Ppx: allow apostrophe in lident (fix #1183)

ppx/ppx_deriving_json/lib/ppx_deriving_json.ml

@@ -48,15 +48,15 @@ let parse_lid s =
         match i, c with
         | 0, ('a' .. 'z' | '_') -> ()
         | 0, _ -> assert false
-        | _, ('a' .. 'z' | 'A' .. 'Z' | '_' | '0' .. '9') -> ()
+        | _, ('a' .. 'z' | 'A' .. 'Z' | '_' | '\'' | '0' .. '9') -> ()
         | _ -> assert false)
   in
   let assert_uid =
     String.iteri ~f:(fun i c ->
         match i, c with
         | 0, 'A' .. 'Z' -> ()
         | 0, _ -> assert false
-        | _, ('a' .. 'z' | 'A' .. 'Z' | '_' | '0' .. '9') -> ()
+        | _, ('a' .. 'z' | 'A' .. 'Z' | '_' | '\'' | '0' .. '9') -> ()
         | _ -> assert false)
   in
   let rec check = function

ppx/ppx_deriving_json/tests/gen.mlt

@@ -695,3 +695,27 @@ let t s =
     (Deriving_Json_lexer.init_lexer (Lexing.from_string s));;
 val t : string -> t * t = <fun>
 |}]
+
+;;
+type id' = int [@@deriving json]
+[%%expect {|
+
+type id' = int[@@deriving json]
+include
+  struct
+    let _ = fun (_ : id') -> ()
+    let rec (id'_of_json : Deriving_Json_lexer.lexbuf -> id') =
+      fun buf -> Deriving_Json.Json_int.read buf
+    let _ = id'_of_json
+    let rec (id'_to_json : Buffer.t -> id' -> unit) =
+      fun buf -> fun a -> Deriving_Json.Json_int.write buf a
+    let _ = id'_to_json
+    let (id'_json : id' Deriving_Json.t) =
+      Deriving_Json.make id'_to_json id'_of_json
+    let _ = id'_json
+  end[@@ocaml.doc "@inline"][@@merlin.hide ];;
+type id' = int
+val id'_of_json : Deriving_Json_lexer.lexbuf -> id' = <fun>
+val id'_to_json : Buffer.t -> id' -> unit = <fun>
+val id'_json : id' Deriving_Json.t = <abstr>
+|}]