6 :source-highlighter: rouge
10 IMPORTANT: the master copy of this document lives in the https://github.com/rust-analyzer/rust-analyzer repository
13 At its core, rust-analyzer is a *library* for semantic analysis of Rust code as it changes over time.
14 This manual focuses on a specific usage of the library -- running it as part of a server that implements the
15 https://microsoft.github.io/language-server-protocol/[Language Server Protocol] (LSP).
16 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.
21 To improve this document, send a pull request: +
22 https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/manual.adoc[https://github.com/rust-analyzer/.../manual.adoc]
24 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.
27 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.
31 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.
32 We are not there yet, so some editor specific setup is required.
34 Additionally, rust-analyzer needs the sources of the standard library.
35 If the source code is not present, rust-analyzer will attempt to install it automatically.
37 To add the sources manually, run the following command:
40 $ rustup component add rust-src
45 This is the best supported editor at the moment.
46 The rust-analyzer plugin for VS Code is maintained
47 https://github.com/rust-analyzer/rust-analyzer/tree/master/editors/code[in tree].
49 You can install the latest release of the plugin from
50 https://marketplace.visualstudio.com/items?itemName=matklad.rust-analyzer[the marketplace].
52 Note that the plugin may cause conflicts with the
53 https://marketplace.visualstudio.com/items?itemName=rust-lang.rust[official Rust plugin].
54 It is recommended to disable the Rust plugin when using the rust-analyzer extension.
56 By default, the plugin will prompt you to download the matching version of the server as well:
58 image::https://user-images.githubusercontent.com/9021944/75067008-17502500-54ba-11ea-835a-f92aac50e866.png[]
62 To disable this notification put the following to `settings.json`
66 { "rust-analyzer.updates.askBeforeDownload": false }
70 The server binary is stored in the extension install directory, which starts with `matklad.rust-analyzer-` and is located under:
72 * Linux: `~/.vscode/extensions`
73 * Linux (Remote, such as WSL): `~/.vscode-server/extensions`
74 * macOS: `~/.vscode/extensions`
75 * Windows: `%USERPROFILE%\.vscode\extensions`
77 As an exception, on NixOS, the extension makes a copy of the server and stores it under `~/.config/Code/User/globalStorage/matklad.rust-analyzer`.
79 Note that we only support the two most recent versions of VS Code.
83 The extension will be updated automatically as new versions become available.
84 It will ask your permission to download the matching language server version binary if needed.
88 We ship nightly releases for VS Code.
89 You can opt in to these by switching to the pre-release version in the Code extension page or settings.
90 To help us out with testing the newest code and follow the bleeding edge of our `master`, please use the following config:
92 ==== Manual installation
94 Alternatively, download a VSIX corresponding to your platform from the
95 https://github.com/rust-analyzer/rust-analyzer/releases[releases] page.
97 Install the extension with the `Extensions: Install from VSIX` command within VS Code, or from the command line via:
100 $ code --install-extension /path/to/rust-analyzer.vsix
103 If you are running an unsupported platform, you can install `rust-analyzer-no-server.vsix` and compile or obtain a server binary.
104 Copy the server anywhere, then add the path to your settings.json, for example:
107 { "rust-analyzer.server.path": "~/.local/bin/rust-analyzer-linux" }
110 ==== Building From Source
112 Both the server and the Code plugin can be installed from source:
116 $ git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
117 $ cargo xtask install
120 You'll need Cargo, nodejs (matching a supported version of VS Code) and npm for this.
122 Note that installing via `xtask install` does not work for VS Code Remote, instead you'll need to install the `.vsix` manually.
124 If you're not using Code, you can compile and install only the LSP server:
128 $ cargo xtask install --server
131 === rust-analyzer Language Server Binary
133 Other editors generally require the `rust-analyzer` binary to be in `$PATH`.
134 You can download pre-built binaries from the https://github.com/rust-analyzer/rust-analyzer/releases[releases] page.
135 You will need to uncompress and rename the binary for your platform, e.g. from `rust-analyzer-aarch64-apple-darwin.gz` on Mac OS to `rust-analyzer`, make it executable, then move it into a directory in your `$PATH`.
