README.org

lang/rust

Table of Contents

• Description
  • Module Flags
  • Plugins
  • Hacks
• Prerequisites
• Features
  • LSP support (rls or rust-analyzer)
  • Format on save
  • Keybinds
• Configuration
  • Enable RLS by default
  • Enabling elgot support for Rust
• Troubleshooting
  • [[#errore0670-async-fn-is-not-permitted-in-the-2015-edition][error[E0670]: `async fn` is not permitted in the 2015 edition]]

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

Module Flags

• +lsp to add support Language server protocol. Will use the first of rust-analyzer or rls (in that order).

Plugins

• rustic
• racer* (unless +lsp)

Hacks

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

Prerequisites

This module requires rust, which can be acquired through rustup:

curl https://sh.rustup.rs -sSf | sh

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 enabled will need racer: cargo +nightly install racer (with requires rust nightly edition).
• Users with +lsp enabled will need:
  • rust-analyzer or rls
• To use The following commands require:
  • cargo-process-check: cargo install cargo-check
  • cargo-process-clippy: rustup component add clippy-preview

Features

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.

Format on save

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

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 b o	cargo outdated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

Configuration

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:

;; in $DOOMDIR/config.el
(after! rustic
  (setq rustic-lsp-server 'rls))

Enabling elgot support for Rust

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

Troubleshooting

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.