Hello. We did recently several cleanups by marking abstract classes as abstract using #isAbstract method (https://github.com/pharo-project/pharo/pull/3087, https://github.com/pharo-ide/Calypso/pull/462) . I would like to discuss here and decide what the right way to implement this method. The logic behind is to only return true when receiver is defining class of this method. And it should be false for any subclasses (if they do not implement own #isAbstract method). There is old pattern for implementation to compare name of class: MyAbstractClass class>>isAbstract ^self name == #MyAbstractClass It is used in many places (mostly tests). And it was used in recent Pharo PR (3087). We have another pattern in other places which simply compare self with class: MyAbstractClass class>>isAbstract ^self == MyAbstractClass And in Calypso I used "more simplified" version using equality: MyAbstractClass class>>isAbstract ^self = MyAbstractClass I think we would all agree that simplest version is last one. It does not raise any question about why we compare name or why we use identity comparison. So this is my choice in this discussion. Please write arguments about your preferred implementation. And let's choose single way at the end. There is an idea to add a command into browser to make classes abstract. And this decision will be used as a template. Best regards, Denis