@CollectionSize.Require(absent = ZERO)
  public void testSpliteratorNullable() {
    initCollectionWithNullElement();
    assertFalse(collection.spliterator().hasCharacteristics(Spliterator.NONNULL));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSpliteratorNotImmutable_collectionAllowsAdd() {
    // If add is supported, verify that IMMUTABLE is not reported.

@GwtCompatible
abstract class ImmutableMapEntrySet<K, V> extends ImmutableSet.CachingAsList<Entry<K, V>> {
  private static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.IMMUTABLE;

  static final class RegularEntrySet<K, V> extends ImmutableMapEntrySet<K, V> {
    private final transient ImmutableMap<K, V> map;
    private final transient ImmutableList<Entry<K, V>> entries;

    // TODO(lowasser): consider an implementation that can support SUBSIZED
    boolean isParallel = false;
    int characteristics = Spliterator.ORDERED | Spliterator.SIZED | Spliterator.NONNULL;
    long estimatedSize = 0L;
    ImmutableList.Builder<Spliterator<? extends T>> splitrsBuilder =
        new ImmutableList.Builder<>(streams.length);
    for (Stream<? extends T> stream : streams) {

   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying
   * to get rid of, and {@code @NonNull} would be wrong for our use case for the same reason as
   * {@code requireNonNull}: Our use case is the one in which {@code T} has parametric nullness—and
   * thus its value may be legitimately {@code null}.)
   */

   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying
   * to get rid of, and {@code @NonNull} would be wrong for our use case for the same reason as
   * {@code requireNonNull}: Our use case is the one in which {@code T} has parametric nullness—and
   * thus its value may be legitimately {@code null}.)
   */

    return new CellSet();
  }

  abstract Iterator<Table.Cell<R, C, V>> cellIterator();

  Spliterator<Table.Cell<R, C, V>> cellSpliterator() {
    return Spliterators.spliterator(cellSet(), Spliterator.NONNULL | Spliterator.DISTINCT);
  }

  @WeakOuter
  private final class CellSet extends AbstractSet<Cell<R, C, V>> {
    @Override
    public boolean contains(@Nullable Object o) {
      if (o instanceof Cell) {

      throw new UnsupportedOperationException();
    }

    @Override
    public @Nullable V merge(
        K key,
        @NonNull V value,
        BiFunction<? super @NonNull V, ? super @NonNull V, ? extends @Nullable V> function) {
      throw new UnsupportedOperationException();
    }

    @Override
    public BiMap<V, K> inverse() {

    // TODO(lowasser): consider an implementation that can support SUBSIZED
    boolean isParallel = false;
    int characteristics = Spliterator.ORDERED | Spliterator.SIZED | Spliterator.NONNULL;
    long estimatedSize = 0L;
    ImmutableList.Builder<Spliterator<? extends T>> splitrsBuilder =
        new ImmutableList.Builder<>(streams.length);
    for (Stream<? extends T> stream : streams) {

    }

    @SuppressWarnings("nullness") // TODO: b/423853632 - Remove after checker is fixed.
    @Override
    public @Nullable V merge(
        K key,
        @NonNull V value,
        BiFunction<? super @NonNull V, ? super @NonNull V, ? extends @Nullable V>
            remappingFunction) {
      synchronized (mutex) {
        return delegate().merge(key, value, remappingFunction);
      }
    }

      assertEquals(strictlyOrderedList, ordering.sortedCopy(shuffledList));

      if (!strictlyOrderedList.contains(null)) {
        List<@NonNull T> nonNullShuffledList = (List<@NonNull T>) shuffledList;
        assertEquals(strictlyOrderedList, ordering.immutableSortedCopy(nonNullShuffledList));
      }
    }
  }

  /**