public static boolean contains(Iterable<?> iterable, @Nullable Object element) {
    if (iterable instanceof Collection) {
      Collection<?> collection = (Collection<?>) iterable;
      return Collections2.safeContains(collection, element);
    }
    return Iterators.contains(iterable.iterator(), element);
  }

  /**
   * Removes, from an iterable, every element that belongs to the provided collection.
   *

        final Entry entry = getEntry(index);
        final E oldValue = entry.element;
        entry.element = element;
        return oldValue;
    }

    /**
     * Returns the position of the element.
     *
     * @param element the element
     * @return the position
     */
    public int indexOf(final E element) {
        int index = 0;
        if (element == null) {

     * {@code list.size()} if there is no such element.
     *
     * <p>Note that the return value will be {@code >= 0} if and only if there is an element of the
     * list that compares as equal to the key.
     *
     * <p>This is equivalent to the behavior of {@link java.util.Collections#binarySearch(List,

  public void testHashCode_containingNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    int expectedHashCode = 0;
    for (E element : elements) {
      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }

    elements.add(null);
    collection = getSubjectGenerator().create(elements.toArray());
    assertEquals(

  public static boolean contains(Iterable<?> iterable, @Nullable Object element) {
    if (iterable instanceof Collection) {
      Collection<?> collection = (Collection<?>) iterable;
      return Collections2.safeContains(collection, element);
    }
    return Iterators.contains(iterable.iterator(), element);
  }

  /**
   * Removes, from an iterable, every element that belongs to the provided collection.
   *

    if (occurrences == 0) {
      return count(element);
    }
    checkArgument(occurrences > 0, "occurrences cannot be negative: %s", occurrences);
    int entryIndex = backingMap.indexOf(element);
    if (entryIndex == -1) {
      backingMap.put(element, occurrences);
      size += occurrences;
      return 0;
    }
    int oldCount = backingMap.getValue(entryIndex);

  private SetImpl impl;

  // the following must be set during setUp
  private Set<Element> setToTest;

  @BeforeExperiment
  void setUp() {
    CollectionBenchmarkSampleData sampleData =
        new CollectionBenchmarkSampleData(true, random, 0.8, size);
    setToTest = (Set<Element>) impl.create(sampleData.getValuesInSet());
  }

  @Benchmark
  int iteration(int reps) {
    int x = 0;

  /**
   * Inserts the specified element into this priority queue.
   *
   * @param e the element to add
   * @return {@code true} (as specified by {@link Queue#offer})
   * @throws ClassCastException if the specified element cannot be compared with elements currently
   *     in the priority queue according to the priority queue's ordering
   * @throws NullPointerException if the specified element is null
   */

   * than one, not just two.
   */
  @SuppressWarnings("EmptyList") // ImmutableList doesn't support nullable element types
  private static final class ToOptionalState {
    static final int MAX_EXTRAS = 4;

    @Nullable Object element;
    List<Object> extras;

    ToOptionalState() {
      element = null;
      extras = emptyList();
    }

     *
     * @param elements the {@code Iterable} to add to the {@code ImmutableList}
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code elements} is null or contains a null element
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<E> add(E... elements) {
      super.add(elements);
      return this;
    }

    /**