diff -r b78574cb00ab Objects/codeobject.c
--- a/Objects/codeobject.c	Tue Nov 08 22:53:59 2016 -0500
+++ b/Objects/codeobject.c	Wed Nov 09 08:43:32 2016 -0500
@@ -77,6 +77,7 @@
             intern_string_constants(v);
         }
         else if (PyFrozenSet_CheckExact(v)) {
+            PyObject *w = v;
             PyObject *tmp = PySequence_Tuple(v);
             if (tmp == NULL) {
                 PyErr_Clear();
@@ -89,6 +90,7 @@
                 }
                 else {
                     PyTuple_SET_ITEM(tuple, i, v);
+                    Py_DECREF(w);
                     modified = 1;
                 }
             }