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/dictobject.c b/Objects/dictobject.c
index 6ca82a7..179cb30 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -3549,7 +3549,8 @@ PyTypeObject PyDict_Type = {
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS,         /* tp_flags */
+        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     dictionary_doc,                             /* tp_doc */
     dict_traverse,                              /* tp_traverse */
     dict_tp_clear,                              /* tp_clear */