https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88084
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- This is a difference between C++17 std::basic_string_view and std::experimental::basic_string_view, introduced by https://cplusplus.github.io/LWG/lwg-defects.html#2777
