anchor.diff:            links                       :: links(),
             logger                      :: pid(),
             message_counter = 1         :: pos_integer(),
  -          messages_new = queue:new()  :: message_queue(),
  -          messages_old = queue:new()  :: message_queue(),
  +          message_queue = queue:new() :: message_queue(),
             monitors                    :: monitors(),
             event = none                :: 'none' | event(),
             notify_when_ready           :: {pid(), boolean()},
  
positive.code:       case is_active(Info) andalso NotDemonitored of
          true ->
            ?debug_flag(?loop, enqueueing_message),
            Old = Info#concuerror_info.messages_new,
            NewInfo =
              Info#concuerror_info{
                messages_new = queue:in(Message, Old)
               },
            ?debug_flag(?loop, enqueued_msg),
            case NewInfo#concuerror_info.status =:= waiting of
  
negative.code:             catch error:badarg -> []
              end;
            messages ->
              #concuerror_info{message_queue = Queue} = TheirInfo,
              [M || #message{data = M} <- queue:to_list(Queue)];
            message_queue_len ->
              #concuerror_info{message_queue = Queue} = TheirInfo,
              queue:len(Queue);
            registered_name ->
              #concuerror_info{processes = Processes} = TheirInfo,
  