6 :source-highlighter: rouge
9 // Master copy of this document lives in the https://github.com/rust-analyzer/rust-analyzer repository
11 At its core, rust-analyzer is a *library* for semantic analysis of Rust code as it changes over time.
12 This manual focuses on a specific usage of the library -- running it as part of a server that implements the
13 https://microsoft.github.io/language-server-protocol/[Language Server Protocol] (LSP).
14 The LSP allows various code editors, like VS Code, Emacs or Vim, to implement semantic features like completion or goto definition by talking to an external language server process.
19 To improve this document, send a pull request: +
20 https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/manual.adoc[https://github.com/rust-analyzer/.../manual.adoc]
22 The manual is written in https://asciidoc.org[AsciiDoc] and includes some extra files which are generated from the source code. Run `cargo test` and `cargo test -p xtask` to create these and then `asciidoctor manual.adoc` to create an HTML copy.
26 If you have questions about using rust-analyzer, please ask them in the https://users.rust-lang.org/c/ide/14["`IDEs and Editors`"] topic of Rust users forum.
30 In theory, one should be able to just install the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>> and have it automatically work with any editor.
31 We are not there yet, so some editor specific setup is required.
33 Additionally, rust-analyzer needs the sources of the standard library.
34 If the source code is not present, rust-analyzer will attempt to install it automatically.
36 To add the sources manually, run the following command:
39 $ rustup component add rust-src
44 This is the best supported editor at the moment.
45 The rust-analyzer plugin for VS Code is maintained
46 https://github.com/rust-analyzer/rust-analyzer/tree/master/editors/code[in tree].
48 You can install the latest release of the plugin from
49 https://marketplace.visualstudio.com/items?itemName=matklad.rust-analyzer[the marketplace].
51 Note that the plugin may cause conflicts with the
52 https://marketplace.visualstudio.com/items?itemName=rust-lang.rust[official Rust plugin].
53 It is recommended to disable the Rust plugin when using the rust-analyzer extension.
55 By default, the plugin will prompt you to download the matching version of the server as well:
57 image::https://user-images.githubusercontent.com/9021944/75067008-17502500-54ba-11ea-835a-f92aac50e866.png[]
61 To disable this notification put the following to `settings.json`
65 { "rust-analyzer.updates.askBeforeDownload": false }
69 The server binary is stored in:
71 * Linux: `~/.config/Code/User/globalStorage/matklad.rust-analyzer`
72 * Linux (Remote, such as WSL): `~/.vscode-server/data/User/globalStorage/matklad.rust-analyzer`
73 * macOS: `~/Library/Application\ Support/Code/User/globalStorage/matklad.rust-analyzer`
74 * Windows: `%APPDATA%\Code\User\globalStorage\matklad.rust-analyzer`
76 Note that we only support two most recent versions of VS Code.
80 The extension will be updated automatically as new versions become available.
81 It will ask your permission to download the matching language server version binary if needed.
85 We ship nightly releases for VS Code.
86 To help us out with testing the newest code and follow the bleeding edge of our `master`, please use the following config:
90 { "rust-analyzer.updates.channel": "nightly" }
93 You will be prompted to install the `nightly` extension version.
94 Just click `Download now` and from that moment you will get automatic updates every 24 hours.
96 If you don't want to be asked for `Download now` every day when the new nightly version is released add the following to your `settings.json`:
99 { "rust-analyzer.updates.askBeforeDownload": false }
102 NOTE: Nightly extension should **only** be installed via the `Download now` action from VS Code.
104 ==== Manual installation
106 Alternatively, procure both `rust-analyzer.vsix` and your platform's matching `rust-analyzer-{platform}`, for example from the
107 https://github.com/rust-analyzer/rust-analyzer/releases[releases] page.
