assertFalse(isThree.apply(3));
  }

  /*
   * Tests that compilation will work when applying explicit types.
   */
  @SuppressWarnings("unused") // compilation test
  public void testIn_compilesWithExplicitSupertype() {
    Collection<Number> nums = ImmutableSet.of();
    Predicate<Number> p1 = Predicates.in(nums);
    Predicate<Object> p2 = Predicates.<Object>in(nums);