tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

    (I hope that this workaround does not cause its own problems in the future.)
-->
<super-source path="super"/>

                return Collections.unmodifiableSet(innerSet);
              }
            })
        .named("unmodifiableSet/HashSet")
        .withFeatures(
            CollectionFeature.NONE,
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ANY)
        .suppressing(suppressForUnmodifiableSet())
        .createTestSuite();
  }

   */
  SUPPORTS_ADD,
  /**
   * Support for {@link ListIterator#set(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_SET;

  /**
   * A set containing none of the optional features of the {@link Iterator} or {@link ListIterator}
   * interfaces.
   */
  public static final Set<IteratorFeature> UNMODIFIABLE = emptySet();

  /**

   */
  SUPPORTS_ADD,
  /**
   * Support for {@link ListIterator#set(Object)}; ignored for plain {@link Iterator}
   * implementations.
   */
  SUPPORTS_SET;

  /**
   * A set containing none of the optional features of the {@link Iterator} or {@link ListIterator}
   * interfaces.
   */
  public static final Set<IteratorFeature> UNMODIFIABLE = emptySet();

  /**

    for (int n = from - 1; n >= to; n--) {
      list.remove(n);
    }
  }

  /** Removes and returns the first matching element, or returns {@code null} if there is none. */
  @CheckForNull
  static <T extends @Nullable Object> T removeFirstMatching(
      Iterable<T> removeFrom, Predicate<? super T> predicate) {
    checkNotNull(predicate);

      }
    }
    return current;
  }

  /**
   * Returns the unique least value of type {@code C} that is greater than {@code value}, or {@code
   * null} if none exists. Inverse operation to {@link #previous}.
   *
   * @param value any value of type {@code C}
   * @return the least value greater than {@code value}, or {@code null} if {@code value} is {@code
   *     maxValue()}

  SUBSET_VIEW,
  DESCENDING_VIEW,

  /**
   * For documenting collections that support no optional features, such as {@link
   * java.util.Collections#emptySet}
   */
  NONE;

  private final Set<Feature<? super Collection>> implied;

  CollectionFeature(Feature<? super Collection>... implied) {
    this.implied = Helpers.copyToSet(implied);
  }

  @Override

   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */
  @SuppressWarnings("unchecked")
  public static <T> Collector<T, ?, Optional<T>> toOptional() {
    return (Collector) TO_OPTIONAL;
  }

  private static final Object NULL_PLACEHOLDER = new Object();

    SerializableTester.reserializeAndAssert(Doubles.stringConverter());
  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Double> none = Arrays.<Double>asList();
    assertThat(Doubles.toArray(none)).isEqualTo(EMPTY);

    List<Double> one = Arrays.asList((double) 1);
    assertThat(Doubles.toArray(one)).isEqualTo(ARRAY1);

    double[] array = {(double) 0, (double) 1, Math.PI};