https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86013
--- Comment #13 from Jan Kratochvil <jan.kratochvil at redhat dot com> --- Why the example code should not work with "a user-provided non-member function with the same signature defined anywhere in the program, in any source file, replaces the default version. Its declaration does not need to be visible."? I would do the real libstdc++ sources patch as that would comply with these requirements but I wanted to know first if there are some technical reasons why it gets rejected, so far I do not see any.
