bpo-42128: Structural Pattern Matching (PEP 634) (GH-22917)

Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Talin <viridia@gmail.com>
Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
diff --git a/Objects/setobject.c b/Objects/setobject.c
index bfe6917..e8912ff 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -2093,7 +2093,8 @@ PyTypeObject PySet_Type = {
     0,                                  /* tp_setattro */
     0,                                  /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE,            /* tp_flags */
+        Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,       /* tp_flags */
     set_doc,                            /* tp_doc */
     (traverseproc)set_traverse,         /* tp_traverse */
     (inquiry)set_clear_internal,        /* tp_clear */
@@ -2193,7 +2194,8 @@ PyTypeObject PyFrozenSet_Type = {
     0,                                  /* tp_setattro */
     0,                                  /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE,            /* tp_flags */
+        Py_TPFLAGS_BASETYPE |
+        _Py_TPFLAGS_MATCH_SELF,       /* tp_flags */
     frozenset_doc,                      /* tp_doc */
     (traverseproc)set_traverse,         /* tp_traverse */
     (inquiry)set_clear_internal,        /* tp_clear */
@@ -2504,4 +2506,3 @@ static PyObject _dummy_struct = {
   _PyObject_EXTRA_INIT
   2, &_PySetDummy_Type
 };
-