* ImmutableSet.Builder but y is an ImmutableSortedSet.Builder (or vice versa). Certainly
       * ImmutableSortedSet.Builder.combine() is written as if its argument will never be a plain
       * ImmutableSet.Builder: It casts immediately to ImmutableSortedSet.Builder.)
       */
      copyIfNecessary();
      this.impl = this.impl.combine(other.impl);

    // path, so we test that separately
    assertTrue(range.containsAll(ImmutableSortedSet.of(3, 3, 4, 5)));
    assertTrue(range.containsAll(ImmutableSortedSet.of(3)));
    assertTrue(range.containsAll(ImmutableSortedSet.<Integer>of()));
    assertFalse(range.containsAll(ImmutableSortedSet.of(3, 3, 4, 5, 6)));

    assertTrue(Range.openClosed(3, 3).containsAll(Collections.<Integer>emptySet()));
  }

      new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.of());

  static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {
    if (Ordering.natural().equals(comparator)) {
      return of();
    } else {
      return new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(comparator), ImmutableList.of());
    }
  }

  /**

      new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.of());

  static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {
    if (Ordering.natural().equals(comparator)) {
      return of();
    } else {
      return new ImmutableSortedMap<>(ImmutableSortedSet.emptySet(comparator), ImmutableList.of());
    }
  }

  /**

    TreeSet<E> set = Sets.newTreeSet();
    set.add(freshElement);
    return set;
  }

  @Generates
  static <E extends Comparable<? super E>> ImmutableSortedSet<E> generateImmutableSortedSet(
      E freshElement) {
    return ImmutableSortedSet.of(freshElement);
  }

  @Generates
  static <E> Multiset<E> generateMultiset(@Nullable E freshElement) {
    return generateHashMultiset(freshElement);
  }

 *       how the collection was created. Typically this is insertion order unless an explicit
 *       ordering is otherwise specified (e.g. {@link ImmutableSortedSet#naturalOrder}). See the
 *       appropriate factory method for details. View collections such as {@link
 *       ImmutableMultiset#elementSet} iterate in the same order as the parent, except as noted.

  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E e1) {
    RegularImmutableSortedSet<E> elementSet =
        (RegularImmutableSortedSet<E>) ImmutableSortedSet.of(e1);
    long[] cumulativeCounts = {0, 1};
    return new RegularImmutableSortedMultiset<>(elementSet, cumulativeCounts, 0, 1);
  }

  /**

  public void testGet_emptyList() {
    testGetOnEmpty(Collections.<String>emptyList());
  }

  public void testGet_sortedSet() {
    testGetOnAbc(ImmutableSortedSet.of("b", "c", "a"));
  }

  public void testGet_emptySortedSet() {
    testGetOnEmpty(ImmutableSortedSet.<String>of());
  }

  public void testGet_iterable() {
    testGetOnAbc(ImmutableSet.of("a", "b", "c"));
  }

 *       how the collection was created. Typically this is insertion order unless an explicit
 *       ordering is otherwise specified (e.g. {@link ImmutableSortedSet#naturalOrder}). See the
 *       appropriate factory method for details. View collections such as {@link
 *       ImmutableMultiset#elementSet} iterate in the same order as the parent, except as noted.

  public static <E extends Comparable<? super E>> ImmutableSortedMultiset<E> of(E e1) {
    RegularImmutableSortedSet<E> elementSet =
        (RegularImmutableSortedSet<E>) ImmutableSortedSet.of(e1);
    long[] cumulativeCounts = {0, 1};
    return new RegularImmutableSortedMultiset<>(elementSet, cumulativeCounts, 0, 1);
  }

  /**