Method release_ptr

tests/test_smart_ptr.cpp:68–68

    explicit unique_ptr_with_addressof_operator(T *p) : impl(p) {}
    T *get() const { return impl.get(); }
    T *release_ptr() { return impl.release(); }
    T **operator&() { throw std::logic_error("Call of overloaded operator& is not expected"); }
};