[Bug c++/108104] ICE in unify, at cp/pt.c:24333 with template partial specialization and pointer to memeber function and nullptr

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108104

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It is definitely a pointer to member function issue.
I tried with just a pointer to a function and it worked and even a pointer to a
member field works too:
```
struct ss {
    int t;
};
template <int, int ss::*m> struct Fred {};
template <int state> struct Fred<state, nullptr> {};
Fred<1, &ss::t> f1;
```