137 On Linux to install the `rust-analyzer` binary into `~/.local/bin`, these commands should work:
141 $ mkdir -p ~/.local/bin
142 $ curl -L https://github.com/rust-analyzer/rust-analyzer/releases/latest/download/rust-analyzer-x86_64-unknown-linux-gnu.gz | gunzip -c - > ~/.local/bin/rust-analyzer
143 $ chmod +x ~/.local/bin/rust-analyzer
146 Make sure that `~/.local/bin` is listed in the `$PATH` variable and use the appropriate URL if you're not on a `x86-64` system.
148 You don't have to use `~/.local/bin`, any other path like `~/.cargo/bin` or `/usr/local/bin` will work just as well.
150 Alternatively, you can install it from source using the command below.
151 You'll need the latest stable version of the Rust toolchain.
155 $ git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
156 $ cargo xtask install --server
159 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].
160 On Unix, running the editor from a shell or changing the `.desktop` file to set the environment should help.
164 `rust-analyzer` is available in `rustup`, but only in the nightly toolchain:
168 $ rustup +nightly component add rust-analyzer-preview
171 However, in contrast to `component add clippy` or `component add rustfmt`, this does not actually place a `rust-analyzer` binary in `~/.cargo/bin`, see https://github.com/rust-lang/rustup/issues/2411[this issue].
175 The `rust-analyzer` binary can be installed from the repos or AUR (Arch User Repository):
177 - https://www.archlinux.org/packages/community/x86_64/rust-analyzer/[`rust-analyzer`] (built from latest tagged source)
178 - https://aur.archlinux.org/packages/rust-analyzer-git[`rust-analyzer-git`] (latest Git version)
180 Install it with pacman, for example:
184 $ pacman -S rust-analyzer
189 `rust-analyzer` is available in the GURU repository:
191 - https://gitweb.gentoo.org/repo/proj/guru.git/tree/dev-util/rust-analyzer?id=9895cea62602cfe599bd48e0fb02127411ca6e81[`dev-util/rust-analyzer`] builds from source
192 - https://gitweb.gentoo.org/repo/proj/guru.git/tree/dev-util/rust-analyzer-bin?id=9895cea62602cfe599bd48e0fb02127411ca6e81[`dev-util/rust-analyzer-bin`] installs an official binary release
194 If not already, GURU must be enabled (e.g. using `app-eselect/eselect-repository`) and sync'd before running `emerge`:
198 $ eselect repository enable guru && emaint sync -r guru
199 $ emerge rust-analyzer-bin
204 The `rust-analyzer` binary can be installed via https://brew.sh/[Homebrew].
208 $ brew install rust-analyzer
213 Note this excellent https://robert.kra.hn/posts/2021-02-07_rust-with-emacs/[guide] from https://github.com/rksm[@rksm].
215 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
217 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].
219 1. Install the most recent version of `emacs-lsp` package by following the https://github.com/emacs-lsp/lsp-mode[Emacs-LSP instructions].
220 2. Set `lsp-rust-server` to `'rust-analyzer`.
221 3. Run `lsp` in a Rust buffer.
222 4. (Optionally) bind commands like `lsp-rust-analyzer-join-lines`, `lsp-extend-selection` and `lsp-rust-analyzer-expand-macro` to keys.
226 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
227 Not needed if the extension can install/update it on its own, coc-rust-analyzer is one example.
229 The are several LSP client implementations for vim or neovim:
231 ==== coc-rust-analyzer
233 1. Install coc.nvim by following the instructions at
234 https://github.com/neoclide/coc.nvim[coc.nvim]
236 2. Run `:CocInstall coc-rust-analyzer` to install
237 https://github.com/fannheyward/coc-rust-analyzer[coc-rust-analyzer],
238 this extension implements _most_ of the features supported in the VSCode extension:
239 * automatically install and upgrade stable/nightly releases
240 * same configurations as VSCode extension, `rust-analyzer.server.path`, `rust-analyzer.cargo.features` etc.
241 * same commands too, `rust-analyzer.analyzerStatus`, `rust-analyzer.ssr` etc.
