diff --git a/mypyc/lib-rt/dict_ops.c b/mypyc/lib-rt/dict_ops.c
index c0cc8d5a7f87..031df8f63c49 100644
--- a/mypyc/lib-rt/dict_ops.c
+++ b/mypyc/lib-rt/dict_ops.c
@@ -230,12 +230,11 @@ PyObject *CPyDict_Keys(PyObject *dict) {
     if (view == NULL) {
         return NULL;
     }
-    PyObject *res = _PyList_Extend((PyListObject *)list, view);
+    int res = PyList_Extend(list, view);
     Py_DECREF(view);
-    if (res == NULL) {
+    if (res < 0) {
         return NULL;
     }
-    Py_DECREF(res);
     return list;
 }
 
@@ -250,12 +249,11 @@ PyObject *CPyDict_Values(PyObject *dict) {
     if (view == NULL) {
         return NULL;
     }
-    PyObject *res = _PyList_Extend((PyListObject *)list, view);
+    int res = PyList_Extend(list, view);
     Py_DECREF(view);
-    if (res == NULL) {
+    if (res < 0) {
         return NULL;
     }
-    Py_DECREF(res);
     return list;
 }
 
@@ -270,12 +268,11 @@ PyObject *CPyDict_Items(PyObject *dict) {
     if (view == NULL) {
         return NULL;
     }
-    PyObject *res = _PyList_Extend((PyListObject *)list, view);
+    int res = PyList_Extend(list, view);
     Py_DECREF(view);
-    if (res == NULL) {
+    if (res < 0) {
         return NULL;
     }
-    Py_DECREF(res);
     return list;
 }
 
diff --git a/mypyc/lib-rt/list_ops.c b/mypyc/lib-rt/list_ops.c
index df87228a0d10..d297ece8f417 100644
--- a/mypyc/lib-rt/list_ops.c
+++ b/mypyc/lib-rt/list_ops.c
@@ -256,7 +256,10 @@ int CPyList_Insert(PyObject *list, CPyTagged index, PyObject *value)
 }
 
 PyObject *CPyList_Extend(PyObject *o1, PyObject *o2) {
-    return _PyList_Extend((PyListObject *)o1, o2);
+    if (PyList_Extend(o1, o2) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
 }
 
 // Return -2 or error, -1 if not found, or index of first match otherwise.