#include<type_traits>

template <typename T>
class bazplate {

public:
    template<class Q = T>
    typename std::enable_if<std::is_same<Q, void>::value, int> ::type foo();

    template<class Q = T>
    [[nodiscard]] typename std::enable_if<!std::is_same<Q, void>::value, int> ::type foo();
};

template <typename T>
int bazplate<T>::foo (){
    return 3;
}


int main(){
    bazplate<int> a;
    bazplate<void> b;
}