diff --git a/src/core/CCArray.ml b/src/core/CCArray.ml
index 245d431b..c02ccfdb 100644
--- a/src/core/CCArray.ml
+++ b/src/core/CCArray.ml
@@ -720,12 +720,11 @@ module Infix = struct
   let (--) = (--)
   let (--^) = (--^)
 
-  include CCShimsMkLet_.Make(struct
-      type 'a t = 'a array
-      let (>>=) = (>>=)
-      let (>|=) = (>|=)
-      let monoid_product a1 a2 = monoid_product (fun x y->x,y) a1 a2
-    end)
+  type 'a t = 'a array
+  let ( let* ) = (>>=)
+  let (let+) = (>|=)
+  let[@inline] (and+) a1 a2 = monoid_product (fun x y->x,y) a1 a2
+  let ( and* ) = (and+)
 end
 
 include Infix
diff --git a/src/core/CCArray.mli b/src/core/CCArray.mli
index 9aa126c0..34f95264 100644
--- a/src/core/CCArray.mli
+++ b/src/core/CCArray.mli
@@ -317,10 +317,14 @@ module Infix : sig
   (** [x --^ y] creates an array containing integers in the range [x .. y]. Right bound excluded.
       @since 0.17 *)
 
+  [@@@ifge 4.8]
+
+  include CCShims_syntax.LET with type 'a t := 'a array
   (** Let operators on OCaml >= 4.08.0, nothing otherwise
       @since 2.8
       @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a array
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCArrayLabels.mli b/src/core/CCArrayLabels.mli
index 4bbedbc7..8be4f679 100644
--- a/src/core/CCArrayLabels.mli
+++ b/src/core/CCArrayLabels.mli
@@ -334,10 +334,14 @@ module Infix : sig
   (** [x --^ y] creates an array containing integers in the range [x .. y]. Right bound excluded.
       @since 0.17 *)
 
+  [@@@ifge 4.8]
+
+  include CCShims_syntax.LET with type 'a t := 'a array
   (** Let operators on OCaml >= 4.08.0, nothing otherwise
       @since 2.8
       @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a array
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCList.ml b/src/core/CCList.ml
index da2d9648..aa777a27 100644
--- a/src/core/CCList.ml
+++ b/src/core/CCList.ml
@@ -2001,16 +2001,16 @@ module Infix = struct
   let (--) = (--)
   let (--^) = (--^)
 
-  include CCShimsMkLet_.Make(struct
-      type 'a t = 'a list
-      let (>|=) = (>|=)
-      let (>>=) = (>>=)
-      let[@inline] monoid_product l1 l2 = product (fun x y -> x,y) l1 l2
-    end)
+  [@@@ifge 4.8]
 
-  include CCShimsMkLetList_.Make(struct
-      let combine_shortest=combine_shortest
-    end)
+  let (let+) = (>|=)
+  let (let*) = (>>=)
+  let[@inline] (and+) l1 l2 = product (fun x y -> x,y) l1 l2
+  let (and*) = (and+)
+
+  let (and&) = combine_shortest
+
+  [@@@endif]
 end
 
 include Infix
diff --git a/src/core/CCList.mli b/src/core/CCList.mli
index a918bb05..bda8c72b 100644
--- a/src/core/CCList.mli
+++ b/src/core/CCList.mli
@@ -938,13 +938,29 @@ module Infix : sig
   (** [i --^ j] is the infix alias for [range']. Second bound [j] excluded.
       @since 0.17 *)
 
-  (** Let operators on OCaml >= 4.08.0, nothing otherwise
-      @since 2.8
-      @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a list
+  [@@@ifge 4.08]
 
-  include CCShimsMkLetList_.S
+  include CCShims_syntax.LET with type 'a t := 'a t
   (** @inline *)
+
+  val (and&) : 'a list -> 'b list -> ('a * 'b) list
+  (** [(and&)] is {!combine_shortest}.
+      It allows to perform a synchronized product between two lists,
+      stopping gently at the shortest. Usable both with [let+] and [let*].
+    {[
+        # let f xs ys zs =
+            let+ x = xs
+            and& y = ys
+            and& z = zs in
+            x + y + z;;
+        val f : int list -> int list -> int list -> int list = <fun>
+        # f [1;2] [5;6;7] [10;10];;
+        - : int list = [16; 18]
+    ]}
+    @since 3.1
+  *)
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCListLabels.mli b/src/core/CCListLabels.mli
index ef937b2e..6b85dfdf 100644
--- a/src/core/CCListLabels.mli
+++ b/src/core/CCListLabels.mli
@@ -852,38 +852,7 @@ val of_gen : 'a gen -> 'a t
 
