diff --git a/Makefile b/Makefile
index 91dd1a49..ae9d00fb 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,9 @@ benchs:
 examples:
 	dune build examples/id_sexp.exe
 
+unlabel:
+	dune build @unlabel
+
 VERSION=$(shell awk '/^version:/ {print $$2}' containers.opam)
 
 update_next_tag:
diff --git a/README.md b/README.md
index e48a345f..1c56b45b 100644
--- a/README.md
+++ b/README.md
@@ -609,18 +609,18 @@ See [the extended documentation](doc/containers.md) for more examples.
 Beforehand, check `grep deprecated -r src` to see whether some functions
 can be removed.
 
-- `make test`
+- `make all`
 - update version in `containers.opam`
 - `make update_next_tag` (to update `@since` comments; be careful not to change symlinks)
 - check status of modules (`{b status: foo}`) and update if required;
    removed deprecated functions, etc.
+- `make unlabel` to see if labelled interfaces are up to date (requires compiler-libs)
 - update `CHANGELOG.adoc` (see its end to find the right git command)
 - commit the changes
 - `make test doc`
-- tag, and push both to github
-- `opam pin add containers https://github.com/c-cube/ocaml-containers.git#<release>`
-- new opam package: `opam publish prepare; opam publish submit`
-- re-generate doc: `make doc push_doc`
+- `export VERSION=<tag here>; git tag -f $VERSION; git push origin :$VERSION; git push origin $VERSION`
+- new opam package: `opam publish https://github.com/c-cube/ocaml-containers/archive/<tag>.tar.gz`
+- re-generate doc: `make doc` and put it into `gh-pages`
 
 ### List Authors
 
diff --git a/benchs/dune b/benchs/dune
index 19a7d5f5..ad6c8d26 100644
--- a/benchs/dune
+++ b/benchs/dune
@@ -4,7 +4,7 @@
   (libraries containers containers.data containers.iter
              containers.thread benchmark gen iter qcheck
              batteries clarity)
-  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string -color always)
+  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -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 b3b4438f..aa930b54 100644
--- a/benchs/run_benchs.ml
+++ b/benchs/run_benchs.ml
@@ -930,7 +930,7 @@ module Deque = struct
     let take_back d =
       match !d with
       | None -> raise Empty
-      | Some first when Pervasives.(==) first first.prev ->
+      | Some first when Stdlib.(==) first first.prev ->
         (* only one element *)
         d := None;
         first.content
@@ -943,7 +943,7 @@ module Deque = struct
     let take_front d =
       match !d with
       | None -> raise Empty
-      | Some first when Pervasives.(==) first first.prev ->
+      | Some first when Stdlib.(==) first first.prev ->
         (* only one element *)
         d := None;
         first.content
diff --git a/qtest/make.ml b/qtest/make.ml
index c8c7c3d6..9398769c 100644
--- a/qtest/make.ml
+++ b/qtest/make.ml
@@ -20,6 +20,7 @@ let do_not_test file =
   is_suffix ~sub:"containers.ml" file ||
   is_suffix ~sub:"containers_top.ml" file ||
   is_suffix ~sub:"mkflags.ml" file ||
+  is_suffix ~sub:"mkshims.ml" file ||
   is_suffix ~sub:"unlabel.ml" file ||
   is_suffix ~sub:"utop.ml" file
 
@@ -44,7 +45,7 @@ let run_qtest target =
     |> String.concat " "
   in
   let cmd =
-    Printf.sprintf "qtest extract --preamble 'open CCFun;;' -o %S %s 2>/dev/null"
+    Printf.sprintf "qtest extract --preamble 'open CCShims_;; open CCFun;;' -o %S %s 2>/dev/null"
       target files
   in
   exit (Sys.command cmd)
diff --git a/src/core/CCArray_slice.ml b/src/core/CCArray_slice.ml
index fb908dea..728e3230 100644
--- a/src/core/CCArray_slice.ml
+++ b/src/core/CCArray_slice.ml
@@ -3,6 +3,8 @@
 
 (** {1 Array Slice} *)
 
+open CCShims_
+
 type 'a sequence = ('a -> unit) -> unit
 type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
 type 'a gen = unit -> 'a option
@@ -85,7 +87,7 @@ let rec _compare cmp a1 i1 j1 a2 i2 j2 =
 let equal eq a b =
   length a = length b && _equal eq a.arr a.i a.j b.arr b.i b.j
 
-let compare_int (a : int) b = Pervasives.compare a b
+let compare_int (a : int) b = Stdlib.compare a b
 let compare cmp a b =
   _compare cmp a.arr a.i a.j b.arr b.i b.j
 
@@ -277,10 +279,10 @@ let sorted cmp a = _sorted cmp a.arr a.i a.j
 (*$= & ~cmp:(=) ~printer:Q.Print.(array int)
   [||] \
     (let a = 1--6 in let s = make a 2 ~len:0 in \
-     sorted Pervasives.compare s)
+     sorted Stdlib.compare s)
   [|2;3;4|] \
     (let a = [|6;5;4;3;2;1|] in let s = make a 2 ~len:3 in \
-    sorted Pervasives.compare s)
+    sorted Stdlib.compare s)
 *)
 
 (*$Q
@@ -288,7 +290,7 @@ let sorted cmp a = _sorted cmp a.arr a.i a.j
   Array.length a > 10 ==> ( Array.length a > 10 && \
   let s = make a 5 ~len:5 in \
   let b = Array.sub a 5 5 in \
-  Array.sort Pervasives.compare b; b = sorted Pervasives.compare s))
+  Array.sort Stdlib.compare b; b = sorted Stdlib.compare s))
 *)
 
 let sort_ranking cmp a =
@@ -299,10 +301,10 @@ let sort_ranking cmp a =
 (*$= & ~cmp:(=) ~printer:Q.Print.(array int)
   [||] \
      (let a = 1--6 in let s = make a 2 ~len:0 in \
-     sort_ranking Pervasives.compare s)
+     sort_ranking Stdlib.compare s)
   [|2;1;3;0|] \
     (let a = [|"d";"c";"b";"e";"a"|] in let s = make a 1 ~len:4 in \
-    sort_ranking Pervasives.compare s)
+    sort_ranking Stdlib.compare s)
 *)
 
 (*$Q
@@ -318,10 +320,10 @@ let sort_indices cmp a = _sort_indices cmp a.arr a.i a.j
 (*$= & ~cmp:(=) ~printer:Q.Print.(array int)
   [||] \
      (let a = 1--6 in let s = make a 2 ~len:0 in \
-     sort_indices Pervasives.compare s)
+     sort_indices Stdlib.compare s)
   [|3;1;0;2|] \
     (let a = [|"d";"c";"b";"e";"a"|] in let s = make a 1 ~len:4 in \
-    sort_indices Pervasives.compare s)
+    sort_indices Stdlib.compare s)
 *)
 
 (*$Q
diff --git a/src/core/CCBool.ml b/src/core/CCBool.ml
index 89a6a9e5..d19e86d1 100644
--- a/src/core/CCBool.ml
+++ b/src/core/CCBool.ml
@@ -1,11 +1,13 @@
 
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
+
 type t = bool
 
-let equal (a:bool) b = Pervasives.(=) a b
+let equal (a:bool) b = Stdlib.(=) a b
 
-let compare (a:bool) b = Pervasives.compare a b
+let compare (a:bool) b = Stdlib.compare a b
 
 let negate = not
 
diff --git a/src/core/CCChar.ml b/src/core/CCChar.ml
index 42036003..4323a764 100644
--- a/src/core/CCChar.ml
+++ b/src/core/CCChar.ml
@@ -4,9 +4,10 @@
 
     @since 0.14 *)
 
+open CCShims_
 include Char
 
-let equal (a:char) b = Pervasives.(=) a b
+let equal (a:char) b = Stdlib.(=) a b
 
 let pp_buf = Buffer.add_char
 let pp = Format.pp_print_char
diff --git a/src/core/CCEqual.ml b/src/core/CCEqual.ml
index 211835b6..407ae6fd 100644
--- a/src/core/CCEqual.ml
+++ b/src/core/CCEqual.ml
@@ -3,15 +3,17 @@
 
 (** {1 Equality Combinators} *)
 
+open CCShims_
+
 type 'a t = 'a -> 'a -> bool
 
-let poly = Pervasives.(=)
-let physical = Pervasives.(==)
+let poly = Stdlib.(=)
+let physical = Stdlib.(==)
 
 let int : int t = (=)
-let string : string t = Pervasives.(=)
-let bool : bool t = Pervasives.(=)
-let float : float t = Pervasives.(=)
+let string : string t = Stdlib.(=)
+let bool : bool t = Stdlib.(=)
+let float : float t = Stdlib.(=)
 let unit () () = true
 
 let rec list f l1 l2 = match l1, l2 with
diff --git a/src/core/CCFloat.ml b/src/core/CCFloat.ml
index 8e189506..241e3228 100644
--- a/src/core/CCFloat.ml
+++ b/src/core/CCFloat.ml
@@ -1,8 +1,10 @@
 
