模板参数T用作模板名称，因此应将其声明为

The template parameter T is used as a template-name, so it should be declared as template template parameter. e.g.

template <template <typename...> class T, typename V>
//        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void f(T<std::tuple<V>> t) {
    std::cout << "2" << std::endl;
}

实时