https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118482
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
```
using what_type = decltype(
[](auto&& self,
decltype([](decltype(self)&){}) x = {}){ return x; });
what_type x;
int main() {
if (x(x)) return 1;
}
```
