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This package is based on rust-mode and provides additional features:

  • cargo popup
  • multiline error parsing
  • translation of ANSI control sequences through xterm-color
  • async org babel
  • automatic LSP configuration with eglot or lsp-mode
  • cask for testing
  • etc.

rustic only shares the rust-mode code from rust-mode.el and rust-utils.el. The other files provide functionality that is similar to some of the features of rustic, however can be considered light-weight compared to some rustic's functionality.

The shared functions and options exist as aliases in the rust-mode and rustic namespace for backwards compatibility reasons(rustic has been a fork).

Known issues

  • rust-syntax-propertize and adaptive-wrap-prefix-mode can lead to severe lag when editing larger files (#107)


First, you may need to install rust-analyzer. See Automatic server installation.

If you can't run rust-analyzer or cargo can't be found, your environment variables probably don't work in emacs. Try exec-path-from-shell to fix this.


This section explains how to install rustic with the default package manager. It's necessary to include elpa for a package dependency:

(require 'package)
(setq package-archives '(("melpa" . "")
                         ("gnu" . "")))
(use-package rustic)

If ‘spinner-1.7.3’ is unavailable” when trying to install rustic, you need to update GPG keys used by the ELPA package manager. Try installing gnu-elpa-keyring-update.


straight.el clones each of your packages directly from its source. There are good additional installation instructions for moving your package management from package.el to straight.


rustfmt and most of the common cargo commands should work remotely. We are currently updating the code base. If you encounter any command that doesn't work remotely, please open an issue.


If you want to use a Makefile you can either use (setq rustic-compile-command "make") or run C-u + rustic-compile.


  • rustic-compile compile project using rustic-compile-command
  • rustic-recompile recompile using compilation-arguments
  • rustic-compile-send-input send string to process of current buffer


  • rustic-compile-display-method choose function that displays the compilation buffer (use the function ignore, if you don't want the buffer to be displayed)
  • rustic-compile-backtrace change backtrace verbosity
  • rustic-compile-rustflags set RUSTFLAGS
  • rustic-compile-command default command for rust compilation
  • rustic-compile-command-remote default command for remote rust compilation

Supported compile.el variables:

  • compilation-arguments
  • compilation-scroll-output (possible values are t for automatic scrolling and first-error to scroll to first error)

Navigating errors

Rustic defines a derived compilation-mode. Colors can be customized with several defcustoms. You can use next-error and compilation-next-error as for any other compilation buffer.

However it's possible to also jump to line numbers that are displayed at the beginning of a line. This feature is provided by a hook around compile-goto-error(RET).

default directory

rustic-compile-directory-method allows you to set the directory that is used for compilation commands. The default is the current crate which is returned by rustic-buffer-crate(there's also rustic-buffer-workspace).

If you want to use the project root you can use rustic-project-root instead.

FTR #174 #179 #236


The colors that are displayed in compilation buffers come from cargo and are translated by xterm-color. You can change these colors by modifying rustic-ansi-faces.

rustic-compilation-mode doesn't use the default faces of compile.el. If you want to change these colors you can use something similar to:

  '(rustic-compilation-column ((t (:inherit compilation-column-number))))
  '(rustic-compilation-line ((t (:foreground "LimeGreen")))))

Additional faces:

  • rustic-message
  • rustic-compilation-error
  • rustic-compilation-warning
  • rustic-compilation-info

rustc errors


Ensure rustfmt is installed by running rustup component add rustfmt-preview in your project's directory.

You can format your code with:

  • rustic-format-buffer format buffer with stdin
  • rustic-format-file format file and revert buffer
  • rustic-cargo-fmt run cargo-fmt on workspace
  • rustic-format-region format active region
  • rustic-format-dwim run format on region,file or cargo fmt

Rustic uses the function rustic-save-some-buffers for saving buffers before compilation.

To save buffers automatically, you can change the value of compilation-ask-about-save, it has higher precedence than buffer-save-without-query when compiling.

