Rust

Catalog v8.

Installs rustup with the Cargo, rustc, rustfmt, Clippy, and rust-analyzer commands, plus GCC, pkg-config, and GDB. rustup downloads the Rust toolchains themselves.

Select

[toolchains]
rust = "stable"

Set the default toolchain in the [toolchains] table of limanix.toml and apply the change. The client guide describes the [toolchains] table.

Toolchains

The value names the default toolchain of the development account:

Value	Toolchain
stable, beta, nightly	The newest release of the channel at install time
nightly-2026-10-01	A channel as it was on that date
1.90, 1.90.0	A Rust release

A user service installs the toolchain with the rustfmt, Clippy, rust-analyzer, and rust-src components, then makes it the default. It runs when the VM starts after the value changes, and needs network access to static.rust-lang.org. Until it finishes, Cargo reports that no default toolchain is configured. Follow it with:

systemctl --user status rust-toolchain

A failed download is tried again, after ten seconds at first and then at most every ten minutes. The toolchain uses the minimal profile. The local documentation from rust-docs is not installed.

rustup keeps toolchains in ~/.rustup and Cargo keeps downloaded crates in ~/.cargo; both stay across VM updates. A channel does not move on its own: run rustup update to fetch its newest release. A default that you set with rustup default stays until the value in limanix.toml changes.

Project toolchains

A project selects its own toolchain with a rust-toolchain.toml file, which rustup installs on first use:

[toolchain]
channel = "1.89.0"
components = ["rustfmt", "clippy"]

See overrides for the order in which rustup chooses a toolchain.

Use

Inside the VM, run from a directory that contains Cargo.toml:

cargo build
cargo test
cargo fmt
cargo clippy

Debug the resulting programs with rust-gdb. Commands from cargo install go to ~/.cargo/bin, which comes first on PATH.

Native dependencies

Crates that bind to system libraries, such as openssl-sys, build with the included GCC and pkg-config. They also need the library's headers and a pkg-config search path; see Handle native dependencies.

Editor support

The module offers rust-analyzer to editors that support the Language Server Protocol. rustup runs the rust-analyzer of the project's toolchain. The server matches the compiler. See Editor integration and the rust-analyzer editor setup.

Configuration and integration

Boundary	Contract
Public option	lmx.rust.toolchain, default stable; the client sets it from [toolchains] rust
Public capability	lmx.capabilities.languageSupport.tools.rust-analyzer; Rust parser
Personal state	~/.rustup toolchains, ~/.cargo crates and commands, project build output
Integration	Declares rust-analyzer without enabling an editor; a user-supplied provider replaces the rustup proxy
Services	rust-toolchain, a user service of the development account that installs the declared toolchain

Corner cases

Case	Behavior or next step
No network when the VM starts	Cargo has no default toolchain; the service retries, or restart it with systemctl --user restart rust-toolchain
Project needs another toolchain	Add rust-toolchain.toml; rustup installs that toolchain on first use
A channel should move	Run rustup update; the module installs a toolchain only when the value changes
Native dependency fails	GCC and pkg-config are present; provide the required library and its search path
Disk fills with toolchains	List them with rustup toolchain list, remove one with rustup toolchain uninstall