[Lorkki]

> We have already seen early Rust code not compiling with new compiler releases.

I haven't really seen that happen with post-1.0 Rust, which is everything onwards of early 2015. I believe they've since tightened a couple of edge cases due to soundness issues, but nothing worse than that.

Would be interesting to hear about your contrary experiences.

[capitol_]

It happened in the lexical-core crate somewhere in 1.5X. Here is a bug report I got about it with compiler errors listed: https://github.com/cortex/ripasso/issues/219

[eldruin]

This issue is on nightly Rust, not stable. A stable Rust compiler update should never break code.

See: https://doc.rust-lang.org/book/appendix-07-nightly-rust.html

[capitol_]

No, it's on stable rust, maybe you got confused by the bug report talking about the nixos-unstable channel, that has nothing to do with the rust nightly builds, it's the version of nixos that is currently under development.

You can reproduce this yourself with:

  git clone https://github.com/cortex/ripasso.git
  cd ripasso
  git checkout release-0.5.1
  cargo build --locked

On my arch system this fails to build with the same errors as the bug report i got, and my rustc version is:

  $ rustc --version --verbose
  rustc 1.57.0 (f1edd0429 2021-11-29)
  binary: rustc
  commit-hash: f1edd0429582dd29cccacaf50fd134b05593bd9c
  commit-date: 2021-11-29
  host: x86_64-unknown-linux-gnu
  release: 1.57.0
  LLVM version: 13.0.0

[zibzab]

A lot of embedded stuff needs nightly. Or at least, it was like this a year or two ago.

A related issue is that for many companies "stable" means the version shipped with Ubuntu LTS.

[couchand]

Depends on the architecture: ARM for instance is a tier 1 target and you can use stable.

[steveklabnik]

This is true for aarch64, but if you're not doing an embedded-linux style project, it's very likely you'll need nightly for inline assembly, though a significant chunk of that is being stabilized as we speak (though sadly not yet enough for my work...)

[couchand]

Good point. Though you can always link to .S for that last bit, right? I don't mean to tell you your business, I know you folks are doing much more intense stuff than I am. It doesn't surprise me that you'd know exactly what's keeping you from using stable.

[zibzab]

IIRC last time we had issues it was something in the core libraries, not the compiler.

I think it was something as fundamental as Error being changed or moved around.

[eldruin]

You may have started getting deprecation warnings because some methods in the `Error` trait have been deprecated [1] in favor of a different mechanism.

Then, you may have configured warnings to result in compilation errors in your build/project, however, I would argue this situation is not what most people would understand as "code not compiling due to a compiler update".

[1]: https://doc.rust-lang.org/std/error/trait.Error.html

[zibzab]

In my case it failed to build, maybe it was a different problem, maybe the compiler had at some point emitted errors instead of warnings.

I don't remember and it doesn't really matter other than we had build issues and it was unexpected.

[steveklabnik]

Deprecation should be the only change to Error in the last six years. It hasn’t moved. If you ever get a repro would love to hear about it! This kind of thing doesn’t happen at the scale we’re at anymore, if it did there would be an uproar.