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
+
 type t = float
-type fpclass = Pervasives.fpclass =
+type fpclass = Stdlib.fpclass =
   | FP_normal
   | FP_subnormal
   | FP_zero
@@ -10,50 +12,50 @@ type fpclass = Pervasives.fpclass =
   | FP_nan
 
 module Infix = struct
-  let (=) : t -> t -> bool = Pervasives.(=)
-  let (<>) : t -> t -> bool = Pervasives.(<>)
-  let (<) : t -> t -> bool = Pervasives.(<)
-  let (>) : t -> t -> bool = Pervasives.(>)
-  let (<=) : t -> t -> bool = Pervasives.(<=)
-  let (>=) : t -> t -> bool = Pervasives.(>=)
-  let (~-) : t -> t = Pervasives.(~-.)
-  let (+) : t -> t -> t = Pervasives.(+.)
-  let (-) : t -> t -> t = Pervasives.(-.)
-  let ( * ) : t -> t -> t = Pervasives.( *. )
-  let (/) : t -> t -> t = Pervasives.(/.)
+  let (=) : t -> t -> bool = Stdlib.(=)
+  let (<>) : t -> t -> bool = Stdlib.(<>)
+  let (<) : t -> t -> bool = Stdlib.(<)
+  let (>) : t -> t -> bool = Stdlib.(>)
+  let (<=) : t -> t -> bool = Stdlib.(<=)
+  let (>=) : t -> t -> bool = Stdlib.(>=)
+  let (~-) : t -> t = Stdlib.(~-.)
+  let (+) : t -> t -> t = Stdlib.(+.)
+  let (-) : t -> t -> t = Stdlib.(-.)
+  let ( * ) : t -> t -> t = Stdlib.( *. )
+  let (/) : t -> t -> t = Stdlib.(/.)
 end
 include Infix
 
-let nan = Pervasives.nan
+let nan = Stdlib.nan
 
-let infinity = Pervasives.infinity
-let neg_infinity = Pervasives.neg_infinity
+let infinity = Stdlib.infinity
+let neg_infinity = Stdlib.neg_infinity
 
 let max_value = infinity
 let min_value = neg_infinity
 
-let max_finite_value = Pervasives.max_float
+let max_finite_value = Stdlib.max_float
 
-let epsilon = Pervasives.epsilon_float
+let epsilon = Stdlib.epsilon_float
 
-let is_nan x = Pervasives.(classify_float x = Pervasives.FP_nan)
+let is_nan x = Stdlib.(classify_float x = Stdlib.FP_nan)
 
 let add = (+.)
 let sub = (-.)
 let mul = ( *. )
 let div = (/.)
 let neg = (~-.)
-let abs = Pervasives.abs_float
+let abs = Stdlib.abs_float
 let scale = ( *. )
 
 let min (x : t) y =
-  match Pervasives.classify_float x, Pervasives.classify_float y with
+  match Stdlib.classify_float x, Stdlib.classify_float y with
     | FP_nan, _ -> y
     | _, FP_nan -> x
     | _ -> if x < y then x else y
 
 let max (x : t) y =
-  match Pervasives.classify_float x, Pervasives.classify_float y with
+  match Stdlib.classify_float x, Stdlib.classify_float y with
     | FP_nan, _ -> y
     | _, FP_nan -> x
     | _ -> if x > y then x else y
@@ -75,7 +77,7 @@ let max (x : t) y =
 let equal (a:float) b = a=b
 
 let hash : t -> int = Hashtbl.hash
-let compare (a:float) b = Pervasives.compare a b
+let compare (a:float) b = Stdlib.compare a b
 
 type 'a printer = Format.formatter -> 'a -> unit
 type 'a random_gen = Random.State.t -> 'a
@@ -85,7 +87,7 @@ let pp = Format.pp_print_float
 let fsign a =
   if is_nan a then nan
   else if a = 0. then a
-  else Pervasives.copysign 1. a
+  else Stdlib.copysign 1. a
 
 exception TrapNaN of string
 
@@ -104,12 +106,12 @@ let round x =
   0. (round 0.)
 *)
 
-let to_int (a:float) = Pervasives.int_of_float a
-let of_int (a:int) = Pervasives.float_of_int a
+let to_int (a:float) = Stdlib.int_of_float a
+let of_int (a:int) = Stdlib.float_of_int a
 
-let to_string (a:float) = Pervasives.string_of_float a
-let of_string_exn (a:string) = Pervasives.float_of_string a
-let of_string (a:string) = Pervasives.float_of_string a
+let to_string (a:float) = Stdlib.string_of_float a
+let of_string_exn (a:string) = Stdlib.float_of_string a
+let of_string (a:string) = Stdlib.float_of_string a
 
 
 let random n st = Random.State.float st n
@@ -118,4 +120,4 @@ let random_range i j st = i +. random (j-.i) st
 
 let equal_precision ~epsilon a b = abs_float (a-.b) < epsilon
 
-let classify = Pervasives.classify_float
+let classify = Stdlib.classify_float
diff --git a/src/core/CCFloat.mli b/src/core/CCFloat.mli
index a4778766..aaf21ce3 100644
--- a/src/core/CCFloat.mli
+++ b/src/core/CCFloat.mli
@@ -4,8 +4,10 @@
 (** {1 Basic operations on floating-point numbers}
     @since 0.6.1 *)
 
+open CCShims_
+
 type t = float
-type fpclass = Pervasives.fpclass =
+type fpclass = Stdlib.fpclass =
   | FP_normal
   | FP_subnormal
   | FP_zero
@@ -13,20 +15,20 @@ type fpclass = Pervasives.fpclass =
   | FP_nan
 
 val nan : t
-(** Equal to {!Pervasives.nan}. *)
+(** Equal to {!Stdlib.nan}. *)
 
 val max_value : t
-(** Positive infinity. Equal to {!Pervasives.infinity}. *)
+(** Positive infinity. Equal to {!Stdlib.infinity}. *)
 
 val min_value : t
-(** Negative infinity. Equal to {!Pervasives.neg_infinity}. *)
+(** Negative infinity. Equal to {!Stdlib.neg_infinity}. *)
 
 val max_finite_value : t
-(** Equal to {!Pervasives.max_float}. *)
+(** Equal to {!Stdlib.max_float}. *)
 
 val epsilon : t
 (** The smallest positive float x such that [1.0 +. x <> 1.0].
-    Equal to {!Pervasives.epsilon_float}. *)
+    Equal to {!Stdlib.epsilon_float}. *)
 
 val is_nan : t -> bool
 (** [is_nan f] returns [true] if f is NaN, [false] otherwise. *)
@@ -42,7 +44,7 @@ val neg : t -> t
 
 val abs : t -> t
 (** The absolute value of a floating-point number.
-    Equal to {!Pervasives.abs_float}. *)
+    Equal to {!Stdlib.abs_float}. *)
 
 val scale : t -> t -> t
 (** Equal to [( *. )]. *)
diff --git a/src/core/CCFormat.ml b/src/core/CCFormat.ml
index dbc2447d..06f5dbbc 100644
--- a/src/core/CCFormat.ml
+++ b/src/core/CCFormat.ml
@@ -294,14 +294,15 @@ let mark_close_tag st ~or_else s =
 (* add color handling to formatter [ppf] *)
 let set_color_tag_handling ppf =
   let open Format in
-  let functions = pp_get_formatter_tag_functions ppf () in
+  let functions = CCShimsFormat_.pp_get_formatter_tag_functions ppf () in
   let st = Stack.create () in (* stack of styles *)
-  let functions' = {functions with
-                      mark_open_tag=(mark_open_tag st ~or_else:functions.mark_open_tag);
-                      mark_close_tag=(mark_close_tag st ~or_else:functions.mark_close_tag);
-                   } in
+  let functions' =
+    CCShimsFormat_.cc_update_funs functions
+      (mark_open_tag st)
+      (mark_close_tag st)
+  in
   pp_set_mark_tags ppf true; (* enable tags *)
-  pp_set_formatter_tag_functions ppf functions'
+  CCShimsFormat_.pp_set_formatter_tag_functions ppf functions'
 
 let set_color_default =
   let first = ref true in
@@ -326,14 +327,14 @@ let set_color_default =
 *)
 
 let with_color s pp out x =
-  Format.pp_open_tag out s;
+  CCShimsFormat_.pp_open_tag out s;
   pp out x;
-  Format.pp_close_tag out ()
+  CCShimsFormat_.pp_close_tag out ()
 
 let with_colorf s out fmt =
-  Format.pp_open_tag out s;
+  CCShimsFormat_.pp_open_tag out s;
   Format.kfprintf
-    (fun out -> Format.pp_close_tag out ())
+    (fun out -> CCShimsFormat_.pp_close_tag out ())
     out fmt
 
 (* c: whether colors are enabled *)
@@ -350,10 +351,10 @@ let with_color_ksf ~f s fmt =
   let buf = Buffer.create 64 in
   let out = Format.formatter_of_buffer buf in
   if !color_enabled then set_color_tag_handling out;
-  Format.pp_open_tag out s;
+  CCShimsFormat_.pp_open_tag out s;
   Format.kfprintf
     (fun out ->
-       Format.pp_close_tag out ();
+       CCShimsFormat_.pp_close_tag out ();
        Format.pp_print_flush out ();
        f (Buffer.contents buf))
     out fmt
diff --git a/src/core/CCFun.ml b/src/core/CCFun.ml
index e9e49878..0796dee4 100644
--- a/src/core/CCFun.ml
+++ b/src/core/CCFun.ml
@@ -13,7 +13,7 @@ let opaque_identity x = x
 (* import standard implementations, if any *)
 
 include Sys
-include Pervasives
+include CCShims_.Stdlib
 
 let compose f g x = g (f x)
 
diff --git a/src/core/CCHashtbl.ml b/src/core/CCHashtbl.ml
index c0db18b7..4bd301bd 100644
--- a/src/core/CCHashtbl.ml
+++ b/src/core/CCHashtbl.ml
@@ -56,7 +56,7 @@ module Poly = struct
 
