[Bug c++/122550] [14/15/16 Regression] constrained hidden template friend alongside existing declaration is ambiguous

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122550

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
member_like_constrained_friend_p is returning true for the template friend
'add', but its constraints don't depend on outer template parameters so
[temp.friend]/9 shouldn't apply.