(defun rustic-mode-auto-save-hook ()
  "Enable auto-saving in rustic-mode buffers."
  (when buffer-file-name
    (setq-local compilation-ask-about-save nil)))
(add-hook 'rustic-mode-hook 'rustic-mode-auto-save-hook)


  • rustic-rustfmt-bin path to rustfmt executable
  • rustic-rustfmt-bin-remote default path to remote rustfmt executable
  • rustic-rustfmt-args additional args like +nightly
  • rustic-rustfmt-config-alist alist of rustfmt configuration options
  • rustic-format-display-method default function used for displaying rustfmt buffer (use the function ignore, if you don't want the buffer to be displayed)
  • rustic-format-on-save-method function to use for on-save formatting
  • rustic-format-trigger
    • 'on-save format buffer before saving
    • 'on-compile run 'cargo fmt' before compilation
    • nil don't format automatically
  • rustic-use-rust-save-some-buffers turn on to use automatic formatting for save-some-buffers

known issues:

in case you are using hideshow you might want to set rustic-format-on-save-method to rustic-format-buffer(#274)

Change default arguments

If you want to configure the following rustfmt call

rustfmt +nightly --config hard_tabs=true --config skip_children=false

you can use

(setq rustic-rustfmt-args "+nightly")
(setq rustic-rustfmt-config-alist '((hard_tabs . t) (skip_children . nil)))

edition 2018

If you are struggling with errors relating to the Rust edition in Cargo.toml, this may in fact be a problem with rustfmt and its default settings. To solve this, even though the error message mentions Cargo.toml, you have to put edition = "2018" in a rustfmt.toml. See here for more info.


Currently only rustic-format-buffer works remotely.

rustic-rustfmt-bin needs to be an absolute path to work remotely.


Disable rustic-lsp-setup-p to turn off automatic LSP configuration. If you want to turn off LSP temporarily you can set rustic-lsp-client to nil. You have to restart emacs when you switch lsp clients.

Don't forget that rustic doesn't contain the code for interacting with lsp servers. Therefore most issues are not related to rustic, but to the lsp client or server you are using.


rust-analyzer is the default and can be changed to rls if required (Note that rls is deprecated and is slated to be removed). lsp-mode related code was moved to the lsp-mode repo. rustic-lsp-server sets the value of lsp-rust-server.

Change rust-analyzer path.

(setq rustic-analyzer-command '("~/.cargo/bin/rust-analyzer"))

If you are using rustup to manage your rust-analyzer, you would have to configure like this to make it work with use-package:

(use-package rustic
  (rustic-analyzer-command '("rustup" "run" "stable" "rust-analyzer")))

Automatic server installation

lsp-mode provides this feature, but eglot doesn't #403

Install rust-analyzer manually.


The default package is lsp-mode. But you can also use eglot.

(setq rustic-lsp-client 'eglot)

LSP commands:

  • xref-find-definitions find definitions
  • xref-find-references with helm and rust-analyzer
  • rustic-cargo-add-missing-dependencies convenient command that adds missing dependencies to a crate's Cargo.toml


Turn off flymake.

(add-hook 'eglot--managed-mode-hook (lambda () (flymake-mode -1)))


  • lsp-describe-thing-at-point display documentation
  • lsp-find-definition makes use of xref

You can find more information in the lsp-mode documentation for Rust.


This command can be extremely convenient when applying code actions or using auto-imports.

Run lsp-execute-code-action when lsp-ui displays code actions at the top of the sideline.

Applying code actions

Auto import

Macro expansion

lsp-rust-analyzer-expand-macro expand macro call at point recursively.

The results are formatted and highlighted by default, but you can use your own function by customizing lsp-rust-analyzer-macro-expansion-method.


rust-analyzer does work over TRAMP, but you have to register the client manually:

(with-eval-after-load "lsp-rust"
   :new-connection (lsp-stdio-connection
                    (lambda ()
                      `(,(or (executable-find
                              (cl-first lsp-rust-analyzer-server-command))
                             (lsp-package-path 'rust-analyzer)
                        ,@(cl-rest lsp-rust-analyzer-server-args))))
   :remote? t
   :major-modes '(rust-mode rustic-mode)
   :initialization-options 'lsp-rust-analyzer--make-init-options
   :notification-handlers (ht<-alist lsp-rust-notification-handlers)
   :action-handlers (ht ("rust-analyzer.runSingle" #'lsp-rust--analyzer-run-single))
   :library-folders-fn (lambda (_workspace) lsp-rust-library-directories)
   :after-open-fn (lambda ()
                    (when lsp-rust-analyzer-server-display-inlay-hints
   :ignore-messages nil
   :server-id 'rust-analyzer-remote)))

