}

    /**
     * The number of permutations with repeated elements is calculated as follows:
     *
     * <ul>
     *   <li>For an empty list, it is 1 (base case).
     *   <li>When r numbers are added to a list of n-r elements, the number of permutations is
     *       increased by a factor of (n choose r).
     * </ul>
     */
    private static <E> int calculateSize(

   * Returns {@code false} if {@code n} is zero, one, or a composite number (one which <i>can</i> be
   * factored into smaller positive integers).
   *
   * <p>To test larger numbers, use {@link LongMath#isPrime} or {@link BigInteger#isProbablePrime}.
   *
   * @throws IllegalArgumentException if {@code n} is negative
   * @since 20.0
   */
  @GwtIncompatible // TODO

   * sets ("constant sets"), with a given comparator. Example:
   *
   * <pre>{@code
   * public static final ImmutableSortedSet<Number> LUCKY_NUMBERS =
   *     new ImmutableSortedSet.Builder<Number>(ODDS_FIRST_COMPARATOR)
   *         .addAll(SINGLE_DIGIT_PRIMES)
   *         .add(42)
   *         .build();
   * }</pre>
   *

   * references, instead of calling {@code equals}, to determine whether a provided object matches
   * an element in the set. For example, {@code contains} returns {@code false} when passed an
   * object that equals a set member, but isn't the same instance. This behavior is similar to the
   * way {@code IdentityHashMap} handles key lookups.
   *
   * @since 8.0
   */
  public static <E extends @Nullable Object> Set<E> newIdentityHashSet() {

   * roughly) 2.5s longer. (2.5s is also the maximum length of time we will wait for a timed get
   * that is expected to succeed; the fact that the numbers match is only a coincidence.) See the
   * comment below for how to restore the fast but hang-y version.
   */
  @J2ktIncompatible
  @GwtIncompatible // used only in GwtIncompatible tests

/**
 * Implementation detail for the internal structure of {@link Range} instances. Represents a unique
 * way of "cutting" a "number line" (actually of instances of type {@code C}, not necessarily
 * "numbers") into two sections; this can be done below a certain value, above a certain value,
 * below all values or above all values. With this object defined in this way, an interval can

    return outputFuture;
  }

  enum RunningState {
    NOT_RUN,
    CANCELLED,
    STARTED,
  }

  /**
   * This class helps avoid a StackOverflowError when large numbers of tasks are submitted with
   * {@link MoreExecutors#directExecutor}. Normally, when the first future completes, all the other
   * tasks would be called recursively. Here, we detect that the delegate executor is executing

   *
   * <pre>{@code
   * Optional<Integer> optionalInt = getSomeOptionalInt();
   * Number value = optionalInt.or(0.5); // error
   *
   * FluentIterable<? extends Number> numbers = getSomeNumbers();
   * Optional<? extends Number> first = numbers.first();
   * Number value = first.or(0.5); // error
   * }</pre>
   *
   * <p>As a workaround, it is always safe to cast an {@code Optional<? extends T>} to {@code

      }
    }
  }

  /**
   * Used to delay string formatting until actually required, as it otherwise shows up in the test
   * execution profile when running an extremely large numbers of tests.
   */
  private String reportContext(List<E> expected) {
    return Platform.format(
        "expected collection %s; actual collection %s", expected, this.collection);
  }

        .addEqualityGroup(isNull)
        .addEqualityGroup(Equivalence.identity().equivalentTo("1"))
        .testEquals();
  }

  /*
   * We use large numbers to avoid the integer cache. Normally, we'd accomplish that merely by using
   * `new Integer` (as we do) instead of `Integer.valueOf`. However, under J2KT, `new Integer`