>>644
Friend declaration `std::ostream& operator<<(std::ostream&, const A<T>&)'
declares a non-template function.
If this is not what you intended, make sure the function template has
already been declared and add <> after the function name here.
-Wno-non-template-friend disables this warning.

・・・ってなワケだ。あとは好きなように対処しな。