anchor.diff:               #concuerror_info{
                   next_event = #event{event_info = EventInfo} = Event
                  } = Info) ->
  +  ?badarg_if_not(is_pid(Pid)),
     case EventInfo of
       %% Replaying...
       #builtin_event{result = OldResult} -> {OldResult, Info};
       %% New event...
       undefined ->
  -      ?badarg_if_not(is_pid(Pid)),
         Message =
           #message{data = {'EXIT', self(), Reason}, message_id = make_ref()},
         MessageEvent =
  
positive.code:   ets:delete_all_objects(Tid),
    {Tid, Info};
  run_built_in(ets, insert, 2, [Tid, _] = Args, Info) ->
    #concuerror_info{ets_tables = EtsTables} = Info,
    check_ets_access_rights(Tid, self(), insert, EtsTables),
    {erlang:apply(ets, insert, Args), Info};
  run_built_in(ets, lookup, 2, [Tid, _] = Args, Info) ->
    #concuerror_info{ets_tables = EtsTables} = Info,
    check_ets_access_rights(Tid, self(), lookup, EtsTables),
    {erlang:apply(ets, lookup, Args), Info};
  run_built_in(ets, delete, 1, [Tid], Info) ->
    #concuerror_info{ets_tables = EtsTables} = Info,
    check_ets_access_rights(Tid, self(), delete, EtsTables),
    Update = [{?ets_owner, none}],
    ets:update_element(EtsTables, Tid, Update),
    ets:delete_all_objects(Tid),
  
negative.code:   #concuerror_info{processes = Processes} = Info,
    Return =
      case ets:lookup(Processes, Pid) of
        [] -> throw(unknown_process);
        [?process_pat_pid_status(Pid, Status)] -> is_active(Status)
      end,
    {Return, Info};
  
  run_built_in(erlang, link, 1, [Pid], #concuerror_info{links = Links} = Info) ->
    case run_built_in(erlang, is_process_alive, 1, [Pid], Info) of
      {true, Info}->
        Self = self(),
        true = ets:insert(Links, [{Self, Pid, active}, {Pid, Self, active}]),
        {true, Info};
      {false, _} ->
        error(noproc)
    end;
  
  run_built_in(erlang, make_ref, 0, [], Info) ->
  