diff --git a/src/core/CCArray.ml b/src/core/CCArray.ml
index e60af1d2..baed3d57 100644
--- a/src/core/CCArray.ml
+++ b/src/core/CCArray.ml
@@ -490,9 +490,6 @@ let shuffle a =
 let shuffle_with st a =
   _shuffle (Random.State.int st) a 0 (Array.length a)
 
-let rec _to_klist a i j () =
-  if i=j then `Nil else `Cons (a.(i), _to_klist a (i+1) j)
-
 let random_choose a =
   let n = Array.length a in
   if n = 0 then invalid_arg "Array.random_choose";
diff --git a/src/core/CCHash.ml b/src/core/CCHash.ml
index 88361648..106d70a3 100644
--- a/src/core/CCHash.ml
+++ b/src/core/CCHash.ml
@@ -9,7 +9,6 @@ type 'a t = 'a -> hash
 
 type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 
 let combine f s x = Hashtbl.seeded_hash s (f x)
 
@@ -87,9 +86,3 @@ let gen f g =
     | None -> s
     | Some x -> aux (combine2 s (f x))
   in aux 0x42
-
-let klist f l =
-  let rec aux l s = match l () with
-    | `Nil -> s
-    | `Cons (x,tail) -> aux tail (combine2 s (f x))
-  in aux l 0x42
diff --git a/src/core/CCHash.mli b/src/core/CCHash.mli
index 0d094d22..1b7379f2 100644
--- a/src/core/CCHash.mli
+++ b/src/core/CCHash.mli
@@ -74,9 +74,7 @@ val combine6 : hash -> hash -> hash -> hash -> hash -> hash -> hash
 
 type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 
 val seq : 'a t -> 'a Seq.t t
 val iter : 'a t -> 'a iter t
 val gen : 'a t -> 'a gen t
-val klist : 'a t -> 'a klist t
diff --git a/src/core/CCHeap.ml b/src/core/CCHeap.ml
index 5b7b9e19..7eba186c 100644
--- a/src/core/CCHeap.ml
+++ b/src/core/CCHeap.ml
@@ -6,7 +6,6 @@
 type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
 type 'a printer = Format.formatter -> 'a -> unit
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a ktree = unit -> [`Nil | `Node of 'a * 'a ktree list]
 
 module type PARTIAL_ORD = sig
@@ -152,9 +151,9 @@ module type S = sig
 
   (** {2 Conversions}
 
-      The interface of [of_gen], [of_iter], [of_klist]
+      The interface of [of_gen], [of_iter]
       has changed since 0.16 (the old signatures
-      are now [add_seq], [add_gen], [add_klist]). *)
+      are now [add_seq], [add_gen]). *)
 
   val to_list : t -> elt list
   (** Return the elements of the heap, in no particular order. *)
@@ -203,14 +202,6 @@ module type S = sig
   (** Iterate on the elements, in increasing order.
       @since 2.8 *)
 
-  val add_klist : t -> elt klist -> t (** @since 0.16 *)
-
-  val of_klist : elt klist -> t
-  (** Build a heap from a given [klist]. Complexity: [O(n log n)]. *)
-
-  val to_klist : t -> elt klist
-  (** Return a [klist] of the elements of the heap. *)
-
   val add_gen : t -> elt gen -> t (** @since 0.16 *)
 
   val of_gen : elt gen -> t
@@ -396,23 +387,6 @@ module Make(E : PARTIAL_ORD) : S with type elt = E.t = struct
     | None -> Seq.Nil
     | Some (h', x) -> Seq.Cons (x, to_seq_sorted h')
 
-  let rec add_klist h l = match l() with
-    | `Nil -> h
-    | `Cons (x, l') ->
-      let h' = add h x in
-      add_klist h' l'
-
-  let of_klist l = add_klist empty l
-
-  let to_klist h =
-    let rec next stack () = match stack with
-      | [] -> `Nil
-      | E :: stack' -> next stack' ()
-      | N (_, x, a, b) :: stack' ->
-        `Cons (x, next (a :: b :: stack'))
-    in
-    next [h]
-
   let rec add_gen h g = match g () with
     | None -> h
     | Some x ->
diff --git a/src/core/CCHeap.mli b/src/core/CCHeap.mli
index fdc67b01..35e71040 100644
--- a/src/core/CCHeap.mli
+++ b/src/core/CCHeap.mli
@@ -10,7 +10,6 @@ type 'a iter = ('a -> unit) -> unit
     @since 2.8 *)
 
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a ktree = unit -> [`Nil | `Node of 'a * 'a ktree list]
 type 'a printer = Format.formatter -> 'a -> unit
 
