public final void isNotSameInstanceAs(@Nullable Object unexpected) {
    if (actual == unexpected) {
      /*
       * We use actualCustomStringRepresentation() because it might be overridden to be better than
       * actual.toString()/unexpected.toString().
       */
      failWithoutActual(
          fact("expected not to be specific instance", actualCustomStringRepresentation()));
    }
  }
@Test
  public void isNotSameInstanceAsWithComparableObjects_nonString() {
    Object a = UnsignedInteger.valueOf(42);
    Object b = UnsignedInteger.fromIntBits(42);
    assertThat(a).isNotSameInstanceAs(b);
  }