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/bytesobject.c b/Objects/bytesobject.c
index 5814e8a..eaedb0b 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -2912,7 +2912,8 @@ PyTypeObject PyBytes_Type = {
     0,                                          /* tp_setattro */
     &bytes_as_buffer,                           /* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-        Py_TPFLAGS_BYTES_SUBCLASS,              /* tp_flags */
+        Py_TPFLAGS_BYTES_SUBCLASS |
+        _Py_TPFLAGS_MATCH_SELF,               /* tp_flags */
     bytes_doc,                                  /* tp_doc */
     0,                                          /* tp_traverse */
     0,                                          /* tp_clear */