assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    // Before JDK6 (including under GWT), the TreeMap keySet is a plain Set.
    if (Maps.newTreeMap().keySet() instanceof SortedSet) {
      assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    }
    assertTrue(
        SortedIterables.hasSameComparator(

    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    // Before JDK6 (including under GWT), the TreeMap keySet is a plain Set.
    if (Maps.newTreeMap().keySet() instanceof SortedSet) {
      assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    }
    assertTrue(
        SortedIterables.hasSameComparator(

      Comparator<? super E> comparator, Iterable<? extends E> elements, boolean fromSortedSet) {
    checkNotNull(comparator);

    boolean hasSameComparator = fromSortedSet || hasSameComparator(elements, comparator);
    if (hasSameComparator && (elements instanceof ImmutableSortedSet)) {
      @SuppressWarnings("unchecked")
      ImmutableSortedSet<E> result = (ImmutableSortedSet<E>) elements;
      boolean isSubset =

    // graduates from labs.
    if (targets instanceof Multiset) {
      targets = ((Multiset<?>) targets).elementSet();
    }
    if (!SortedIterables.hasSameComparator(comparator(), targets) || (targets.size() <= 1)) {
      return super.containsAll(targets);
    }

    /*
     * If targets is a sorted set with the same comparator, containsAll can run

  private SortedIterables() {}

  /**
   * Returns {@code true} if {@code elements} is a sorted collection using an ordering equivalent to
   * {@code comparator}.
   */
  public static boolean hasSameComparator(Comparator<?> comparator, Iterable<?> elements) {
    checkNotNull(comparator);
    checkNotNull(elements);
    Comparator<?> comparator2;
    if (elements instanceof SortedSet) {

   */
  public static <E> ImmutableSortedSet<E> copyOf(
      Comparator<? super E> comparator, Iterable<? extends E> elements) {
    checkNotNull(comparator);
    boolean hasSameComparator = SortedIterables.hasSameComparator(comparator, elements);

    if (hasSameComparator && (elements instanceof ImmutableSortedSet)) {
      @SuppressWarnings("unchecked")
      ImmutableSortedSet<E> original = (ImmutableSortedSet<E>) elements;

   */
  public static <E> ImmutableSortedSet<E> copyOf(
      Comparator<? super E> comparator, Iterable<? extends E> elements) {
    checkNotNull(comparator);
    boolean hasSameComparator = SortedIterables.hasSameComparator(comparator, elements);

    if (hasSameComparator && (elements instanceof ImmutableSortedSet)) {
      @SuppressWarnings("unchecked")
      ImmutableSortedSet<E> original = (ImmutableSortedSet<E>) elements;