109 Install the extension with the `Extensions: Install from VSIX` command within VS Code, or from the command line via:
112 $ code --install-extension /path/to/rust-analyzer.vsix
115 Copy the `rust-analyzer-{platform}` binary anywhere, then add the path to your settings.json, for example:
118 { "rust-analyzer.server.path": "~/.local/bin/rust-analyzer-linux" }
121 ==== Building From Source
123 Alternatively, both the server and the Code plugin can be installed from source:
127 $ git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
128 $ cargo xtask install
131 You'll need Cargo, nodejs and npm for this.
133 Note that installing via `xtask install` does not work for VS Code Remote, instead you'll need to install the `.vsix` manually.
135 If you're not using Code, you can compile and install only the LSP server:
139 $ cargo xtask install --server
144 Here are some useful self-diagnostic commands:
146 * **Rust Analyzer: Show RA Version** shows the version of `rust-analyzer` binary.
147 * **Rust Analyzer: Status** prints some statistics about the server, and dependency information for the current file.
148 * To enable server-side logging, run with `env RA_LOG=info` and see `Output > Rust Analyzer Language Server` in VS Code's panel.
149 * To log project loading (sysroot & `cargo metadata`), set `RA_LOG=project_model=debug`.
150 * To log all LSP requests, add `"rust-analyzer.trace.server": "verbose"` to the settings and look for `Rust Analyzer Language Server Trace` in the panel.
151 * To enable client-side logging, add `"rust-analyzer.trace.extension": true` to the settings and open `Output > Rust Analyzer Client` in the panel.
153 === rust-analyzer Language Server Binary
155 Other editors generally require the `rust-analyzer` binary to be in `$PATH`.
156 You can download the pre-built binary from the https://github.com/rust-analyzer/rust-analyzer/releases[releases] page.
157 Typically, you then need to rename the binary for your platform, e.g. `rust-analyzer-mac` if you're on Mac OS, to `rust-analyzer` and make it executable in addition to moving it into a directory in your `$PATH`.
159 On Linux to install the `rust-analyzer` binary into `~/.local/bin`, this commands could be used
163 $ curl -L https://github.com/rust-analyzer/rust-analyzer/releases/latest/download/rust-analyzer-linux -o ~/.local/bin/rust-analyzer
164 $ chmod +x ~/.local/bin/rust-analyzer
167 Ensure `~/.local/bin` is listed in the `$PATH` variable.
169 Alternatively, you can install it from source using the command below.
170 You'll need the latest stable version of the Rust toolchain.
174 $ git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
175 $ cargo xtask install --server
178 If your editor can't find the binary even though the binary is on your `$PATH`, the likely explanation is that it doesn't see the same `$PATH` as the shell, see https://github.com/rust-analyzer/rust-analyzer/issues/1811[this issue].
179 On Unix, running the editor from a shell or changing the `.desktop` file to set the environment should help.
183 `rust-analyzer` is available in `rustup`, but only in the nightly toolchain:
187 $ rustup +nightly component add rust-analyzer-preview
192 The `rust-analyzer` binary can be installed from the repos or AUR (Arch User Repository):
194 - https://www.archlinux.org/packages/community/x86_64/rust-analyzer/[`rust-analyzer`] (built from latest tagged source)
195 - https://aur.archlinux.org/packages/rust-analyzer-git[`rust-analyzer-git`] (latest Git version)
197 Install it with pacman, for example:
201 $ pacman -S rust-analyzer
206 Note this excellent https://robert.kra.hn/posts/2021-02-07_rust-with-emacs/[guide] from https://github.com/rksm[@rksm].
208 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
210 Emacs support is maintained as part of the https://github.com/emacs-lsp/lsp-mode[Emacs-LSP] package in https://github.com/emacs-lsp/lsp-mode/blob/master/lsp-rust.el[lsp-rust.el].
212 1. Install the most recent version of `emacs-lsp` package by following the https://github.com/emacs-lsp/lsp-mode[Emacs-LSP instructions].
213 2. Set `lsp-rust-server` to `'rust-analyzer`.
214 3. Run `lsp` in a Rust buffer.