242 * inlay hints for variables and method chaining, _Neovim Only_
243 * semantic highlighting is not implemented yet
245 Note: for code actions, use `coc-codeaction-cursor` and `coc-codeaction-selected`; `coc-codeaction` and `coc-codeaction-line` are unlikely to be useful.
247 ==== LanguageClient-neovim
249 1. Install LanguageClient-neovim by following the instructions
250 https://github.com/autozimu/LanguageClient-neovim[here]
251 * The GitHub project wiki has extra tips on configuration
253 2. Configure by adding this to your vim/neovim config file (replacing the existing Rust-specific line if it exists):
257 let g:LanguageClient_serverCommands = {
258 \ 'rust': ['rust-analyzer'],
264 Install YouCompleteMe by following the instructions
265 https://github.com/ycm-core/YouCompleteMe#installation[here].
267 rust-analyzer is the default in ycm, it should work out of the box.
271 To use the LSP server in https://github.com/dense-analysis/ale[ale]:
275 let g:ale_linters = {'rust': ['analyzer']}
280 NeoVim 0.5 has built-in language server support.
281 For a quick start configuration of rust-analyzer, use https://github.com/neovim/nvim-lspconfig#rust_analyzer[neovim/nvim-lspconfig].
282 Once `neovim/nvim-lspconfig` is installed, use `+lua require'lspconfig'.rust_analyzer.setup({})+` in your `init.vim`.
284 You can also pass LSP settings to the server:
289 local nvim_lsp = require'lspconfig'
291 local on_attach = function(client)
292 require'completion'.on_attach(client)
295 nvim_lsp.rust_analyzer.setup({
298 ["rust-analyzer"] = {
300 importGranularity = "module",
301 importPrefix = "by_self",
304 loadOutDirsFromCheck = true
315 See https://sharksforarms.dev/posts/neovim-rust/ for more tips on getting started.
317 Check out https://github.com/simrat39/rust-tools.nvim for a batteries included rust-analyzer setup for neovim.
321 vim-lsp is installed by following https://github.com/prabirshrestha/vim-lsp[the plugin instructions].
322 It can be as simple as adding this line to your `.vimrc`:
326 Plug 'prabirshrestha/vim-lsp'
329 Next you need to register the `rust-analyzer` binary.
330 If it is available in `$PATH`, you may want to add this to your `.vimrc`:
334 if executable('rust-analyzer')
335 au User lsp_setup call lsp#register_server({
336 \ 'name': 'Rust Language Server',
337 \ 'cmd': {server_info->['rust-analyzer']},
338 \ 'whitelist': ['rust'],
343 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.
344 Here is an example of how to enable the proc-macro support:
348 if executable('rust-analyzer')
349 au User lsp_setup call lsp#register_server({
350 \ 'name': 'Rust Language Server',
351 \ 'cmd': {server_info->['rust-analyzer']},
352 \ 'whitelist': ['rust'],
353 \ 'initialization_options': {
355 \ 'loadOutDirsFromCheck': v:true,
367 Prerequisites: You have installed the <<rust-analyzer-language-server-binary,`rust-analyzer` binary>>.
369 You also need the `LSP` package.
372 1. If you've never installed a Sublime Text package, install Package Control:
373 * Open the command palette (Win/Linux: `ctrl+shift+p`, Mac: `cmd+shift+p`)
374 * Type `Install Package Control`, press enter
375 2. In the command palette, run `Package control: Install package`, and in the list that pops up, type `LSP` and press enter.
377 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.
378 The latter means that rust-analyzer is enabled by default in Rust projects.
380 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.
382 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.
386 GNOME Builder 3.37.1 and newer has native `rust-analyzer` support.
387 If the LSP binary is not available, GNOME Builder can install it when opening a Rust file.
392 Support for Rust development in the Eclipse IDE is provided by link:https://github.com/eclipse/corrosion[Eclipse Corrosion].
393 If available in PATH or in some standard location, `rust-analyzer` is detected and powers editing of Rust files without further configuration.
394 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.
