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4 days ago

Neovim Lua Rust Nix

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:link: Quick Links

:grey_question: Do I need rustaceanvim

If you are starting out with Rust, nvim-lspconfig.rust_analyzer is probably enough for you. It provides the lowest common denominator of LSP support. This plugin is for those who would like additional non-standard features that are specific to rust-analyzer.

:pencil: Prerequisites



  • dot from graphviz, for crate graphs.
  • cargo, required for Cargo projects.
  • A debug adapter (e.g. lldb or codelldb) and nvim-dap, required for debugging.
  • A tree-sitter parser for Rust (required for the :Rustc unpretty command). Can be installed using nvim-treesitter, which also provides highlights, etc.

:inbox_tray: Installation

This plugin is available on LuaRocks:

:Rocks install rustaceanvim

Example using lazy.nvim:

  version = '^4', -- Recommended
  lazy = false, -- This plugin is already lazy


It is suggested to pin to tagged releases if you would like to avoid breaking changes.

To manually generate documentation, use :helptags ALL.


For NixOS users with flakes enabled, this project provides outputs in the form of a package and an overlay; use it as you wish in your NixOS or home-manager configuration. It is also available in nixpkgs.

Look at the configuration information below to get started.

:zap: Quick Setup

This plugin automatically configures the rust-analyzer builtin LSP client and integrates with other Rust tools. See the Usage / Features section for more info.


Do not call the nvim-lspconfig.rust_analyzer setup or set up the LSP client for rust-analyzer manually, as doing so may cause conflicts.

This is a filetype plugin that works out of the box, so there is no need to call a setup function or configure anything to get this plugin working.

You will most likely want to add some keymaps. Most keymaps are only useful in rust files, so I suggest you define them in ~/.config/nvim/after/ftplugin/rust.lua[^1]

[^1]: See :help base-directories


local bufnr = vim.api.nvim_get_current_buf()
    vim.cmd.RustLsp('codeAction') -- supports rust-analyzer's grouping
    -- or vim.lsp.buf.codeAction() if you don't want grouping.
  { silent = true, buffer = bufnr }


  • For more LSP related keymaps, see the nvim-lspconfig suggestions.
  • If you want to share keymaps with nvim-lspconfig, you can also use the vim.g.rustaceanvim.server.on_attach function, or an LspAttach autocommand.
  • See the Advanced configuration section or :h rustaceanvim.config for more configuration options.


  • Do not set vim.g.rustaceanvim in after/ftplugin/rust.lua, as the file is sourced after the plugin is initialized.

:books: Usage / Features

  • debuggables opens a prompt to select from available targets.
  • debug searches for a target at the current cursor position.
:RustLsp[!] debuggables {args[]}?
:RustLsp[!] debug {args[]}?
-- or, to run the previous debuggable:
vim.cmd.RustLsp { 'debuggables', bang = true }
-- or, to override the executable's args:
vim.cmd.RustLsp {'debuggables', 'arg1', 'arg2' }

Calling the command with a bang ! will rerun the last debuggable.


By default, this plugin will silently attempt to autoload nvim-dap configurations when the LSP client attaches. You can call them with require('dap').continue() or :DapContinue once they have been loaded. The feature can be disabled by setting vim.g.rustaceanvim.dap.autoload_configurations = false. It is disabled by default in neovim 0.9, as it can block the UI.

  • :RustLsp debuggables will only load debug configurations created by rust-analyzer.
  • require('dap').continue() will load all Rust debug configurations, including those specified in a .vscode/launch.json (see :h dap-launch.json).
  • Note that rustaceanvim may only be able to load DAP configurations when rust-analyzer has finished initializing (which may be after the client attaches, in large projects). This means that the DAP configurations may not be loaded immediately upon startup.

  • runnables opens a prompt to select from available targets.
  • run searches for a target at the current cursor position.
:RustLsp[!] runnables {args[]}?
:RustLsp[!] run {args[]}?
-- or, to run the previous runnable:
vim.cmd.RustLsp { 'runnables', bang = true }
-- or, to override the executable's args:
vim.cmd.RustLsp {'runnables', 'arg1', 'arg2' }

Calling the command with a bang ! will rerun the last runnable.

If you are using Neovim >= 0.10, you can set the option to 'background', and this plugin will run tests in the background, parse the results, and - if possible - display failed tests as diagnostics.

This is also possible in Neovim 0.9, but tests won't be run in the background, and will block the UI.

:RustLsp[!] testables {args[]}?
-- or, to run the previous testables:
vim.cmd.RustLsp { 'testables', bang = true }
-- or, to override the executable's args:
vim.cmd.RustLsp {'testables', 'arg1', 'arg2' }

Calling the command with a bang ! will rerun the last testable.

