https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78462
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- That is: #include <string> const std::string test="wish";//global var or const, but const gives me headaches int a(int b, int wish1=2, const std::string wish2=test) { } Works just fine in C++ and always has.