This does not paint the full picture. Rust can be bootstrapped with mrustc, which is written in C++
https://github.com/thepowersgang/mrustc
Now, mrustc supports only Rust 1.74. To build Rust 1.92, you need almost 20 builds. But this can be done from source
Guix has written about bootstrapping Rust from source (they care a lot about this). Here is how it looked like in 2018
https://ferrous-systems.com/blog/ferrocene-25-11-0/
Lets not forget not having a formal spec apparently wasn't an issue for C, which only got standardized in 1989, and even K&R C only specified a subset of its behaviours, which is a reason why there is so much UB, and implementation specific behaviours with YOLO C, as the Fil-C author likes to call it.
This is not true. Since kernel 6.11 they have specified a minimum version that is already stable. The strategy for the Rust kernel is to use the version of Rust that ships with Debian Stable. That is very far from using "the newly prototyped features right away".
https://rust-for-linux.com/rust-version-policy
Of course, the kernel continues to inform Rust evolution. But you do not need an unstable version of Rust to compile Linux.
Are there many architectures that NetBSD supports where GCC is not available?
The rustc_codegen_gcc project allows using the rustc compiler to target any architecture that GCC supports. I think it is pretty far along.
https://github.com/rust-lang/rustc_codegen_gcc
> getting a Rust compiler running in the first place is hard
> bootstrap relies on a binary package
> the compiler would also have to be part of the base system
The gccrs project aims to make Rust a fully supported language in GCC. It is fully self-hosting and can be built from source. Once accepted, it will be one of the languages you get when you build GCC.
https://github.com/Rust-GCC/gccrs
When gccrs is ready, it will address all the above objections.
Linux faces the same issues. Today, Rust is optional in Linux and can be skipped on any platform not supported in LLVM and rustc. For Rust to become mandatory in Linux, gccrs is going to be required (for some platforms).
> the release cycles of Rust are not compatible with the NetBSD ones
I do not fully grasp the objection here. Obviously NetBSD would not be forced to use any Rust features they cannot compile. And using gccrs for the NetBSD kernel would not prevent them from bundling LLVM and rustc as well if they want.
Anyway, I am not advocating the use of Rust in NetBSD. I am merely pointing out that solutions to the issues raised are being worked on.
https://github.com/rust-lang/rust/pull/151156
This means that you will be able to use either GCC or LLVM to build your Rust code with rustc (the main Rust compiler). That means you can compile your Rust for any platform that GCC supports.
This only addresses the first point in the blog post (architecture support) but it is an interesting development.