Ensure that PySet_Add() operates on a newly created frozenset, like PyTuple_SetItem does.
Add PyFrozenSet_Check(), which was not needed before; The list of Py*Set_Check* macros seems to be complete now.
Add missing NEWS entries about all this.
diff --git a/Include/setobject.h b/Include/setobject.h
index fc32367..102796d 100644
--- a/Include/setobject.h
+++ b/Include/setobject.h
@@ -74,7 +74,11 @@
PyType_IsSubtype(Py_TYPE(ob), &PySet_Type) || \
PyType_IsSubtype(Py_TYPE(ob), &PyFrozenSet_Type))
#define PySet_Check(ob) \
- (Py_TYPE(ob) == &PySet_Type || PyType_IsSubtype(Py_TYPE(ob), &PySet_Type))
+ (Py_TYPE(ob) == &PySet_Type || \
+ PyType_IsSubtype(Py_TYPE(ob), &PySet_Type))
+#define PyFrozenSet_Check(ob) \
+ (Py_TYPE(ob) == &PyFrozenSet_Type || \\
+ PyType_IsSubtype(Py_TYPE(ob), &PyFrozenSet_Type))
PyAPI_FUNC(PyObject *) PySet_New(PyObject *);
PyAPI_FUNC(PyObject *) PyFrozenSet_New(PyObject *);