I removed dummy module [MBytes] an use [Hex] directly.

AST.ml

@@ -453,7 +453,7 @@ and expr =
 | MapExpr    of map_expr
 | Var        of Lexer.lexeme reg
 | FunCall    of fun_call
-| Bytes      of (Lexer.lexeme * MBytes.t) reg
+| Bytes      of (Lexer.lexeme * Hex.t) reg
 | Unit       of c_Unit
 | Tuple      of tuple
 | ParExpr    of expr par reg
@@ -590,7 +590,7 @@ and pattern =
 | PVar    of Lexer.lexeme reg
 | PWild   of wild
 | PInt    of (Lexer.lexeme * Z.t) reg
-| PBytes  of (Lexer.lexeme * MBytes.t) reg
+| PBytes  of (Lexer.lexeme * Hex.t) reg
 | PString of Lexer.lexeme reg
 | PUnit   of c_Unit
 | PFalse  of c_False
@@ -773,7 +773,7 @@ let print_string {region; value=lexeme} =
 let print_bytes {region; value = lexeme, abstract} =
   printf "%s: Bytes (\"%s\", \"0x%s\")\n"
          (compact region) lexeme
-         (MBytes.to_hex abstract |> Hex.to_string)
+         (Hex.to_string abstract)
 
 let print_int {region; value = lexeme, abstract} =
   printf "%s: Int (\"%s\", %s)\n"

AST.mli

@@ -437,7 +437,7 @@ and expr =
 | MapExpr    of map_expr
 | Var        of Lexer.lexeme reg
 | FunCall    of fun_call
-| Bytes      of (Lexer.lexeme * MBytes.t) reg
+| Bytes      of (Lexer.lexeme * Hex.t) reg
 | Unit       of c_Unit
 | Tuple      of tuple
 | ParExpr    of expr par reg
@@ -574,7 +574,7 @@ and pattern =
 | PVar    of Lexer.lexeme reg
 | PWild   of wild
 | PInt    of (Lexer.lexeme * Z.t) reg
-| PBytes  of (Lexer.lexeme * MBytes.t) reg
+| PBytes  of (Lexer.lexeme * Hex.t) reg
 | PString of Lexer.lexeme reg
 | PUnit   of c_Unit
 | PFalse  of c_False

AST2.ml

@@ -18,7 +18,7 @@ module O = struct
     PVar    of var_name
   | PWild
   | PInt    of Z.t
-  | PBytes  of MBytes.t
+  | PBytes  of Hex.t
   | PString of string
   | PUnit
   | PFalse
@@ -81,7 +81,7 @@ module O = struct
 
   and constant =
     Unit
-  | Int of Z.t | String of string | Bytes of MBytes.t
+  | Int of Z.t | String of string | Bytes of Hex.t
   | False | True
   | Null of type_expr
   | EmptySet of type_expr
@@ -654,7 +654,7 @@ let s_ast (ast : I.ast) : O.ast =
 (* and s_bytes {region; value = lexeme, abstract} = *)
 (*   printf "%s: Bytes (\"%s\", \"0x%s\")\n" *)
 (*          (compact region) lexeme *)
-(*          (MBytes.to_hex abstract |> Hex.to_string) *)
+(*          (Hex.to_string abstract) *)
 
 (* and s_int {region; value = lexeme, abstract} = *)
 (*   printf "%s: Int (\"%s\", %s)\n" *)

LexToken.mli

@@ -29,7 +29,7 @@ type t =
   (* Literals *)
 
   String of lexeme Region.reg
-| Bytes  of (lexeme * MBytes.t) Region.reg
+| Bytes  of (lexeme * Hex.t) Region.reg
 | Int    of (lexeme * Z.t) Region.reg
 | Ident  of lexeme Region.reg
 | Constr of lexeme Region.reg

LexToken.mll

@@ -28,7 +28,7 @@ type t =
   (* Literals *)
 