   (*$T
     of_list [1,"a"; 2,"b"] |> map_list (fun x y -> string_of_int x ^ y) \
-      |> List.sort Pervasives.compare = ["1a"; "2b"]
+      |> List.sort Stdlib.compare = ["1a"; "2b"]
   *)
 
   let to_seq tbl k = Hashtbl.iter (fun key v -> k (key,v)) tbl
diff --git a/src/core/CCHeap.ml b/src/core/CCHeap.ml
index 22093c1b..5afc9d2d 100644
--- a/src/core/CCHeap.ml
+++ b/src/core/CCHeap.ml
@@ -396,8 +396,8 @@ module Make(E : PARTIAL_ORD) : S with type elt = E.t = struct
         extract_list (H.of_gen (CCList.to_gen l)))
     Q.(list int) (fun l -> \
       let h = H.of_list l in \
-      (H.to_gen h |> CCList.of_gen |> List.sort Pervasives.compare) \
-        = (H.to_list h |> List.sort Pervasives.compare))
+      (H.to_gen h |> CCList.of_gen |> List.sort Stdlib.compare) \
+        = (H.to_list h |> List.sort Stdlib.compare))
   *)
 
   let rec to_tree h () = match h with
diff --git a/src/core/CCInt.ml b/src/core/CCInt.ml
index 9b595c8d..6cb7ba3e 100644
--- a/src/core/CCInt.ml
+++ b/src/core/CCInt.ml
@@ -1,10 +1,12 @@
 
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
+
 type t = int
 type 'a sequence = ('a -> unit) -> unit
 
-let equal (a:int) b = Pervasives.(=) a b
+let equal (a:int) b = Stdlib.(=) a b
 
 let compare (a:int) b = compare a b
 
@@ -95,15 +97,15 @@ module Infix : sig
   val (lsr) : t -> int -> t
   val (asr) : t -> int -> t
 end = struct
-  include Pervasives
+  include Stdlib
   let (--) = range
   let (--^) = range'
   let ( ** ) = pow
 end
 include Infix
 
-let min : t -> t -> t = Pervasives.min
-let max : t -> t -> t = Pervasives.max
+let min : t -> t -> t = Stdlib.min
+let max : t -> t -> t = Stdlib.max
 
 let floor_div a n =
   if a < 0 && n >= 0 then
@@ -143,7 +145,7 @@ let floor_div a n =
       (fun (n, m) -> floor_div n (-m) = int_of_float @@ floor (float n /. float (-m)))
 *)
 
-let bool_neq (a : bool) b = Pervasives.(<>) a b
+let bool_neq (a : bool) b = Stdlib.(<>) a b
 
 let rem a n =
   let y = a mod n in
diff --git a/src/core/CCInt32.ml b/src/core/CCInt32.ml
index 74aaab63..1be2d6d3 100644
--- a/src/core/CCInt32.ml
+++ b/src/core/CCInt32.ml
@@ -1,8 +1,9 @@
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
 include Int32
 
-let equal (x:t) y = Pervasives.(=) x y
+let equal (x:t) y = Stdlib.(=) x y
 
 module Infix = struct
   let (+) = add
@@ -33,15 +34,15 @@ module Infix = struct
 
   let (=) = equal
 
-  let (<>) = Pervasives.(<>)
-  let (<) = Pervasives.(<)
-  let (<=) = Pervasives.(<=)
-  let (>) = Pervasives.(>)
-  let (>=) = Pervasives.(>=)
+  let (<>) = Stdlib.(<>)
+  let (<) = Stdlib.(<)
+  let (<=) = Stdlib.(<=)
+  let (>) = Stdlib.(>)
+  let (>=) = Stdlib.(>=)
 end
 include Infix
 
-let hash x = Pervasives.abs (to_int x)
+let hash x = Stdlib.abs (to_int x)
 
 (** {2 Conversion} *)
 
diff --git a/src/core/CCInt64.ml b/src/core/CCInt64.ml
index bfaed6f9..b2dbad44 100644
--- a/src/core/CCInt64.ml
+++ b/src/core/CCInt64.ml
@@ -1,8 +1,9 @@
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
 include Int64
 
-let equal (x:t) y = Pervasives.(=) x y
+let equal (x:t) y = Stdlib.(=) x y
 
 module Infix = struct
   let (+) = add
@@ -33,16 +34,16 @@ module Infix = struct
 
   let (=) = equal
 
-  let (<>) = Pervasives.(<>)
-  let (<) = Pervasives.(<)
-  let (<=) = Pervasives.(<=)
-  let (>) = Pervasives.(>)
-  let (>=) = Pervasives.(>=)
+  let (<>) = Stdlib.(<>)
+  let (<) = Stdlib.(<)
+  let (<=) = Stdlib.(<=)
+  let (>) = Stdlib.(>)
+  let (>=) = Stdlib.(>=)
 end
 
 include Infix
 
-let hash x = Pervasives.abs (to_int x)
+let hash x = Stdlib.abs (to_int x)
 
 (** {2 Conversion} *)
 
diff --git a/src/core/CCList.ml b/src/core/CCList.ml
index 278931d7..fb483d73 100644
--- a/src/core/CCList.ml
+++ b/src/core/CCList.ml
@@ -3,11 +3,11 @@
 
 (** {1 Complements to list} *)
 
-(*$inject
-  let lsort l = List.sort Pervasives.compare l
-*)
+open CCShims_
 
-type 'a t = 'a list
+(*$inject
+  let lsort l = List.sort Stdlib.compare l
+*)
 
 (* backport new functions from stdlib here *)
 
@@ -56,17 +56,17 @@ let rec compare_length_with l n = match l, n with
 
 let rec assoc_opt x = function
   | [] -> None
-  | (y,v) :: _ when Pervasives.(=) x y -> Some v
+  | (y,v) :: _ when Stdlib.(=) x y -> Some v
   | _ :: tail -> assoc_opt x tail
 
 let rec assq_opt x = function
   | [] -> None
-  | (y,v) :: _ when Pervasives.(==) x y -> Some v
+  | (y,v) :: _ when Stdlib.(==) x y -> Some v
   | _ :: tail -> assq_opt x tail
 
 (* end of backport *)
 
-include List
+include CCShimsList_
 
 let empty = []
 
@@ -443,7 +443,7 @@ let diagonal l =
   diagonal [] = []
   diagonal [1] = []
   diagonal [1;2] = [1,2]
-  diagonal [1;2;3] |> List.sort Pervasives.compare = [1, 2; 1, 3; 2, 3]
+  diagonal [1;2;3] |> List.sort Stdlib.compare = [1, 2; 1, 3; 2, 3]
 *)
 
 let partition_map f l =
@@ -634,7 +634,7 @@ let is_sorted ~cmp l =
 
 (*$Q
   Q.(list small_int) (fun l -> \
-    is_sorted ~cmp:CCInt.compare (List.sort Pervasives.compare l))
+    is_sorted ~cmp:CCInt.compare (List.sort Stdlib.compare l))
 *)
 
 let sorted_insert ~cmp ?(uniq=false) x l =
@@ -652,20 +652,20 @@ let sorted_insert ~cmp ?(uniq=false) x l =
 
 (*$Q
     Q.(pair small_int (list small_int)) (fun (x,l) -> \
-      let l = List.sort Pervasives.compare l in \
+      let l = List.sort Stdlib.compare l in \
       is_sorted ~cmp:CCInt.compare (sorted_insert ~cmp:CCInt.compare x l))
     Q.(pair small_int (list small_int)) (fun (x,l) -> \
-      let l = List.sort Pervasives.compare l in \
+      let l = List.sort Stdlib.compare l in \
       is_sorted ~cmp:CCInt.compare (sorted_insert ~cmp:CCInt.compare ~uniq:true x l))
     Q.(pair small_int (list small_int)) (fun (x,l) -> \
-      let l = List.sort Pervasives.compare l in \
+      let l = List.sort Stdlib.compare l in \
       is_sorted ~cmp:CCInt.compare (sorted_insert ~cmp:CCInt.compare ~uniq:false x l))
     Q.(pair small_int (list small_int)) (fun (x,l) -> \
-      let l = List.sort Pervasives.compare l in \
+      let l = List.sort Stdlib.compare l in \
       let l' = sorted_insert ~cmp:CCInt.compare ~uniq:false x l in \
       List.length l' = List.length l + 1)
     Q.(pair small_int (list small_int)) (fun (x,l) -> \
-      let l = List.sort Pervasives.compare l in \
+      let l = List.sort Stdlib.compare l in \
       List.mem x (sorted_insert ~cmp:CCInt.compare x l))
 *)
 
@@ -726,14 +726,14 @@ let sorted_merge_uniq ~cmp l1 l2 =
 
 (*$Q
   Q.(list int) (fun l -> \
-    let l = List.sort Pervasives.compare l in \
+    let l = List.sort Stdlib.compare l in \
     sorted_merge_uniq ~cmp:CCInt.compare l [] = uniq_succ ~eq:CCInt.equal l)
   Q.(list int) (fun l -> \
-    let l = List.sort Pervasives.compare l in \
+    let l = List.sort Stdlib.compare l in \
     sorted_merge_uniq ~cmp:CCInt.compare [] l = uniq_succ ~eq:CCInt.equal l)
   Q.(pair (list int) (list int)) (fun (l1, l2) -> \
-    let l1 = List.sort Pervasives.compare l1 \
-    and l2 = List.sort Pervasives.compare l2 in \
+    let l1 = List.sort Stdlib.compare l1 \
+    and l2 = List.sort Stdlib.compare l2 in \
     let l3 = sorted_merge_uniq ~cmp:CCInt.compare l1 l2 in \
     uniq_succ ~eq:CCInt.equal l3 = l3)
 *)
@@ -1054,7 +1054,7 @@ let all_ok l =
       | Some e -> Result.Error e
     end
 
-let group_by (type k) ?(hash=Hashtbl.hash) ?(eq=Pervasives.(=)) l =
+let group_by (type k) ?(hash=Hashtbl.hash) ?(eq=Stdlib.(=)) l =
   let module Tbl = Hashtbl.Make(struct type t = k let equal = eq let hash = hash end) in
   (* compute group table *)
   let tbl = Tbl.create 32 in
@@ -1078,7 +1078,7 @@ let join ~join_row s1 s2 : _ t =
   OUnit.assert_equal ["1 = 1"; "2 = 2"] s;
 *)
 
