Debian does it the hard way, by making a Debian package for every crates-io dependency used and patching Rust programs to use Debian's forked deps instead. It's seems like a massive pain for them, and has zero value for Rust end users, since normal Cargo won't use any of this.
Rust often carries its own bugfixes to its LLVM version (before they're accepted upstream). Debian unbundles LLVM from Rust and makes Rust use Debian's LLVM, which creates a risk of undoing Rust's bugfixes and causing miscompilations.
I don't think anyone should be using Debian-packaged Rust. Debian's and Rust's policies are fundamentally incompatible. This results in Debian having a hopelessly outdated inferior package that is a pain for both Debian users and the rest of the Rust ecosystem.
At the most recent RustConf William Brown spoke about how OpenSUSE deals with Rust[1]. If I remember correctly from his talk they started doing something very similar to Debian and then eventually settled on "just use rustup". I wish I had taken better notes because there was more nuance to the history there but I think they'll release the videos of the talks soon.
We're both talking about the same elephant but we're obviously touching different ends of it. The end I'm touching smells really bad.
The fact that so many distros have to go extremely far out of their way, breaking their standard processes, shows that Rust is unique in it's tomfoolery. You guys are advocating for the tail to wag the dog.
