It's funny how people always allude to fanatical Rust developers in the most tangential threads, but they never actually turn up and demand we rewrite the entire Kernel in Rust or whatever terrible takes they're alleged to have.
Check out https://github.com/ansuz/RIIR/issues/ for more.
Gosh... and people on HN tell us that they have yet to meet a Rust fanatic. Just look around the GitHub Issues I linked.
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BTW I stumbled upon https://github.com/r9os/r9 as well. Reading the source code, it is mainly unsafe blocks and assembly. :| Who would have thought?