-let join_by (type a) ?(eq=Pervasives.(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
+let join_by (type a) ?(eq=Stdlib.(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
   let module Tbl = Hashtbl.Make(struct type t = a let equal = eq let hash = hash end) in
   let tbl = Tbl.create 32 in
   List.iter
@@ -1104,7 +1104,7 @@ type ('a, 'b) join_all_cell = {
   mutable ja_right: 'b list;
 }
 
-let join_all_by (type a) ?(eq=Pervasives.(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
+let join_all_by (type a) ?(eq=Stdlib.(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge c1 c2 =
   let module Tbl = Hashtbl.Make(struct type t = a let equal = eq let hash = hash end) in
   let tbl = Tbl.create 32 in
   (* build the map [key -> cell] *)
@@ -1132,7 +1132,7 @@ let join_all_by (type a) ?(eq=Pervasives.(=)) ?(hash=Hashtbl.hash) f1 f2 ~merge
        | Some z -> z :: res)
     tbl []
 
-let group_join_by (type a) ?(eq=Pervasives.(=)) ?(hash=Hashtbl.hash) f c1 c2 =
+let group_join_by (type a) ?(eq=Stdlib.(=)) ?(hash=Hashtbl.hash) f c1 c2 =
   let module Tbl = Hashtbl.Make(struct type t = a let equal = eq let hash = hash end) in
   let tbl = Tbl.create 32 in
   List.iter (fun x -> Tbl.replace tbl x []) c1;
@@ -1154,8 +1154,8 @@ let group_join_by (type a) ?(eq=Pervasives.(=)) ?(hash=Hashtbl.hash) f c1 c2 =
   (group_join_by (fun s->s.[0]) \
     (CCString.to_list "abc") \
     ["abc"; "boom"; "attic"; "deleted"; "barbary"; "bop"] \
-  |> map (fun (c,l)->c,List.sort Pervasives.compare l) \
-  |> sort Pervasives.compare)
+  |> map (fun (c,l)->c,List.sort Stdlib.compare l) \
+  |> sort Stdlib.compare)
 *)
 
 (*$inject
@@ -1207,13 +1207,13 @@ let uniq ~eq l =
   in uniq eq [] l
 
 (*$T
-  uniq ~eq:CCInt.equal [1;2;3] |> List.sort Pervasives.compare = [1;2;3]
-  uniq ~eq:CCInt.equal [1;1;2;2;3;4;4;2;4;1;5] |> List.sort Pervasives.compare = [1;2;3;4;5]
+  uniq ~eq:CCInt.equal [1;2;3] |> List.sort Stdlib.compare = [1;2;3]
+  uniq ~eq:CCInt.equal [1;1;2;2;3;4;4;2;4;1;5] |> List.sort Stdlib.compare = [1;2;3;4;5]
 *)
 
 (*$Q
   Q.(small_list small_int) (fun l -> \
-    sort_uniq ~cmp:CCInt.compare l = (uniq ~eq:CCInt.equal l |> sort Pervasives.compare))
+    sort_uniq ~cmp:CCInt.compare l = (uniq ~eq:CCInt.equal l |> sort Stdlib.compare))
 *)
 
 let union ~eq l1 l2 =
@@ -1492,9 +1492,9 @@ module Assoc = struct
       ~f:(fun x _ l -> (x,y)::l)
 
   (*$T
-    Assoc.set ~eq:CCInt.equal 2 "two" [1,"1"; 2, "2"] |> List.sort Pervasives.compare \
+    Assoc.set ~eq:CCInt.equal 2 "two" [1,"1"; 2, "2"] |> List.sort Stdlib.compare \
       = [1, "1"; 2, "two"]
-    Assoc.set ~eq:CCInt.equal 3 "3" [1,"1"; 2, "2"] |> List.sort Pervasives.compare \
+    Assoc.set ~eq:CCInt.equal 3 "3" [1,"1"; 2, "2"] |> List.sort Stdlib.compare \
       = [1, "1"; 2, "2"; 3, "3"]
   *)
 
diff --git a/src/core/CCNativeint.ml b/src/core/CCNativeint.ml
index b9692c38..171426be 100644
--- a/src/core/CCNativeint.ml
+++ b/src/core/CCNativeint.ml
@@ -1,8 +1,9 @@
 (* This file is free software, part of containers. See file "license" for more details. *)
 
+open CCShims_
 include Nativeint
 
-let equal (x:t) y = Pervasives.(=) x y
+let equal (x:t) y = Stdlib.(=) x y
 
 module Infix = struct
   let (+) = add
@@ -33,15 +34,15 @@ module Infix = struct
 
   let (=) = equal
 
-  let (<>) = Pervasives.(<>)
-  let (<) = Pervasives.(<)
-  let (<=) = Pervasives.(<=)
-  let (>) = Pervasives.(>)
-  let (>=) = Pervasives.(>=)
+  let (<>) = Stdlib.(<>)
+  let (<) = Stdlib.(<)
+  let (<=) = Stdlib.(<=)
+  let (>) = Stdlib.(>)
+  let (>=) = Stdlib.(>=)
 end
 include Infix
 
-let hash x = Pervasives.abs (to_int x)
+let hash x = Stdlib.abs (to_int x)
 
 (** {2 Conversion} *)
 
diff --git a/src/core/CCOrd.ml b/src/core/CCOrd.ml
index 0b38fcfb..413b2453 100644
--- a/src/core/CCOrd.ml
+++ b/src/core/CCOrd.ml
@@ -3,10 +3,12 @@
 
 (** {1 Comparisons} *)
 
+open CCShims_
+
 type 'a t = 'a -> 'a -> int
 (** Comparison (total ordering) between two elements, that returns an int *)
 
-let compare = Pervasives.compare
+let compare = Stdlib.compare
 
 let opp f x y = - (f x y)
 
@@ -32,10 +34,10 @@ let equiv i j =
     if (equiv x y && equiv y z) then (equiv x z) else true)
 *)
 
-let int (x:int) y = Pervasives.compare x y
-let string (x:string) y = Pervasives.compare x y
-let bool (x:bool) y = Pervasives.compare x y
-let float (x:float) y = Pervasives.compare x y
+let int (x:int) y = Stdlib.compare x y
+let string (x:string) y = Stdlib.compare x y
+let bool (x:bool) y = Stdlib.compare x y
+let float (x:float) y = Stdlib.compare x y
 
 (*$T
   bool true false > 0
@@ -101,7 +103,7 @@ let rec list ord l1 l2 = match l1, l2 with
 
 (*$Q
   Q.(pair (list int)(list int)) CCOrd.(fun (l1,l2) -> \
-    equiv (list int l1 l2) (Pervasives.compare l1 l2))
+    equiv (list int l1 l2) (Stdlib.compare l1 l2))
 *)
 
 let array ord a1 a2 =
diff --git a/src/core/CCParse.ml b/src/core/CCParse.ml
index 50dd98ca..954d61b1 100644
--- a/src/core/CCParse.ml
+++ b/src/core/CCParse.ml
@@ -3,6 +3,8 @@
 
 (** {1 Very Simple Parser Combinators} *)
 
+open CCShims_
+
 (*$inject
   module T = struct
     type tree = L of int | N of tree * tree
@@ -139,8 +141,8 @@ type state = {
 
 exception ParseError of parse_branch * (unit -> string)
 
-let char_equal (a : char) b = Pervasives.(=) a b
-let string_equal (a : string) b = Pervasives.(=) a b
+let char_equal (a : char) b = Stdlib.(=) a b
+let string_equal (a : string) b = Stdlib.(=) a b
 
 let rec string_of_branch l =
   let pp_s () = function
diff --git a/src/core/CCRandom.ml b/src/core/CCRandom.ml
index a6babfb9..090431d8 100644
--- a/src/core/CCRandom.ml
+++ b/src/core/CCRandom.ml
@@ -3,6 +3,7 @@
 
 (** {1 Random Generators} *)
 
+open CCShims_
 include Random
 
 type state = Random.State.t
@@ -225,7 +226,7 @@ let uniformity_test ?(size_hint=10) k rng st =
   let confidence = 4. in
   let std = confidence *. (sqrt (kf *. variance)) in
   let predicate _key n acc =
-    let (<) (a : float) b = Pervasives.(<) a b in
+    let (<) (a : float) b = Stdlib.(<) a b in
     acc && abs_float (average -. float_of_int n) < std in
   Hashtbl.fold predicate histogram true
 
diff --git a/src/core/CCString.ml b/src/core/CCString.ml
index d8eefd07..74442efd 100644
--- a/src/core/CCString.ml
+++ b/src/core/CCString.ml
@@ -3,6 +3,8 @@
 
 (** {1 Basic String Utils} *)
 
+open CCShims_
+
 type 'a gen = unit -> 'a option
 type 'a sequence = ('a -> unit) -> unit
 type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
@@ -61,9 +63,9 @@ module type S = sig
   val pp : Format.formatter -> t -> unit
 end
 
-let equal (a:string) b = Pervasives.(=) a b
+let equal (a:string) b = Stdlib.(=) a b
 
-let compare_int (a : int) b = Pervasives.compare a b
+let compare_int (a : int) b = Stdlib.compare a b
 let compare = String.compare
 
 let hash s = Hashtbl.hash s
@@ -696,7 +698,7 @@ let prefix ~pre s =
   else (
     let rec check i =
       if i=len then true
-      else if Pervasives.(<>) (String.unsafe_get s i) (String.unsafe_get pre i) then false
+      else if Stdlib.(<>) (String.unsafe_get s i) (String.unsafe_get pre i) then false
       else check (i+1)
     in
     check 0
@@ -719,7 +721,7 @@ let suffix ~suf s =
     let off = String.length s - len in
     let rec check i =
       if i=len then true
-      else if Pervasives.(<>) (String.unsafe_get s (off+i)) (String.unsafe_get suf i) then false
+      else if Stdlib.(<>) (String.unsafe_get s (off+i)) (String.unsafe_get suf i) then false
       else check (i+1)
     in
     check 0
diff --git a/src/core/CCUtf8_string.ml b/src/core/CCUtf8_string.ml
index 21856a90..2fc60809 100644
--- a/src/core/CCUtf8_string.ml
+++ b/src/core/CCUtf8_string.ml
@@ -5,11 +5,13 @@
 