395 You'll need to close and reopen all .rs and Cargo files, or to restart the IDE, for this change to take effect.
399 Support for the language server protocol is built into Kate through the LSP plugin, which is included by default.
400 It is preconfigured to use rust-analyzer for Rust sources since Kate 21.12.
402 Earlier versions allow you to use rust-analyzer through a simple settings change.
403 In the LSP Client settings of Kate, copy the content of the third tab "default parameters" to the second tab "server configuration".
404 Then in the configuration replace:
409 "rootIndicationFileNames": ["Cargo.lock", "Cargo.toml"],
410 "url": "https://github.com/rust-lang/rls",
411 "highlightingModeRegex": "^Rust$"
418 "command": ["rust-analyzer"],
419 "rootIndicationFileNames": ["Cargo.lock", "Cargo.toml"],
420 "url": "https://github.com/rust-analyzer/rust-analyzer",
421 "highlightingModeRegex": "^Rust$"
424 Then click on apply, and restart the LSP server for your rust project.
428 https://gitlab.com/cppit/jucipp[juCi++] has built-in support for the language server protocol, and since version 1.7.0 offers installation of both Rust and rust-analyzer when opening a Rust file.
432 Start with looking at the rust-analyzer version.
433 Try **Rust Analyzer: Show RA Version** in VS Code and `rust-analyzer --version` in the command line.
434 If the date is more than a week ago, it's better to update rust-analyzer version.
436 The next thing to check would be panic messages in rust-analyzer's log.
437 Log messages are printed to stderr, in VS Code you can see then in the `Output > Rust Analyzer Language Server` tab of the panel.
438 To see more logs, set the `RA_LOG=info` environment variable, this can be done either by setting the environment variable manually or by using `rust-analyzer.server.extraEnv`, note that both of these approaches require the server to be restarted.
440 To fully capture LSP messages between the editor and the server, set `"rust-analyzer.trace.server": "verbose"` config and check
441 `Output > Rust Analyzer Language Server Trace`.
443 The root cause for many "`nothing works`" problems is that rust-analyzer fails to understand the project structure.
444 To debug that, first note the `rust-analyzer` section in the status bar.
445 If it has an error icon and red, that's the problem (hover will have somewhat helpful error message).
446 **Rust Analyzer: Status** prints dependency information for the current file.
447 Finally, `RA_LOG=project_model=debug` enables verbose logs during project loading.
449 If rust-analyzer outright crashes, try running `rust-analyzer analysis-stats /path/to/project/directory/` on the command line.
450 This command type checks the whole project in batch mode bypassing LSP machinery.
452 When filing issues, it is useful (but not necessary) to try to minimize examples.
453 An ideal bug reproduction looks like this:
456 $ git clone https://github.com/username/repo.git && cd repo && git switch --detach commit-hash
457 $ rust-analyzer --version
458 rust-analyzer dd12184e4 2021-05-08 dev
459 $ rust-analyzer analysis-stats .
463 It is especially useful when the `repo` doesn't use external crates or the standard library.
465 If you want to go as far as to modify the source code to debug the problem, be sure to take a look at the
466 https://github.com/rust-analyzer/rust-analyzer/tree/master/docs/dev[dev docs]!
470 **Source:** https://github.com/rust-analyzer/rust-analyzer/blob/master/crates/rust-analyzer/src/config.rs[config.rs]
472 The <<_installation,Installation>> section contains details on configuration for some of the editors.
473 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.
475 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`.
477 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].
478 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.
479 Name of the setting, ignoring the `rust-analyzer.` prefix, is used as a path, and value of the setting becomes the JSON property value.
481 For example, a very common configuration is to enable proc-macro support, can be achieved by sending this JSON:
487 "loadOutDirsFromCheck": true,
495 Please consult your editor's documentation to learn more about how to configure https://microsoft.github.io/language-server-protocol/[LSP servers].
497 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.
498 Logs should show both the JSON that `rust-analyzer` sees as well as the updated config.
500 This is the list of config options `rust-analyzer` supports:
502 include::./generated_config.adoc[]
504 == Non-Cargo Based Projects
506 rust-analyzer does not require Cargo.
507 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:
511 interface JsonProject {
512 /// Path to the directory with *source code* of
515 /// It should point to the directory where std,
516 /// core, and friends can be found:
518 /// https://github.com/rust-lang/rust/tree/master/library.
