diff --git a/src/tef/mpsc_queue.mli b/src/tef/mpsc_queue.mli
index a14444b..594c8dc 100644
--- a/src/tef/mpsc_queue.mli
+++ b/src/tef/mpsc_queue.mli
@@ -1,6 +1,6 @@
 (** A multi-producer, single-consumer queue (from picos) *)
 
-type !'a t
+type 'a t
 
 val create : unit -> 'a t
 val enqueue : 'a t -> 'a -> unit