diff --git a/types.ml b/types.ml
index 557993c6addf83616b0a7068dba165d28ee91037..a21758936ff441f1f6175df93a75a211a73aac1c 100644
--- a/types.ml
+++ b/types.ml
@@ -53,7 +53,7 @@ type statement =
 
 type stylesheet = statement list
 
-type traversal_box =
+type box =
   | Expr of expr
   | Declaration of declaration
   | Selector of selector
diff --git a/util.ml b/util.ml
index e97ab256edd42dab2c042140d9cf5b20436d28dd..c5227e4270111168884fdfff1303b2348e8286aa 100644
--- a/util.ml
+++ b/util.ml
@@ -111,7 +111,7 @@ let prerr_loc_msg verbose loc msg =
     | constructor decl -> decl \
     | _ -> failwith ("expected " ^ #constructor)
 
-let transform_stylesheet (f : traversal_box -> traversal_box) stylesheet =
+let transform_stylesheet f stylesheet =
   let rec trav_expr = function
     | Concat terms -> f (Expr (Concat (trav_all_expr terms)))
     | Function (name, arg) -> f (Expr (Function (name, expect_expr arg)))