https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86273
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:
namespace std {
template<typename> struct vector { };
}
struct Input {
std::vector<float>;
};
id.cc:6:8: error: a template-id may not appear in a using-declaration
std::vector<float>;
^~~~~~~~~~~~~
