* unchecked cast at some later point:
   *
   * {@snippet :
   * @SuppressWarnings("unchecked") // safe because of ::isInstance check
   * ImmutableList<NewType> result =
   *     (ImmutableList) stream.filter(NewType.class::isInstance).collect(toImmutableList());
   * }
   */
  @GwtIncompatible // Class.isInstance
  public final <T> FluentIterable<T> filter(Class<T> type) {

   * unchecked cast at some later point:
   *
   * {@snippet :
   * @SuppressWarnings("unchecked") // safe because of ::isInstance check
   * ImmutableList<NewType> result =
   *     (ImmutableList) stream.filter(NewType.class::isInstance).collect(toImmutableList());
   * }
   */
  @GwtIncompatible // Class.isInstance
  public final <T> FluentIterable<T> filter(Class<T> type) {

    T defaultValue = (T) defaultValues.getInstance(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // ArbitraryInstances always returns generics-safe dummies.
    T value = (T) ArbitraryInstances.get(rawType);
    if (value != null) {
      return value;
    }
    if (rawType.isInterface()) {
      return new SerializableDummyProxy(this).newProxy(type);
    }