а "рц гц" - это без викрефов, прямо как трейсинг-гц, только не трейсинг, а на основе поиска циклов
тлдр на затравку:
We initially started with the assumption that the solution would take the form of automatic ref counting (so the programmer couldn't forget) plus some other stuff to detect and handle cycles automatically. We looked at adding conservative collection or tracing to the mix, GC algorithms that could collect a single object without doing an entire graph trace, etc. For a variety of reasons (more on this below), we ultimately concluded that this was not going to work in the general case.