}

  public void testIntersection_empty() {
    ContiguousSet<Integer> set = ContiguousSet.closed(1, 3);
    ContiguousSet<Integer> emptySet = ContiguousSet.closedOpen(2, 2);
    assertEquals(ImmutableSet.of(), set.intersection(emptySet));
    assertEquals(ImmutableSet.of(), emptySet.intersection(set));
    assertEquals(
        ImmutableSet.of(),
        ContiguousSet.create(Range.closed(-5, -1), integers())

      return this;
    } else if (newFromIndex < newToIndex) {
      return new RegularImmutableSortedSet<>(
          elements.subList(newFromIndex, newToIndex), comparator);
    } else {
      return emptySet(comparator);
    }
  }

  @Override
  int indexOf(@Nullable Object target) {
    if (target == null) {
      return -1;
    }
    int position;
    try {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableSet;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableSet;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

  SERIALIZABLE_INCLUDING_VIEWS(SERIALIZABLE),

  SUBSET_VIEW,
  DESCENDING_VIEW,

  /**
   * For documenting collections that support no optional features, such as {@link
   * java.util.Collections#emptySet}
   */
  NONE;

  private final Set<Feature<? super Collection>> implied;

  CollectionFeature(Feature<? super Collection>... implied) {
    this.implied = copyToSet(implied);
  }

  @Override

package com.google.common.collect.testing.google;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.testing.Helpers.copyToList;
import static java.util.Collections.emptySet;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Multiset;
import com.google.common.collect.Multiset.Entry;
import com.google.common.collect.Multisets;

  SERIALIZABLE_INCLUDING_VIEWS(SERIALIZABLE),

  SUBSET_VIEW,
  DESCENDING_VIEW,

  /**
   * For documenting collections that support no optional features, such as {@link
   * java.util.Collections#emptySet}
   */
  NONE;

  private final Set<Feature<? super Collection>> implied;

  CollectionFeature(Feature<? super Collection>... implied) {
    this.implied = copyToSet(implied);
  }

  @Override

      Comparator<? super E> comparator) {
    return CollectCollectors.toImmutableSortedSet(comparator);
  }

  static <E> RegularImmutableSortedSet<E> emptySet(Comparator<? super E> comparator) {
    if (Ordering.natural().equals(comparator)) {
      @SuppressWarnings("unchecked") // The natural-ordered empty set supports all types.
      RegularImmutableSortedSet<E> result =

  private static final long RANDOM_SEED = 177L;

  public void testCombineOrdered_empty() {
    assertThrows(
        IllegalArgumentException.class,
        () -> Hashing.combineOrdered(Collections.<HashCode>emptySet()));
  }

  public void testCombineOrdered_differentBitLengths() {
    assertThrows(
        IllegalArgumentException.class,
        () -> {
          HashCode unused =

import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE_INCLUDING_VIEWS;
import static java.util.Arrays.asList;
import static java.util.Collections.emptySet;
import static java.util.Collections.sort;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.BoundType;
import com.google.common.collect.ImmutableList;