This plugin provides a neotest adapter, which you can add to neotest as follows:

require('neotest').setup {
    -- ...,
    adapters = {
      -- ...,

Note: If you use rustaceanvim's neotest adapter, do not add neotest-rust.

Here is a comparison between rustaceanvim's adapter and neotest-rust:

rustaceanvim neotest-rust
Test discovery rust-analyzer (LSP) tree-sitter
Command construction rust-analyzer (LSP) tree-sitter
DAP strategy Automatic DAP detection (reuses debuggables); overridable with vim.g.rustaceanvim.dap Defaults to codelldb; manual configuration
Test runner cargo or cargo-nextest, if detected cargo-nextest

If you configure rustaceanvim to use neotest, the tools.test_executor will default to using neotest for testables and runnables that are tests.

:RustLsp expandMacro

:RustLsp rebuildProcMacros
:RustLsp moveItem {up|down}
vim.cmd.RustLsp { 'moveItem',  'up' }
vim.cmd.RustLsp { 'moveItem',  'down' }

Sometimes, rust-analyzer groups code actions by category, which is not supported by Neovim's built-in vim.lsp.buf.codeAction. This plugin provides a command with a UI that does:

:RustLsp codeAction

If you set the option to true (defaults to false), it will fall back to if there are no grouped code actions.

Note: To activate hover actions, run the command twice. This will move you into the window, then press enter on the selection you want. Alternatively, you can set auto_focus to true in your config and you will automatically enter the hover actions window.

:RustLsp hover actions
vim.cmd.RustLsp { 'hover', 'actions' }

By default, this plugin replaces Neovim's built-in hover handler with hover actions, so you can also use vim.lsp.buf.hover().

:RustLsp hover range
vim.cmd.RustLsp { 'hover', 'range' }

Display a hover window with explanations from the rust error codes index over error diagnostics (if they have an error code).

:RustLsp explainError

Like vim.diagnostic.goto_next, explainError will cycle diagnostics, starting at the cursor position, until it can find a diagnostic with an error code.

Display a hover window with the rendered diagnostic, as displayed during cargo build. Useful for solving bugs around borrowing and generics, as it consolidates the important bits (sometimes across files) together.

:RustLsp renderDiagnostic

Like vim.diagnostic.goto_next, renderDiagnostic will cycle diagnostics, starting at the cursor position, until it can find a diagnostic with rendered data.

:RustLsp openCargo

Open documentation for the symbol under the cursor.

:RustLsp openDocs
:RustLsp parentModule

rust-analyzer supports filtering workspace symbol searches.

:RustLsp[!] workspaceSymbol {onlyTypes?|allSymbols?} {query?}
-- or
vim.cmd.RustLsp { 
  '<onlyTypes|allSymbols>' --[[ optional ]], 
  '<query>' --[[ optional ]], 
  bang = true --[[ optional ]]
  • Calling the command with a bang ! will include dependencies in the search.
  • You can also influence the behaviour of vim.lsp.buf.workspace_symbol() by setting the rust-analyzer server option.

Join selected lines into one, smartly fixing up whitespace, trailing commas, and braces. Works with individual lines in normal mode and multiple lines in visual mode.

:RustLsp joinLines

  • Searches the entire buffer in normal mode.
  • Searches the selection in visual mode.
:RustLsp ssr {query}
vim.cmd.RustLsp { 'ssr', '<query>' --[[ optional ]] }


:RustLsp crateGraph {backend {output}}
vim.cmd.RustLsp { 'crateGraph', '[backend]', '[output]' }


:RustLsp syntaxTree

Run cargo check or another compatible command (f.x. clippy) in a background thread and provide LSP diagnostics based on the output of the command.

Useful in large projects where running cargo check on each save can be costly.

:RustLsp flyCheck {run?|clear?|cancel?}
vim.cmd.RustLsp('flyCheck') -- defaults to 'run'
vim.cmd.RustLsp { 'flyCheck', 'run' }
vim.cmd.RustLsp { 'flyCheck', 'clear' }
vim.cmd.RustLsp { 'flyCheck', 'cancel' }


This is only useful if you set the option, ['rust-analzyer'].checkOnSave = false.

Opens a buffer with a textual representation of the HIR or MIR of the function containing the cursor. Useful for debugging or when working on rust-analyzer itself.

:RustLsp view {hir|mir}
vim.cmd.RustLsp { 'view', 'hir' }
vim.cmd.RustLsp { 'view', 'mir' }

Opens a buffer with a textual representation of the MIR or others things, of the function closest to the cursor. Achieves an experience similar to Rust Playground.

NOTE: This currently requires a tree-sitter parser for Rust, and a nightly compiler toolchain.

:Rustc unpretty {hir|mir|...}
vim.cmd.Rustc { 'unpretty', 'hir' }
vim.cmd.Rustc { 'unpretty', 'mir' }
-- ...