520 /// If provided, rust-analyzer automatically adds
521 /// dependencies on sysroot crates. Conversely,
522 /// if you omit this path, you can specify sysroot
523 /// dependencies yourself and, for example, have
524 /// several different "sysroots" in one graph of
526 sysroot_src?: string;
527 /// The set of crates comprising the current
528 /// project. Must include all transitive
529 /// dependencies as well as sysroot crate (libstd,
530 /// libcore and such).
535 /// Optional crate name used for display purposes,
536 /// without affecting semantics. See the `deps`
537 /// key for semantically-significant crate names.
538 display_name?: string;
539 /// Path to the root module of the crate.
541 /// Edition of the crate.
542 edition: "2015" | "2018" | "2021";
545 /// Should this crate be treated as a member of
546 /// current "workspace".
548 /// By default, inferred from the `root_module`
549 /// (members are the crates which reside inside
550 /// the directory opened in the editor).
552 /// Set this to `false` for things like standard
553 /// library and 3rd party crates to enable
554 /// performance optimizations (rust-analyzer
555 /// assumes that non-member crates don't change).
556 is_workspace_member?: boolean;
557 /// Optionally specify the (super)set of `.rs`
558 /// files comprising this crate.
560 /// By default, rust-analyzer assumes that only
561 /// files under `root_module.parent` can belong
562 /// to a crate. `include_dirs` are included
563 /// recursively, unless a subdirectory is in
566 /// Different crates can share the same `source`.
568 /// If two crates share an `.rs` file in common,
569 /// they *must* have the same `source`.
570 /// rust-analyzer assumes that files from one
571 /// source can't refer to files in another source.
573 include_dirs: string[],
574 exclude_dirs: string[],
576 /// The set of cfgs activated for a given crate, like
577 /// `["unix", "feature=\"foo\"", "feature=\"bar\""]`.
579 /// Target triple for this Crate.
581 /// Used when running `rustc --print cfg`
582 /// to get target-specific cfgs.
584 /// Environment variables, used for
586 env: { [key: string]: string; },
588 /// Whether the crate is a proc-macro crate.
589 is_proc_macro: boolean;
590 /// For proc-macro crates, path to compiled
591 /// proc-macro (.so file).
592 proc_macro_dylib_path?: string;
596 /// Index of a crate in the `crates` array.
598 /// Name as should appear in the (implicit)
599 /// `extern crate name` declaration.
604 This format is provisional and subject to change.
605 Specifically, the `roots` setup will be different eventually.
607 There are three ways to feed `rust-project.json` to rust-analyzer:
609 * Place `rust-project.json` file at the root of the project, and rust-analyzer will discover it.
610 * 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).
611 * Specify `"rust-analyzer.linkedProjects": [ { "roots": [...], "crates": [...] }]` inline.
613 Relative paths are interpreted relative to `rust-project.json` file location or (for inline JSON) relative to `rootUri`.
615 See https://github.com/rust-analyzer/rust-project.json-example for a small example.
617 You can set the `RA_LOG` environment variable to `rust_analyzer=info` to inspect how rust-analyzer handles config and project loading.
619 Note that calls to `cargo check` are disabled when using `rust-project.json` by default, so compilation errors and warnings will no longer be sent to your LSP client. To enable these compilation errors you will need to specify explicitly what command rust-analyzer should run to perform the checks using the `checkOnSave.overrideCommand` configuration. As an example, the following configuration explicitly sets `cargo check` as the `checkOnSave` command.
623 { "rust-analyzer.checkOnSave.overrideCommand": ["cargo", "check", "--message-format=json"] }
626 The `checkOnSave.overrideCommand` requires the command specified to output json error messages for rust-analyzer to consume. The `--message-format=json` flag does this for `cargo check` so whichever command you use must also output errors in this format. See the <<Configuration>> section for more information.
630 At the moment, rust-analyzer assumes that all code is trusted.
631 Here is a **non-exhaustive** list of ways to make rust-analyzer execute arbitrary code:
633 * proc macros and build scripts are executed by default
634 * `.cargo/config` can override `rustc` with an arbitrary executable
635 * `rust-toolchain.toml` can override `rustc` with an arbitrary executable
636 * 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.
