#include <iostream>
 
using namespace std;
 
template<class T>
class IDetachable {
public:
    virtual T* detached() const = 0;
};
 
 
class A: public IDetachable<A> {
    virtual A* detached() const override {
        cout << "some implementation which returns a detached A object" << endl;
    }
};
 
class B: public A, public IDetachable<B> {
    virtual B* detached() const override {
        cout << "some implementation which returns a detached B object" << endl;
    }
};
 
int main() {
    IDetachable<A> *da = new A;
    A *a = da->detached();
    IDetachable<B> *db = new B;
    A *ba = db->detached();
    B *bb = db->detached();
}

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