https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98687
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Adjusted test: extern "C" namespace std { double log1p(double); } namespace std_fallback { template <typename> void log1p(); } template <typename> struct log1p_impl { static int run() { using std::log1p; using std_fallback::log1p; return 0; } }; void log1p() { log1p_impl<int>::run(); }