template<class A, class B>
class Pair{
    A fst;
    B snd;
}

template<class A, class B>
A get_fst(Pair<A,B> p){
    return p.fst;
}


void main(){
    Pair<()->i32, i32> p{() => 42, 17};
    auto x = get_fst(p);
    // does this compile?
    // whats the type of x?
}