/**
   * Creates a new {@code HashMultiset} containing the specified elements.
   *
   * <p>This implementation is highly efficient when {@code elements} is itself a {@link Multiset}.
   *
   * @param elements the elements that the multiset should contain
   */
  public static <E extends @Nullable Object> HashMultiset<E> create(
      Iterable<? extends E> elements) {

  static final RegularImmutableSet<Object> EMPTY =
      new RegularImmutableSet<>(EMPTY_ARRAY, 0, EMPTY_ARRAY, 0, 0);

  // The first `size` elements are non-null.
  @VisibleForTesting final transient @Nullable Object[] elements;
  private final transient int hashCode;
  // the same values as `elements` in hashed positions (plus nulls)
  @VisibleForTesting final transient @Nullable Object[] table;
  // 'and' with an int to get a valid table index.

  private SortedIterables() {}

  /**
   * Returns {@code true} if {@code elements} is a sorted collection using an ordering equivalent to
   * {@code comparator}.
   */
  public static boolean hasSameComparator(Comparator<?> comparator, Iterable<?> elements) {
    checkNotNull(comparator);
    checkNotNull(elements);
    Comparator<?> comparator2;
    if (elements instanceof SortedSet) {
      comparator2 = comparator((SortedSet<?>) elements);

    return Spliterators.spliterator(elements, SPLITERATOR_CHARACTERISTICS);
  }

  @Override
  Object[] internalArray() {
    return elements;
  }

  @Override
  int internalArrayStart() {
    return 0;
  }

  @Override
  int internalArrayEnd() {
    return elements.length;
  }

  @Override
  int copyIntoArray(@Nullable Object[] dst, int offset) {
    arraycopy(elements, 0, dst, offset, elements.length);

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {
                  @Override
                  protected Set<String> create(String[] elements) {
                    return CompactLinkedHashSet.create(asList(elements));
                  }
                })
            .named("CompactLinkedHashSet")
            .withFeatures(allFeatures)
            .createTestSuite());
    suite.addTest(

            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherContainsNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);
    Set<E> other = MinimalSet.from(elements);

    assertFalse(

            + " even if some elements are null.",
        getSet().equals(MinimalSet.from(elements)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherContainsNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);
    Set<E> other = MinimalSet.from(elements);

    assertFalse(

              protected List<String> create(String[] elements) {
                return new AbstractList<String>() {
                  @Override
                  public int size() {
                    return elements.length;
                  }

                  @Override
                  public String get(int index) {
                    return elements[index];
                  }
                };

              protected List<String> create(String[] elements) {
                return new AbstractList<String>() {
                  @Override
                  public int size() {
                    return elements.length;
                  }

                  @Override
                  public String get(int index) {
                    return elements[index];
                  }
                };

  public void testForEachUnknownOrder() {
    List<E> elements = new ArrayList<>();
    collection.forEach(elements::add);
    Helpers.assertEqualIgnoringOrder(asList(createSamplesArray()), elements);
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testForEachKnownOrder() {
    List<E> elements = new ArrayList<>();
    collection.forEach(elements::add);
    List<E> expected = Helpers.copyToList(getOrderedElements());