anchor.diff:      T1GCState = on_bp(Msg, UState, GCState),
       Module  = gc_mod(T1GCState),
       Handler = gc_hand(T1GCState),
  -    T2State =
  -        try Handler(Msg, UState)
  -        catch Level:Reason ->
  -                Stacktrace = erlang:get_stacktrace(),
  -                case Stacktrace of
  -                    %% erlang < R15 : {Module, Handler, [Msg, State]}
  -                    %% erlang >= R15: {Module, Handler, [Msg, State], _}
  -                    [T | _] when
  -                          erlang:element(1, T) =:= Module andalso
  -                          %% erlang:element(2, T) =:= Handler andalso
  -                          erlang:element(3, T) =:= [Msg, UState] andalso
  -                          Reason =:= function_clause andalso
  -                          Level =:= error ->
  -                        on_unknown_event(Msg, UState, T1GCState),
  -                        {'$gc_unknown_event'};
  -                    _ ->
  -                        on_exception(Msg, Level, Reason, Stacktrace,
  -                                     UState, T1GCState),
  -                        {'$gc_exception'}
  -                end
  -        end,
  -    case T2State of
  +    try Handler(Msg, UState) of
           kill ->
               log:log(info, "[ gen_component ] ~.0p killed (~.0p:~.0p/2):",
                       [self(), Module, Handler]),
  
positive.code:                 true -> loop(UState, bp_step_done(Msg, T1GCState))
              end;
          NewUState ->
              case element(?BP_ACTIVE, T1GCState) andalso gc_bpstepped(T1GCState) of
                  false -> loop(NewUState, T1GCState);
                  true -> loop(NewUState, bp_step_done(Msg, T1GCState))
              end
      end.
  
  -spec on_traced_msg(comm:message(), user_state(), gc_state())
  
negative.code:     T1GCState = on_bp(Msg, UState, GCState),
      Module  = gc_mod(T1GCState),
      Handler = gc_hand(T1GCState),
      try Handler(Msg, UState) of
          kill ->
              log:log(info, "[ gen_component ] ~.0p killed (~.0p:~.0p/2):",
                      [self(), Module, Handler]),
  