Add missing decref
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index b8ba7e1..eca8677 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -981,6 +981,7 @@
 		return NULL;
 	if (!PyDict_Check(d)) {
 		PyErr_BadInternalCall();
+		Py_DECREF(d);
 		return NULL;
 	}