static String create(String s) {
      return checkNotNull(s);
    }
  }

  private interface InterfaceDefaultMethodFailsToCheckNull {
    static InterfaceDefaultMethodFailsToCheckNull create() {
      return new InterfaceDefaultMethodFailsToCheckNull() {};
    }

    default void doNotCheckNull(String unused) {}
  }

  private interface InterfaceDefaultMethodChecksNull {