* (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}.)
   */

public abstract class ImmutableCollection<E> extends AbstractCollection<E> implements Serializable {
  static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

  ImmutableCollection() {}

  @Override
  public abstract UnmodifiableIterator<E> iterator();

  @Override
  public boolean contains(@Nullable Object object) {

    // 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) {

      int index = e.ordinal();
      return index < enumConstants.length && enumConstants[index] == e;
    }
    return false;
  }

  /**
   * Returns {@code element} cast to {@code E}, if it actually is a nonnull E. Otherwise, throws
   * either a NullPointerException or a ClassCastException as appropriate.
   */
  private void checkIsE(Object element) {
    checkNotNull(element);
    if (!isActuallyE(element)) {

        strategy.forEach(spliteratorSupplier.get(), resultsForStrategy::add);

        // TODO(cpovirk): better failure messages
        if ((characteristics & Spliterator.NONNULL) != 0) {
          assertFalse(resultsForStrategy.contains(null));
        }
        if ((characteristics & Spliterator.SORTED) != 0) {
          Comparator<? super E> comparator = spliterator.getComparator();

        strategy.forEach(spliteratorSupplier.get(), resultsForStrategy::add);

        // TODO(cpovirk): better failure messages
        if ((characteristics & Spliterator.NONNULL) != 0) {
          assertFalse(resultsForStrategy.contains(null));
        }
        if ((characteristics & Spliterator.SORTED) != 0) {
          Comparator<? super E> comparator = spliterator.getComparator();

        new ListFuture<V>(ImmutableList.copyOf(futures), true);
    // allAsList ensures that it fills the output list with V instances.
    @SuppressWarnings("nullness")
    ListenableFuture<List<V>> nonNull = nullable;
    return nonNull;
  }

  /**
   * Creates a new {@code ListenableFuture} whose value is a list containing the values of all its
   * input futures, if all succeed.
   *

import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.RandomAccess;
import java.util.Set;
import java.util.SortedSet;
import java.util.stream.Stream;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * An assortment of mainly legacy static utility methods that operate on or return objects of type

import java.util.RandomAccess;
import java.util.Set;
import java.util.SortedSet;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.stream.Stream;
import org.jspecify.annotations.NonNull;
import org.jspecify.annotations.Nullable;

/**
 * An assortment of mainly legacy static utility methods that operate on or return objects of type

      int maxRunBeforeFallback = maxRunBeforeFallback(hashTable.length);
      int mask = hashTable.length - 1;

      // Invariant: all elements at indices in [knownRunStart, knownRunEnd) are nonnull.
      // If knownRunStart == knownRunEnd, this is vacuously true.
      // When knownRunEnd exceeds hashTable.length, it "wraps", detecting runs around the end
      // of the table.
      int knownRunStart = 0;