[Bug c++/69623] Invalid deduction of non-trailing template parameter pack

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69623

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Full testcase where both declarations should be an error:

  template<class... T, class... U> void f() { } // error
  template<class... T, class U> void g() { } // error