Почему не работает перегрузка?

#include <iostream>
using namespace std;
///////////////////////////////////////////////////////////
class Distance   
{
    private:
        int number;
 
    public:
        Distance(): number(0)
        {}
        Distance(int n): number(n)
        {}
 
        Distance operator+ (Distance2)
        {
            Distance i = number + d2.number;
            return i;
        }
 
};
 
int main(){
    
    Distance d1(10);
    Distance d2(20);
 
    cout << d1 + d2 << endl;        // Где 30?????
 
    return 0;
}

Distance operator +(const Distance &d2) const

        friend std::ostream &operator <<(std::ostream &out, const Distance &d) 
        {
            return out << d.number;
        }

#include <iostream>
using namespace std;
 
#define dOUT_TO_STDSTREAM(classname) \
    template<class T> friend         \
    ::std::basic_ostream<T>&         \
    operator<<(::std::basic_ostream<T>& out, const classname& obj)
 
///////////////////////////////////////////////////////////
class Distance   
{
    dOUT_TO_STDSTREAM(Distance)
    {
        return out << obj.number;
    }
    
private:
    int number;
 
public:
    Distance(): number(0)
    {}
    Distance(int n): number(n)
    {}
 
    Distance operator+ (const Distance& d2)
    {
        Distance i = number + d2.number;
        return i;
    }
};
 
int main()
{
    Distance d1(10);
    Distance d2(20);
    cout << d1 + d2 << endl;
}