     @since 0.16 *)
 
-module Infix : sig
-  val (>|=) : 'a t -> ('a -> 'b) -> 'b t
-  (** [l >|= f] is the infix version of [map] with reversed arguments. *)
-
-  val (@) : 'a t -> 'a t -> 'a t
-  (** [l1 @ l2] concatenates two lists [l1] and [l2].
-      As {!append}. *)
-
-  val (<*>) : ('a -> 'b) t -> 'a t -> 'b t
-  (** [funs <*> l] is [product (fun f x -> f x) funs l]. *)
-
-  val (<$>) : ('a -> 'b) -> 'a t -> 'b t
-  (** [f <$> l] is like {!map}. *)
-
-  val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
-  (** [l >>= f] is [flat_map f l]. *)
-
-  val (--) : int -> int -> int t
-  (** [i -- j] is the infix alias for [range]. Bounds included. *)
-
-  val (--^) : int -> int -> int t
-  (** [i --^ j] is the infix alias for [range']. Second bound [j] excluded.
-      @since 0.17 *)
-
-  (** Let operators on OCaml >= 4.08.0, nothing otherwise
-      @since 2.8
-      @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a list
-
-  include CCShimsMkLetList_.S
-  (** @inline *)
-end
+module Infix : module type of CCList.Infix
 
 include module type of Infix
 
diff --git a/src/core/CCOption.ml b/src/core/CCOption.ml
index 327278f4..81a522ca 100644
--- a/src/core/CCOption.ml
+++ b/src/core/CCOption.ml
@@ -176,14 +176,16 @@ module Infix = struct
   let (<$>) = map
   let (<+>) = (<+>)
 
-  include CCShimsMkLet_.Make(struct
-      type 'a t = 'a option
-      let (>|=) = (>|=)
-      let (>>=) = (>>=)
-      let[@inline] monoid_product o1 o2 = match o1, o2 with
-        | Some x, Some y -> Some (x,y)
-        | _ -> None
-    end)
+  [@@@ifge 4.8]
+
+  let (let+) = (>|=)
+  let (let*) = (>>=)
+  let[@inline] (and+) o1 o2 = match o1, o2 with
+    | Some x, Some y -> Some (x,y)
+    | _ -> None
+  let (and*) = (and+)
+
+  [@@@endif]
 end
 
 include Infix
diff --git a/src/core/CCOption.mli b/src/core/CCOption.mli
index 81b8884c..0c46ddbf 100644
--- a/src/core/CCOption.mli
+++ b/src/core/CCOption.mli
@@ -171,11 +171,15 @@ module Infix : sig
   val (<+>) : 'a t -> 'a t -> 'a t
   (** [o1 <+> o2] is [o1] if [o1] is [Some _], [o2] if [o1] is [None]. *)
 
+  [@@@ifge 4.08]
+
+  include CCShims_syntax.LET with type 'a t := 'a t
   (** Let operators on OCaml >= 4.08.0, nothing otherwise
       @since 2.8
       @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a option
 
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCParse.ml b/src/core/CCParse.ml
index 0d33f9ea..5849a6ac 100644
--- a/src/core/CCParse.ml
+++ b/src/core/CCParse.ml
@@ -355,12 +355,14 @@ module Infix = struct
   let (|||) = both
   let[@inline] (<?>) p msg = set_error_message msg p
 
-  include CCShimsMkLet_.Make(struct
-      type nonrec 'a t = 'a t
-      let (>>=) = (>>=)
-      let (>|=) = (>|=)
-      let monoid_product = both
-    end)
+  [@@@ifge 4.8]
+
+  let (let+) = (>|=)
+  let (let*) = (>>=)
+  let (and+) = both
+  let (and*) = (and+)
+
+  [@@@endif]
 end
 
 include Infix
diff --git a/src/core/CCParse.mli b/src/core/CCParse.mli
index 86d59a9d..f34bc00a 100644
--- a/src/core/CCParse.mli
+++ b/src/core/CCParse.mli
@@ -665,10 +665,14 @@ module Infix : sig
       [a ||| b] parses [a], then [b], then returns the pair of their results.
       @since 3.6 *)
 
+  [@@@ifge 4.08]
+
+  include CCShims_syntax.LET with type 'a t := 'a t
   (** Let operators on OCaml >= 4.08.0, nothing otherwise
       @since 2.8
       @inline *)
-  include CCShimsMkLet_.S with type 'a t_let := 'a t
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCRandom.ml b/src/core/CCRandom.ml
index 0f24d77b..c1567b65 100644
--- a/src/core/CCRandom.ml
+++ b/src/core/CCRandom.ml
@@ -196,12 +196,14 @@ let pure x _st = x
 
 let (<*>) f g st = f st (g st)
 
