diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index e89c9d5..464d28d 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -6419,7 +6419,7 @@
 {
     mod_ty res;
     init_types();
-    if (!PyObject_IsInstance(ast, mod_type)) {
+    if (!PyObject_IsInstance(ast, (PyObject*)mod_type)) {
         PyErr_SetString(PyExc_TypeError, "expected either Module, Interactive "
                         "or Expression node");
         return NULL;