[Bug c++/83145] Ambiguous overload with templates, only GCC7 C++17 mode (regression?)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83145

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The new rule was introduced by
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0522r0.html