215 4. (Optionally) bind commands like `lsp-rust-analyzer-join-lines`, `lsp-extend-selection` and `lsp-rust-analyzer-expand-macro` to keys.
219 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
220 Not needed if the extension can install/update it on its own, coc-rust-analyzer is one example.
222 The are several LSP client implementations for vim or neovim:
224 ==== coc-rust-analyzer
226 1. Install coc.nvim by following the instructions at
227 https://github.com/neoclide/coc.nvim[coc.nvim]
229 2. Run `:CocInstall coc-rust-analyzer` to install
230 https://github.com/fannheyward/coc-rust-analyzer[coc-rust-analyzer],
231 this extension implements _most_ of the features supported in the VSCode extension:
232 * automatically install and upgrade stable/nightly releases
233 * same configurations as VSCode extension, `rust-analyzer.server.path`, `rust-analyzer.cargo.features` etc.
234 * same commands too, `rust-analyzer.analyzerStatus`, `rust-analyzer.ssr` etc.
235 * inlay hints for variables and method chaining, _Neovim Only_
236 * semantic highlighting is not implemented yet
238 Note: for code actions, use `coc-codeaction-cursor` and `coc-codeaction-selected`; `coc-codeaction` and `coc-codeaction-line` are unlikely to be useful.
240 ==== LanguageClient-neovim
242 1. Install LanguageClient-neovim by following the instructions
243 https://github.com/autozimu/LanguageClient-neovim[here]
244 * The GitHub project wiki has extra tips on configuration
246 2. Configure by adding this to your vim/neovim config file (replacing the existing Rust-specific line if it exists):
250 let g:LanguageClient_serverCommands = {
251 \ 'rust': ['rust-analyzer'],
257 Install YouCompleteMe by following the instructions
258 https://github.com/ycm-core/YouCompleteMe#installation[here].
260 rust-analyzer is the default in ycm, it should work out of the box.
264 To use the LSP server in https://github.com/dense-analysis/ale[ale]:
268 let g:ale_linters = {'rust': ['analyzer']}
273 NeoVim 0.5 (not yet released) has built-in language server support.
274 For a quick start configuration of rust-analyzer, use https://github.com/neovim/nvim-lspconfig#rust_analyzer[neovim/nvim-lspconfig].
275 Once `neovim/nvim-lspconfig` is installed, use `+lua require'lspconfig'.rust_analyzer.setup({})+` in your `init.vim`.
277 You can also pass LSP settings to the server:
282 local nvim_lsp = require'lspconfig'
284 local on_attach = function(client)
285 require'completion'.on_attach(client)
288 nvim_lsp.rust_analyzer.setup({
291 ["rust-analyzer"] = {
293 importMergeBehavior = "last",
294 importPrefix = "by_self",
297 loadOutDirsFromCheck = true
308 See https://sharksforarms.dev/posts/neovim-rust/ for more tips on getting started.
312 vim-lsp is installed by following https://github.com/prabirshrestha/vim-lsp[the plugin instructions].
313 It can be as simple as adding this line to your `.vimrc`:
317 Plug 'prabirshrestha/vim-lsp'
320 Next you need to register the `rust-analyzer` binary.
321 If it is available in `$PATH`, you may want to add this to your `.vimrc`:
325 if executable('rust-analyzer')
326 au User lsp_setup call lsp#register_server({
327 \ 'name': 'Rust Language Server',
328 \ 'cmd': {server_info->['rust-analyzer']},
329 \ 'whitelist': ['rust'],
334 There is no dedicated UI for the server configuration, so you would need to send any options as a value of the `initialization_options` field, as described in the <<_configuration,Configuration>> section.
