https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115888
--- Comment #3 from Jason Liam <jlame646 at gmail dot com> ---
Reduced program to show the intent more clearly:
```
#include <iostream>
struct C{
int f(this int);
};
decltype(C::f) func; //msvc accepts but clang and gcc rejects
int func(int j)
{
std::cout << "called with: " << j << std::endl;
return 5;
}
```
The main problem is with `decltype(C::f)` which as per current wording is
well-formed.
