I actually suspect that `known` solves an existing problem of C++, in which you can't be sure whether a name is that of an argument, a local variable or a field

I actually suspect that `known` solves an existing problem of C++, in which you can't be sure whether a name is that of an argument, a local variable or a field. Problem solved (at least partially) in other languages by requesting the `this` or `self` to be explicitly mentioned.