diff --git a/mu4e/mu4e-compose.el b/mu4e/mu4e-compose.el
index 8c4613a0..698c2289 100644
--- a/mu4e/mu4e-compose.el
+++ b/mu4e/mu4e-compose.el
@@ -293,11 +293,10 @@ Ie. either 'name <email>' or 'email')."
   "Set up auto-completion of addresses."
   (set (make-local-variable 'completion-ignore-case) t)
   (set (make-local-variable 'completion-cycle-threshold) 7)
-  (add-to-list (make-local-variable 'completion-styles) 'substring t)
+  (add-to-list (make-local-variable 'completion-styles) 'substring)
   (add-hook 'completion-at-point-functions
     'mu4e~compose-complete-contact nil t))
 
-
 (defun mu4e~remove-refs-maybe ()
   "Remove the References: header if the In-Reply-To header is
 missing. This allows the user to effectively start a new