ARC makes ref counting a part of semantics in the sense that the deref that reaches zero immediately runs the destructor, and destructors can have any effects they like.
Therefore, it’s not really valid to say that ARC “is” garbage collection.
Reference counting is only a form of garbage collection if it is totally transparent to the programmer, and it’s not like that in ARC.
Which is why when Apple introduced new ARC optimizations last year, they had a talk about possible gotchas that might crash the application due to them.
Therefore, it’s not really valid to say that ARC “is” garbage collection.
Reference counting is only a form of garbage collection if it is totally transparent to the programmer, and it’s not like that in ARC.