     We only deal with UTF8 strings as they naturally map to OCaml bytestrings *)
 
+open CCShims_
+
 type uchar = Uchar.t
 type 'a gen = unit -> 'a option
 type 'a sequence = ('a -> unit) -> unit
 
-let equal (a:string) b = Pervasives.(=) a b
+let equal (a:string) b = Stdlib.(=) a b
 let hash : string -> int = Hashtbl.hash
 let pp = Format.pp_print_string
 
@@ -208,7 +210,7 @@ let flat_map f s : t =
   iter (fun c -> iter (code_to_string buf) (f c)) s;
   Buffer.contents buf
 
-let append = Pervasives.(^)
+let append = Stdlib.(^)
 
 let unsafe_of_string s = s
 
diff --git a/src/core/CCVector.ml b/src/core/CCVector.ml
index 03c749b9..3bde49e1 100644
--- a/src/core/CCVector.ml
+++ b/src/core/CCVector.ml
@@ -317,7 +317,7 @@ let compare cmp v1 v2 =
   Q.(pair (small_list small_int)(small_list small_int)) (fun (l1,l2) ->
     let v1 = of_list l1 in
     let v2 = of_list l2 in
-    compare Pervasives.compare v1 v2 = CCList.compare Pervasives.compare l1 l2)
+    compare Stdlib.compare v1 v2 = CCList.compare Stdlib.compare l1 l2)
 *)
 
 exception Empty
@@ -422,9 +422,9 @@ let sort cmp v =
 (*$QR
   (gen Q.small_int) (fun v ->
     let v' = copy v in
-    sort' Pervasives.compare v';
+    sort' Stdlib.compare v';
     let l = to_list v' in
-    List.sort Pervasives.compare l = l
+    List.sort Stdlib.compare l = l
   )
 *)
 
@@ -452,14 +452,14 @@ let uniq_sort cmp v =
 
 (*$T
   let v = of_list [1;4;5;3;2;4;1] in \
-  uniq_sort Pervasives.compare v; to_list v = [1;2;3;4;5]
+  uniq_sort Stdlib.compare v; to_list v = [1;2;3;4;5]
 *)
 
 (*$QR & ~long_factor:10
   Q.(small_list small_int) (fun l ->
     let v = of_list l in
-    uniq_sort Pervasives.compare v;
-    to_list v = (CCList.sort_uniq ~cmp:Pervasives.compare l))
+    uniq_sort Stdlib.compare v;
+    to_list v = (CCList.sort_uniq ~cmp:Stdlib.compare l))
 *)
 
 let iter k v =
diff --git a/src/core/containers.ml b/src/core/containers.ml
index ae54d23c..86dccf6d 100644
--- a/src/core/containers.ml
+++ b/src/core/containers.ml
@@ -45,4 +45,6 @@ module Vector = CCVector
 module Monomorphic = CCMonomorphic
 module Utf8_string = CCUtf8_string
 
+module Stdlib = CCShims_.Stdlib
+
 include Monomorphic
diff --git a/src/core/dune b/src/core/dune
index fcd0cc4f..828b2edb 100644
--- a/src/core/dune
+++ b/src/core/dune
@@ -1,38 +1,44 @@
-(rule
-  (targets CCArray.mli)
+(alias
+  (name unlabel)
   (deps (:mli CCArrayLabels.mli) ../unlabel.exe)
-  (mode promote)
-  (action (run ../unlabel.exe %{mli} %{targets})))
+  (action (run ../unlabel.exe %{mli} CCArray.mli)))
 
-(rule
-  (targets CCArray_slice.mli)
+(alias
+  (name unlabel)
   (deps (:mli CCArray_sliceLabels.mli) ../unlabel.exe)
-  (mode promote)
-  (action (run ../unlabel.exe %{mli} %{targets})))
+  (action (run ../unlabel.exe %{mli} CCArray_slice.mli)))
 
-(rule
-  (targets CCEqual.mli)
+(alias
+  (name unlabel)
   (deps (:mli CCEqualLabels.mli) ../unlabel.exe)
-  (mode promote)
-  (action (run ../unlabel.exe %{mli} %{targets})))
+  (action (run ../unlabel.exe %{mli} CCEqual.mli)))
 
-(rule
-  (targets CCList.mli)
+(alias
+  (name unlabel)
   (deps (:mli CCListLabels.mli) ../unlabel.exe)
-  (mode promote)
-  (action (run ../unlabel.exe %{mli} %{targets})))
+  (action (run ../unlabel.exe %{mli} CCList.mli)))
+
+(alias
+  (name unlabel)
+  (deps (:mli CCStringLabels.mli) ../unlabel.exe)
+  (action (run ../unlabel.exe %{mli} CCString.mli)))
+
+
+(executable
+  (name mkshims)
+  (modules mkshims)
+  (libraries dune.configurator))
 
 (rule
-  (targets CCString.mli)
-  (deps (:mli CCStringLabels.mli) ../unlabel.exe)
-  (mode promote)
-  (action (run ../unlabel.exe %{mli} %{targets})))
+  (targets CCShims_.ml CCShimsList_.ml CCShimsFormat_.ml)
+  (deps ./mkshims.exe)
+  (action (run ./mkshims.exe)))
 
 (library
   (name containers)
   (public_name containers)
   (wrapped false)
+  (modules :standard \ mkshims)
   (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string -nolabels -open CCMonomorphic)
   (ocamlopt_flags (:include ../flambda.flags))
-  (libraries result uchar containers.monomorphic)
-  )
+  (libraries result uchar containers.monomorphic))
diff --git a/src/core/mkshims.ml b/src/core/mkshims.ml
new file mode 100644
index 00000000..724910f9
--- /dev/null
+++ b/src/core/mkshims.ml
@@ -0,0 +1,55 @@
+
+module C = Configurator.V1
+
+let shims_pre_408 = "module Stdlib = Pervasives"
+
+let shims_post_408 = "module Stdlib = Stdlib"
+
+let shims_fmt_pre_408 = "
+include Format
+let cc_update_funs funs f1 f2 =
+  let open Format in
+  {
+    funs with
+    mark_open_tag = f1 funs.mark_open_tag;
+    mark_close_tag = f2 funs.mark_close_tag;
+  }
+
+"
+let shims_fmt_post_408 = "
+open Format
+
+[@@@ocaml.warning \"-3\"]
+
+let pp_open_tag = pp_open_tag
+let pp_close_tag = pp_close_tag
+let pp_get_formatter_tag_functions = pp_get_formatter_tag_functions
+let pp_set_formatter_tag_functions = pp_set_formatter_tag_functions
+
+let cc_update_funs funs f1 f2 =
+  let open Format in
+  {
+    funs with
+    mark_open_tag = f1 ~or_else:funs.mark_open_tag;
+    mark_close_tag = f2 ~or_else:funs.mark_close_tag;
+  }
+"
+
+let shims_list_pre_408 = "
+  include List
+  type +'a t = 'a list
+"
+let shims_list_post_408 = "include List"
+
+let write_file f s =
+  let out = open_out f in
+  output_string out s; flush out; close_out out
+
+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 "CCShims_.ml" (if (major, minor) >= (4,8) then shims_post_408 else shims_pre_408);
+    write_file "CCShimsList_.ml" (if (major, minor) >= (4,8) then shims_list_post_408 else shims_list_pre_408);
+    write_file "CCShimsFormat_.ml" (if (major, minor) >= (4,8) then shims_fmt_post_408 else shims_fmt_pre_408);
+  )
diff --git a/src/data/CCCache.ml b/src/data/CCCache.ml
index e8cf3426..4de7e637 100644
--- a/src/data/CCCache.ml
+++ b/src/data/CCCache.ml
@@ -222,7 +222,7 @@ module LRU(X:HASH) = struct
   (* take first from queue *)
   let take_ c =
     match c.first with
-      | Some n when Pervasives.(==) n.next n ->
+      | Some n when Stdlib.(==) n.next n ->
         (* last element *)
         c.first <- None;
         n
@@ -241,7 +241,7 @@ module LRU(X:HASH) = struct
         n.next <- n;
         n.prev <- n;
         c.first <- Some n
-      | Some n1 when Pervasives.(==) n1 n -> ()
+      | Some n1 when Stdlib.(==) n1 n -> ()
       | Some n1 ->
         n.prev <- n1.prev;
         n.next <- n1;
diff --git a/src/data/CCDeque.ml b/src/data/CCDeque.ml
index 923bf95b..58e14705 100644
--- a/src/data/CCDeque.ml
+++ b/src/data/CCDeque.ml
@@ -74,7 +74,7 @@ let is_zero_ n = match n.cell with
   | Two _
   | Three _ -> false
 
