Thanks! What I do not quite understand is the need for a capture clause that lists the captured variables. As a user, I do not want to list my captures. As a code reviewer I certainly do not want value capture that create a modifiable copy with the same name, or any ambiguity on whether something is a copy or not. I just want to access my variables. So what is really the point here?

Regarding "also possible to make wide pointers from regular functions", this exactly the reason why I like the qualifer version: The usual conversion rules for qualifiers would allow this conversion implicitly, while back-conversion is not allowed (or only with cast).