(based on

If you have Emacs 28, due to some compatibility issues, you might have to additionally use:

(defun start-file-process-shell-command@around (start-file-process-shell-command name buffer &rest args)
  "Start a program in a subprocess.  Return the process object for it. Similar to `start-process-shell-command', but calls `start-file-process'."
  ;; On remote hosts, the local `shell-file-name' might be useless.
  (let ((command (mapconcat 'identity args " ")))
    (funcall start-file-process-shell-command name buffer command)))

(advice-add 'start-file-process-shell-command :around #'start-file-process-shell-command@around)

(thanks to emacs-lsp/lsp-mode#2514 (comment))

You'll have to have rust-analyzer already installed on the target machine.

Detached file

This is an early experimental feature, and is disabled by default.

Source files not belonging to any crate, or detached source files, are supported by rust-analyzer, and this feature can be enabled via rustic-enable-detached-file-support. (Currently, only eglot is supported.)

Caveat: Due to some current limitations, you should avoid opening a detached file in a large directory with this feature enabled.


Since the cargo commands also use the derived compilation mode, you can use the commands that are mentioned in the "compilation" section.


  • rustic-cargo-bin Path to cargo executable
  • rustic-cargo-bin-remote Path to remote cargo executable
  • rustic-cargo-build-arguments default arguments for cargo build
  • rustic-cargo-check-arguments default arguments for cargo check
  • rustic-cargo-auto-add-missing-dependencies automatically add missing dependencies to Cargo.toml by checking new diagnostics for 'unresolved import' errors
  • rustic-cargo-use-last-stored-arguments always use stored arguments that were provided with C-u(instead of requiring to run rustic "rerun" commands)


cargo-edit provides commands to edit your dependencies quickly.

The rustic commands can be called with prefix C-u if you want to modify the parameters of a command.

  • rustic-cargo-add Add crate to Cargo.toml using 'cargo add'
  • rustic-cargo-rm Remove crate from Cargo.toml using 'cargo rm'
  • rustic-cargo-upgrade Upgrade dependencies as specified in the local manifest file using 'cargo upgrade'
  • rustic-cargo-add-missing-dependencies Add the missing dependencies for the current buffer to Cargo.toml


If you want to disable warnings when running cargo-test commands, you can set (setq rustic-cargo-test-disable-warnings t).


rustic-cargo-nextest-exec-command command for running nextest rustic-cargo-test run 'cargo test', when called with C-u store arguments in rustic-test-arguments

rustic-cargo-test-rerun rerun 'cargo test' with arguments stored in rustic-test-arguments

rustic-cargo-current-test run test at point, whether it's a function or a module


Based on the usecase, we provide three variants of it:

  • rustic-cargo-run

This is meant for non interactive programs. It's creates a new mode which is built on top of rustic-compilation-mode. You can press g in this mode's buffer to make it re-run.

  • rustic-cargo-comint-run

This is meant for both interactive and non interactive programs. For non interactive programs, you would need to pass data to it via stdin. It's creates a new mode which is built on top of comint-mode. You can press C-c C-g in this mode's buffer to make it re-run. You can pass input to the program directly in it's output buffer and press RET.

  • rustic-cargo-plain-run

This is similar to the above rustic-cargo-comint-run. Input can be sent to the program in one of two ways:

  • rustic-compile-send-input, which reads the input from the minibuffer.
  • rustic-cargo-run-use-comint: when this variable is set to t, the input can be typed directly into the output buffer of 'cargo run' and sent off with RET, just like in comint-mode. You need polymode installed for this to work.


Use rustic-cargo-outdated to get a list of dependencies that are out of date. The results are displayed in tabulated-list-mode and you can use most commands you know from the emacs package menu. This option requires the rust package cargo-outdated to be installed before being used.

  • u mark single crate for upgrade and prompt user for version.
  • U mark all upgradable crates.
  • l mark single crate for upgrading to latest version.
  • L mark all crates to latest version.
  • m remove mark
  • x perform marked package menu actions
  • r refresh crate list
  • q quit window


cargo-expand provides the ability to expand macros. It also provides the ability to target a specific modules or a named item within a module (eg: module::Type).

  • rustic-cargo-expand: runs cargo expand. You can also use universal argument to target a specific named item to expand.


cargo spellcheck checks the documentation for spelling and grammar mistakes.