@@ -146,16 +145,6 @@ module type S = sig
       Renamed from [to_std_seq_sorted] since NEXT_RELEASE.
       @since NEXT_RELEASE *)
 
-  val add_klist : t -> elt klist -> t
-  (** [add_klist h klist] adds the klist [klist] to the heap [h].
-      @since 0.16 *)
-
-  val of_klist : elt klist -> t
-  (** [of_klist klist] builds a heap from a given [klist]. Complexity: [O(n log n)]. *)
-
-  val to_klist : t -> elt klist
-  (** [to_klist h] returns a [klist] of the elements of the heap [h]. *)
-
   val add_gen : t -> elt gen -> t
   (** [add_gen h gen] adds the gen [gen] to the heap [h].
       @since 0.16 *)
diff --git a/src/core/CCList.ml b/src/core/CCList.ml
index 5658dc09..362e7689 100644
--- a/src/core/CCList.ml
+++ b/src/core/CCList.ml
@@ -1672,7 +1672,6 @@ end
 
 type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a printer = Format.formatter -> 'a -> unit
 type 'a random_gen = Random.State.t -> 'a
 
@@ -1770,24 +1769,6 @@ let of_gen g =
   Q.(list int) (fun l -> of_gen(to_gen l) = l)
 *)
 
-let to_klist l =
-  let rec make l () = match l with
-    | [] -> `Nil
-    | x::l' -> `Cons (x, make l')
-  in make l
-
-let of_klist l =
-  let rec direct i g =
-    if i = 0 then safe [] g
-    else match l () with
-      | `Nil -> []
-      | `Cons (x,l') -> x :: direct (i-1) l'
-  and safe acc l = match l () with
-    | `Nil -> List.rev acc
-    | `Cons (x,l') -> safe (x::acc) l'
-  in
-  direct direct_depth_default_ l
-
 module Infix = struct
   let[@inline] (>|=) l f = map f l
   let[@inline] (>>=) l f = flat_map f l
diff --git a/src/core/CCList.mli b/src/core/CCList.mli
index c85fa092..7863d77e 100644
--- a/src/core/CCList.mli
+++ b/src/core/CCList.mli
@@ -8,7 +8,6 @@ type 'a iter = ('a -> unit) -> unit
     @since 2.8 *)
 
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a printer = Format.formatter -> 'a -> unit
 type 'a random_gen = Random.State.t -> 'a
 
@@ -782,13 +781,6 @@ val of_gen : 'a gen -> 'a t
 (** [of_gen gen] builds a list from a given [gen].
     In the result, elements appear in the same order as they did in the source [gen]. *)
 
-val to_klist : 'a t -> 'a klist
-(** [to_klist l] returns a [klist] of the elements of the list [l]. *)
-
-val of_klist : 'a klist -> 'a t
-(** [of_klist klist] builds a list from a given [klist].
-    In the result, elements appear in the same order as they did in the source [klist]. *)
-
 (** {2 Infix Operators}
     It is convenient to {!open CCList.Infix} to access the infix operators
     without cluttering the scope too much.
diff --git a/src/core/CCListLabels.mli b/src/core/CCListLabels.mli
index 6f9af16b..083b3b4a 100644
--- a/src/core/CCListLabels.mli
+++ b/src/core/CCListLabels.mli
@@ -8,7 +8,6 @@ type 'a iter = ('a -> unit) -> unit
     @since 2.8 *)
 
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a printer = Format.formatter -> 'a -> unit
 type 'a random_gen = Random.State.t -> 'a
 
@@ -786,13 +785,6 @@ val of_gen : 'a gen -> 'a t
 (** [of_gen gen] builds a list from a given [gen].
     In the result, elements appear in the same order as they did in the source [gen]. *)
     
-val to_klist : 'a t -> 'a klist
-(** [to_klist l] returns a [klist] of the elements of the list [l]. *)
-
-val of_klist : 'a klist -> 'a t
-(** [of_klist klist] builds a list from a given [klist].
-    In the result, elements appear in the same order as they did in the source [klist]. *)
-
 (** {2 Infix Operators}
     It is convenient to {!open CCList.Infix} to access the infix operators
     without cluttering the scope too much.
diff --git a/src/core/CCString.ml b/src/core/CCString.ml
index 946c5451..157bbfed 100644
--- a/src/core/CCString.ml
+++ b/src/core/CCString.ml
@@ -7,7 +7,6 @@ open CCShims_
 
 type 'a iter = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 
 (* standard implementations *)
 
