[Bug libstdc++/93983] std::filesystem::path is not concept-friendly

[rs2740 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93983

--- Comment #8 from TC <rs2740 at gmail dot com> ---
(really from Tim)

This is https://cplusplus.github.io/LWG/issue3420