anchor.diff:                           JSON),
           true = is_binary(ModuleName),
           true = is_binary(ModuleSource),
  -        State = #state{
  -                   module_name = ModuleName,
  -                   module_source = ModuleSource},
  -        {ok, State, Req2}
  +        {ok, {ModuleName, ModuleSource}, Req2}
       catch _:_ ->
                 {error, wrong_json, Req2}
       end.
  
positive.code: 
  -spec rest_init(cowboy_req:req(), [atom()]) -> {ok, cowboy_req:req(), state()}.
  rest_init(Req, _Opts) ->
      {ok, Req, #state{}}.
  
  -spec allowed_methods(cowboy_req:req(), state()) -> 
      {[binary()], cowboy_req:req(), state()}.
  
negative.code:          to_json/2,
           from_json/2]).
  
  -type state() :: [].
  
  -spec trails() -> trails:trails().
  trails() ->
  