-let bool_eq (a : bool) b = Pervasives.(=) a b
+let bool_eq (a : bool) b = Stdlib.(=) a b
 
 let is_empty d =
   let res = d.size = 0 in
@@ -163,7 +163,7 @@ let take_back_node_ n = match n.cell with
 
 let take_back d =
   if is_empty d then raise Empty
-  else if Pervasives.(==) d.cur d.cur.prev
+  else if Stdlib.(==) d.cur d.cur.prev
   then (
     (* only one cell *)
     decr_size_ d;
@@ -196,7 +196,7 @@ let take_front_node_ n = match n.cell with
 
 let take_front d =
   if is_empty d then raise Empty
-  else if Pervasives.(==) d.cur.prev d.cur
+  else if Stdlib.(==) d.cur.prev d.cur
   then (
     (* only one cell *)
     decr_size_ d;
@@ -255,7 +255,7 @@ let fold f acc d =
       | Two (x,y) -> f (f acc x) y
       | Three (x,y,z) -> f (f (f acc x) y) z
     in
-    if Pervasives.(==) n.next first then acc else aux ~first f acc n.next
+    if Stdlib.(==) n.next first then acc else aux ~first f acc n.next
   in
   aux ~first:d.cur f acc d.cur
 
@@ -337,7 +337,7 @@ let to_gen q =
   let cell = ref q.cur.cell in
   let cur = ref q.cur in
   let rec next () = match !cell with
-    | Zero when Pervasives.(==) (!cur).next first -> None
+    | Zero when Stdlib.(==) (!cur).next first -> None
     | Zero ->
       (* go to next node *)
       let n = !cur in
@@ -399,8 +399,8 @@ let compare ~cmp a b =
 
 (*$Q
    Q.(pair (list int) (list int)) (fun (l1,l2) -> \
-    CCOrd.equiv (compare ~cmp:Pervasives.compare (of_list l1) (of_list l2)) \
-      (CCList.compare Pervasives.compare l1 l2))
+    CCOrd.equiv (compare ~cmp:Stdlib.compare (of_list l1) (of_list l2)) \
+      (CCList.compare Stdlib.compare l1 l2))
 *)
 
 type 'a printer = Format.formatter -> 'a -> unit
diff --git a/src/data/CCFun_vec.ml b/src/data/CCFun_vec.ml
index 4ba201c8..140519ea 100644
--- a/src/data/CCFun_vec.ml
+++ b/src/data/CCFun_vec.ml
@@ -6,7 +6,7 @@
     let g = Q.(small_list (pair small_int small_int)) in
     Q.map_same_type
       (fun l ->
-        CCList.sort_uniq ~cmp:(fun a b -> Pervasives.compare (fst a)(fst b)) l
+        CCList.sort_uniq ~cmp:(fun a b -> Stdlib.compare (fst a)(fst b)) l
       ) g
   ;;
 *)
@@ -24,7 +24,7 @@ type 'a ktree = unit -> [`Nil | `Node of 'a * 'a ktree list]
    type state = { mutable frozen: bool }
    type t = Nil | St of state
    let empty = Nil
-   let equal a b = Pervasives.(==) a b
+   let equal a b = Stdlib.(==) a b
    let create () = St {frozen=false}
    let active = function Nil -> false | St st -> not st.frozen
    let frozen = function Nil -> true | St st -> st.frozen
@@ -324,9 +324,9 @@ let to_seq m yield = iteri ~f:(fun _ v -> yield v) m
 
 (*$Q
   _listuniq (fun l -> \
-    (List.sort Pervasives.compare l) = \
+    (List.sort Stdlib.compare l) = \
       (l |> Iter.of_list |> of_seq |> to_seq |> Iter.to_list \
-        |> List.sort Pervasives.compare) )
+        |> List.sort Stdlib.compare) )
 *)
 
 let rec add_gen m g = match g() with
@@ -355,9 +355,9 @@ let to_gen m =
 
 (*$Q
   _listuniq (fun l -> \
-    (List.sort Pervasives.compare l) = \
+    (List.sort Stdlib.compare l) = \
       (l |> Gen.of_list |> of_gen |> to_gen |> Gen.to_list \
-        |> List.sort Pervasives.compare) )
+        |> List.sort Stdlib.compare) )
 *)
 
 let choose m = to_gen m ()
diff --git a/src/data/CCHashTrie.ml b/src/data/CCHashTrie.ml
index 0dbc9720..85f8f726 100644
--- a/src/data/CCHashTrie.ml
+++ b/src/data/CCHashTrie.ml
@@ -7,7 +7,7 @@
     let g = Q.(list (pair small_int small_int)) in
     Q.map_same_type
       (fun l ->
-        CCList.sort_uniq ~cmp:(fun a b -> Pervasives.compare (fst a)(fst b)) l
+        CCList.sort_uniq ~cmp:(fun a b -> Stdlib.compare (fst a)(fst b)) l
       ) g
   ;;
 *)
@@ -23,7 +23,7 @@ type 'a ktree = unit -> [`Nil | `Node of 'a * 'a ktree list]
 module Transient = struct
   type t = { mutable frozen: bool }
   let empty = {frozen=true} (* special value *)
-  let equal a b = Pervasives.(==) a b
+  let equal a b = Stdlib.(==) a b
   let create () = {frozen=false}
   let active st =not st.frozen
   let frozen st = st.frozen
@@ -232,13 +232,13 @@ module A_SPARSE = struct
       (* insert at [real_idx] in a new array *)
       let bits = a.bits lor idx in
       let n = Array.length a.arr in
-      let arr = Array.make Pervasives.(n+1) x in
+      let arr = Array.make Stdlib.(n+1) x in
       arr.(real_idx) <- x;
       if real_idx>0 then (
         Array.blit a.arr 0 arr 0 real_idx;
       );
       if real_idx<n then (
-        let open Pervasives in
+        let open Stdlib in
         Array.blit a.arr real_idx arr (real_idx+1) (n-real_idx);
       );
       {a with bits; arr}
@@ -264,12 +264,12 @@ module A_SPARSE = struct
       (* insert at [real_idx] in a new array *)
       let bits = a.bits lor idx in
       let n = Array.length a.arr in
-      let arr = Array.make Pervasives.(n+1) x in
+      let arr = Array.make Stdlib.(n+1) x in
       if real_idx>0 then (
         Array.blit a.arr 0 arr 0 real_idx;
       );
       if real_idx<n then (
-        let open Pervasives in
+        let open Stdlib in
         Array.blit a.arr real_idx arr (real_idx+1) (n-real_idx);
       );
       {a with bits; arr}
@@ -291,8 +291,8 @@ module A_SPARSE = struct
       (* remove at [real_idx] *)
       let bits = a.bits land (lnot idx) in
       let n = Array.length a.arr in
-      let arr = if n=1 then [||] else Array.make Pervasives.(n-1) a.arr.(0) in
-      let open Pervasives in
+      let arr = if n=1 then [||] else Array.make Stdlib.(n-1) a.arr.(0) in
+      let open Stdlib in
       if real_idx > 0 then (
         Array.blit a.arr 0 arr 0 real_idx;
       );
@@ -329,7 +329,7 @@ module Make(Key : KEY)
     let make = Key.hash
     let zero = 0
     let is_0 h = h = 0
-    let equal : int -> int -> bool = Pervasives.(=)
+    let equal : int -> int -> bool = Stdlib.(=)
     let rem h = h land (A.length - 1)
     let quotient h = h lsr A.length_log
   end
@@ -496,7 +496,7 @@ module Make(Key : KEY)
     add_ ~id k v ~h:(hash_ k) m
 
   (*$R
-    let lsort = List.sort Pervasives.compare in
+    let lsort = List.sort Stdlib.compare in
     let m = M.of_list [1, 1; 2, 2] in
     let id = Transient.create() in
     let m' = M.add_mut ~id 3 3 m in
@@ -608,7 +608,7 @@ module Make(Key : KEY)
       | Some _ -> Some 0
       ) m
     in
-    assert_equal [1,1; 2,2; 4,4; 5,5] (M.to_list m' |> List.sort Pervasives.compare);
+    assert_equal [1,1; 2,2; 4,4; 5,5] (M.to_list m' |> List.sort Stdlib.compare);
   *)
 
   let iter ~f t =
@@ -643,7 +643,7 @@ module Make(Key : KEY)
     let l = CCList.(1 -- 10 |> map (fun x->x,x)) in  \
     M.of_list l \
       |> M.fold ~f:(fun acc x y -> (x,y)::acc) ~x:[] \
-      |> List.sort Pervasives.compare = l
+      |> List.sort Stdlib.compare = l
   *)
 
   let cardinal m = fold ~f:(fun n _ _ -> n+1) ~x:0 m
@@ -672,9 +672,9 @@ module Make(Key : KEY)
 
   (*$Q
     _listuniq (fun l -> \
-      (List.sort Pervasives.compare l) = \
+      (List.sort Stdlib.compare l) = \
         (l |> Iter.of_list |> M.of_seq |> M.to_seq |> Iter.to_list \
-          |> List.sort Pervasives.compare) )
+          |> List.sort Stdlib.compare) )
   *)
 
   let rec add_gen_mut ~id m g = match g() with
@@ -716,9 +716,9 @@ module Make(Key : KEY)
 
   (*$Q
     _listuniq (fun l -> \
-      (List.sort Pervasives.compare l) = \
+      (List.sort Stdlib.compare l) = \
         (l |> Gen.of_list |> M.of_gen |> M.to_gen |> Gen.to_list \
-          |> List.sort Pervasives.compare) )
+          |> List.sort Stdlib.compare) )
   *)
 
   let choose m = to_gen m ()
diff --git a/src/data/CCHet.ml b/src/data/CCHet.ml
index b6254dfc..abd9ec0e 100644
--- a/src/data/CCHet.ml
+++ b/src/data/CCHet.ml
@@ -139,7 +139,7 @@ end
 module Map = struct
   module M = Map.Make(struct
       type t = int
-      let compare (i:int) j = Pervasives.compare i j
+      let compare (i:int) j = Stdlib.compare i j
     end)
 
   type t = exn_pair M.t
diff --git a/src/data/CCIntMap.ml b/src/data/CCIntMap.ml
index 7174dbcd..14faf74f 100644
--- a/src/data/CCIntMap.ml
+++ b/src/data/CCIntMap.ml
@@ -23,7 +23,7 @@ end = struct
 
   let min_int = min_int
 
-  let equal : t -> t -> bool = Pervasives.(=)
+  let equal : t -> t -> bool = Stdlib.(=)
 
   let rec highest_bit_naive x m =
     if x=m then m
@@ -54,7 +54,7 @@ end = struct
 
   let gt a b = (b != min_int) && (a = min_int || a > b)
   let lt a b = gt b a
-  let equal_int = Pervasives.(=)
+  let equal_int = Stdlib.(=)
 end
 
