Problems passing an anonymous temporary function object to the template constructor

Question

I am trying to attach an object object that needs to be called when the template class is destroyed. However, I don't seem to be able to pass the object to the function as temporary. The warning I get (if a line comment xi.data = 5;):

    warning C4930: 'X<T> xi2(writer (__cdecl *)(void))': 
    prototyped function not called (was a variable definition intended?)
            with
            [
                T=int
            ]

and if I try to use the constructed object, I get a compilation error:

error C2228: left of '.data' must have class/struct/union

I apologize for the long piece of code, but I think that all components should be visible to assess the situation.

template<typename T>
struct Base
{
    virtual void run( T& ){}
    virtual ~Base(){}
};

template<typename T, typename D>
struct Derived : public Base<T>
{
    virtual void run( T& t )
    {
        D d;
        d(t);
    }
};

template<typename T>
struct X
{
    template<typename R>
    X(const R& r)
    {
       std::cout << "X(R)" << std::endl;
       ptr = new Derived<T,R>(); 
    }

    X():ptr(0)
    { 
        std::cout << "X()" << std::endl; 
    }

    ~X()
    {
        if(ptr) 
        {
            ptr->run(data);
            delete ptr;
        }
        else
        {
            std::cout << "no ptr" << std::endl;
        }
    }

    Base<T>* ptr; 
    T data;
};

struct writer
{
    template<typename T>
    void operator()( const T& i )
    { 
        std::cout << "T : " << i << std::endl;
    }
};

int main()
{
    {
        writer w;
        X<int> xi2(w);
        //X<int> xi2(writer()); //This does not work!
        xi2.data = 15;       
    }

    return 0;
};

, , , "- " - , - . , class X, class writer, Base<T> ( , <T> , ).

, , , writer, X, X<int> xi(writer();

- , ?

Answer 1

" ".

X<int> xi2 = X<int>(writer());

X<int> xi2((writer()));

Answer 2

X<int> xi2((writer()));. , . ( STL- 6).

Answer 3

X<int> xi2(writer()); - , xi2, X<int>, , . " ".

, , , .