https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120640
--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
It looks to me like an extension of the "struct stat" hack, where typename
takes the role of struct such as in:
```
namespace N {
class A {};
int A();
}
class N::A a; // everyone accepts
```
