511     subclass: object
518 _abc__abc_register_impl(PyObject *module, PyObject *self, PyObject *subclass)  in _abc__abc_register_impl()  argument
521     if (!PyType_Check(subclass)) {  in _abc__abc_register_impl()
525     int result = PyObject_IsSubclass(subclass, self);  in _abc__abc_register_impl()
527         Py_INCREF(subclass);  in _abc__abc_register_impl()
528         return subclass;  /* Already a subclass. */  in _abc__abc_register_impl()
533     /* Subtle: test for cycles *after* testing for "already a subclass";  in _abc__abc_register_impl()
535     result = PyObject_IsSubclass(self, subclass);  in _abc__abc_register_impl()
548     if (_add_to_weak_set(&impl->_abc_registry, subclass) < 0) {  in _abc__abc_register_impl()
561             set_collection_flag_recursive((PyTypeObject *)subclass, collection_flag);  in _abc__abc_register_impl()
564     Py_INCREF(subclass);  in _abc__abc_register_impl()
565     return subclass;  in _abc__abc_register_impl()
584     PyObject *subtype, *result = NULL, *subclass = NULL;  in _abc__abc_instancecheck_impl()  local
590     subclass = PyObject_GetAttr(instance, &_Py_ID(__class__));  in _abc__abc_instancecheck_impl()
591     if (subclass == NULL) {  in _abc__abc_instancecheck_impl()
596     int incache = _in_weak_set(impl->_abc_cache, subclass);  in _abc__abc_instancecheck_impl()
606     if (subtype == subclass) {  in _abc__abc_instancecheck_impl()
608             incache = _in_weak_set(impl->_abc_negative_cache, subclass);  in _abc__abc_instancecheck_impl()
618         /* Fall back to the subclass check. */  in _abc__abc_instancecheck_impl()
620                                            subclass);  in _abc__abc_instancecheck_impl()
624                                        subclass);  in _abc__abc_instancecheck_impl()
647     Py_XDECREF(subclass);  in _abc__abc_instancecheck_impl()
655 static int subclasscheck_check_registry(_abc_data *impl, PyObject *subclass,
662     subclass: object
670                              PyObject *subclass)  in _abc__abc_subclasscheck_impl()  argument
673     if (!PyType_Check(subclass)) {  in _abc__abc_subclasscheck_impl()
688     incache = _in_weak_set(impl->_abc_cache, subclass);  in _abc__abc_subclasscheck_impl()
709         incache = _in_weak_set(impl->_abc_negative_cache, subclass);  in _abc__abc_subclasscheck_impl()
719     /* 3. Check the subclass hook. */  in _abc__abc_subclasscheck_impl()
721             (PyObject *)self, &_Py_ID(__subclasshook__), subclass);  in _abc__abc_subclasscheck_impl()
727         if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {  in _abc__abc_subclasscheck_impl()
735         if (_add_to_weak_set(&impl->_abc_negative_cache, subclass) < 0) {  in _abc__abc_subclasscheck_impl()
749     /* 4. Check if it's a direct subclass. */  in _abc__abc_subclasscheck_impl()
750     PyObject *mro = ((PyTypeObject *)subclass)->tp_mro;  in _abc__abc_subclasscheck_impl()
756             if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {  in _abc__abc_subclasscheck_impl()
764     /* 5. Check if it's a subclass of a registered class (recursive). */  in _abc__abc_subclasscheck_impl()
765     if (subclasscheck_check_registry(impl, subclass, &result)) {  in _abc__abc_subclasscheck_impl()
770     /* 6. Check if it's a subclass of a subclass (recursive). */  in _abc__abc_subclasscheck_impl()
782         int r = PyObject_IsSubclass(subclass, scls);  in _abc__abc_subclasscheck_impl()
785             if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {  in _abc__abc_subclasscheck_impl()
797     if (_add_to_weak_set(&impl->_abc_negative_cache, subclass) < 0) {  in _abc__abc_subclasscheck_impl()
811 subclasscheck_check_registry(_abc_data *impl, PyObject *subclass,  in subclasscheck_check_registry()  argument
814     // Fast path: check subclass is in weakref directly.  in subclasscheck_check_registry()
815     int ret = _in_weak_set(impl->_abc_registry, subclass);  in subclasscheck_check_registry()
861         int r = PyObject_IsSubclass(subclass, rkey);  in subclasscheck_check_registry()
868             if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) {  in subclasscheck_check_registry()