-include CCShimsMkLet_.Make(struct
-    type nonrec 'a t = 'a t
-    let (>>=) = (>>=)
-    let (>|=) = (>|=)
-    let monoid_product a1 a2 st = a1 st, a2 st
-  end)
+[@@@ifge 4.8]
+
+let (let+) = (>|=)
+let (let*) = (>>=)
+let[@inline] (and+) a1 a2 st = a1 st, a2 st
+let (and*) = (and+)
+
+[@@@endif]
 
 let __default_state = Random.State.make_self_init ()
 
diff --git a/src/core/CCRandom.mli b/src/core/CCRandom.mli
index b8a86626..f351f8e7 100644
--- a/src/core/CCRandom.mli
+++ b/src/core/CCRandom.mli
@@ -150,10 +150,14 @@ val pure : 'a -> 'a t
 
 val (<*>) : ('a -> 'b) t -> 'a t -> 'b t
 
+[@@@ifge 4.08]
+
+include CCShims_syntax.LET with type 'a t := 'a t
 (** Let operators on OCaml >= 4.08.0, nothing otherwise
     @since 2.8
     @inline *)
-include CCShimsMkLet_.S with type 'a t_let := 'a t
+
+[@@@endif]
 
 (** {4 Run a generator} *)
 
diff --git a/src/core/CCResult.ml b/src/core/CCResult.ml
index 90e6159d..469c143a 100644
--- a/src/core/CCResult.ml
+++ b/src/core/CCResult.ml
@@ -295,15 +295,17 @@ module Infix = struct
   let (>>=) e f = flat_map f e
   let (<*>) = (<*>)
 
-  include CCShimsMkLet_.Make2(struct
-      type ('a,'e) t = ('a,'e) result
-      let (>>=) = (>>=)
-      let (>|=) = (>|=)
-      let monoid_product x1 x2 = match x1, x2 with
-        | Ok x, Ok y -> Ok (x,y)
-        | Error e, _ -> Error e
-        | _, Error e -> Error e
-    end)
+  [@@@ifge 4.8]
+
+  let (let+) = (>|=)
+  let (let*) = (>>=)
+  let[@inline] (and+) x1 x2 = match x1, x2 with
+    | Ok x, Ok y -> Ok (x,y)
+    | Error e, _ -> Error e
+    | _, Error e -> Error e
+  let (and*) = (and+)
+
+  [@@@endif]
 end
 
 include Infix
diff --git a/src/core/CCResult.mli b/src/core/CCResult.mli
index 78f21ef8..ac6b19d4 100644
--- a/src/core/CCResult.mli
+++ b/src/core/CCResult.mli
@@ -194,10 +194,21 @@ module Infix : sig
       [Ok (a b)]. Otherwise, it fails, and the error of [a] is chosen
       over the error of [b] if both fail. *)
 
-  (** Let operators on OCaml >= 4.08.0, nothing otherwise
-      @since 2.8
-      @inline *)
-  include CCShimsMkLet_.S2 with type ('a,'e) t_let2 := ('a,'e) result
+  [@@@ifge 4.08]
+
+  val (let+) : ('a,'e) t -> ('a -> 'b) -> ('b,'e) t
+  (** @since 2.8 *)
+
+  val (and+) : ('a,'e) t -> ('b,'e) t -> ('a * 'b, 'e) t
+  (** @since 2.8 *)
+
+  val (let*) : ('a,'e) t -> ('a -> ('b,'e) t) -> ('b,'e) t
+  (** @since 2.8 *)
+
+  val (and*) : ('a,'e) t -> ('b,'e) t -> ('a * 'b,'e) t
+  (** @since 2.8 *)
+
+  [@@@endif]
 end
 
 include module type of Infix
diff --git a/src/core/CCVector.ml b/src/core/CCVector.ml
index 719ea85e..5a906b46 100644
--- a/src/core/CCVector.ml
+++ b/src/core/CCVector.ml
@@ -1141,9 +1141,13 @@ let pp ?(pp_start=fun _ () -> ()) ?(pp_stop=fun _ () -> ())
     ) v;
   pp_stop fmt ()
 
