There&#x27;s never been a C-based compiler. Rust started out as OCaml. A true bootstrap would take weeks of non-stop compiling. You&#x27;d end up compiling rustc itself about 900 times, ignoring all the different LLVM builds, I think. Rust bootstraps from a binary snapshot of itself, and so you would have to work through the list of every snapshot ever (about 300, but you need to build rustc 3 times for each snapshot to properly bootstrap that copy). The snapshots are listed here: <a href="https:&#x2F;&#x2F;github.com&#x2F;rust-lang&#x2F;rust&#x2F;blob&#x2F;master&#x2F;src&#x2F;snapshots.txt" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;rust-lang&#x2F;rust&#x2F;blob&#x2F;master&#x2F;src&#x2F;snapshots....</a><p>In the past the snapshots were taken almost weekly as massive language churn dictated. Now they&#x27;re quite rare.