Yeah, making it accept a universal reference would fix it... ...but that requires the argument to be a type from a template D: so you'd have to write: tem

Yeah, making it accept a universal reference would fix it... ...but that requires the argument to be a type from a template D: so you'd have to write: template<typename String = std::string> void dosomething(String &&str) ...and that's not quite right either, since you'd want it to be either an rvalue reference or a const lvalue reference