diff --git a/src/emacs/lean-info.el b/src/emacs/lean-info.el
index 5a9c54866..5bf8d2c5d 100644
--- a/src/emacs/lean-info.el
+++ b/src/emacs/lean-info.el
@@ -1,9 +1,9 @@
+;; -*- lexical-binding: t; -*-
 ;; Copyright (c) 2014 Microsoft Corporation. All rights reserved.
 ;; Released under Apache 2.0 license as described in the file LICENSE.
 ;;
 ;; Author: Soonho Kong
 ;;
-
 (require 'cl-lib)
 (require 'dash)
 (require 'dash-functional)
diff --git a/src/emacs/lean-server.el b/src/emacs/lean-server.el
index 36123f28e..bf6b7c020 100644
--- a/src/emacs/lean-server.el
+++ b/src/emacs/lean-server.el
@@ -1,3 +1,4 @@
+;; -*- lexical-binding: t; -*-
 ;; Copyright (c) 2014 Microsoft Corporation. All rights reserved.
 ;; Released under Apache 2.0 license as described in the file LICENSE.
 ;;