* since the Equivalence base type now implements this logic itself
       */
      assertTrue(item + " must be inequivalent to null", !equivalence.equivalent(item, null));
      assertTrue("null must be inequivalent to " + item, !equivalence.equivalent(null, item));
      assertTrue(item + " must be equivalent to itself", equivalence.equivalent(item, item));
      assertEquals(

    Predicate<@Nullable Object> isNull = Equivalence.equals().equivalentTo(null);
    assertFalse(isNull.apply("1"));
    assertFalse(isNull.apply("2"));
    assertTrue(isNull.apply(null));

    new EqualsTester()
        .addEqualityGroup(equalTo1, Equivalence.equals().equivalentTo("1"))
        .addEqualityGroup(isNull)
        .addEqualityGroup(Equivalence.identity().equivalentTo("1"))
        .testEquals();
  }

    Predicate<@Nullable Object> isNull = Equivalence.equals().equivalentTo(null);
    assertFalse(isNull.apply("1"));
    assertFalse(isNull.apply("2"));
    assertTrue(isNull.apply(null));

    new EqualsTester()
        .addEqualityGroup(equalTo1, Equivalence.equals().equivalentTo("1"))
        .addEqualityGroup(isNull)
        .addEqualityGroup(Equivalence.identity().equivalentTo("1"))
        .testEquals();
  }

   */
  @Nullable Range<C> rangeContaining(C value);

  /**
   * Returns {@code true} if there exists a non-empty range enclosed by both a member range in this
   * range set and the specified range. This is equivalent to calling {@code
   * subRangeSet(otherRange)} and testing whether the resulting range set is non-empty.
   *
   * @since 20.0
   */
  boolean intersects(Range<C> otherRange);

  /**

import java.util.Iterator;
import org.jspecify.annotations.Nullable;

@GwtCompatible
final class PairwiseEquivalence<E, T extends @Nullable E> extends Equivalence<Iterable<T>>
    implements Serializable {
  final Equivalence<E> elementEquivalence;

  PairwiseEquivalence(Equivalence<E> elementEquivalence) {
    this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
  }

  @Override

   * directly against {@code equals()} rather than through the {@code Equivalence}.
   */
  private final Equivalence<? super T> equivalence;

  private final String relationshipName;
  private final String hashName;
  private final ItemReporter itemReporter;
  private final List<ImmutableList<T>> groups = new ArrayList<>();

  RelationshipTester(
      Equivalence<? super T> equivalence,
      String relationshipName,
      String hashName,

   * directly against {@code equals()} rather than through the {@code Equivalence}.
   */
  private final Equivalence<? super T> equivalence;

  private final String relationshipName;
  private final String hashName;
  private final ItemReporter itemReporter;
  private final List<ImmutableList<T>> groups = new ArrayList<>();

  RelationshipTester(
      Equivalence<? super T> equivalence,
      String relationshipName,
      String hashName,

import java.util.Iterator;
import org.jspecify.annotations.Nullable;

@GwtCompatible
final class PairwiseEquivalence<E, T extends @Nullable E> extends Equivalence<Iterable<T>>
    implements Serializable {
  final Equivalence<E> elementEquivalence;

  PairwiseEquivalence(Equivalence<E> elementEquivalence) {
    this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
  }

  @Override

    } catch (AssertionFailedError expected) {
      assertThat(expected)
          .hasMessageThat()
          .contains(
              "TestObject{group=1, item=2} [group 1, item 2] must be equivalent to "
                  + "TestObject{group=1, item=1} [group 1, item 1]");
      return;
    }
    fail();
  }

  public void testTest_transitive() {
    Object group1Item1 = new TestObject(1, 1);

    } catch (AssertionFailedError expected) {
      assertThat(expected)
          .hasMessageThat()
          .contains(
              "TestObject{group=1, item=2} [group 1, item 2] must be equivalent to "
                  + "TestObject{group=1, item=1} [group 1, item 1]");
      return;
    }
    fail();
  }

  public void testTest_transitive() {
    Object group1Item1 = new TestObject(1, 1);