Open polyvars in functions of Io_errors.S

src/irmin-pack/unix/errors.ml

@@ -69,16 +69,16 @@ exception RO_not_allowed = Irmin_pack.RO_not_allowed
 
 (** Error manager *)
 module type S = sig
-  type t
-
-  val pp : Format.formatter -> t -> unit
-  val raise_error : t -> 'a
-  val log_error : string -> t -> unit
-  val catch : (unit -> 'a) -> ('a, t) result
-  val raise_if_error : ('a, t) result -> 'a
-  val log_if_error : string -> (unit, t) result -> unit
-  val to_json_string : (int63, t) result -> string
-  val of_json_string : string -> (int63, t) result
+  type t = error
+
+  val pp : Format.formatter -> [< t ] -> unit
+  val raise_error : [< t ] -> 'a
+  val log_error : string -> [< t ] -> unit
+  val catch : (unit -> 'a) -> ('a, [> t ]) result
+  val raise_if_error : ('a, [< t ]) result -> 'a
+  val log_if_error : string -> (unit, [< t ]) result -> unit
+  val to_json_string : (int63, [< t ]) result -> string
+  val of_json_string : string -> (int63, [> t ]) result
 end
 
 module Base : S with type t = error = struct
@@ -98,7 +98,7 @@ module Base : S with type t = error = struct
 
   let catch f =
     try Ok (f ()) with
-    | Pack_error e -> Error (e : base_error :> t)
+    | Pack_error e -> Error (e : base_error :> [> t ])
     | RO_not_allowed -> Error `Ro_not_allowed
     | Closed -> Error `Closed
 
@@ -119,7 +119,7 @@ module Base : S with type t = error = struct
   let err_to_t = function
     | Closed -> `Closed
     | Ro_not_allowed -> `Ro_not_allowed
-    | Pack_error e -> (e : base_error :> t)
+    | Pack_error e -> (e : base_error :> [> t ])
 
   let err_result = Irmin.Type.(result int63 err_t)
 

src/irmin-pack/unix/io_errors.ml

@@ -21,12 +21,20 @@ open Errors
     {!Io.S.misc_error} *)
 module type S = sig
   module Io : Io.S
-  include Errors.S with type t = [ Base.t | `Io_misc of Io.misc_error ]
+
+  type t = [ Base.t | `Io_misc of Io.misc_error ]
+
+  val pp : Format.formatter -> [< t ] -> unit
+  val raise_error : [< t ] -> 'a
+  val log_error : string -> [< t ] -> unit
+  val catch : (unit -> 'a) -> ('a, [> t ]) result
+  val raise_if_error : ('a, [< t ]) result -> 'a
+  val log_if_error : string -> (unit, [< t ]) result -> unit
+  val to_json_string : (int63, [< t ]) result -> string
+  val of_json_string : string -> (int63, [> t ]) result
 end
 
-module Make (Io : Io.S) :
-  S with module Io = Io and type t = [ Base.t | `Io_misc of Io.misc_error ] =
-struct
+module Make (Io : Io.S) : S with module Io = Io = struct
   module Io = Io
 
   type misc_error = Io.misc_error [@@deriving irmin ~pp]
@@ -44,9 +52,7 @@ struct
   let log_error context e = [%log.err "%s failed: %a" context pp e]
 
   let catch f =
-    try Io.catch_misc_error f
-    with _ as ex ->
-      (Base.catch (fun () -> raise ex) : ('a, Base.t) result :> ('a, t) result)
+    try Io.catch_misc_error f with _ as ex -> Base.catch (fun () -> raise ex)
 
   let raise_if_error = function Ok x -> x | Error e -> raise_error e
 
@@ -66,9 +72,6 @@ struct
 
   let of_json_string string =
     match Irmin.Type.of_json_string io_err_result string with
-    | Error (`Msg _) ->
-        (Base.of_json_string string
-          : (int63, Base.t) result
-          :> (int63, t) result)
-    | Ok result -> (result : (int63, io_error) result :> (int63, t) result)
+    | Error (`Msg _) -> Base.of_json_string string
+    | Ok result -> (result : (_, io_error) result :> (_, [> t ]) result)
 end