> Probably, they exist but are just kept proprietary. So your theory is that this is an excellent design, but for some reason all of the implementations are pr

> Probably, they exist but are just kept proprietary. So your theory is that this is an excellent design, but for some reason all of the implementations are proprietary and by chance we never saw any of them in the years since. Is the alternative hypothesis too obvious to spell out? This is a bad design, Bloomberg got the thing they wanted baked into the C++ ISO document so it's a success for that team but nothing more. Big pieces of the PMR design rely on an old C++ fallback which isn't available in (safe) Rust. Undefined Behaviour. This simplifies implementation greatly of course, you just don't need to care about those cases at all, even if they're widespread, since you said they were "Undefined Behaviour" so it's not your fault when everything catches fire. And it looks like it simplifies end user code too, their code is often faulty of course, but it compiles and if you get lucky it doesn't blow up at runtime.