diff --git a/Python/ast.c b/Python/ast.c
index 76588c3..5cef3fd 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -702,6 +702,8 @@
 new_type_comment(const char *s, struct compiling *c)
 {
     PyObject *res = PyUnicode_DecodeUTF8(s, strlen(s), NULL);
+    if (res == NULL)
+        return NULL;
     if (PyArena_AddPyObject(c->c_arena, res) < 0) {
         Py_DECREF(res);
         return NULL;