[Bug c++/100741] [enhancement] Should show better error message if using ‘typedef’ instead of ‘using’.

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100741

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Complete testcase:

struct X { };
typedef Rng = X;