diff --git a/src/action.ml b/src/action.ml
index add0fcd8..4cc10353 100644
--- a/src/action.ml
+++ b/src/action.ml
@@ -10,16 +10,10 @@ module Outputs = struct
     | Outputs -> "outputs"
 end
 
-module type Sexpable = sig
-  type t
-  val t : t Sexp.Of_sexp.t
-  val sexp_of_t : t Sexp.To_sexp.t
-end
-
 module Make_ast
-    (Program : Sexpable)
-    (Path    : Sexpable)
-    (String  : Sexpable)
+    (Program : Sexp.Sexpable)
+    (Path    : Sexp.Sexpable)
+    (String  : Sexp.Sexpable)
     (Ast : Action_intf.Ast
      with type program := Program.t
      with type path    := Path.t
@@ -676,7 +670,7 @@ module Promotion = struct
   let do_promote db =
     let by_targets = group_by_targets db  in
     let potential_build_contexts =
-      match Path.readdir Path.build_dir with
+      match Path.readdir_unsorted Path.build_dir with
       | exception _ -> []
       | files ->
         List.filter_map files ~f:(fun fn ->
diff --git a/src/action.mli b/src/action.mli
index 87df693b..484debf3 100644
--- a/src/action.mli
+++ b/src/action.mli
@@ -87,8 +87,7 @@ module Unexpanded : sig
     with type path    := String_with_vars.t
     with type string  := String_with_vars.t
 
-  val t : t Sexp.Of_sexp.t
-  val sexp_of_t : t Sexp.To_sexp.t
+  include Sexp.Sexpable with type t := t
 
   module Partial : sig
     include Action_intf.Ast
diff --git a/src/build_system.ml b/src/build_system.ml
index ede25ba7..b239f5c8 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -408,7 +408,7 @@ let get_dir_status t ~dir =
       Dir_status.Loaded Path.Set.empty
     else if not (Path.is_local dir) then
       Dir_status.Loaded
-        (match Path.readdir dir with
+        (match Path.readdir_unsorted dir with
          | exception _ -> Path.Set.empty
          | files ->
            Path.Set.of_list (List.map files ~f:(Path.relative dir)))
@@ -637,7 +637,7 @@ let remove_old_artifacts t ~dir ~subdirs_to_keep =
      Hashtbl.mem t.files (Path.relative dir Config.jbuilder_keep_fname) then
     ()
   else
-    match Path.readdir dir with
+    match Path.readdir_unsorted dir with
     | exception _ -> ()
     | files ->
       List.iter files ~f:(fun fn ->
diff --git a/src/file_tree.ml b/src/file_tree.ml
index 8d120783..8cf4afd6 100644
--- a/src/file_tree.ml
+++ b/src/file_tree.ml
@@ -180,7 +180,7 @@ let load ?(extra_ignored_subtrees=Path.Set.empty) path =
   let rec walk path ~dirs_visited ~project ~ignored : Dir.t =
     let contents = lazy (
       let files, sub_dirs =
-        Path.readdir path
+        Path.readdir_unsorted path
         |> List.filter_partition_map ~f:(fun fn ->
           let path = Path.relative path fn in
           let is_directory, file =
diff --git a/src/installed_dune_file.ml b/src/installed_dune_file.ml
index c2a9b4e3..fcd88858 100644
--- a/src/installed_dune_file.ml
+++ b/src/installed_dune_file.ml
@@ -3,7 +3,7 @@ open Import
 let parse_sub_systems sexps =
   List.filter_map sexps ~f:(fun sexp ->
     let name, ver, data =
-      Sexp.Of_sexp.(triple string (located Syntax.Version.t_of_sexp) raw) sexp
+      Sexp.Of_sexp.(triple string (located Syntax.Version.t) raw) sexp
     in
     match Sub_system_name.get name with
     | None ->
diff --git a/src/ordered_set_lang.mli b/src/ordered_set_lang.mli
index 010de4c3..f3154b8e 100644
--- a/src/ordered_set_lang.mli
+++ b/src/ordered_set_lang.mli
@@ -52,8 +52,8 @@ val is_standard : t -> bool
 module Unexpanded : sig
   type expanded = t
   type t
-  val t : t Sexp.Of_sexp.t
-  val sexp_of_t : t Sexp.To_sexp.t
+
+  include Sexp.Sexpable with type t := t
   val standard : t
 
   val field : ?default:t -> string -> t Sexp.Of_sexp.record_parser
diff --git a/src/stdune/path.ml b/src/stdune/path.ml
index cdb1dae6..d4934334 100644
--- a/src/stdune/path.ml
+++ b/src/stdune/path.ml
@@ -465,7 +465,7 @@ let explode_exn t =
 let exists t =
   try Sys.file_exists (to_string t)
   with Sys_error _ -> false
-let readdir t = Sys.readdir (to_string t) |> Array.to_list
+let readdir_unsorted t = Sys.readdir (to_string t) |> Array.to_list
 let is_directory t =
   try Sys.is_directory (to_string t)
   with Sys_error _ -> false
diff --git a/src/stdune/path.mli b/src/stdune/path.mli
index 7936ed11..dc7e0fb3 100644
--- a/src/stdune/path.mli
+++ b/src/stdune/path.mli
@@ -128,7 +128,7 @@ val split_first_component : t -> (string * t) option
 val insert_after_build_dir_exn : t -> string -> t
 
 val exists : t -> bool
-val readdir : t -> string list
+val readdir_unsorted : t -> string list
 val is_directory : t -> bool
 val rmdir : t -> unit
 val unlink : t -> unit
diff --git a/src/stdune/sexp.ml b/src/stdune/sexp.ml
index 6a918df9..092c749c 100644
--- a/src/stdune/sexp.ml
+++ b/src/stdune/sexp.ml
@@ -452,3 +452,9 @@ module Of_sexp = struct
                     String.uncapitalize name) }
           "Unknown value %s" s
 end
+
+module type Sexpable = sig
+  type t
+  val t : t Of_sexp.t
+  val sexp_of_t : t To_sexp.t
+end
diff --git a/src/stdune/sexp.mli b/src/stdune/sexp.mli
index f4f826e5..722d1bac 100644
--- a/src/stdune/sexp.mli
+++ b/src/stdune/sexp.mli
@@ -169,3 +169,9 @@ module Of_sexp : sig
 
   val enum : (string * 'a) list -> 'a t
 end
+
+module type Sexpable = sig
+  type t
+  val t : t Of_sexp.t
+  val sexp_of_t : t To_sexp.t
+end
diff --git a/src/syntax.ml b/src/syntax.ml
index 81d123a9..751a5287 100644
--- a/src/syntax.ml
+++ b/src/syntax.ml
@@ -7,7 +7,7 @@ module Version = struct
 
   let sexp_of_t t = Sexp.unsafe_atom_of_string (to_string t)
 
-  let t_of_sexp : t Sexp.Of_sexp.t = function
+  let t : t Sexp.Of_sexp.t = function
     | Atom (loc, A s) -> begin
         try
           Scanf.sscanf s "%u.%u" (fun a b -> (a, b))
diff --git a/src/syntax.mli b/src/syntax.mli
index 219e376c..4287a763 100644
--- a/src/syntax.mli
+++ b/src/syntax.mli
@@ -9,8 +9,7 @@ module Version : sig
       [Z <= Y]. *)
   type t = int * int
 
-  val sexp_of_t : t Sexp.To_sexp.t
-  val t_of_sexp : t Sexp.Of_sexp.t
+  include Sexp.Sexpable with type t := t
 
   (** Whether the parser can read the data or not *)
   val can_read : parser_version:t -> data_version:t -> bool