Access to deleted objects is detected by marking objects deleted and not reclaiming their memory until the containing pages are mostly full of deleted objects, then they relocate still-live objects and unmap the pages. That is, they use MMU tricks but they amortize the MMU cost (otherwise performance would be absolutely abysmal).<p>Note that they still need to rewrite object references, which is a lot like a GC. EDIT: No, sorry, they lazy patch references, though this requires some overhead.<p>Also, this does nothing to protect against leaks.<p>Interesting idea, but too-little-too-late. I think Rust is the better answer for now.<p>EDIT: Great question from the Q&A of the video, "why are you not getting killed by TLB misses?", and the presenter did not know. This is a really important question.