Using inheritance in this way is a hack to emulate some of the functionality of ADTs. Grammars are perhaps one of the most poignant examples where the various c

Using inheritance in this way is a hack to emulate some of the functionality of ADTs. Grammars are perhaps one of the most poignant examples where the various constructors in your type might have no behaviors in common, so adherence to a shared interface is nothing but a vague indication that these types are somehow related. Sealed classes let you recover a little bit more of the functionality.