 (*$inject
@@ -74,7 +74,7 @@ end
   *)
 
 (*$inject
-  let _list_uniq l = CCList.sort_uniq ~cmp:(fun a b-> Pervasives.compare (fst a)(fst b)) l
+  let _list_uniq l = CCList.sort_uniq ~cmp:(fun a b-> Stdlib.compare (fst a)(fst b)) l
 *)
 
 type +'a t =
@@ -270,13 +270,13 @@ let update k f t =
   [1,1; 2, 22; 3, 3] \
   (of_list [1,1;2,2;3,3] \
     |> update 2 (function None -> assert false | Some _ -> Some 22) \
-    |> to_list |> List.sort Pervasives.compare)
+    |> to_list |> List.sort Stdlib.compare)
 *)
 
 let doubleton k1 v1 k2 v2 = add k1 v1 (singleton k2 v2)
 
 let rec equal ~eq a b =
-  Pervasives.(==) a b ||
+  Stdlib.(==) a b ||
   begin match a, b with
     | E, E -> true
     | L (ka, va), L (kb, vb) -> ka = kb && eq va vb
@@ -562,7 +562,7 @@ let rec merge ~f t1 t2 : _ t =
 (*$QR
   Q.(let p = small_list (pair small_int unit) in pair p p) (fun (l1,l2) ->
     let l1 = _list_uniq l1 and l2 = _list_uniq l2 in
-    equal Pervasives.(=)
+    equal Stdlib.(=)
       (union (fun _ v1 _ -> v1) (of_list l1) (of_list l2))
       (merge ~f:merge_union (of_list l1) (of_list l2)))
   *)
@@ -570,7 +570,7 @@ let rec merge ~f t1 t2 : _ t =
 (*$QR
   Q.(let p = small_list (pair small_int unit) in pair p p) (fun (l1,l2) ->
     let l1 = _list_uniq l1 and l2 = _list_uniq l2 in
-    equal Pervasives.(=)
+    equal Stdlib.(=)
       (inter (fun _ v1 _ -> v1) (of_list l1) (of_list l2))
       (merge ~f:merge_inter (of_list l1) (of_list l2)))
   *)
@@ -636,7 +636,7 @@ let to_gen m =
 
 (*$T
   doubleton 1 "a" 2 "b" |> to_gen |> of_gen |> to_list \
-    |> List.sort Pervasives.compare = [1, "a"; 2, "b"]
+    |> List.sort Stdlib.compare = [1, "a"; 2, "b"]
 *)
 
 (*$Q
@@ -663,7 +663,7 @@ let compare ~cmp a b =
 (*$Q
   Q.(list (pair int bool)) ( fun l -> \
     let m1 = of_list l and m2 = of_list (List.rev l) in \
-    compare ~cmp:Pervasives.compare m1 m2 = 0)
+    compare ~cmp:Stdlib.compare m1 m2 = 0)
 
 *)
 
@@ -672,8 +672,8 @@ let compare ~cmp a b =
     let l1 = List.map (fun (k,v) -> abs k,v) l1 in
     let l2 = List.map (fun (k,v) -> abs k,v) l2 in
     let m1 = of_list l1 and m2 = of_list l2 in
-    let c = compare ~cmp:Pervasives.compare m1 m2
-    and c' = compare ~cmp:Pervasives.compare m2 m1 in
+    let c = compare ~cmp:Stdlib.compare m1 m2
+    and c' = compare ~cmp:Stdlib.compare m2 m1 in
     (c = 0) = (c' = 0) && (c < 0) = (c' > 0) && (c > 0) = (c' < 0))
 *)
 
@@ -682,7 +682,7 @@ let compare ~cmp a b =
     let l1 = List.map (fun (k,v) -> abs k,v) l1 in
     let l2 = List.map (fun (k,v) -> abs k,v) l2 in
     let m1 = of_list l1 and m2 = of_list l2 in
-    (compare ~cmp:Pervasives.compare m1 m2 = 0) = equal ~eq:(=) m1 m2)
+    (compare ~cmp:Stdlib.compare m1 m2 = 0) = equal ~eq:(=) m1 m2)
 *)
 
 let rec add_klist m l = match l() with
@@ -833,7 +833,7 @@ let pp pp_x out m =
   let rec remove_m i s = match s with
     | [] -> []
     | (j,v)::s' -> if i=j then s' else (j,v)::(remove_m i s')
-  let add_m k v s = List.sort Pervasives.compare ((k,v)::remove_m k s)
+  let add_m k v s = List.sort Stdlib.compare ((k,v)::remove_m k s)
   let rec union_m s s' = match s,s' with
     | [], _ -> s'
     | _, [] -> s
@@ -848,7 +848,7 @@ let pp pp_x out m =
       then (k,min v (List.assoc k s'))::(inter_m s s')
       else inter_m s s'
 
-  let abstract s = List.sort Pervasives.compare (fold (fun k v acc -> (k,v)::acc) s [])
+  let abstract s = List.sort Stdlib.compare (fold (fun k v acc -> (k,v)::acc) s [])
 *)
 
 (* A bunch of agreement properties *)
diff --git a/src/data/CCPersistentHashtbl.ml b/src/data/CCPersistentHashtbl.ml
index 8eedf828..a58a6cc9 100644
--- a/src/data/CCPersistentHashtbl.ml
+++ b/src/data/CCPersistentHashtbl.ml
@@ -130,7 +130,7 @@ end
   let my_seq = Iter.of_list my_list
 
   let _list_uniq = CCList.sort_uniq
-    ~cmp:(fun a b -> Pervasives.compare (fst a) (fst b))
+    ~cmp:(fun a b -> Stdlib.compare (fst a) (fst b))
 
   let _list_int_int = Q.(
     map_same_type _list_uniq
diff --git a/src/data/CCRAL.ml b/src/data/CCRAL.ml
index e66e52fb..2bc3353e 100644
--- a/src/data/CCRAL.ml
+++ b/src/data/CCRAL.ml
@@ -604,7 +604,7 @@ let compare ~cmp l1 l2 =
 
 (*$Q
   Q.(pair (list int)(list int)) (fun (l1,l2) -> \
-    compare ~cmp:CCInt.compare (of_list l1) (of_list l2) = (Pervasives.compare l1 l2))
+    compare ~cmp:CCInt.compare (of_list l1) (of_list l2) = (Stdlib.compare l1 l2))
 *)
 
 (** {2 Infix} *)
diff --git a/src/data/CCTrie.ml b/src/data/CCTrie.ml
index a2c00fc6..01cde777 100644
--- a/src/data/CCTrie.ml
+++ b/src/data/CCTrie.ml
@@ -398,7 +398,7 @@ module Make(W : WORD)
 
   (*$T
     T.fold (fun acc k v -> (k,v) :: acc) [] t1 \
-      |> List.sort Pervasives.compare = List.sort Pervasives.compare l1
+      |> List.sort Stdlib.compare = List.sort Stdlib.compare l1
   *)
 
   let mapi f t =
@@ -418,9 +418,9 @@ module Make(W : WORD)
     in map_ _id t
 
   (*$= & ~printer:Q.Print.(list (pair (list int) string))
-    (List.map (fun (k, v) -> (k, v ^ "!")) l1 |> List.sort Pervasives.compare) \
+    (List.map (fun (k, v) -> (k, v ^ "!")) l1 |> List.sort Stdlib.compare) \
       (T.mapi (fun k v -> v ^ "!") t1 \
-        |> T.to_list |> List.sort Pervasives.compare)
+        |> T.to_list |> List.sort Stdlib.compare)
   *)
 
   let map f t =
@@ -435,9 +435,9 @@ module Make(W : WORD)
         in Node (v', map')
     in map_ t
   (*$= & ~printer:Q.Print.(list (pair (list int) string))
-    (List.map (fun (k, v) -> (k, v ^ "!")) l1 |> List.sort Pervasives.compare) \
+    (List.map (fun (k, v) -> (k, v ^ "!")) l1 |> List.sort Stdlib.compare) \
       (T.map (fun v -> v ^ "!") t1 \
-        |> T.to_list |> List.sort Pervasives.compare)
+        |> T.to_list |> List.sort Stdlib.compare)
   *)
 
 
diff --git a/src/data/CCWBTree.ml b/src/data/CCWBTree.ml
index bd471239..8363d93f 100644
--- a/src/data/CCWBTree.ml
+++ b/src/data/CCWBTree.ml
@@ -34,7 +34,7 @@
 
   let op = Q.make ~print:pp_op gen_op
 
-  let _list_uniq = CCList.sort_uniq ~cmp:(CCFun.compose_binop fst Pervasives.compare)
+  let _list_uniq = CCList.sort_uniq ~cmp:(CCFun.compose_binop fst Stdlib.compare)
 *)
 
 (*$Q & ~count:200
@@ -539,7 +539,7 @@ module MakeFull(K : KEY) : S with type key = K.t = struct
       ~cmp:(CCList.equal (CCPair.equal CCInt.equal CCInt.equal))
       ~printer:CCFormat.(to_string (list (pair int int)))
       [1, 2; 4, 8]
-      (M.to_list m |> List.sort Pervasives.compare)
+      (M.to_list m |> List.sort Stdlib.compare)
   *)
 
