1 unstable release

Uses old Rust 2015

0.1.0 Aug 27, 2018

#1521 in Rust patterns

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298 downloads per month
Used in 3 crates (via racer-cargo-metadata)

MIT license

103 lines

Racer - code completion for Rust

Build Status

racer completion screenshot

racer eldoc screenshot

RACER = Rust Auto-Complete-er. A utility intended to provide Rust code completion for editors and IDEs. Maybe one day the 'er' bit will be exploring + refactoring or something.


Racer is not actively developped now. Please consider using newer software such as rust-analyzer.


NOTE From 2.1, racer needs nightly rust


Current nightly Rust

If you're using rustup, run

rustup toolchain install nightly
rustup component add rustc-dev --toolchain=nightly

Note: The second command adds the rustc-dev component to the nightly toolchain, which is necessary to compile Racer.


Internally, racer calls cargo as a CLI tool, so please make sure cargo is installed

With cargo install

Simply run:

cargo +nightly install racer

As mentioned in the command output, don't forget to add the installation directory to your PATH.

From sources

  1. Clone the repository: git clone https://github.com/racer-rust/racer.git

  2. cd racer; cargo +nightly build --release. The binary will now be in ./target/release/racer

  3. Add the binary to your PATH. This can be done by moving it to a directory already in your PATH (i.e. /usr/local/bin) or by adding the ./target/release/ directory to your PATH


  1. Fetch the Rust sourcecode

    1. automatically via rustup and run rustup component add rust-src in order to install the source to $(rustc --print sysroot)/lib/rustlib/src/rust/library (or $(rustc --print sysroot)/lib/rustlib/src/rust/src in older toolchains). Rustup will keep the sources in sync with the toolchain if you run rustup update.

    2. manually from git: https://github.com/rust-lang/rust


    If you want to use racer with multiple release channels (Rust has 3 release channels: stable, beta and nightly), you have to also download Rust source code for each release channel you install.

    e.g. (rustup case) Add a nightly toolchain build and install nightly sources too

    rustup toolchain add nightly

    rustup component add rust-src

  2. (Optional) Set RUST_SRC_PATH environment variable to point to the 'src' dir in the Rust source installation e.g. % export RUST_SRC_PATH=$(rustc --print sysroot)/lib/rustlib/src/rust/library or % export RUST_SRC_PATH="$(rustc --print sysroot)/lib/rustlib/src/rust/src" (older)

    It's recommended to set RUST_SRC_PATH for speed up, but racer detects it automatically if you don't set it.

  3. Test on the command line:

    racer complete std::io::B (should show some completions)


To complete names in external crates, Racer needs Cargo.lock. So, when you add a dependency in your Cargo.toml, you have to run a build command such as cargo build or cargo test, to get completions.

Editors/IDEs Supported


Racer is used as a static library in RLS

Eclipse integration

Racer can be used with Eclipse through the use of RustDT. (User guide is linked in repo description)

Emacs integration

Emacs integration has been moved to a separate project: emacs-racer.

Gedit integration

Gedit integration can be found here.

Builder integration

Gnome Builder integration can be found here

Kate integration

The Kate community maintains a plugin. It is bundled with recent releases of Kate (tested with 16.08 - read more here).

  1. Enable 'Rust code completion' in the plugin list in the Kate config dialog;

  2. On the new 'Rust code completion' dialog page, make sure 'Racer command' and 'Rust source tree location' are set correctly.

Sublime Text integration

The Sublime Text community maintains some packages that integrates Racer

  • RustAutoComplete that offers auto completion and goto definition.
  • AnacondaRUST from the anaconda plugins family that offers auto completion, goto definition and show documentation

Vim integration

Vim integration has been moved to a separate project: vim-racer.

Visual Studio Code extension

Racer recommends the official Rust (rls) extension based on RLS, which uses Racer for completion.

Atom integration

You can find the racer package for Atom here

Kakoune integration

Kakoune comes with a builtin integration for racer auto completion.


string interner same as cargo::core::interning.rs, but thread local and Deserializable