diff --git a/Python/ast_opt.c b/Python/ast_opt.c
index 1393c3473bf..1766321a11a 100644
--- a/Python/ast_opt.c
+++ b/Python/ast_opt.c
@@ -19,6 +19,7 @@ make_const(expr_ty node, PyObject *val, PyArena *arena)
         return 0;
     }
     node->kind = Constant_kind;
+    node->v.Constant.kind = NULL;
     node->v.Constant.value = val;
     return 1;
 }