anchor.diff:                            erlang:element(3, T) =:= [Msg, UState] andalso
                             Reason =:= function_clause andalso
                             Level =:= error ->
  -                        {'$gc_unknown_event',
  -                         on_unknown_event(Msg, T1State)};
  +                        on_unknown_event(Msg, UState, T1GCState),
  +                        {'$gc_unknown_event'};
                       _ ->
  -                        {'$gc_exception',
  -                         on_exception(Msg, Level, Reason, Stacktrace, T1State)}
  +                        on_exception(Msg, Level, Reason, Stacktrace,
  +                                     UState, T1GCState),
  +                        {'$gc_exception'}
                   end
           end,
       case T2State of
  
positive.code: -type gc_state() ::
          { module(),
            handler(),
            user_state(),       %% users state
            Options :: list(),
            Slowest :: float(),
            [bp()],             %% registered breakpoints
            boolean(),          %% bp active?
            [bp_msg()],         %% queued bp messages
  
negative.code: %% define macros for the tuple positions to use them also in guards.
  -define(MOD,         1).
  -define(HAND,        2).
  %-define(OPTS,        3).
  %-define(SLOWEST,     4).
  -define(BPS,         3).
  -define(BP_ACTIVE,   4).
  -define(BP_QUEUE,    5).
  -define(BP_STEPPED,  6).
  -define(BP_STEPPER,  7).
  
  %% userdevguide-begin gen_component:behaviour
  -ifdef(have_callback_support).
  