Oxalica's Rust overlay has more complete examples of `shell.nix` (and cross compilation) under its
[`examples` directory](https://github.com/oxalica/rust-overlay/tree/e53e8853aa7b0688bc270e9e6a681d22e01cf299/examples).

### Using Rust nightly in a derivation with `buildRustPackage` {#using-rust-nightly-in-a-derivation-with-buildrustpackage}

You can also use Rust nightly to build rust packages using `makeRustPlatform`.
The below snippet demonstrates invoking `buildRustPackage` with a Rust toolchain from oxalica's overlay:

```nix
with import <nixpkgs> {
  overlays = [
    (import (fetchTarball "https://github.com/oxalica/rust-overlay/archive/master.tar.gz"))
  ];
};
let
  rustPlatform = makeRustPlatform {
    cargo = rust-bin.selectLatestNightlyWith (toolchain: toolchain.default);
    rustc = rust-bin.selectLatestNightlyWith (toolchain: toolchain.default);
  };
in

rustPlatform.buildRustPackage (finalAttrs: {
  pname = "ripgrep";
  version = "14.1.1";

  src = fetchFromGitHub {
    owner = "BurntSushi";
    repo = "ripgrep";
    tag = finalAttrs.version;
    hash = "sha256-gyWnahj1A+iXUQlQ1O1H1u7K5euYQOld9qWm99Vjaeg=";
  };

  cargoHash = "sha256-9atn5qyBDy4P6iUoHFhg+TV6Ur71fiah4oTJbBMeEy4=";

  # Tests require network access. Skipping.
  doCheck = false;

  meta = {
    description = "Fast line-oriented regex search tool, similar to ag and ack";
    homepage = "https://github.com/BurntSushi/ripgrep";
    license = with lib.licenses; [
      mit
      unlicense
    ];
    maintainers = with lib.maintainers; [ ];
  };
})
```

Follow the below steps to try that snippet.
1. save the above snippet as `default.nix` in that directory
2. cd into that directory and run `nix-build`

Fenix also has examples with `buildRustPackage`,
[crane](https://github.com/ipetkov/crane),
[naersk](https://github.com/nix-community/naersk),
and cross compilation in its [Examples](https://github.com/nix-community/fenix#examples) section.

## Using `git bisect` on the Rust compiler {#using-git-bisect-on-the-rust-compiler}

Sometimes an upgrade of the Rust compiler (`rustc`) will break a
downstream package.  In these situations, being able to `git bisect`
the `rustc` version history to find the offending commit is quite
useful.  Nixpkgs makes it easy to do this.

First, roll back your nixpkgs to a commit in which its `rustc` used