> Does that mean that the compiler is doing erasure for generics coming in from Objective C, inserting runtime casts where needed The runtime types of Obj-C ob

> Does that mean that the compiler is doing erasure for generics coming in from Objective C, inserting runtime casts where needed The runtime types of Obj-C objects do not matter, as long as they can respond to the messages sent to them. In fact, you can cast any object to any class and gets no runtime errors, as long as the message you send is recognized. So reification is really not something useful in Obj-C.