEqual(a, b));

    // An element differs.
    a = asList(4, 8, 15, 12, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterables.elementsEqual(a, b));

    // null versus non-null.
    a = Arrays.<@Nullable Integer>asList(4, 8, 15, null, 23, 42);
    b = asList(4, 8, 15, 16, 23, 42);
    assertFalse(Iterables.elementsEqual(a, b));

    assertTrue(Iterables.elementsEqual(LegacyComparable.VALUES_FORWARD, set));
  }

  public void testLegacyComparable_copyOf_iterator() {
    ImmutableSortedSet<LegacyComparable> set =
        ImmutableSortedSet.copyOf(LegacyComparable.VALUES_BACKWARD.iterator());
    assertTrue(Iterables.elementsEqual(LegacyComparable.VALUES_FORWARD, set));
  }

   * number of elements and every element of {@code iterable1} is equal to the corresponding element
   * of {@code iterable2}.
   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;

   * number of elements and every element of {@code iterable1} is equal to the corresponding element
   * of {@code iterable2}.
   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {
      Collection<?> collection1 = (Collection<?>) iterable1;