[Bug c++/121850] ICE: in dependent_alias_template_spec_p, at cp/pt.cc:6801

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121850

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reduced testcase:
```
template<class T>
using AllSame = int;

template<class T, class... Rest>
struct AllSame<T, Rest...>;
```