assertThat(TypeToken.of(Types.supertypeOf(Object[].class)).getComponentType()).isNull();
  }

  private interface NumberList<T extends Number> {}

  public void testImplicitUpperBoundForWildcards() {
    assertAssignable(
        new TypeToken<NumberList<? extends Number>>() {}, new TypeToken<NumberList<?>>() {});
    assertAssignable(