:lang rust

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1. Description

This module adds support for the Rust language and integration for its tools, e.g. cargo.

  • Code completion (racer or an LSP server)
  • Syntax checking (flycheck)
  • LSP support (for rust-analyzer and rls) (rustic)
  • Snippets

1.1. Maintainers

This module has no dedicated maintainers. Become a maintainer?

1.2. Module flags

+lsp
Enable LSP support for rustic-mode. Requires :tools lsp and a langserver (supports rust-analyzer and rls).

1.3. Packages

1.4. Hacks

  • rustic has been modified not to automatically install lsp-mode or eglot if they’re missing. Doom expects you to have enabled the :tools lsp module yourself.

2. Prerequisites

2.1. Install

This module requires rustc, which can be acquired through rustup.

2.1.1. Arch Linux

# ⎘
$ pacman -S rustup

See also the Rust article on the Arch Wiki.

Note that when the Rust language has updates, you are to run rustup such that it doesn’t upgrade itself:

# ⎘
$ rustup update --no-self-update

2.1.2. General

# ⎘
$ curl https://sh.rustup.rs -sSf | sh

2.2. Other Requirements

Additional requirements depend on the module’s configuration:

  • If :editor format is enabled, you’ll need rustfmt: $ rustup component add rustfmt-preview.
  • Users without +lsp will need racer: $ cargo +nightly install racer (with requires rust nightly edition).
  • Users with +lsp will need rust-analyzer or rls
  • Using the following commands requires:
    • cargo-process-check: $ cargo install cargo-check
    • cargo-process-clippy: $ rustup component add clippy-preview

3. Usage

3.1. LSP support (rls or rust-analyzer)

This module supports LSP integration. For it to work you’ll need:

  1. Either rust-analyzer or the Rust Language Server installed (e.g. through your OS package manager).
  2. The :tools lsp module enabled.
  3. The +lsp flag on this module enabled.

3.2. Format on save

Enable the :editor format module’s +onsave flag to get formatting on save with rustfmt. No additional configuration is necessary.

3.3. Keybinds

Binding Description
<localleader> b a cargo audit
<localleader> b b cargo build
<localleader> b B cargo bench
<localleader> b c cargo check
<localleader> b C cargo clippy
<localleader> b d cargo doc
<localleader> b n cargo update
<localleader> b o cargo outdated
<localleader> b r cargo run
<localleader> t a cargo test
<localleader> t t run current test

4. TODO Configuration

4.1. Enable RLS by default

If both rls and rust-analyzer are present on your system, rust-analyzer is selected by default. Modify rustic-lsp-server to change the default:

# ⎘
;; add to $DOOMDIR/config.el
(after! rustic
  (setq rustic-lsp-server 'rls))

4.2. Enabling eglot support for Rust

Doom’s :tools lsp module has an +eglot flag. Enable it and this module will use eglot instead.

5. Troubleshooting

5.1. error[E0670]: `async fn` is not permitted in the 2015 edition

You may be seeing this error, despite having edition = "2018" in your Cargo.toml. This error actually originates from rustfmt, which the LSP server tries to invoke on save (if you have rustic-format-on-save or :editor format enabled).

To fix this your project needs a rustfmt.toml with edition = "2018" in it.

6. TODO Appendix

This module has no appendix yet. Write one?