@@ -420,20 +419,6 @@ module Split = struct
 
   let seq_cpy ?(drop=default_drop) ~by s = _mkseq ~drop ~by s String.sub
 
-  let _mkklist ~drop ~by s k =
-    let by = Find.compile by in
-    let rec make state () = match _split ~by s state with
-      | None -> `Nil
-      | Some (state', 0, 0) when drop.first -> make state' ()
-      | Some (_, i, 0) when drop.last && i=length s -> `Nil
-      | Some (state', i, len) ->
-        `Cons (k s i len , make state')
-    in make (SplitAt 0)
-
-  let klist ?(drop=default_drop) ~by s = _mkklist ~drop ~by s _tuple3
-
-  let klist_cpy ?(drop=default_drop) ~by s = _mkklist ~drop ~by s String.sub
-
   let _mk_iter ~drop ~by s f k =
     let by = Find.compile by in
     let rec aux state = match _split ~by s state with
@@ -828,22 +813,6 @@ let of_seq seq =
   Seq.iter (Buffer.add_char b) seq;
   Buffer.contents b
 
-let rec _to_klist s i len () =
-  if len=0 then `Nil
-  else `Cons (s.[i], _to_klist s (i+1)(len-1))
-
-let of_klist l =
-  let b = Buffer.create 15 in
-  let rec aux l = match l() with
-    | `Nil ->
-      Buffer.contents b
-    | `Cons (x,l') ->
-      Buffer.add_char b x;
-      aux l'
-  in aux l
-
-let to_klist s = _to_klist s 0 (String.length s)
-
 let to_list s = _to_list s [] 0 (String.length s)
 
 let of_list l =
diff --git a/src/core/CCString.mli b/src/core/CCString.mli
index 1aa42861..f92d8a9c 100644
--- a/src/core/CCString.mli
+++ b/src/core/CCString.mli
@@ -10,7 +10,6 @@ type 'a iter = ('a -> unit) -> unit
     @since 2.8 *)
 
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 
 include module type of struct include String end
 (** {{: https://caml.inria.fr/pub/docs/manual-ocaml/libref/String.html} Documentation for the standard String module}*)
diff --git a/src/core/CCStringLabels.mli b/src/core/CCStringLabels.mli
index 535e9f3c..72e4536e 100644
--- a/src/core/CCStringLabels.mli
+++ b/src/core/CCStringLabels.mli
@@ -8,7 +8,6 @@ type 'a iter = ('a -> unit) -> unit
     @since 2.8 *)
 
 type 'a gen = unit -> 'a option
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 
 include module type of struct include StringLabels end
 (** {{: https://caml.inria.fr/pub/docs/manual-ocaml/libref/StringLabels.html} Documentation for the standard StringLabels module}*)
diff --git a/src/core/CCVector.ml b/src/core/CCVector.ml
index 9774a395..39f602ad 100644
--- a/src/core/CCVector.ml
+++ b/src/core/CCVector.ml
@@ -6,7 +6,6 @@ type rw = [`RW]
 type ro = [`RO]
 
 type 'a iter = ('a -> unit) -> unit
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a gen = unit -> 'a option
 type 'a equal = 'a -> 'a -> bool
 type 'a ord = 'a -> 'a -> int
@@ -1067,18 +1066,6 @@ let to_gen v =
   let v = (1--10) in to_list v = Gen.to_list (to_gen v)
 *)
 
-let of_klist ?(init=create ()) l =
-  let rec aux l = match l() with
-    | `Nil -> init
-    | `Cons (x,l') -> push init x; aux l'
-  in aux l
-
-let to_klist v =
-  let rec aux i () =
-    if i=v.size then `Nil
-    else `Cons (v.vec.(i), aux (i+1))
-  in aux 0
-
 let to_string ?(start="") ?(stop="") ?(sep=", ") item_to_string v =
   start ^ (to_list v |> List.map item_to_string |> String.concat sep) ^ stop
 
diff --git a/src/core/CCVector.mli b/src/core/CCVector.mli
index 1e5fa42c..037bbec4 100644
--- a/src/core/CCVector.mli
+++ b/src/core/CCVector.mli
@@ -22,7 +22,6 @@ type 'a iter = ('a -> unit) -> unit
 (** Fast internal iterator.
     @since 2.8 *)
 
-type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a gen = unit -> 'a option
 type 'a equal = 'a -> 'a -> bool
 type 'a ord = 'a -> 'a -> int
@@ -339,8 +338,6 @@ val slice_iter : ('a,_) t -> int -> int -> 'a iter
     @since NEXT_RELEASE
 *)
 
-val of_klist : ?init:('a, rw) t -> 'a klist -> ('a, rw) t
-val to_klist : ('a,_) t -> 'a klist
 val of_gen : ?init:('a, rw) t -> 'a gen -> ('a, rw) t
 val to_gen : ('a,_) t -> 'a gen