  • rustic-cargo-spellcheck: runs cargo spellcheck and will open a buffer where you can go through the various errors pointed out by it.

More cargo commands

  • rustic-cargo-init run 'cargo init' to initialize a directory
  • rustic-cargo-new use 'cargo new' to create a new package
  • rustic-cargo-bench run 'cargo bench' for the current project
  • rustic-cargo-build-doc build the documentation for the current project
  • rustic-cargo-doc open the documentation for the current project in a browser
  • rustic-cargo-lints called with rustic-lints-arguments
  • rustic-cargo-install run 'cargo install' on the current package.
  • rustic-cargo-update run cargo update on the current package.


Currently cargo does not display the correct installation command for some toolchains when clippy isn't installed. If you have problems try it with rustup component add --toolchain nightly clippy.

You can change the parameters rustic-default-clippy-arguments that default to "--benches --tests --all-features".

auto-fixing before compilation

It's possible to run 'clippy --fix' automatically when starting a compile process by setting rustic-cargo-clippy-trigger-fix to 'on-compile. You can also use 'on-save, but this doesn't work in combination with automatic formatting.

This feature can be used in combination with auto-formatting.

Works for:

  • rustic-cargo-build
  • rustic-compile
  • rustic-recompile


  • rustic-cargo-clippy to view the results in a derived compilation mode
  • rustic-cargo-clippy-fix run 'clippy fix' using rustic-cargo-clippy-fix-args the default value is "--allow-dirty"


In case you want to use clippy with flycheck but without LSP, you can activate this checker and use the command flycheck-list-errors

(push 'rustic-clippy flycheck-checkers)

Turn off flycheck.

(remove-hook 'rustic-mode-hook 'flycheck-mode)

The checker automatically detects the active toolchain and applies the correct parameters. You can set a default value for both stable and nightly toolchains. These are the default values.

  • rustic-flycheck-clippy-params-stable "--message-format=json"
  • rustic-flycheck-clippy-params-nightly "--message-format=json -Zunstable-options"


If you are using lsp-mode with rust-analyzer, you can set lsp-rust-analyzer-cargo-watch-command to clippy instead of activating the checker rustic-clippy.



Blocks run asynchronously and a running babel process is indicated by a spinner in the mode-line. It's possible to use crates in babel blocks. Execute babel block with org-babel-execute-src-block.

Supported org babel parameters:

Write to file :results file :file ~/babel-output


  • rustic-babel-format-src-block format block after successful build
  • rustic-babel-display-compilation-buffer display compilation buffer of babel process
  • rustic-babel-auto-wrap-main wrap body into main function
  • rustic-babel-default-toolchain active toolchain for babel blocks


You can use lsp in babel blocks with lsp-org.


  • rustic-babel-format-block format block at point
  • rustic-babel-header-insert-crates include missing dependencies in :crates header arg
  • rustic-babel-visit-project find generated project of block at point
  • rustic-babel-clippy run clippy on block(currently doesn't honor babel params, you can open a feature request if you miss it)



This block shows how to use crates with the latest version for both serde and regex.

The "*" will be added automatically for serde.

#+BEGIN_SRC rust :crates '(serde (regex . *))
  extern crate regex;
  extern crate serde;
  use regex::Regex;

  fn main() {
      let re = Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();


If specific crate features are required then these can be specified with the :features argument. Note that if it is just a single feature then a string, instead of a list, will also be accepted:

#+BEGIN_SRC rust :crates '((tokio . 1.0)) :features '((tokio . ("rt-multi-thread" "time")))
  extern crate tokio;

  fn main() {
          .block_on(async {


Similarly, to depend on local Rust crates, you can set the :paths argument:

#+BEGIN_SRC rust :crates '((foo . 1.0)) :paths '((foo . "/home/you/code/foo"))
  use foo::Foo;

  fn main() {
    // Your code.


You can specify the :toolchain by quoted 'stable/'nightly/'beta, or specify a toolchain version like "1.63.0", "nightly-2022-08-08".

#+begin_src rust :toolchain 'nightly
fn main() {
    let foo: String = vec!["a", "b", "c"].into_iter().intersperse(",").collect();

    println!("{}", foo);

: a,b,c


Auto wrap whole block body in a fn main function call if none exists.

