GC specifically means you leave unreferenced mem on the heap until it gets collected in one big sweep later.

ObjC/Swift are also their own special class of refcounting because it's done at compile time at least partially. Whereas spamming Rc/shared_ptr would do it always at runtime and be quite slow.

You're referring specifically to tracing garbage collection. When a reference count reaches zero, that garbage is collected, often recursively. Among programming language designers, ARC is considered a GC strategy.

https://en.wikipedia.org/wiki/Garbage_collection_(computer_s...

https://users.rust-lang.org/t/reference-counting-garbage-col...