rust-analyzer/docs/user

The main interface to rust-analyzer is the LSP implementation. To install lsp server, use cargo xtask install --server, which is a shorthand for cargo install --package ra_lsp_server. The binary is named ra_lsp_server, you should be able to use it with any LSP-compatible editor. We use custom extensions to LSP, so special client-side support is required to take full advantage of rust-analyzer. This repository contains support code for VS Code and Emacs.

Rust Analyzer needs sources of rust standard library to work, so you might need to execute

$ rustup component add rust-src

See ./features.md document for a list of features that are available.

VS Code

Prerequisites:

In order to build the VS Code plugin, you need to have node.js and npm with a minimum version of 10 installed. Please refer to node.js and npm documentation for installation instructions.

You will also need the most recent version of VS Code: we don't try to maintain compatibility with older versions yet.

The experimental VS Code plugin can then be built and installed by executing the following commands:

$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
$ cd rust-analyzer
$ cargo xtask install

The automatic installation is expected to just work for common cases, if it doesn't, report bugs!

If you have an unusual setup (for example, code is not in the PATH), you should adapt these manual installation instructions:

$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
$ cd rust-analyzer
$ cargo install --path ./crates/ra_lsp_server/ --force --locked
$ cd ./editors/code
$ npm install
$ ./node_modules/vsce/out/vsce package
$ code --install-extension ./ra-lsp-0.0.1.vsix

It's better to remove existing Rust plugins to avoid interference.

Beyond basic LSP features, there are some extension commands which you can invoke via Ctrl+Shift+P or bind to a shortcut. See ./features.md for details.

For updates, pull the latest changes from the master branch, run cargo xtask install again, and restart VS Code instance. See microsoft/vscode#72308 for why a full restart is needed.

VS Code Remote

You can also use rust-analyzer with the Visual Studio Code Remote extensions (Remote SSH, Remote WSL, Remote Containers). In this case, however, you have to manually install the .vsix package:

1. Build the extension on the remote host using the instructions above (ignore the error if code cannot be found in your PATH: VSCode doesn't need to be installed on the remote host).
2. In Visual Studio Code open a connection to the remote host.
3. Open the Extensions View (View > Extensions, keyboard shortcut: Ctrl+Shift+X).
4. From the top-right kebab menu (···) select Install from VSIX...
5. Inside the rust-analyzer directory find the editors/code subdirectory and choose the ra-lsp-0.0.1.vsix file.
6. Restart Visual Studio Code and re-establish the connection to the remote host.

In case of errors please make sure that ~/.cargo/bin is in your PATH on the remote host.

Settings

• rust-analyzer.highlightingOn: enables experimental syntax highlighting.
• rust-analyzer.scopeMappings -- a scheme backed JSON object to tweak Rust Analyzer scopes to TextMate scopes.

   {
       //Will autocomplete keys to available RA scopes. 
       "keyword.unsafe": ["keyword", "keyword.control"],
       //Values are string | TextMateScope | [string | TextMateScope]
       "variable.mut": "variable"
   }
  

• rust-analyzer.enableEnhancedTyping: by default, rust-analyzer intercepts Enter key to make it easier to continue comments. Note that it may conflict with VIM emulation plugin.
• rust-analyzer.raLspServerPath: path to ra_lsp_server executable
• rust-analyzer.enableCargoWatchOnStartup: prompt to install & enable cargo watch for live error highlighting (note, this does not use rust-analyzer)
• rust-analyzer.excludeGlobs: a list of glob-patterns for exclusion (see globset docs for syntax). Note: glob patterns are applied to all Cargo packages and a rooted at a package root. This is not very intuitive and a limitation of a current implementation.
• rust-analyzer.useClientWatching: use client provided file watching instead of notify watching.
• rust-analyzer.cargo-watch.command: cargo-watch command. (e.g: clippy will run as cargo watch -x clippy )
• rust-analyzer.cargo-watch.arguments: cargo-watch check arguments. (e.g: --features="shumway,pdf" will run as cargo watch -x "check --features="shumway,pdf"" )
• rust-analyzer.cargo-watch.ignore: list of patterns for cargo-watch to ignore (will be passed as --ignore)
• rust-analyzer.trace.server: enables internal logging
• rust-analyzer.trace.cargo-watch: enables cargo-watch logging
• RUST_SRC_PATH: environment variable that overwrites the sysroot
• rust-analyzer.featureFlags -- a JSON object to tweak fine-grained behavior:

  {
      // Show diagnostics produced by rust-analyzer itself.
      "lsp.diagnostics": true,
      // Automatically insert `()` and `<>` when completing functions and types.
      "completion.insertion.add-call-parenthesis": true,
      // Enable completions like `.if`, `.match`, etc.
      "completion.enable-postfix": true,
      // Show notification when workspace is fully loaded
      "notifications.workspace-loaded": true,
  }
  

Emacs

Prerequisites:

emacs-lsp, dash and ht packages.

Installation:

• add ra-emacs-lsp.el to load path and require it in init.el
• run lsp in a rust buffer
• (Optionally) bind commands like rust-analyzer-join-lines, rust-analyzer-extend-selection and rust-analyzer-expand-macro to keys, and enable rust-analyzer-inlay-hints-mode to get inline type hints

Vim and NeoVim

• Install coc.nvim by following the instructions at coc.nvim
  • You will need nodejs installed.
  • You may want to include some of the sample vim configurations from here
  • Note that if you use a plugin manager other than vim-plug, you may need to manually checkout the release branch wherever your plugin manager cloned it. Otherwise you will get errors about a missing javascript file.
• Run :CocInstall coc-rust-analyzer to install coc-rust-analyzer, this extension implemented most of the features supported in the VSCode extension:
  • same configurations as VSCode extension, rust-analyzer.raLspServerPath, rust-analyzer.enableCargoWatchOnStartup etc.
  • same commands too, rust-analyzer.analyzerStatus, rust-analyzer.startCargoWatch etc.
  • highlighting and inlay_hints are not implemented yet

Vim and NeoVim Alternative

• Install LanguageClient-neovim by following the instructions here

  • No extra run-time is required as this server is written in Rust
  • The github project wiki has extra tips on configuration

• Configure by adding this to your vim/neovim config file (replacing the existing rust specific line if it exists):

let g:LanguageClient_serverCommands = {
\ 'rust': ['ra_lsp_server'],
\ }

Sublime Text 3

Prequisites:

LSP package.

Installation:

• Invoke the command palette with Ctrl+Shift+P
• Type LSP Settings to open the LSP preferences editor
• Add the following LSP client definition to your settings:

"rust-analyzer": {
    "command": ["ra_lsp_server"],
    "languageId": "rust",
    "scopes": ["source.rust"],
    "syntaxes": [
        "Packages/Rust/Rust.sublime-syntax",
        "Packages/Rust Enhanced/RustEnhanced.sublime-syntax"
    ],
    "initializationOptions": {
      "featureFlags": {
      }
    },
}

• You can now invoke the command palette and type LSP enable to locally/globally enable the rust-analyzer LSP (type LSP enable, then choose either locally or globally, then select rust-analyzer)

• Note that ra_lsp_server binary must be in $PATH for this to work. If it's not the case, you can specify full path to the binary, which is typically .cargo/bin/ra_lsp_server.