Comment #7 on issue 3817 by camillob...@gmail.com: make Object >> error: deprecated http://code.google.com/p/pharo/issues/detail?id=3817 I agree that `self error:` is amazingly useful, but it should be used with caution. Lazyness is never an argument for keeping a partly broken design! It is similar to using dictionaries or arrays instead of real objects with a proper class attached. If your error is just to inform the user, then it belongs into the View, nowhere else! And then you should use something like a UserNotificationError to make this very explicit. If your error should inform the "user" from within the model, then you should use an explicit class which gives additional semantics (besides the human readable string) to it. So what I suggest is to replace `Object >> error:` with something like a GenericError or UndefinedError, to encourage the use of proper error classes.