Since this is very handy in most code snippets, so the default value is yes. no if you don't want this feature(for example, you don't want regex search slow things down).

You can also set a default value by:

;; By setq this default to `nil`, you'll have to explict set params to ":main yes" in each block
(setq rustic-babel-auto-wrap-main nil)
#+begin_src rust :main yes
let x = vec![1, 2, 3].iter().map(|&x| x + 1).collect::<Vec<_>>();
println!("{:?}", x);

: [2, 3, 4]


This parameter allows you to run code that is located in different babel blocks by using named blocks with the :include keyword. This feature only concats the blocks so you don't need to import the code you want to use.

You can still use :main to wrap the code of the main block.

#+name: b1
#+begin_src rust
pub fn b1_func() -> String {
    String::from("b1 function called")

#+name: b2
#+begin_src rust
pub fn b2_func() -> String {
    String::from("b2 function called")

#+begin_src rust :include '(b1 b2)
  fn main() {
      println!("{:?}", b1_func());
      println!("{:?}", b2_func());

: "b1 function called"
: "b2 function called"


When using this keyword blocks are treated as modules. The files are generated automatically.

#+name: mymodule
#+begin_src rust
pub fn myfunc() -> String {
    String::from("mymodule function called")

#+begin_src rust :use '(mymodule)
use mymodule::myfunc;

fn main() {
    println!("{:?}", myfunc());

: "mymodule function called"


To load your Rust toolchain via envrc, ensure that the inheritenv package is available before loading rustic, so that auxiliary rustic buffers acquire the correct environment to find the toolchain.


In case you want to use a different spinner type you can modify rustic-spinner-type or turn it off completely with rustic-display-spinner.(Available spinner types).

rust docs in org-mode

It is possible to read rust documentation inside Emacs! This currently requires LSP-mode and cargo. Unfortunately, this probably won't work on Windows. Rustic-doc example



  • pandoc preferably at least version 2.11, as it will give somewhat nicer generated documentation. Versions older than 2.9 may not work - if you're on a debian based distro installing through your regular repo might not work out.
  • cargo
  • cargo-makedocs
  • fd-find Old versions, especially before 2.x, may not work. Install through Cargo if you're having issues.


ripgrep and helm-ag are optional but highly recommended.

If only ripgrep is installed, it will be used with the emacs grep command. In case neither is available, the emacs grep command will use grep, like in the good old days.

When a required cargo package is missing you will be asked if you want to install them when running rustic-doc-setup.


  • Enable rustic-doc-mode.
  • Run rustic-doc-setup to download files that rustic-doc needs to convert rust documentation and also convert std.
  • You can now convert package-specific documentation with rustic-doc-convert-current-package
  • Search the org files with rustic-doc-search (bound to C-# by default) if you are in Rust mode, Rustic mode or Org mode. If you hover over a symbol when you invoke the command, rustic-doc-search will insert a default value.
  • Add universal argument to only search for level 1 headers like struct or enum names.

You can change the defaults by modifying

  • rustic-doc-rg-search-command
  • rustic-doc-search-function


  • You should re-run rustic-doc-setup once in a while, to update the pandoc filter.
  • If rustic-doc does not find the documentation for something, the first thing to do is check the project's target/doc folder for the corresponding .html-file. If there is no file there, there is nothing for rustic-doc to convert. If there is a file there, please create an issue!


You can execute commands with rustic-popup(call it with optional argument C-u to choose a directory). The list of commands can be customized with rustic-popup-commands. The command rustic-popup-default-action (RET or TAB) allows you to change:

  • RUST_BACKTRACE environment variable
  • compilation-arguments for recompile
  • arguments for cargo test

If you want to close the popup after you ran a command you can set rustic-kill-buffer-and-window to t.

View help buffer containing a command's flags with h:


rustic-mode derives from rust-mode, however we replace default key bindings and some hooks.

There are also some additional commands:

  • rust-dbg-wrap-or-unwrap Either remove or add the dbg! macro
  • rust-toggle-mutability Toggles the mutability of the variable defined on the current line
  • rust-promote-module-into-dir Promote the module file visited by the current buffer into its own directory

elisp tests

To run the tests, you will need Cask.

cask exec ert-runner

alternatively you can use make test


PRs, feature requests and bug reports are very welcome. If you want to add a new feature please open an issue in advance so we can discuss the details.