* Tests that we workaround GWT bug #3621 (or that it is already fixed).
   *
   * A call to of() with a parameter that is not a plain Object[] (here,
   * Interface[]) creates a RegularImmutableSortedSet backed by an array of that
   * type. Later, RegularImmutableSortedSet.toArray() calls System.arraycopy()
   * to copy from that array to the destination array. This would be fine, but

  }

  private static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  // TODO(b/345814817): Move this to RegularImmutableSortedSet?
  @SuppressWarnings({"unchecked", "ClassInitializationDeadlock"})
  private static final ImmutableSortedSet<Object> NATURAL_EMPTY_SET =
      new RegularImmutableSortedSet<Object>(
          new TreeSet<Object>((Comparator<Object>) NATURAL_ORDER), false);

      return ImmutableMap.of();
    }
    RegularImmutableSortedSet<Range<K>> rangeSet =
        new RegularImmutableSortedSet<>(ranges, rangeLexOrdering());
    return new ImmutableSortedMap<>(rangeSet, values);
  }

  @Override
  public ImmutableMap<Range<K>, V> asDescendingMapOfRanges() {
    if (ranges.isEmpty()) {
      return ImmutableMap.of();
    }
    RegularImmutableSortedSet<Range<K>> rangeSet =

  }

  /** Returns an immutable sorted multiset containing a single element. */
  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);
  }

  /**

  }

  /** Returns an immutable sorted multiset containing a single element. */
  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);
  }

  /**

    if (ranges.isEmpty()) {
      return ImmutableSet.of();
    }
    return new RegularImmutableSortedSet<>(ranges, rangeLexOrdering());
  }

  @Override
  public ImmutableSet<Range<C>> asDescendingSetOfRanges() {
    if (ranges.isEmpty()) {
      return ImmutableSet.of();
    }
    return new RegularImmutableSortedSet<>(ranges.reverse(), Range.<C>rangeLexOrdering().reverse());
  }

   * Tests that we workaround GWT bug #3621 (or that it is already fixed).
   *
   * A call to of() with a parameter that is not a plain Object[] (here,
   * Interface[]) creates a RegularImmutableSortedSet backed by an array of that
   * type. Later, RegularImmutableSortedSet.toArray() calls System.arraycopy()
   * to copy from that array to the destination array. This would be fine, but