Or for the as/is PM proposal: using namespace A is in(X, Y, Z) Similar to lamda captures: using namespace A [X, Y, Z] But aligning a better using with other language features should take more consideration to not only have similar syntax, but real meaning and consistency. -----Ursprüngliche Nachricht----- Von:Sebastian Wittmeier <wittmeier_at_[hidden]> Gesendet:Do 27.04.2023 09:48 Betreff:AW: [std-proposals] Grouped-namespace "using" statements (floating the idea) An:std-proposals_at_[hidden]; using namespace A if any_of{X, Y, Z} One could see it as limitation of using namespace instead. any_of loosely based on pattern matching proposals.