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Rust

The languages.rust module provides comprehensive support for Rust development, offering flexible toolchain management through two distinct approaches.

Getting started

Enable Rust support in your devenv.nix:

{
  languages.rust.enable = true;
}

This will provide a complete Rust development environment with rustc, cargo, clippy, rustfmt, and rust-analyzer.

Toolchain management

devenv supports two approaches for managing Rust toolchains:

1. nixpkgs channel (default)

The nixpkgs channel is easy to set up and uses the Rust version currently available in your nixpkgs revision. However, it's limited to the version in nixpkgs.

{
  languages.rust = {
    enable = true;
    channel = "nixpkgs"; # default
  };
}

2. rust-overlay channels

For more control over versions and features, use the stable, beta, or nightly channels powered by rust-overlay:

  • ✅ Rustup-like channel selection
  • ✅ Access to any Rust version
  • ✅ Support for cross-compilation targets
{
  languages.rust = {
    enable = true;
    channel = "stable";
    version = "1.81.0"; # or "latest"
  };
}

Examples

Basic setup with latest stable

{
  languages.rust = {
    enable = true;
    channel = "stable";
  };
}

Nightly Rust with extra components

{
  languages.rust = {
    enable = true;
    channel = "nightly";
    components = [ "rustc" "cargo" "clippy" "rustfmt" "rust-analyzer" "miri" ];
  };
}

Cross-compilation setup

{
  languages.rust = {
    enable = true;
    channel = "stable";
    targets = [ "wasm32-unknown-unknown" "aarch64-unknown-linux-gnu" ];
  };
}

Minimal installation

{
  languages.rust = {
    enable = true;
    channel = "stable";
    components = [ "rustc" "cargo" "rust-std" ];
  };
}

Using rust-toolchain.toml

If your project uses a rust-toolchain.toml file, devenv can automatically configure the toolchain from it:

{
  languages.rust = {
    enable = true;
    toolchainFile = ./rust-toolchain.toml;
  };
}

Example rust-toolchain.toml: 

[toolchain]
channel = "stable"
components = ["rustfmt", "clippy"]
profile = "minimal"

Integration with other tools

Git hooks

Rust tools integrate seamlessly with git hooks:

{
  languages.rust.enable = true;

  git-hooks.hooks = {
    rustfmt.enable = true;
    clippy.enable = true;
  };
}

Options

languages.rust.enable

Whether to enable tools for Rust development.

Type: boolean

Default:

false

Example:

true

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.channel

The rustup toolchain to install.

Type: one of “nixpkgs”, “stable”, “beta”, “nightly”

Default:

"nixpkgs"

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.components

List of Rustup components to install. Defaults to those available in nixpkgs.

Type: list of string

Default:

[ "rustc" "cargo" "clippy" "rustfmt" "rust-analyzer" ]

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.cranelift.enable

Use Cranelift as the codegen backend for dev builds.

Cranelift compiles significantly faster than LLVM at the cost of less optimized output. Requires the nightly channel.

Type: boolean

Default:

false

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.cranelift.excludePackages

List of crate names that should use the LLVM backend instead of Cranelift.

Generates per-package overrides in .cargo/config.toml.

Type: list of string

Default:

[ ]

Example:

[
  "aws-lc-sys"
  "aws-lc-rs"
  "rustls"
]

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.cranelift.forceBuildScriptsLlvm

Force build scripts and proc macros to use the LLVM backend.

Some build scripts may not work with Cranelift. Enable this to fall back to LLVM for build scripts while keeping Cranelift for regular code.

Type: boolean

Default:

false

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.import

Import a Cargo project using cargo2nix.

This function takes a path to a directory containing a Cargo.toml file and returns a derivation that builds the Rust project using cargo2nix.

Example usage:

let
mypackage = config.languages.rust.import ./path/to/cargo/project {};
in {
languages.rust.enable = true;
packages = [ mypackage ];
}

Type: function that evaluates to a(n) function that evaluates to a(n) package

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.lld.enable

Use lld as the linker.

lld is LLVM’s linker and is the recommended fast linker for Darwin. Works on both Linux and macOS.

Type: boolean

Default:

false

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.lsp.enable

Whether to enable Rust Language Server.

Type: boolean

Default:

true

Example:

true

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.lsp.package

The Rust language server package to use.

Type: package

Default: Depends on the configured toolchain:

  • nixpkgs channel: pkgs.rust-analyzer.
  • non-nixpkgs channel: the rust-analyzer component from the rust-overlay toolchain, with a fallback to pkgs.rust-analyzer if not present in the manifest.
  • toolchainFile: the aggregated toolchain package derived from the file.

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.mold.enable

Use mold as the linker.

mold is a faster drop-in replacement for existing Unix linkers. It is several times quicker than the LLVM lld linker.

Type: boolean

Default:

false

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.rustflags

Extra flags to pass to the Rust compiler.

Type: string

Default:

""

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.targets

List of extra targets to install. Defaults to only the native target.

Type: list of string

Default:

[ ]

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain

Rust component packages. May optionally define additional components, for example miri.

Type: open submodule of attribute set of package

Default:

nixpkgs

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain.cargo

cargo package

Type: null or package

Default:

pkgs.cargo

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain.clippy

clippy package

Type: null or package

Default:

pkgs.clippy

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain.rust-analyzer

rust-analyzer package

Type: null or package

Default:

pkgs.rust-analyzer

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain.rustc

rustc package

Type: null or package

Default:

pkgs.rustc

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchain.rustfmt

rustfmt package

Type: null or package

Default:

pkgs.rustfmt

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchainFile

Path to a rust-toolchain or rust-toolchain.toml file for automatic toolchain configuration.

When set, devenv will use rust-overlay’s fromRustupToolchainFile to automatically configure the toolchain based on the file contents (channel, components, targets, profile).

This follows the standard Rust toolchain file format documented at: https://rust-lang.github.io/rustup/overrides.html#the-toolchain-file

Cannot be used together with manual channel or version configuration.

Example:

languages.rust.toolchainFile = ./rust-toolchain.toml;

Type: null or absolute path

Default:

null

Example:

./rust-toolchain.toml

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.toolchainPackage

The aggregated toolchain package, which includes the configured components and targets. This is automatically set based on the channel and components configuration.

Type: package

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.version

Which version of rust to use, this value could be latest,1.81.0, 2021-01-01. Only works when languages.rust.channel is NOT nixpkgs.

Type: string

Default:

"latest"

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix

languages.rust.wild.enable

Use wild as the linker.

wild is a very fast linker for Linux.

Type: boolean

Default:

false

Declared by: - https://github.com/cachix/devenv/blob/main/src/modules/languages/rust.nix