* elements.
   */
  @SafeVarargs
  public static <T extends @Nullable Object> Iterator<T> cycle(T... elements) {
    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Returns an Iterator that walks the specified array, nulling out elements behind it. This can
   * avoid memory leaks when an element is no longer necessary.
   *

   * elements.
   */
  @SafeVarargs
  public static <T extends @Nullable Object> Iterator<T> cycle(T... elements) {
    return cycle(Lists.newArrayList(elements));
  }

  /**
   * Returns an Iterator that walks the specified array, nulling out elements behind it. This can
   * avoid memory leaks when an element is no longer necessary.
   *

    }

    List<T> iterationOrder(T... elements) {
        return elements
    }

    abstract boolean isExternalProviderAllowed()

    abstract boolean isDirectElementAdditionAllowed()

    abstract boolean isElementRemovalAllowed()

    void containerAllowsElementAddition() {
        assumeTrue("the container doesn't allow direct element addition", isDirectElementAdditionAllowed())
    }

  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {
    if (elements instanceof ImmutableEnumSet) {
      return (ImmutableEnumSet<E>) elements;
    } else if (elements instanceof Collection) {
      Collection<E> collection = (Collection<E>) elements;
      if (collection.isEmpty()) {
        return ImmutableSet.of();
      } else {

  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {
    if (elements instanceof ImmutableEnumSet) {
      return (ImmutableEnumSet<E>) elements;
    } else if (elements instanceof Collection) {
      Collection<E> collection = (Collection<E>) elements;
      if (collection.isEmpty()) {
        return ImmutableSet.of();
      } else {

        action.execute(_, 12) >> { bean, value -> bean.value = "[12]" }

        expect:
        registry.realize("bar", Bean).value == "[12]"
    }

    def "transitions elements that depend on a particular state of an element when the target element leaves target state"() {
        given:
        registry.registerInstance("a", new Bean())
        registry.registerInstance("b", new Bean())

  }

  // TODO b/327389044 - `Set<? extends Object> elements` should be enough but J2KT needs the <E>
  private static <E> void assertPowerSetHashCode(int expected, Set<E> elements) {
    assertEquals(expected, powerSet(elements).hashCode());
  }

  private static void assertPowerSetSize(int i, Object... elements) {
    assertEquals(i, powerSet(newHashSet(elements)).size());
  }

        ex.message == "Cannot add a null element to a property of type ${type().simpleName}."
    }

    def "ignores convention after element added"() {
        expect:
        property.add("a")
        property.convention(["other"])
        assertValueIs(["a"])
    }

    def "ignores convention after element added using provider"() {
        expect:

	t, err := sliceElementType(s)
	if err != nil {
		return nil, err
	}

	// If the elements are not maps...
	if t.Kind() != reflect.Map {
		// Sort the elements, because they may have been merged out of order.
		return deduplicateAndSortScalars(s), nil
	}

	// Elements are maps - if one of the keys of the map is a map or a
	// list, we may need to recurse into it.
	newS := []interface{}{}

  private static final class PickyIterable<E> implements Iterable<E> {
    final List<E> elements;
    int modCount = 0;

    PickyIterable(E... elements) {
      this.elements = new ArrayList<E>(asList(elements));
    }

    @Override
    public Iterator<E> iterator() {
      return new PickyIterator();
    }