[Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion

[jlame646 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111

--- Comment #2 from Jason Liam <jlame646 at gmail dot com> ---
Also gcc rejects `V...()` but clang accepts that. Demo:
https://godbolt.org/z/bfx9rv6hP