diff --git a/src/unix/Lwt_fmt.ml b/src/unix/Lwt_fmt.ml
index ed8276fb60..c811caf58c 100644
--- a/src/unix/Lwt_fmt.ml
+++ b/src/unix/Lwt_fmt.ml
@@ -29,7 +29,7 @@ type formatter = {
 let write_pending ppft = ppft.commit ()
 let flush ppft = Format.pp_print_flush ppft.ppf () ; ppft.commit ()
 
-let make_formatter ~commit ~ppf = { commit ; ppf }
+let make_formatter ~commit ~ppf () = { commit ; ppf }
 
 (** Stream formatter *)
 
@@ -48,7 +48,7 @@ let make_stream () =
   (* Not sure about that one *)
   Gc.finalise (fun _ -> push None) ppf ;
   let commit () = Lwt.return_unit in
-  stream, make_formatter ~commit ~ppf
+  stream, make_formatter ~commit ~ppf ()
           
 (** Channel formatter *)
 
@@ -75,7 +75,7 @@ let of_channel oc =
   in
   let ppf = Format.make_formatter out_string flush in
   let commit () = write_orders oc q in
-  make_formatter ~commit ~ppf
+  make_formatter ~commit ~ppf ()
 
 (** Printing functions *)