rustc: 1.30.1 -> 1.31.0

[Mic92]

Motivation for this change

• aarch64-linux
• x86_64-linux
• x86_64-darwin

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[Mic92]

I am looking for someone who wants to volunteer for macOS.
For testing I would recommend to build a rust package such as fd and test it.

[grahamc]

on darwin: rustc 1.31 built fine, and I built the rust / cargo package fd and that worked fine, too :)

[Mic92]

pushed to staging: 3a5b4a6

[djahandarie]

@Mic92 Thanks for this! Is there someone that should be cc'd to make the staging->master merge happen, or is that process fairly automated/alive on its own at this point?

[Mic92]

It is a manual task. Currently staging-next is under stabilization: #51444
This pull request is not included there, so it will be in the next round.
If you want to use rustc right now, you can use either the mozilla-overlay,
rustup or override rustc.src in your packageOverrides/overlay.