Fix one hex printing bug

src/stages/common/PP.ml

@@ -188,10 +188,14 @@ let literal ppf (l:literal) = match l with
   | Literal_timestamp n -> fprintf ppf "+%d" n
   | Literal_mutez n -> fprintf ppf "%dmutez" n
   | Literal_string s -> fprintf ppf "%S" s
-  | Literal_bytes b -> fprintf ppf "0x%s" @@ Bytes.to_string @@ Bytes.escaped b
+  | Literal_bytes b -> fprintf ppf "0x%a" Hex.pp (Hex.of_bytes b)
   | Literal_address s -> fprintf ppf "@%S" s
   | Literal_operation _ -> fprintf ppf "Operation(...bytes)"
   | Literal_key s      -> fprintf ppf "key %s" s
   | Literal_key_hash s -> fprintf ppf "key_hash %s" s
   | Literal_signature s -> fprintf ppf "Signature %s" s
   | Literal_chain_id s -> fprintf ppf "Chain_id %s" s
+
+let%expect_test _ =
+  Format.printf "%a" literal (Literal_bytes (Bytes.of_string "foo")) ;
+  [%expect{| 0x666f6f |}]

src/stages/common/dune

@@ -5,8 +5,9 @@
     simple-utils
     tezos-utils
   )
+  (inline_tests)
   (preprocess
-    (pps ppx_let)
+    (pps ppx_let ppx_expect)
   )
   (flags (:standard -open Simple_utils))
 )

src/stages/mini_c/PP.ml

@@ -58,8 +58,7 @@ let rec value ppf : value -> unit = function
   | D_unit -> fprintf ppf "unit"
   | D_string s -> fprintf ppf "\"%s\"" s
   | D_bytes x ->
-     let (`Hex hex) = Hex.of_bytes x in
-     fprintf ppf "0x%s" hex
+     fprintf ppf "0x%a" Hex.pp @@ Hex.of_bytes x
   | D_pair (a, b) -> fprintf ppf "(%a), (%a)" value a value b
   | D_left a -> fprintf ppf "L(%a)" value a
   | D_right b -> fprintf ppf "R(%a)" value b
@@ -124,6 +123,10 @@ let tl_statement ppf (ass, _) = assignment ppf ass
 let program ppf (p:program) =
   fprintf ppf "Program:\n---\n%a" (pp_print_list ~pp_sep:pp_print_newline tl_statement) p
 
+let%expect_test _ =
+  Format.printf "%a" value (D_bytes (Bytes.of_string "foo")) ;
+  [%expect{| 0x666f6f |}]
+
 let%expect_test _ =
   let pp = expression' Format.std_formatter in
   let dummy_type = T_base Base_unit in