anchor.diff:          action = PrivateAction(
             action.type,
             payload: action.payload,
  -          current: ctx.state,
  +          target: ctx.state,
           );
         }
         superDispatch(action);
  
positive.code: import 'logic.dart';
  
  class PrivateAction extends Action {
    final Object current;
    PrivateAction(Object type, {dynamic payload, this.current})
        : super(type, payload: payload);
  
    Action asAction() => Action(type, payload: payload);
  
negative.code:     final Reducer<T> superReducer = super.privateReducer;
      return superReducer != null
          ? (T state, Action action) {
              if (action is PrivateAction && action.target == state) {
                return superReducer(state, action.asAction());
              }
              return state;
  