C++ could adopt the UFCS universal-function-call feature of D-language that allows any ordinary free function to be called as if they were methods, without any special kind of type annotation. One of major advantages of UFCS is that it enhances the discoverability of free functions in IDEs. An user could write 'Object' followed by dot '.' and the IDE could show all possible functions applicable to that type. In D-language, the UFCS also works for primitive types such as int, double and so on.
D-Language UFCS: http://ddili.org/ders/d.en/ufcs.html and https://tour.dlang.org/tour/en/gems/uniform-function-call-sy...