335 Here is an example of how to enable the proc-macro support:
339 if executable('rust-analyzer')
340 au User lsp_setup call lsp#register_server({
341 \ 'name': 'Rust Language Server',
342 \ 'cmd': {server_info->['rust-analyzer']},
343 \ 'whitelist': ['rust'],
344 \ 'initialization_options': {
346 \ 'loadOutDirsFromCheck': v:true,
358 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
360 You also need the `LSP` package.
363 1. If you've never installed a Sublime Text package, install Package Control:
364 * Open the command palette (Win/Linux: `ctrl+shift+p`, Mac: `cmd+shift+p`)
365 * Type `Install Package Control`, press enter
366 2. In the command palette, run `Package control: Install package`, and in the list that pops up, type `LSP` and press enter.
368 Finally, with your Rust project open, in the command palette, run `LSP: Enable Language Server In Project` or `LSP: Enable Language Server Globally`, then select `rust-analyzer` in the list that pops up to enable the rust-analyzer LSP.
369 The latter means that rust-analyzer is enabled by default in Rust projects.
371 If it worked, you should see "rust-analyzer, Line X, Column Y" on the left side of the bottom bar, and after waiting a bit, functionality like tooltips on hovering over variables should become available.
373 If you get an error saying `No such file or directory: 'rust-analyzer'`, see the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>> section on installing the language server binary.
377 GNOME Builder 3.37.1 and newer has native `rust-analyzer` support.
378 If the LSP binary is not available, GNOME Builder can install it when opening a Rust file.
383 Support for Rust development in the Eclipse IDE is provided by link:https://github.com/eclipse/corrosion[Eclipse Corrosion].
384 If available in PATH or in some standard location, `rust-analyzer` is detected and powers editing of Rust files without further configuration.
385 If `rust-analyzer` is not detected, Corrosion will prompt you for configuration of your Rust toolchain and language server with a link to the __Window > Preferences > Rust__ preference page; from here a button allows to download and configure `rust-analyzer`, but you can also reference another installation.
386 You'll need to close and reopen all .rs and Cargo files, or to restart the IDE, for this change to take effect.
390 **Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/rust-analyzer/src/config.rs[config.rs]
392 The <<_installation,Installation>> section contains details on configuration for some of the editors.
393 In general `rust-analyzer` is configured via LSP messages, which means that it's up to the editor to decide on the exact format and location of configuration files.
395 Some clients, such as <<vs-code,VS Code>> or <<coc-rust-analyzer,COC plugin in Vim>> provide `rust-analyzer` specific configuration UIs. Others may require you to know a bit more about the interaction with `rust-analyzer`.
397 For the later category, it might help to know that the initial configuration is specified as a value of the `initializationOptions` field of the https://microsoft.github.io/language-server-protocol/specifications/specification-current/#initialize[`InitializeParams` message, in the LSP protocol].
398 The spec says that the field type is `any?`, but `rust-analyzer` is looking for a JSON object that is constructed using settings from the list below.
399 Name of the setting, ignoring the `rust-analyzer.` prefix, is used as a path, and value of the setting becomes the JSON property value.
401 For example, a very common configuration is to enable proc-macro support, can be achieved by sending this JSON:
407 "loadOutDirsFromCheck": true,
415 Please consult your editor's documentation to learn more about how to configure https://microsoft.github.io/language-server-protocol/[LSP servers].
417 To verify which configuration is actually used by `rust-analyzer`, set `RA_LOG` environment variable to `rust_analyzer=info` and look for config-related messages.
418 Logs should show both the JSON that `rust-analyzer` sees as well as the updated config.
420 This is the list of config options `rust-analyzer` supports:
422 include::./generated_config.adoc[]
424 == Non-Cargo Based Projects
426 rust-analyzer does not require Cargo.
427 However, if you use some other build system, you'll have to describe the structure of your project for rust-analyzer in the `rust-project.json` format:
431 interface JsonProject {
432 /// Path to the directory with *source code* of sysroot crates.
434 /// It should point to the directory where std, core, and friends can be found:
435 /// https://github.com/rust-lang/rust/tree/master/library.
437 /// If provided, rust-analyzer automatically adds dependencies on sysroot
438 /// crates. Conversely, if you omit this path, you can specify sysroot
439 /// dependencies yourself and, for example, have several different "sysroots" in
440 /// one graph of crates.
