}

  /**
   * Not supported. Use {@link #toImmutableSortedSet} instead. This method exists only to hide
   * {@link ImmutableSet#toImmutableSet} from consumers of {@code ImmutableSortedSet}.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Use {@link ImmutableSortedSet#toImmutableSortedSet}.
   * @since 21.0
   */
  @DoNotCall("Use toImmutableSortedSet")
  @Deprecated

  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static <E> Collector<E, ?, ImmutableSortedSet<E>> toImmutableSortedSet(
      Comparator<? super E> comparator) {
    return CollectCollectors.toImmutableSortedSet(comparator);
  }

  static <E> RegularImmutableSortedSet<E> emptySet(Comparator<? super E> comparator) {
    if (Ordering.natural().equals(comparator)) {

 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.Comparators.isInOrder;
import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;
import static com.google.common.collect.Iterables.elementsEqual;
import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.Sets.newHashSet;

  @SuppressWarnings({"rawtypes", "unchecked"})
  static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
    return (Collector) TO_IMMUTABLE_SET;
  }

  static <E> Collector<E, ?, ImmutableSortedSet<E>> toImmutableSortedSet(
      Comparator<? super E> comparator) {
    checkNotNull(comparator);
    return Collector.of(
        () -> new ImmutableSortedSet.Builder<E>(comparator),
        ImmutableSortedSet.Builder::add,

   * stream.iterator())}, or pass {@link ImmutableSortedSet#toImmutableSortedSet} to {@code
   * stream.collect()}.
   *
   * @param comparator the function by which to sort set elements
   * @throws NullPointerException if any element of this iterable is {@code null}
   * @since 14.0 (since 12.0 as {@code toImmutableSortedSet()}).
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.