  • A tree-sitter parser for Rust (required for the :Rustc unpretty command). Can be installed using nvim-treesitter.

:gear: Advanced configuration

To modify the default configuration, set vim.g.rustaceanvim.

You only need to specify the keys that you want to be changed, because defaults are applied for keys that are not provided.

Example config:

vim.g.rustaceanvim = {
  -- Plugin configuration
  tools = {
  -- LSP configuration
  server = {
    on_attach = function(client, bufnr)
      -- you can also put keymaps in here
    default_settings = {
      -- rust-analyzer language server configuration
      ['rust-analyzer'] = {
  -- DAP configuration
  dap = {


vim.g.rustaceanvim can also be a function that returns a table.

Using codelldb for debugging

For Rust, codelldb from the CodeLLDB VSCode extension provides a better experience than lldb. If you are using a distribution that lets you install the codelldb executable, this plugin will automatically detect it and configure itself to use it as a debug adapter.

Some examples:

If your distribution does not have a codelldb package, you can configure it as follows:

  1. Install the CodeLLDB VSCode extension.
  2. Find out where it is installed. On Linux, this is typically in $HOME/.vscode/extensions/
  3. Update your configuration:
vim.g.rustaceanvim = function()
  -- Update this path
  local extension_path = vim.env.HOME .. '/.vscode/extensions/vadimcn.vscode-lldb-1.10.0/'
  local codelldb_path = extension_path .. 'adapter/codelldb'
  local liblldb_path = extension_path .. 'lldb/lib/liblldb'
  local this_os = vim.uv.os_uname().sysname;

  -- The path is different on Windows
  if this_os:find "Windows" then
    codelldb_path = extension_path .. "adapter\\codelldb.exe"
    liblldb_path = extension_path .. "lldb\\bin\\liblldb.dll"
    -- The liblldb extension is .so for Linux and .dylib for MacOS
    liblldb_path = liblldb_path .. (this_os == "Linux" and ".so" or ".dylib")

  local cfg = require('rustaceanvim.config')
  return {
    dap = {
      adapter = cfg.get_codelldb_adapter(codelldb_path, liblldb_path),

How to dynamically load different rust-analyzer settings per project

By default, this plugin will look for a rust-analyzer.json[^2] file in the project root directory, and attempt to load it. If the file does not exist, or it can't be decoded, the server.default_settings will be used.

[^2]: See this example and the rust-analyzer configuration manual.

You can change this behaviour with the server.settings config:

vim.g.rustaceanvim = {
  -- ...
  server = {
    ---@param project_root string Path to the project root
    settings = function(project_root)
      local ra = require('rustaceanvim.config.server')
      return ra.load_rust_analyzer_settings(project_root, {
        settings_file_pattern = 'rust-analyzer.json'

:stethoscope: Troubleshooting

Health checks

For a health check, run :checkhealth rustaceanvim

rust-analyzer log file

To open the rust-analyzer log file, run :RustLsp logFile.

Minimal config

To troubleshoot this plugin with a minimal config in a temporary directory, you can try minimal.lua.

mkdir -p /tmp/minimal/
NVIM_DATA_MINIMAL="/tmp/minimal" NVIM_APP_NAME="nvim-minimal" nvim -u NORC -u minimal.lua


If you use Nix, you can run nix run "github:mrcjkb/rustaceanvim#nvim-minimal-stable". or nix run "github:mrcjkb/rustaceanvim#nvim-minimal-nightly".

If you cannot reproduce your issue with a minimal config, it may be caused by another plugin, or a setting of your plugin manager. In this case, add additional plugins and configurations to minimal.lua, until you can reproduce it.

rust-analyzer troubleshooting

For issues related to rust-analyzer (e.g. LSP features not working), see also the rust-analyzer troubleshooting guide.

:left_speech_bubble: FAQ

Where are inlay hints / type hints?

As Neovim >= 0.10 supports inlay hints natively (:h lsp-inlay_hint), I have removed the code from this plugin.

To enable inlay hints in Neovim < 0.10, see this discussion.

How to enable auto completion?

Neovim does not have built-in support for auto-completion, and adding support for that is beyond the scope of this plugin.

You have a few choices for completion:

  • Use Neovim's built-in omni completion (see :h omnifunc). This supports basic LSP completions, but not autocompletion.
  • For autocompletion, you need a plugin, for example nvim-cmp and an LSP completion source like cmp-nvim-lsp. This plugin will automatically register the necessary client capabilities if you have cmp-nvim-lsp installed.

mason.nvim and nvim-lspconfig

See :h rustaceanvim.mason for details about troubleshooting mason.nvim and nvim-lspconfig issues, or configuring rustaceanvim to use a rust-analyzer installation that is managed by mason.nvim.

:link: Related Projects


rust-tools.nvim draws inspiration from akinsho/flutter-tools.nvim