diff --git a/benchs/dune b/benchs/dune
index 962fc524..ff3ac80f 100644
--- a/benchs/dune
+++ b/benchs/dune
@@ -3,6 +3,6 @@
   (libraries containers containers-data
              containers-thread benchmark gen iter qcheck oseq
              batteries base sek)
-  (flags :standard -warn-error -3 -safe-string -color always -open CCShims_)
+  (flags :standard -warn-error -3-5 -safe-string -color always -open CCShims_)
   (ocamlopt_flags :standard -O3 -color always
                    -unbox-closures -unbox-closures-factor 20))
diff --git a/benchs/run_benchs.ml b/benchs/run_benchs.ml
index cedf2f60..6539ad7a 100644
--- a/benchs/run_benchs.ml
+++ b/benchs/run_benchs.ml
@@ -1,5 +1,7 @@
 (** Generic benchs *)
 
+[@@@warning "-5"]
+
 module B = Benchmark
 let (@>) = B.Tree.(@>)
 let (@>>) = B.Tree.(@>>)
@@ -952,7 +954,7 @@ module Iter_ = struct
         if !saw_x then (saw_x := true; Some x)
         else xs ()
     in
-    let xs = Array.init n Fun.id in
+    let xs = Array.init n CCFun.id in
     let iter () = ignore (Array.fold_right Iter.cons xs Iter.empty : int Iter.t) in
     let gen () = ignore (Array.fold_right gen_cons xs Gen.empty : int Gen.t) in
     let oseq () = ignore (Array.fold_right OSeq.cons xs OSeq.empty : int OSeq.t) in
@@ -969,7 +971,7 @@ module Iter_ = struct
         if !saw_x then (saw_x := true; Some x)
         else xs ()
     in
-    let xs = Array.init n Fun.id in
+    let xs = Array.init n CCFun.id in
     let iter () = Iter.fold (+) 0 (Array.fold_right Iter.cons xs Iter.empty) in
     let gen () = Gen.fold (+) 0 (Array.fold_right gen_cons xs Gen.empty) in
     let oseq () = OSeq.fold (+) 0 (Array.fold_right OSeq.cons xs OSeq.empty) in
diff --git a/benchs/run_objsize.ml b/benchs/run_objsize.ml
index 98e378d5..8b078820 100644
--- a/benchs/run_objsize.ml
+++ b/benchs/run_objsize.ml
@@ -1,6 +1,6 @@
 (* module Deque = Core_kernel.Deque *)
-module Int_map = Map.Make(CCInt)
-module Int_set = Set.Make(CCInt)
+module Int_map = CCMap.Make(CCInt)
+module Int_set = CCSet.Make(CCInt)
 
 let dup = CCPair.dup
 let id = CCFun.id
@@ -19,10 +19,10 @@ let dummy = 0
 let types = [
   "Stdlib.List", (fun n -> Obj.magic @@ ns n);
   "Stdlib.Array", (fun n -> Obj.magic @@ Array.init n id);
-  "Stdlib.Hashtbl", (fun n -> Obj.magic @@ Hashtbl.of_seq (OSeq.init ~n dup));
+  "Stdlib.Hashtbl", (fun n -> Obj.magic @@ CCHashtbl.of_iter Iter.(init dup |> take n));
   "Base.Hashtbl", (fun n -> Obj.magic @@ Base.Hashtbl.Poly.of_alist_exn (List.init n dup));
-  "Stdlib.Map", (fun n -> Obj.magic @@ Int_map.of_seq (OSeq.init ~n dup));
-  "Stdlib.Set", (fun n -> Obj.magic @@ Int_set.of_seq (OSeq.init ~n id));
+  "Stdlib.Map", (fun n -> Obj.magic @@ Int_map.of_iter Iter.(init dup |> take n));
+  "Stdlib.Set", (fun n -> Obj.magic @@ Int_set.of_iter Iter.(init id |> take n));
   "CCFun_vec", (fun n -> Obj.magic @@ CCFun_vec.of_list (ns n));
   "CCRAL", (fun n -> Obj.magic @@ CCRAL.of_list (ns n));
   "BatVect", (fun n -> Obj.magic @@ BatVect.of_list (ns n));
@@ -31,7 +31,7 @@ let types = [
   "CCVector", (fun n -> Obj.magic @@ let c = CCVector.create () in iter_range n (CCVector.push c); c);
   (* "Core_kernel.Deque", (fun n -> Obj.magic @@ let c = Deque.create () in iter_range n (Deque.enqueue_back c); c); *)
   "Base.Queue", (fun n -> Obj.magic @@ let c = Base.Queue.create () in iter_range n (Base.Queue.enqueue c); c);
-  "Stdlib.Queue", (fun n -> Obj.magic @@ Queue.of_seq (OSeq.init ~n id));
+  "Stdlib.Queue", (fun n -> Obj.magic @@ (let q = Queue.create () in iter_range n (fun x -> Queue.push x q); q));
   "CCQueue", (fun n -> Obj.magic @@ CCDeque.of_list (ns n));
   "Iter", (fun n -> Obj.magic @@ List.fold_right Iter.cons (ns n) Iter.empty);
   "Gen", (fun n -> Obj.magic @@ List.fold_right gen_cons (ns n) Gen.empty);
diff --git a/src/core/CCSexp.ml b/src/core/CCSexp.ml
index eea0ece2..f31a2378 100644
--- a/src/core/CCSexp.ml
+++ b/src/core/CCSexp.ml
@@ -5,7 +5,6 @@
 open CCShims_
 
 type 'a or_error = ('a, string) result
-type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
 
 module type SEXP = CCSexp_intf.SEXP
diff --git a/src/data/CCBitField.mli b/src/data/CCBitField.mli
index b5f29d2e..43680ad9 100644
--- a/src/data/CCBitField.mli
+++ b/src/data/CCBitField.mli
@@ -60,7 +60,7 @@ module type S = sig
 end
 
 (** Create a new bitfield type *)
-module Make(X : sig end) : S
+module Make : functor(_ : sig end) -> S
 
 (**/**)
 val all_bits_ : int -> int -> int