Apply my own comment again.

Author: rlepigre

src/core/extra.ml

@@ -240,14 +240,13 @@ module List =
       in in_sorted
 
     (** [insert cmp x l] inserts [x] in the list [l] assuming that [l] is
-       sorted wrt [cmp]. *)
+        sorted wrt [cmp]. *)
     let insert : 'a cmp -> 'a -> 'a list -> 'a list = fun cmp x ->
       let rec insert acc l =
         match l with
-        | y :: m when cmp x y > 0 -> insert (y::acc) m
-        | _ -> List.rev_append acc (x::l)
+        | y :: l when cmp x y > 0 -> insert (y::acc) l
+        | _                       -> List.rev_append acc (x::l)
       in insert []
-
   end
 
 module Array =