   (*$QR
diff --git a/src/data/dune b/src/data/dune
index ed738693..cda5e3ae 100644
--- a/src/data/dune
+++ b/src/data/dune
@@ -3,7 +3,6 @@
   (name containers_data)
   (public_name containers.data)
   (wrapped false)
-  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string)
+  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string -open CCShims_)
   (ocamlopt_flags :standard (:include ../flambda.flags))
-  (libraries result)
-  )
+  (libraries result containers))
diff --git a/src/dune b/src/dune
index 6863ff71..ff298374 100644
--- a/src/dune
+++ b/src/dune
@@ -8,6 +8,9 @@
   (modules unlabel)
   (libraries compiler-libs.common))
 
+(env
+  (_ (flags :standard -warn-error -3)))
+
 (rule
   (targets flambda.flags)
   (mode fallback)
diff --git a/src/monomorphic/CCMonomorphic.ml b/src/monomorphic/CCMonomorphic.ml
index 2f402823..462cf2b1 100644
--- a/src/monomorphic/CCMonomorphic.ml
+++ b/src/monomorphic/CCMonomorphic.ml
@@ -1,23 +1,25 @@
 
 (* This file is free software, part of containers. See file "license" for more details. *)
 
-let (=) : int -> int -> bool = Pervasives.(=)
-let (<>) : int -> int -> bool  = Pervasives.(<>)
-let (<) : int -> int -> bool = Pervasives.(<)
-let (>) : int -> int -> bool = Pervasives.(>)
-let (<=) : int -> int -> bool = Pervasives.(<=)
-let (>=) : int -> int -> bool = Pervasives.(>=)
+open CCMonomorphicShims_
 
-let compare : int -> int -> int = Pervasives.compare
-let min : int -> int -> int = Pervasives.min
-let max : int -> int -> int = Pervasives.max
+let (=) : int -> int -> bool = Stdlib.(=)
+let (<>) : int -> int -> bool  = Stdlib.(<>)
+let (<) : int -> int -> bool = Stdlib.(<)
+let (>) : int -> int -> bool = Stdlib.(>)
+let (<=) : int -> int -> bool = Stdlib.(<=)
+let (>=) : int -> int -> bool = Stdlib.(>=)
 
-let (=.) : float -> float -> bool = Pervasives.(=)
-let (<>.) : float -> float -> bool = Pervasives.(<>)
-let (<.) : float -> float -> bool = Pervasives.(<)
-let (>.) : float -> float -> bool = Pervasives.(>)
-let (<=.) : float -> float -> bool = Pervasives.(<=)
-let (>=.) : float -> float -> bool = Pervasives.(>=)
+let compare : int -> int -> int = Stdlib.compare
+let min : int -> int -> int = Stdlib.min
+let max : int -> int -> int = Stdlib.max
+
+let (=.) : float -> float -> bool = Stdlib.(=)
+let (<>.) : float -> float -> bool = Stdlib.(<>)
+let (<.) : float -> float -> bool = Stdlib.(<)
+let (>.) : float -> float -> bool = Stdlib.(>)
+let (<=.) : float -> float -> bool = Stdlib.(<=)
+let (>=.) : float -> float -> bool = Stdlib.(>=)
 
 
 let (==) = `Consider_using_CCEqual_physical
diff --git a/src/monomorphic/dune b/src/monomorphic/dune
index 0322d471..06b39722 100644
--- a/src/monomorphic/dune
+++ b/src/monomorphic/dune
@@ -1,8 +1,18 @@
 
+(executable
+  (name mkshims)
+  (modules mkshims)
+  (libraries dune.configurator))
+
+(rule
+  (targets CCMonomorphicShims_.ml)
+  (deps ./mkshims.exe)
+  (action (with-stdout-to %{targets} (run ./mkshims.exe))))
+
 (library
   (name containers_monomorphic)
   (public_name containers.monomorphic)
+  (modules CCMonomorphic CCMonomorphicShims_)
   (wrapped false)
   (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string)
-  (ocamlopt_flags :standard (:include ../flambda.flags))
-  )
+  (ocamlopt_flags :standard (:include ../flambda.flags)))
diff --git a/src/monomorphic/mkshims.ml b/src/monomorphic/mkshims.ml
new file mode 100644
index 00000000..f391a32c
--- /dev/null
+++ b/src/monomorphic/mkshims.ml
@@ -0,0 +1,11 @@
+
+module C = Configurator.V1
+
+let shims_pre_408 = "module Stdlib = Pervasives"
+let shims_post_408 = "module Stdlib = Stdlib"
+
+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
+    print_endline (if (major, minor) >= (4,8) then shims_post_408 else shims_pre_408))
diff --git a/src/sexp/CCSexp.ml b/src/sexp/CCSexp.ml
index 25857c31..7c4a8471 100644
--- a/src/sexp/CCSexp.ml
+++ b/src/sexp/CCSexp.ml
@@ -3,6 +3,8 @@
 
 (** {1 Simple S-expression parsing/printing} *)
 
+open CCShims_
+
 type 'a or_error = ('a, string) Result.result
 type 'a sequence = ('a -> unit) -> unit
 type 'a gen = unit -> 'a option
@@ -13,7 +15,7 @@ type t = [
 ]
 type sexp = t
 
-let equal_string (a : string) b = Pervasives.(=) a b
+let equal_string (a : string) b = Stdlib.(=) a b
 
 let rec equal a b = match a, b with
   | `Atom s1, `Atom s2 ->
@@ -22,7 +24,7 @@ let rec equal a b = match a, b with
     begin try List.for_all2 equal l1 l2 with Invalid_argument _ -> false end
   | `Atom _, _ | `List _, _ -> false
 
-let compare_string (a : string) b = Pervasives.compare a b
+let compare_string (a : string) b = Stdlib.compare a b
 
 let rec compare_list a b = match a, b with
   | [], [] -> 0
diff --git a/src/sexp/CCSexp_lex.mll b/src/sexp/CCSexp_lex.mll
index 024d0a6b..3db73cd6 100644
--- a/src/sexp/CCSexp_lex.mll
+++ b/src/sexp/CCSexp_lex.mll
@@ -1,4 +1,5 @@
 {
+  open CCShims_
   type token =
     | ATOM of string
     | LIST_OPEN
@@ -20,7 +21,7 @@
     | Escaped_int_1 of int
     | Escaped_int_2 of int
 
-  let char_equal (a : char) b = Pervasives.(=) a b
+  let char_equal (a : char) b = Stdlib.(=) a b
 
   (* remove quotes + unescape *)
   let remove_quotes lexbuf s =
diff --git a/src/sexp/dune b/src/sexp/dune
index 0066e698..bf1a6f9d 100644
--- a/src/sexp/dune
+++ b/src/sexp/dune
@@ -5,7 +5,6 @@
   (wrapped false)
   (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string)
   (ocamlopt_flags :standard (:include ../flambda.flags))
-  (libraries result)
-  )
+  (libraries result containers))
 
 (ocamllex (modules CCSexp_lex))
diff --git a/src/threads/CCBlockingQueue.ml b/src/threads/CCBlockingQueue.ml
index 9a5a0f9f..053c085a 100644
--- a/src/threads/CCBlockingQueue.ml
+++ b/src/threads/CCBlockingQueue.ml
@@ -73,7 +73,7 @@ let take q =
     done)
   in
   Thread.join t1; Thread.join t2; Thread.join t3;
-  assert_equal [1;2;3;4] (List.sort Pervasives.compare (CCLock.get l))
+  assert_equal [1;2;3;4] (List.sort Stdlib.compare (CCLock.get l))
 *)
 
 let push_list q l =
@@ -156,7 +156,7 @@ let take_list q n =
     )
   in
   CCThread.Arr.join senders; CCThread.Arr.join receivers;
-  let l = CCLock.get res |> List.sort Pervasives.compare in
+  let l = CCLock.get res |> List.sort Stdlib.compare in
   assert_equal CCList.(1 -- 3*n) l
 *)
 
diff --git a/src/threads/CCLock.ml b/src/threads/CCLock.ml
index 61daccfe..d916f371 100644
--- a/src/threads/CCLock.ml
+++ b/src/threads/CCLock.ml
@@ -120,9 +120,9 @@ let set l x =
   let l = create 0 in set l 4; set l 5; get l = 5
 *)
 
-let incr l = update l Pervasives.succ
+let incr l = update l Stdlib.succ
 
-let decr l = update l Pervasives.pred
+let decr l = update l Stdlib.pred
 
 
 (*$R
diff --git a/src/threads/CCTimer.ml b/src/threads/CCTimer.ml
index 9ad6e2c4..2315c028 100644
--- a/src/threads/CCTimer.ml
+++ b/src/threads/CCTimer.ml
@@ -6,10 +6,10 @@
 type job =
   | Job : float * (unit -> 'a) -> job
 
-let (<=) (a : float) b = Pervasives.(<=) a b
-let (>=) (a : float) b = Pervasives.(>=) a b
-let (<) (a : float) b = Pervasives.(<) a b
-let (>) (a : float) b = Pervasives.(>) a b
+let (<=) (a : float) b = Stdlib.(<=) a b
+let (>=) (a : float) b = Stdlib.(>=) a b
+let (<) (a : float) b = Stdlib.(<) a b
+let (>) (a : float) b = Stdlib.(>) a b
 
 module TaskHeap = CCHeap.Make(struct
     type t = job
diff --git a/src/threads/dune b/src/threads/dune
index 504d9d99..4df73ac3 100644
--- a/src/threads/dune
+++ b/src/threads/dune
@@ -4,8 +4,7 @@
   (public_name containers.thread)
   (wrapped false)
   (optional)
-  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string)
+  (flags :standard -w +a-4-42-44-48-50-58-32-60@8 -safe-string -open CCShims_)
   (ocamlopt_flags :standard (:include ../flambda.flags))
-  (libraries containers threads)
-  )
+  (libraries containers threads))