a-mir-formality

It's a work in progress. The Reference (https://doc.rust-lang.org/reference) is slowly getting more complete over time. Other ongoing efforts include a-mir-formality (https://github.com/rust-lang/a-mir-formality), minirust (https://github.com/minirust/minirust), the FLS (https://github.com/rust-lang/fls), and Rust via Desugarings (https://nadrieril.github.io/rust-via-desugarings/). But writing a 100% complete and correct formal spec is hard! Not even C gets this right, the C standard has holes which lead to miscompilations and UB in practice: https://www.ralfj.de/blog/2020/12/14/provenance.html

The comparison isn't with rust today, but the long term differences between the languages. Rust has a straightforward path to rectifying the standardization issue and enough community momentum to succeed. For example, Rust has an in-progress specification, here's the (currently empty) repo: https://github.com/rust-lang/spec. There's also MIR, a de-sugared internal representation that's sufficiently well specified to build formal models of (see https://github.com/rust-lang/a-mir-formality and https://github.com/rust-lang/miri), as well as the ferrocene spec (https://spec.ferrocene.dev/general.html) that's suitable for certification authorities (if not actually useful) and of course the rust reference/RFCs that are actually usable by people. Plus, the fact that everyone in the rust community has standardized on one compiler and one package

Racket is very used in the PLT community (programming language theory) for prototyping programming languages. Lots of cool stuff in this area. For example, the MIR formality [0] project of the Rust programming language to formalize MIR (their intermediate language) was first prototyped in Racket [1], then rewritten in Rust. [1]'s readme give a rationale: > For the time being, the model is implemented in PLT Redex. PLT Redex was chosen because it is ridiculously accessible and fun to use. It lets you write down type system rules and operational semantics and then execute them, using a notation that is very similar to what is commonly used in published papers. You can also write collections of unit tests and fuzz your model by generating test programs automatically. > The hope is that PLT Redex will prove to be a sufficiently accessible too