   String of lexeme Region.reg
-| Bytes  of (lexeme * MBytes.t) Region.reg
+| Bytes  of (lexeme * Hex.t) Region.reg
 | Int    of (lexeme * Z.t) Region.reg
 | Ident  of lexeme Region.reg
 | Constr of lexeme Region.reg
@@ -142,7 +142,7 @@ let proj_token = function
 | Bytes Region.{region; value = s,b} ->
     region,
     sprintf "Bytes (\"%s\", \"0x%s\")"
-      s (MBytes.to_hex b |> Hex.to_string)
+      s (Hex.to_string b)
 
 | Int Region.{region; value = s,n} ->
     region, sprintf "Int (\"%s\", %s)" s (Z.to_string n)
@@ -470,7 +470,7 @@ let mk_string lexeme region = String Region.{region; value=lexeme}
 
 let mk_bytes lexeme region =
   let norm = Str.(global_replace (regexp "_") "" lexeme) in
-  let value = lexeme, MBytes.of_hex (Hex.of_string norm)
+  let value = lexeme, Hex.of_string norm
   in Bytes Region.{region; value}
 
 type int_err = Non_canonical_zero

MBytes.ml

@@ -1,6 +0,0 @@
-(* TEMPORARY: SHOULD BE ERASED *)
-
-type t = Hex.t
-
-let of_hex x = x
-let to_hex x = x

MBytes.mli

@@ -1,6 +0,0 @@
-(* TEMPORARY: SHOULD BE ERASED *)
-
-type t
-
-val of_hex : Hex.t -> t
-val to_hex : t -> Hex.t

ParToken.mly

@@ -6,7 +6,7 @@
   (* Literals *)
 
 %token           <LexToken.lexeme Region.reg> String
-%token <(LexToken.lexeme * MBytes.t) Region.reg> Bytes
+%token <(LexToken.lexeme * Hex.t) Region.reg> Bytes
 %token   <(LexToken.lexeme * Z.t) Region.reg> Int
 %token           <LexToken.lexeme Region.reg> Ident
 %token           <LexToken.lexeme Region.reg> Constr

Tests/crowdfunding.ligo

@@ -19,7 +19,7 @@ entrypoint contribute (storage store : store;
     else
       case store.backers[sender] of
         None -> store.backers[sender] := Some (amount)
-//        patch store.backers with map sender -> amount end
+//        None -> patch store.backers with map sender -> amount end
       |    _ -> skip
       end
   end with (store, operations)
@@ -32,8 +32,8 @@ entrypoint withdraw (storage store : store; const sender : address)
       if now >= store.deadline then
         if balance >= store.goal then
           begin
-//           patch store with record funded = True end;
              store.funded := True;
+//           patch store with record funded = True end;
              operations := [Transfer (owner, balance)]
           end
         else fail "Below target"

Typecheck2.ml

@@ -18,7 +18,7 @@ module O = struct
     PVar    of var_name
   | PWild
   | PInt    of Z.t
-  | PBytes  of MBytes.t
+  | PBytes  of Hex.t
   | PString of string
   | PUnit
   | PFalse
@@ -85,7 +85,7 @@ module O = struct
 
   and constant =
     Unit
-  | Int of Z.t | String of string | Bytes of MBytes.t
+  | Int of Z.t | String of string | Bytes of Hex.t
   | False | True
   | Null
   | EmptySet
@@ -272,4 +272,3 @@ let a_ast I.{types; storage_decl; declarations; orig} =
   O.{types; storage_decl; declarations; orig}
 
 let annotate : I.ast -> O.ast = a_ast
-

Typecheck2.mli

@@ -16,7 +16,7 @@ module O : sig
     PVar    of var_name
   | PWild
   | PInt    of Z.t
-  | PBytes  of MBytes.t
+  | PBytes  of Hex.t
   | PString of string
   | PUnit
   | PFalse
@@ -83,7 +83,7 @@ module O : sig
 
   and constant =
     Unit
-  | Int of Z.t | String of string | Bytes of MBytes.t
+  | Int of Z.t | String of string | Bytes of Hex.t
   | False | True
   | Null
   | EmptySet