Repository navigation
CWG3103 [basic.scope.scope] Corresponding object members and by-value object parameter #776
Description
Activity
I don't think we want different outcomes here, and I'd lean towards making the second case ill-formed as well.
If we want any of these to be well-formed, I think we also need to discuss how a using-declaration in a derived class then behaves for these cases, i.e.
struct OK { void f(this OK); void f() &; }; struct D : OK { using OK::f; };
as there is special treatment for implicit object member functions, but not for explicit object member functions (over.match.funcs/4)
- changed the title
[-][basic.scope.scope] Corresponding object members and by-value object parameter[/-][+]CWG3103 [basic.scope.scope] Corresponding object members and by-value object parameter[/+]on Nov 2, 2025
Following discussions about CWG2555
Consider
Here, exactly one (
#2) function has an implicit object parameter and no ref qualifier, and after removing references, both have the same type (K)- per https://eel.is/c++draft/over.match.funcs#general-4 - although whether this rule applies could be clearer.So #1 and #2 correspond, even though they do have different object parameter type (
KandK&respectively)All compilers reject that code.
However, consider a very similar example
Here, no overload has "an implicit object parameter and no ref qualifier" so references are not stripped, we compare
KandK&, which are not the same type, the parameter do not correspond and we can declare a distinct overload.What makes us want a different outcome in both scenarios, when the model is that the lack of
&does not implies by value?