The Rust Programming Language

This is the main source code repository for Rust. It contains the rustc compiler, the standard library (std, core, alloc, proc_macro, and friends), rustdoc, the bootstrap build system, the compiletest-based test suite, and a long list of subtree tools (miri, clippy, rustfmt, rust-analyzer, etc.). The repository is the canonical home of the language's reference implementation and ships every nightly, beta, and stable Rust release.

What lives here

The repository is structured around four top-level directories that each form a major area:

• compiler/ — the rustc compiler crates (~70 rustc_* crates)
• library/ — the Rust standard library and surrounding runtime crates (core, alloc, std, proc_macro, panic_unwind, compiler-builtins, etc.)
• src/ — the bootstrap build system, rustdoc, documentation, and subtree tools (src/tools/)
• tests/ — the language test suite, run by the compiletest harness

Build, test, and ship orchestration is done by x.py (a thin wrapper around src/bootstrap/) which manages the multi-stage bootstrap process — using a downloaded "stage 0" compiler to build the stage 1 compiler, then using stage 1 to build the stage 2 (final) compiler.

Where to start

You want to...	Read
Install Rust as a user	rust-lang.org/learn/get-started
Build the compiler from source	Getting started, INSTALL.md
Understand how rustc is structured	Architecture
Learn the project's vocabulary (HIR, MIR, query, …)	Glossary
Contribute a fix or feature	How to contribute
Find the deeper compiler dev manual	rustc-dev-guide
Browse the standard library	Library packages
Read about a specific compiler crate	Compiler systems

Project size at a glance

A snapshot taken from the current checkout (commit f53b654a888):

• ~70 rustc_* crates under compiler/
• ~25 crates under library/ (standard library, runtime, test infrastructure)
• ~50 subtree tools under src/tools/ (rustdoc, miri, clippy, rustfmt, rust-analyzer, tidy, compiletest, …)
• 25,000+ test files under tests/ driven by compiletest
• ~9,000 Rust source files in compiler + library + tools combined

For a richer breakdown see By the numbers.

Governance and contribution model

Rust is governed by the Rust project teams — T-compiler, T-libs, T-lang, T-types, T-bootstrap, T-rustdoc, etc. — and the day-to-day workflow is heavily automated:

• bors / homu / rust-bors merges PRs only after a full CI run, ensuring main stays green
• triagebot assigns reviewers, applies labels, and routes nominations (configured in triagebot.toml)
• rustbot issues rollups of small PRs
• subtree tools (clippy, miri, rustfmt, rust-analyzer) live in their own repos and are pulled in via git subtree

See How to contribute and the upstream rustc-dev-guide for the full workflow.

License

Rust is dual-licensed under MIT and Apache-2.0, with portions covered by other BSD-style licenses listed in COPYRIGHT.