Assigning a nullptr to a refptr must make this refptr a nullptr, otherwise its destructor would try to destroy its object if another refptr remained.

Assigning a nullptr to a refptr must make this refptr a nullptr, otherwise its destructor would try to destroy its object if another refptr remained.However, a refptr behaves like a weakptr if its object dies, i.e. when no other refptr exists for this object, in which case the hash value of the refptr remains valid even after death of its object.