class foo
{
public:
    int a;
    foo(int i) {
        a = i;
    }
    foo(foo &&f)
    {
        this->a = f.a;
        f.a = 0;
        std::cout << "move";
    }
    foo(const foo &f)
    {
        this->a = f.a;
        std::cout << "ref";
    }
};

template <typename A>
void E(A &&a)
{
    cout << endl << is_lvalue_reference<A>::value << is_rvalue_reference<A>::value << is_reference<A>::value << endl;
    a.a = 5;
}

template <typename A>
void f(A &&a)
{
    cout << is_lvalue_reference<A>::value << is_rvalue_reference<A>::value << is_reference<A>::value << endl;
    std::cout << a.a;
    E(std::forward<A>(a));
    std::cout << a.a;
}

int main()
{
    f(foo(1));
}

After struggling with the rvalue and lvalue, I still get confused with the output of the code snippet below:

000
1
000
5

why the value of is_rvalue_reference<A>::value in function f got 0 instead of 1 ?