Optional<Number> optionalInt = Optional.of((Number) 1);
    Number value = optionalInt.or(0.5); // fine
  }

  @SuppressWarnings("unused") // compilation test
  public void testSampleCodeFine2() {
    FluentIterable<? extends Number> numbers = getSomeNumbers();

    // Sadly, the following is what users will have to do in some circumstances.

    @SuppressWarnings("unchecked") // safe covariant cast