The problem is that we suddenly changed rules. It was not required that the object's type should be visited in tp_visit. It was incorrect to visit it, because object did not have strong reference to its type. User never created it, and it was not created implicitly.

Now we changed rules. A strong reference is created implicitly. Who is responsible to manage a strong reference? Whose who created it, ant it is the interpreter, not the user. User does not know anything about it. If we pass the responsibility for the strong reference to the type on the user, we makes all user code incorrect, and we add a burden of fixing it and maintaining compatibility with incompatible Python versions on the user. I think it is very bad.