#+title:    :lang rust
#+subtitle: Fe2O3.unwrap().unwrap().unwrap().unwrap()
#+created:  September 30, 2015
#+since:    0.7

* Description :unfold:
This module adds support for the Rust language and integration for its tools,
e.g. ~cargo~.

- Code completion ([[doom-package:racer]] or an LSP server)
- Syntax checking ([[doom-package:flycheck]])
- LSP support (for rust-analyzer and rls) ([[doom-package:rustic]])
- Snippets

** Maintainers
- @hlissner

[[doom-contrib-maintainer:][Become a maintainer?]]

** Module flags
- +lsp ::
  Enable LSP support for ~rustic-mode~. Requires [[doom-module::tools lsp]] and a langserver
  (supports [[https://rust-analyzer.github.io/][rust-analyzer]] and rls).
- +tree-sitter ::
  Leverages tree-sitter for better syntax highlighting and structural text
  editing. Requires [[doom-module::tools tree-sitter]].

** Packages
- [[doom-package:rustic]]

** Hacks
- rustic has been modified /not/ to automatically install lsp-mode or eglot if
  they're missing. Doom expects you to have enabled the [[doom-module::tools lsp]] module
  yourself.

** TODO Changelog
# This section will be machine generated. Don't edit it by hand.
/This module does not have a changelog yet./

* Installation
[[id:01cffea4-3329-45e2-a892-95a384ab2338][Enable this module in your ~doom!~ block.]]

This module requires a working installation of [[https://www.rust-lang.org/][Rust]] for its more advanced
features, and offer only syntax highlighting otherwise. The simplest way to
install it is through [[https://rustup.rs][rustup]]:
#+begin_src sh
$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# And can be updated later with:
$ rustup update --no-self-update
#+end_src

To install and manage Rust on Windows, consult [[https://forge.rust-lang.org/infra/other-installation-methods.html][Rust's official documentation]].

#+begin_quote
 󰐃 Once installed, I recommended that you add Cargo's executable to your
    ~$PATH~, so that the Emacs utilities that depend on it -- or any tools
    installed through it -- can easily locate them (without any added
    configuration on your part).

    Also, if you have used ~$ doom env~ in the past, changes to your ~$PATH~
    won't be visible to Doom until you run it (or ~$ doom sync~) again.
#+end_quote

** Other Requirements
- If [[doom-module::editor format]] is enabled, you'll need =rustfmt=: ~$ rustup component add
  rustfmt~.
- Users with [[doom-module:+lsp]] enabled will need [[github:rust-analyzer/rust-analyzer][rust-analyzer]] (rls is supported,
  but [[https://blog.rust-lang.org/2022/07/01/RLS-deprecation.html][deprecated]]).
- Using the following commands requires:
  - ~cargo-process-check~: ~$ cargo install cargo-check~
  - ~cargo-process-clippy~: ~$ rustup component add clippy-preview~

* TODO Usage
#+begin_quote
 󱌣 /This module's usage documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** LSP support (rust-analyzer)
This module supports [[https://github.com/rust-lang/rust-analyzer][rust-analyzer]] ([[https://github.com/rust-lang/rls][RLS]] too, but it is [[https://blog.rust-lang.org/2022/07/01/RLS-deprecation.html][deprecated]]), which must be installed outside of Emacs, typically with rustup or your OS package manager.

Installation through rustup is simplest:
#+begin_src sh
$ rustup component add rust-analyzer rust-src
#+end_src

If your needs are more complex, consult [[https://rust-analyzer.github.io/manual.html#installation][rust-analyzer's documentation]].

Finally, enable Doom's [[doom-module::tools lsp]] module, and this module's
[[doom-module:+lsp]] flag ([[id:01cffea4-3329-45e2-a892-95a384ab2338][how to enable modules and their flags]]), and you're good
to go!

** Format on save
Enable [[doom-module::editor format +onsave]] to get formatting on save with
=rustfmt=. No additional configuration is necessary.

** Keybinds
| Binding             | Description                 |
|---------------------+-----------------------------|
| =<localleader> b a= | ~cargo audit~               |
| =<localleader> b b= | ~cargo build~               |
| =<localleader> b B= | ~cargo bench~               |
| =<localleader> b c= | ~cargo check~               |
| =<localleader> b C= | ~cargo clippy~              |
| =<localleader> b d= | ~cargo doc~                 |
| =<localleader> b n= | ~cargo update~              |
| =<localleader> b o= | ~cargo outdated~            |
| =<localleader> b r= | ~cargo run~                 |
| =<localleader> t a= | ~cargo test~                |
| =<localleader> t t= | ~run current test~          |

* TODO Configuration
#+begin_quote
 󱌣 /This module's configuration documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** Enabling eglot support for Rust
Doom's [[doom-module::tools lsp]] module has an [[doom-module:+eglot]] flag. Enable it and this module will use
eglot instead.

* Troubleshooting
[[doom-report:][Report an issue?]]

** error[E0670]: `async fn` is not permitted in the 2015 edition
You may be seeing this error, despite having ~edition = "2018"~ in your
=Cargo.toml=. This error actually originates from ~rustfmt~, which the LSP
server tries to invoke on save (if you have ~rustic-format-trigger~ or [[doom-module::editor
format]] enabled).

To fix this your project needs a =rustfmt.toml= with ~edition = "2018"~ in it.

* Frequently asked questions
/This module has no FAQs yet./ [[doom-suggest-faq:][Ask one?]]

* TODO Appendix
#+begin_quote
 󱌣 This module has no appendix yet. [[doom-contrib-module:][Write one?]]
#+end_quote
