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 =