441 sysroot_src?: string;
442 /// The set of crates comprising the current project.
443 /// Must include all transitive dependencies as well as sysroot crate (libstd, libcore and such).
448 /// Optional crate name used for display purposes, without affecting semantics.
449 /// See the `deps` key for semantically-significant crate names.
450 display_name?: string;
451 /// Path to the root module of the crate.
453 /// Edition of the crate.
454 edition: "2015" | "2018" | "2021";
457 /// Should this crate be treated as a member of current "workspace".
459 /// By default, inferred from the `root_module` (members are the crates which reside
460 /// inside the directory opened in the editor).
462 /// Set this to `false` for things like standard library and 3rd party crates to
463 /// enable performance optimizations (rust-analyzer assumes that non-member crates
465 is_workspace_member?: boolean;
466 /// Optionally specify the (super)set of `.rs` files comprising this crate.
468 /// By default, rust-analyzer assumes that only files under `root_module.parent` can belong to a crate.
469 /// `include_dirs` are included recursively, unless a subdirectory is in `exclude_dirs`.
471 /// Different crates can share the same `source`.
473 /// If two crates share an `.rs` file in common, they *must* have the same `source`.
474 /// rust-analyzer assumes that files from one source can't refer to files in another source.
476 include_dirs: string[],
477 exclude_dirs: string[],
479 /// The set of cfgs activated for a given crate, like `["unix", "feature=\"foo\"", "feature=\"bar\""]`.
481 /// Target triple for this Crate.
483 /// Used when running `rustc --print cfg` to get target-specific cfgs.
485 /// Environment variables, used for the `env!` macro
486 env: : { [key: string]: string; },
488 /// For proc-macro crates, path to compiles proc-macro (.so file).
489 proc_macro_dylib_path?: string;
493 /// Index of a crate in the `crates` array.
495 /// Name as should appear in the (implicit) `extern crate name` declaration.
500 This format is provisional and subject to change.
501 Specifically, the `roots` setup will be different eventually.
503 There are tree ways to feed `rust-project.json` to rust-analyzer:
505 * Place `rust-project.json` file at the root of the project, and rust-anlayzer will discover it.
506 * Specify `"rust-analyzer.linkedProjects": [ "path/to/rust-project.json" ]` in the settings (and make sure that your LSP client sends settings as a part of initialize request).
507 * Specify `"rust-analyzer.linkedProjects": [ { "roots": [...], "crates": [...] }]` inline.
509 Relative paths are interpreted relative to `rust-project.json` file location or (for inline JSON) relative to `rootUri`.
511 See https://github.com/rust-analyzer/rust-project.json-example for a small example.
513 You can set `RA_LOG` environmental variable to `rust_analyzer=info` to inspect how rust-analyzer handles config and project loading.
517 At the moment, rust-analyzer assumes that all code is trusted.
518 Here is a **non-exhaustive** list of ways to make rust-analyzer execute arbitrary code:
520 * proc macros and build scripts are executed by default
521 * `.cargo/config` can override `rustc` with an arbitrary executable
522 * VS Code plugin reads configuration from project directory, and that can be used to override paths to various executables, like `rustfmt` or `rust-analyzer` itself.
523 * rust-analyzer's syntax trees library uses a lot of `unsafe` and hasn't been properly audited for memory safety.
525 rust-analyzer itself doesn't access the network.
526 The VS Code plugin doesn't access the network unless the nightly channel is selected in the settings.
527 In that case, the plugin uses the GitHub API to check for and download updates.
531 include::./generated_features.adoc[]
533 == Assists (Code Actions)
535 Assists, or code actions, are small local refactorings, available in a particular context.
536 They are usually triggered by a shortcut or by clicking a light bulb icon in the editor.
537 Cursor position or selection is signified by `┃` character.
539 include::./generated_assists.adoc[]
543 While most errors and warnings provided by rust-analyzer come from the `cargo check` integration, there's a growing number of diagnostics implemented using rust-analyzer's own analysis.
