https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113884
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I know cppreference is not the standard but it is a decent reference to start with. https://en.cppreference.com/w/cpp/container/vector/vector Without the explicit, clang will also reject it as being ambiguous. As I mentioned this is not a bug in gcc but rather a bug in clang.
