jaxx / rls-vscode

RLS-based plugin for VSCode

Rust support for Visual Studio Code

Adds language support for Rust to Visual Studio Code. Supports:

• code completion
• jump to definition, peek definition, find all references, symbol search
• types and documentation on hover
• code formatting
• refactoring (rename, deglob)
• error squiggles and apply suggestions from errors
• snippets
• build tasks

Rust support is powered by the Rust Language Server (RLS). If you don't have it installed, the extension will install the RLS for you.

This extension is built and maintained by the RLS team, part of the Rust Developer Tools team. It is the reference client implementation for the RLS. Our focus is on providing a stable, high quality extension that makes best use of the RLS. We aim to support as many features as possible, but our priority is supporting the essential features as well as possible.

For support, please file an issue on the repo or talk to us in #rust-dev-tools on IRC (Mozilla servers). There is also some troubleshooting and debugging advice.

Contributing code, tests, documentation, and bug reports is appreciated! For more details on building and debugging, etc., see contributing.md.

Quick start

• Install rustup (Rust toolchain manager).
• Install this extension from the VSCode Marketplace (or by entering ext install rust at the command palette).
• Open a Rust project (File > Open Folder...). Open the folder for the whole project (i.e., the folder containing 'Cargo.toml'), not the 'src' folder.
• The extension will start when you open a Rust file. You'll be prompted to install the RLS. Once installed, the RLS should start building your project.

Configuration

This extension provides some options into VSCode's configuration settings. These options have names which start with rust.. You can find the settings under File > Preferences > Settings, they all have Intellisense help.

Some highlights:

• rust.show_warnings - set to false to silence warnings in the editor.
• rust.build_lib - if you have both a binary and library in your crate, set to true to build the library.
• rust.build_bin - if you have multiple binaries, you can specify which to build using this option.
• rust.cfg_test - build and index test code (i.e., code with #[cfg(test)]/#[test])
• rust.workspace_mode - experimental cargo workspace support. Note that using this feature will slow down builds significantly and may be broken in surprising and undocumented ways.

Features

Commands

Commands can be found in the command palette (ctrl + shift + p). We provide the following commands:

• deglob - replace a glob (*) import with an explicit import. E.g., replace use foo::*; with use foo::{bar, baz};. Select only the * when running the command.

Snippets

Snippets are code templates which expand into common boilerplate. Intellisense includes snippet names as options when you type; select one by pressing 'enter'. You can move to the next 'hole' in the template by pressing 'tab'. We provide the following snippets:

• for - a for loop
• unimplemented
• unreachable
• println
• macro_rules - declare a macro
• if let Option - an if let statement for executing code only in the Some case.
• spawn - spawn a thread

Tasks

The plugin provides tasks for building, running, and testing using the relevant cargo commands. You can build using ctrl + shift + b. Access other tasks via Run tasks in the command palette.

The plugin writes these into tasks.json. The plugin will not overwrite existing tasks, so you can customise these tasks. To refresh back to the defaults, delete tasks.json and restart VSCode.

Format on save

To enable formatting on save, you need to set the editor.formatOnSave setting to true. Find it under File > Preferences > Settings.

Requirements

• Rustup,
• A nightly Rust toolchain (the extension will configure this for you, with permission),
• RLS, rust-src, and rust-analysis components (the extension will install these for you, with permission).

Implementation

This extension almost exclusively uses the RLS for its feature support (syntax highlighting, snippets, and build tasks are provided client-side). The RLS uses the Rust compiler (rustc) to get data about Rust programs. It uses Cargo to manage building. Both Cargo and rustc are run in-process by the RLS. Formatting and code completion are provided by rustfmt and Racer, again both of these are run in-process by the RLS.