544 These diagnostics don't respect `#[allow]` or `#[deny]` attributes yet, but can be turned off using the `rust-analyzer.diagnostics.enable`, `rust-analyzer.diagnostics.enableExperimental` or `rust-analyzer.diagnostics.disabled` settings.
546 include::./generated_diagnostic.adoc[]
551 ==== Color configurations
553 It is possible to change the foreground/background color of inlay hints.
554 Just add this to your `settings.json`:
559 "workbench.colorCustomizations": {
560 // Name of the theme you are currently using
562 "rust_analyzer.inlayHints.foreground": "#868686f0",
563 "rust_analyzer.inlayHints.background": "#3d3d3d48",
565 // Overrides for specific kinds of inlay hints
566 "rust_analyzer.inlayHints.foreground.typeHints": "#fdb6fdf0",
567 "rust_analyzer.inlayHints.foreground.paramHints": "#fdb6fdf0",
568 "rust_analyzer.inlayHints.background.chainingHints": "#6b0c0c81"
574 ==== Semantic style customizations
576 You can customize the look of different semantic elements in the source code.
577 For example, mutable bindings are underlined by default and you can override this behavior by adding the following section to your `settings.json`:
582 "editor.semanticTokenColorCustomizations": {
585 "fontStyle": "", // underline is the default
592 Most themes doesn't support styling unsafe operations differently yet. You can fix this by adding overrides for the rules `operator.unsafe`, `function.unsafe`, and `method.unsafe`:
597 "editor.semanticTokenColorCustomizations": {
599 "operator.unsafe": "#ff6600",
600 "function.unsafe": "#ff6600"
601 "method.unsafe": "#ff6600"
607 In addition to the top-level rules you can specify overrides for specific themes. For example, if you wanted to use a darker text color on a specific light theme, you might write:
612 "editor.semanticTokenColorCustomizations": {
614 "operator.unsafe": "#ff6600"
618 "operator.unsafe": "#572300"
625 Make sure you include the brackets around the theme name. For example, use `"[Ayu Light]"` to customize the theme Ayu Light.
627 ==== Special `when` clause context for keybindings.
628 You may use `inRustProject` context to configure keybindings for rust projects only.
635 "command": "rust-analyzer.toggleInlayHints",
636 "when": "inRustProject"
639 More about `when` clause contexts https://code.visualstudio.com/docs/getstarted/keybindings#_when-clause-contexts[here].
641 ==== Setting runnable environment variables
642 You can use "rust-analyzer.runnableEnv" setting to define runnable environment-specific substitution variables.
643 The simplest way for all runnables in a bunch:
645 "rust-analyzer.runnableEnv": {
646 "RUN_SLOW_TESTS": "1"
650 Or it is possible to specify vars more granularly:
652 "rust-analyzer.runnableEnv": [
654 // "mask": null, // null mask means that this rule will be applied for all runnables
663 "APP_ID": "2", // overwrites only APP_ID
669 You can use any valid regular expression as a mask.
670 Also note that a full runnable name is something like *run bin_or_example_name*, *test some::mod::test_name* or *test-mod some::mod*, so it is possible to distinguish binaries, single tests, and test modules with this masks: `"^run"`, `"^test "` (the trailing space matters!), and `"^test-mod"` respectively.
672 ==== Compiler feedback from external commands
674 Instead of relying on the built-in `cargo check`, you can configure Code to run a command in the background and use the `$rustc-watch` problem matcher to generate inline error markers from its output.
676 To do this you need to create a new https://code.visualstudio.com/docs/editor/tasks[VS Code Task] and set `rust-analyzer.checkOnSave.enable: false` in preferences.
678 For example, if you want to run https://crates.io/crates/cargo-watch[`cargo watch`] instead, you might add the following to `.vscode/tasks.json`:
685 "command": "cargo watch",
686 "problemMatcher": "$rustc-watch",