637 * rust-analyzer's syntax trees library uses a lot of `unsafe` and hasn't been properly audited for memory safety.
641 The LSP server performs no network access in itself, but runs `cargo metadata` which will update or download the crate registry and the source code of the project dependencies.
642 If enabled (the default), build scripts and procedural macros can do anything.
644 The Code extension does not access the network.
646 Any other editor plugins are not under the control of the `rust-analyzer` developers. For any privacy concerns, you should check with their respective developers.
648 For `rust-analyzer` developers, `cargo xtask release` uses the GitHub API to put together the release notes.
652 include::./generated_features.adoc[]
654 == Assists (Code Actions)
656 Assists, or code actions, are small local refactorings, available in a particular context.
657 They are usually triggered by a shortcut or by clicking a light bulb icon in the editor.
658 Cursor position or selection is signified by `┃` character.
660 include::./generated_assists.adoc[]
664 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.
665 Some of 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.
667 include::./generated_diagnostic.adoc[]
672 ==== Color configurations
674 It is possible to change the foreground/background color of inlay hints.
675 Just add this to your `settings.json`:
680 "workbench.colorCustomizations": {
681 // Name of the theme you are currently using
683 "rust_analyzer.inlayHints.foreground": "#868686f0",
684 "rust_analyzer.inlayHints.background": "#3d3d3d48",
686 // Overrides for specific kinds of inlay hints
687 "rust_analyzer.inlayHints.foreground.typeHints": "#fdb6fdf0",
688 "rust_analyzer.inlayHints.foreground.paramHints": "#fdb6fdf0",
689 "rust_analyzer.inlayHints.background.chainingHints": "#6b0c0c81"
695 ==== Semantic style customizations
697 You can customize the look of different semantic elements in the source code.
698 For example, mutable bindings are underlined by default and you can override this behavior by adding the following section to your `settings.json`:
703 "editor.semanticTokenColorCustomizations": {
706 "fontStyle": "", // underline is the default
713 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`:
718 "editor.semanticTokenColorCustomizations": {
720 "operator.unsafe": "#ff6600",
721 "function.unsafe": "#ff6600"
722 "method.unsafe": "#ff6600"
728 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:
733 "editor.semanticTokenColorCustomizations": {
735 "operator.unsafe": "#ff6600"
739 "operator.unsafe": "#572300"
746 Make sure you include the brackets around the theme name. For example, use `"[Ayu Light]"` to customize the theme Ayu Light.
748 ==== Special `when` clause context for keybindings.
749 You may use `inRustProject` context to configure keybindings for rust projects only.
756 "command": "rust-analyzer.toggleInlayHints",
757 "when": "inRustProject"
760 More about `when` clause contexts https://code.visualstudio.com/docs/getstarted/keybindings#_when-clause-contexts[here].
762 ==== Setting runnable environment variables
763 You can use "rust-analyzer.runnableEnv" setting to define runnable environment-specific substitution variables.
764 The simplest way for all runnables in a bunch:
766 "rust-analyzer.runnableEnv": {
767 "RUN_SLOW_TESTS": "1"
771 Or it is possible to specify vars more granularly:
773 "rust-analyzer.runnableEnv": [
775 // "mask": null, // null mask means that this rule will be applied for all runnables
784 "APP_ID": "2", // overwrites only APP_ID
790 You can use any valid regular expression as a mask.
791 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.
793 ==== Compiler feedback from external commands
795 Instead of relying on the built-in `cargo check`, you can configure Code to run a command in the background and use the `$rustc-watch` problem matcher to generate inline error markers from its output.
797 To do this you need to create a new https://code.visualstudio.com/docs/editor/tasks[VS Code Task] and set `rust-analyzer.checkOnSave.enable: false` in preferences.
799 For example, if you want to run https://crates.io/crates/cargo-watch[`cargo watch`] instead, you might add the following to `.vscode/tasks.json`:
806 "command": "cargo watch",
807 "problemMatcher": "$rustc-watch",