Error with variadiac template: “parameter pack must be expanded”

Question

Here\'s a variadic template function that I\'ve written:

template
Value& insert(Container& c, Args&         


        

Answer 1

The error is due to the missing ellipsis (...) after args when passing all individual parameters (rather than the parameter pack) to emplace_back.

The fixed (and improved) version:

template<class Container, class... Args>
auto insert(Container& c, Args&&... args) -> decltype (c.back()) {
    c.emplace_back(std::forward<Args>(args)...);
    return c.back();
}