-include CCShimsMkLet_.Make2(struct
-    type nonrec ('a,'e) t = ('a,'e) t
-    let (>|=) = (>|=)
-    let (>>=) = (>>=)
-    let monoid_product a1 a2 = monoid_product (fun x y->x,y) a1 a2
-  end)
+[@@@ifge 4.8]
+
+let (let+) = (>|=)
+let (let*) = (>>=)
+let[@inline] (and+) a1 a2 = monoid_product (fun x y->x,y) a1 a2
+let (and*) = (and+)
+
+[@@@endif]
+
+
diff --git a/src/core/CCVector.mli b/src/core/CCVector.mli
index c631a721..9858048a 100644
--- a/src/core/CCVector.mli
+++ b/src/core/CCVector.mli
@@ -383,7 +383,20 @@ val pp : ?pp_start:unit printer -> ?pp_stop:unit printer -> ?pp_sep:unit printer
     By defaults [pp_start] and [pp_stop] does nothing and [pp_sep] defaults to
     (fun out -> Format.fprintf out ",@ "). *)
 
-(** Let operators on OCaml >= 4.08.0, nothing otherwise
-    @since 2.8
-    @inline *)
-include CCShimsMkLet_.S2 with type ('a,'e) t_let2 := ('a,'e) t
+
+
+[@@@ifge 4.08]
+
+val (let+) : ('a,'e) t -> ('a -> 'b) -> ('b,'e) t
+(** @since 2.8 *)
+
+val (and+) : ('a,'e) t -> ('b,'e) t -> ('a * 'b, 'e) t
+(** @since 2.8 *)
+
+val (let*) : ('a,'e) t -> ('a -> ('b,'e) t) -> ('b,'e) t
+(** @since 2.8 *)
+
+val (and*) : ('a,'e) t -> ('b,'e) t -> ('a * 'b,'e) t
+(** @since 2.8 *)
+
+[@@@endif]
diff --git a/src/core/cpp/cpp.ml b/src/core/cpp/cpp.ml
index de808207..d3581859 100644
--- a/src/core/cpp/cpp.ml
+++ b/src/core/cpp/cpp.ml
@@ -41,17 +41,18 @@ let preproc_lines ~file ~major ~minor (ic:in_channel) : unit =
     match input_line ic with
       | exception End_of_file -> Eof
       | line ->
+        let line' = String.trim line in
         incr pos;
-        if prefix line ~pre:"[@@@ifle" then
-          Scanf.sscanf line "[@@@ifle %d.%d]" (fun x y -> If(Le,x,y))
-        else if prefix line ~pre:"[@@@ifge" then
-          Scanf.sscanf line "[@@@ifge %d.%d]" (fun x y -> If(Ge,x,y))
-        else if prefix line ~pre:"[@@@elifle" then
-          Scanf.sscanf line "[@@@elifle %d.%d]" (fun x y -> Elseif(Le,x,y))
-        else if prefix line ~pre:"[@@@elifge" then
-          Scanf.sscanf line "[@@@elifge %d.%d]" (fun x y -> Elseif(Ge,x,y))
-        else if line="[@@@else_]" then Else
-        else if line="[@@@endif]" then Endif
+        if prefix line' ~pre:"[@@@ifle" then
+          Scanf.sscanf line' "[@@@ifle %d.%d]" (fun x y -> If(Le,x,y))
+        else if prefix line' ~pre:"[@@@ifge" then
+          Scanf.sscanf line' "[@@@ifge %d.%d]" (fun x y -> If(Ge,x,y))
+        else if prefix line' ~pre:"[@@@elifle" then
+          Scanf.sscanf line' "[@@@elifle %d.%d]" (fun x y -> Elseif(Le,x,y))
+        else if prefix line' ~pre:"[@@@elifge" then
+          Scanf.sscanf line' "[@@@elifge %d.%d]" (fun x y -> Elseif(Ge,x,y))
+        else if line'="[@@@else_]" then Else
+        else if line'="[@@@endif]" then Endif
         else Raw line
   in
 
diff --git a/src/core/dune b/src/core/dune
index 2d804bf1..6b86380d 100644
--- a/src/core/dune
+++ b/src/core/dune
@@ -5,8 +5,7 @@
  (libraries dune.configurator))
 
