[amaranth]

This is eventually going to be a feature-complete compiler, targeting a specific rustc version. I believe the plan is to use polonius [1], presumably as an "optional" feature so they can build a stage 1 without it, use that to build polonius, then build the final compiler with it included.

[1] https://github.com/rust-lang/polonius

[wofo]

You are right, this much more ambitious than I though! Here is more information about the project, for the curious: https://rust-gcc.github.io/