yep. I was referring to "If not via rustup, I would expect everything that can be fetched via rustup to be in the package repo."
What I meant was: instead of users installing rustup and then installing all the toolchains through rustup (`rustup install stable`, `rustup install arm-linux-gnueabi`, `rustup install clippy`), they can also install `rustc`, `rustc-arm-linux-androideabi` (cross toolchain), `rust-clippy` through the package manager (apt-get install or whatever). Cross compile toolchains for C are often similarly packaged (gcc-cross, etc).
The way I understand it (again, unofficial, not sure if it's the actual plan :) ), we would like most users to use rustup as the single source of truth for Rust. This won't work for some setups, including distro packaging, and I'm not sure what the plan is there, but I'd expect it to be something similar to what I wrote above. The binaries that rustup downloads will always be available, regardless, if you are okay with downloading a signed binary once and internally distributing it. But I don't expect it will come to that. Though right now Rust hasn't yet gotten all the ducks in a row for proper distro packaging, so that's all you can use. This is being actively worked on, and IIRC all the major work is done (?)
If rustup isn't part of the base (distro-provided) packages, it will definitely be part of some popular add-on repos though.
I was super annoyed when I found out Ubuntu ships an ancient node and nvm doesn't exist in the distro. I would love for rustup to exist in the distro, but we should (and probably are doing so) plan for cases without it.
rustup.rs already does check against Rust release signing keys, so that part is at least trivial to integrate.
I saw that (which is good!), but that's actually a step removed from what I was referring to. If a repo provides rustup, the rustup package itself is verified, which is useful way to get rustup itself compared to the fairly prominent and obvious suggestion at Rust's download page[1], which is "$ curl -sSf https://static.rust-lang.org/rustup.sh | sh". Targeting rustup.sh itself would actually be a fairly effective attack, since it's the tool that does the download, that verifies the binary, and that is often (I assume) run in a transient manner, since it's suggested you pipe the web response directly to an interpreter. If it was attached successfully, we would all be lucky if all they did was do nefarious stuff directly from rustup.sh, and not try to install their own,slightly changed, builds of the compiler[2].
1: https://www.rust-lang.org/downloads.html
2: http://www.ouah.org/acmken.htm is a classic, and kind of a worst case scenario.
My only point in this part of the thread, which has little to do with the "we use gcc because it's stable" argument, is just that you shouldn't expect the distros the change how they ship just for rust, which expecting them to use rustup would be (in what I think are the majority of cases). If rust as a community expects rustup to be what distros use, then I think there's a disconnect from reality happening, and it's worth looking at because if that's important to rust (which I don't know, honestly), then it should be addressed. I understand that you may not know if this is the actual plan.
Note: I don't particularly think rust requirly a nightly build for this is important. Organizations will look at it and assess it as a tool as needed, and if they think it's worth using and they want to roll it out, they'll package it in some manner if that's important to them (and that might just be a tarball, at the simpler level), or they won't if it's not. Stability is important, but at the tooling level, it's much less so, and being able to make sure all yours devs are in lockstep is probably more important (for large orgs).