In faster schemes, garbage collection is not based on reference counting.
Instead, it is based on the idea that any non-dead object must ultimately be traceable back to a reference that lives either on the stack or in static storage. The chain might go through several layers of objects.
Thus, if you start in the stack and in the static storage area and walk through all the references, you’ll find all the live objects.
For each reference that you find, you must trace into the object that it points to and then follow all the references in that object, tracing into the objects they point to, etc., until you’ve moved through the entire Web that originated with the reference on the stack or in static storage.
Each object that you move through must still be alive. Note that there is no problem with detached self-referential groups—these are simply no<愛尬聊_尬聊生活>t found, and are therefore automatically garbage.

最后提到 detached self-referential groups 不會被gc發現是為什么呢？按照從stack and static storage出發應該會經過這些自參照（self-referential）的引用。其中說到的`chain也不是很理解，感覺太突兀了，希望有所了解的人可以幫助一下我。萬分感謝！