diff --git a/lib/CFStream_stream.ml b/lib/CFStream_stream.ml
index 25c0e5a..94da2e3 100644
--- a/lib/CFStream_stream.ml
+++ b/lib/CFStream_stream.ml
@@ -287,7 +287,7 @@ let group_aux xs map eq =
 ;;
 
 let group xs ~f = group_aux xs f Poly.( = )
-let group_by xs ~eq = group_aux xs ident eq
+let group_by xs ~eq = group_aux xs Fn.id eq
 
 let chunk2 xs =
   from (fun _ ->
@@ -615,11 +615,11 @@ let to_hashtbl xs =
 let of_map t = of_list (Map.to_alist t)
 
 let to_map xs =
-  fold xs ~init:Map.Poly.empty ~f:(fun accu (key, data) -> Map.Poly.set accu ~key ~data)
+  fold xs ~init:Map.Poly.empty ~f:(fun accu (key, data) -> Map.set accu ~key ~data)
 ;;
 
 let of_set t = of_list (Set.to_list t)
-let to_set xs = fold xs ~init:Set.Poly.empty ~f:(fun accu e -> Set.Poly.add accu e)
+let to_set xs = fold xs ~init:Set.Poly.empty ~f:(fun accu e -> Set.add accu e)
 
 module Infix = struct
   let ( -- ) x y = range x ~until:y
@@ -660,7 +660,7 @@ module Result = struct
       | M.E e -> Result.Error e
     ;;
 
-    let all xs ~f = all_gen ident xs ~f
+    let all xs ~f = all_gen Fn.id xs ~f
     let all' xs ~f = all_gen (fun x -> Ok x) xs ~f
     let to_exn = result_to_exn