anchor.diff:               #concuerror_info{processes = Processes} = Info) ->
     try
       true = is_atom(Name),
  -    true = is_pid(Pid) orelse is_port(Pid),
       {true, Info} = run_built_in(erlang, is_process_alive, 1, [Pid], Info),
       [] = ets:match(Processes, ?process_match_name_to_pid(Name)),
       ?process_name_none = ets:lookup_element(Processes, Pid, ?process_name),
  
positive.code:       %% New event...
        undefined -> make_ref()
      end,
    NewInfo =
      case ets:lookup(Processes, Pid) of
        [] -> throw(monitoring_non_concuerror_process);
        [?process_pat_pid_status(Pid, Status)] ->
          IsActive = is_active(Status),
          case IsActive of
            true -> true = ets:insert(Monitors, {Pid, {Ref, self()}, active});
            false -> ok
          end,
          case EventInfo of
            %% Replaying...
            #builtin_event{} -> Info;
            %% New event...
            undefined ->
              case IsActive of
                false ->
                  Message =
                    #message{data = {'DOWN', Ref, process, Pid, noproc},
                             message_id = make_ref()},
                  MessageEvent =
                    #message_event{
                    cause_label = Event#event.label,
                    message = Message,
                    recipient = self()},
                  NewEvent = Event#event{special = {message, MessageEvent}},
                  Info#concuerror_info{next_event = NewEvent};
                true -> Info
              end
          end
      end,
    {Ref, NewInfo};
  
negative.code: run_built_in(erlang, monitor, 2, [Type, Pid], Info) ->
    #concuerror_info{
       monitors = Monitors,
       next_event = #event{event_info = EventInfo} = Event} = Info,
    ?badarg_if_not(Type =:= process andalso is_pid(Pid)),
    Ref =
      case EventInfo of
  