 (rule
- (targets
-   CCShimsFormat_.ml CCShimsMkLet_.ml CCShimsMkLetList_.ml)
+ (targets CCShimsFormat_.ml)
  (deps ./mkshims.exe)
  (action
   (run ./mkshims.exe)))
@@ -16,6 +15,7 @@
  (public_name containers)
  (wrapped false)
  (modules :standard \ mkshims)
+ (modules_without_implementation CCShims_syntax)
  (preprocess (action (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
  (flags :standard -warn-error -a+8 -w -32-70 -safe-string
         -strict-sequence -nolabels -open CCMonomorphic)
diff --git a/src/core/mkshims.ml b/src/core/mkshims.ml
index 1134f9d6..9e2c4330 100644
--- a/src/core/mkshims.ml
+++ b/src/core/mkshims.ml
@@ -93,38 +93,10 @@ let shims_let_op_list_pre_408 =
    module type S = sig end
    module Make(X:sig end) = struct end
 "
-let shims_let_op_list_post_408 =
-  "module type S = sig
-   val (and&) : 'a list -> 'b list -> ('a * 'b) list
-   (** [(and&)] is {!combine_shortest}.
-      It allows to perform a synchronized product between two lists,
-        stopping gently at the shortest. Usable both with [let+] and [let*].
-    {[
-        # let f xs ys zs =
-            let+ x = xs
-            and& y = ys
-            and& z = zs in
-            x + y + z;;
-        val f : int list -> int list -> int list -> int list = <fun>
-        # f [1;2] [5;6;7] [10;10];;
-        - : int list = [16; 18]
-    ]}
-    @since 3.1
-  *)
-  end
-
-  module Make(X:sig
-    val combine_shortest : 'a list -> 'b list -> ('a*'b) list
-  end) = struct
-    let (and&) = X.combine_shortest
-  end
-"
 
 let () =
   C.main ~name:"mkshims" (fun c ->
     let version = C.ocaml_config_var_exn c "version" in
     let major, minor = Scanf.sscanf version "%u.%u" (fun maj min -> maj, min) in
     write_file "CCShimsFormat_.ml" (if (major, minor) >= (4,8) then shims_fmt_post_408 else shims_fmt_pre_408);
-    write_file "CCShimsMkLet_.ml" (if (major, minor) >= (4,8) then shims_let_op_post_408 else shims_let_op_pre_408);
-    write_file "CCShimsMkLetList_.ml" (if (major, minor) >= (4,8) then shims_let_op_list_post_408 else shims_let_op_list_pre_408);
   )
diff --git a/src/threads/CCPool.ml b/src/threads/CCPool.ml
index eee1dd73..60e8687d 100644
--- a/src/threads/CCPool.ml
+++ b/src/threads/CCPool.ml
@@ -710,13 +710,14 @@ module Make(P : PARAM) = struct
       let (>|=) a f = map f a
       let (<*>) = app
 
+      [@@@ifge 4.8]
 
-    include CCShimsMkLet_.Make(struct
-        type nonrec 'a t = 'a t
-        let (>>=) = (>>=)
-        let (>|=) = (>|=)
-        let monoid_product a1 a2 = monoid_product (fun x y->x,y) a1 a2
-      end)
+      let (let+) = (>|=)
+      let (let*) = (>>=)
+      let[@inline] (and+) a1 a2 = monoid_product (fun x y->x,y) a1 a2
+      let (and*) = (and+)
+
+      [@@@endif]
     end
 
     include Infix
diff --git a/src/threads/CCPool.mli b/src/threads/CCPool.mli
index 603cc1e3..b9892fc2 100644
--- a/src/threads/CCPool.mli
+++ b/src/threads/CCPool.mli
@@ -154,23 +154,15 @@ module Make(P : PARAM) : sig
       val (>|=) : 'a t -> ('a -> 'b) -> 'b t
       val (<*>) : ('a -> 'b) t -> 'a t -> 'b t
 
+      [@@@ifge 4.08]
+
+      include CCShims_syntax.LET with type 'a t := 'a t
       (** Let operators on OCaml >= 4.08.0, nothing otherwise
           @since 2.8 *)
-      include CCShimsMkLet_.S with type 'a t_let := 'a t
+
+      [@@@endif]
     end
 
-    val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
-
-    val (>>) : 'a t -> (unit -> 'b t) -> 'b t
-
-    val (>|=) : 'a t -> ('a -> 'b) -> 'b t
-    (** Alias to {!map}. *)
-
-    val (<*>): ('a -> 'b) t -> 'a t -> 'b t
-    (** Alias to {!app}. *)
-
-    (** Let operators on OCaml >= 4.08.0, nothing otherwise
-        @since 2.8 *)
-    include CCShimsMkLet_.S with type 'a t_let := 'a t
+    include module type of Infix
   end
 end
diff --git a/src/threads/dune b/src/threads/dune
index f27b5e65..1959f433 100644
--- a/src/threads/dune
+++ b/src/threads/dune
@@ -5,5 +5,6 @@
   (wrapped false)
   (optional)
   (flags :standard -warn-error -a+8 -w -32 -safe-string -open CCShims_)
+  (preprocess (action (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
   (libraries containers threads))