public typeof(this) opPostInc(T = int)(T unused = 0) {
    static assert(
      is(typeof(swigOpInc(int.init))),
      "opPostInc called on " ~ typeof(this).stringof ~ ", but no postfix " ~
      "increment operator exists in the corresponding C++ class."
    );
    return swigOpInc(int.init);
  }