This was recently posted to /r/rust with the engagement of the author (mutabah) if you'd like to ask questions or get involved. In particular here's him answering why he started this project: https://www.reddit.com/r/rust/comments/718gbh/mrustc_alterna...
One of the interesting things about this project is that because its initial goal is to validate the reproducibility of the main Rust compiler it doesn't actually need to implement a borrow checker, as the borrow checker strictly rejects programs and has no role in code generation.
One of the interesting things about this project is that because its initial goal is to validate the reproducibility of the main Rust compiler it doesn't actually need to implement a borrow checker, as the borrow checker strictly rejects programs and has no role in code generation.