diff --git a/Modules/clinic/_struct.c.h b/Modules/clinic/_struct.c.h
index 71ac290..9573769 100644
--- a/Modules/clinic/_struct.c.h
+++ b/Modules/clinic/_struct.c.h
@@ -206,6 +206,7 @@ unpack(PyObject *module, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
 
     if (!_PyArg_ParseStack(args, nargs, "O&y*:unpack",
         cache_struct_converter, &s_object, &buffer)) {
+        _clearcache_impl(NULL);
         goto exit;
     }