-# Contributing to Clippy
+# Contributing to Rust
-Hello fellow Rustacean! Great to see your interest in compiler internals and lints!
+Thank you for your interest in contributing to Rust! There are many ways to contribute
+and we appreciate all of them.
-**First**: if you're unsure or afraid of _anything_, just ask or submit the issue or pull request anyway. You won't be
-yelled at for giving it your best effort. The worst that can happen is that you'll be politely asked to change
-something. We appreciate any sort of contributions, and don't want a wall of rules to get in the way of that.
+The best way to get started is by asking for help in the [#new
+members](https://rust-lang.zulipchat.com/#narrow/stream/122652-new-members)
+Zulip stream. We have lots of docs below of how to get started on your own, but
+the Zulip stream is the best place to *ask* for help.
-Clippy welcomes contributions from everyone. There are many ways to contribute to Clippy and the following document
-explains how you can contribute and how to get started. If you have any questions about contributing or need help with
-anything, feel free to ask questions on issues or visit the `#clippy` on [Zulip].
+Documentation for contributing to the compiler or tooling is located in the [Guide to Rustc
+Development][rustc-dev-guide], commonly known as the [rustc-dev-guide]. Documentation for the
+standard library in the [Standard library developers Guide][std-dev-guide], commonly known as the [std-dev-guide].
-All contributors are expected to follow the [Rust Code of Conduct].
+## About the [rustc-dev-guide]
-- [Contributing to Clippy](#contributing-to-clippy)
- - [The Clippy book](#the-clippy-book)
- - [High level approach](#high-level-approach)
- - [Finding something to fix/improve](#finding-something-to-fiximprove)
- - [Getting code-completion for rustc internals to work](#getting-code-completion-for-rustc-internals-to-work)
- - [IntelliJ Rust](#intellij-rust)
- - [Rust Analyzer](#rust-analyzer)
- - [How Clippy works](#how-clippy-works)
- - [Issue and PR triage](#issue-and-pr-triage)
- - [Bors and Homu](#bors-and-homu)
- - [Contributions](#contributions)
- - [License](#license)
+The [rustc-dev-guide] is meant to help document how rustc –the Rust compiler– works,
+as well as to help new contributors get involved in rustc development. It is recommend
+to read and understand the [rustc-dev-guide] before making a contribution. This guide
+talks about the different bots in the Rust ecosystem, the Rust development tools,
+bootstrapping, the compiler architecture, source code representation, and more.
-[Zulip]: https://rust-lang.zulipchat.com/#narrow/stream/clippy
-[Rust Code of Conduct]: https://www.rust-lang.org/policies/code-of-conduct
+## [Getting help](https://rustc-dev-guide.rust-lang.org/getting-started.html#asking-questions)
-## The Clippy book
+There are many ways you can get help when you're stuck. Rust has many platforms for this:
+[internals], [rust-zulip], and [rust-discord]. It is recommended to ask for help on
+the [rust-zulip], but any of these platforms are a great way to seek help and even
+find a mentor! You can learn more about asking questions and getting help in the
+[Asking Questions](https://rustc-dev-guide.rust-lang.org/getting-started.html#asking-questions) chapter of the [rustc-dev-guide].
-If you're new to Clippy and don't know where to start, the [Clippy book] includes
-a [developer guide] and is a good place to start your journey.
+## Bug reports
-[Clippy book]: https://doc.rust-lang.org/nightly/clippy/index.html
-[developer guide]: https://doc.rust-lang.org/nightly/clippy/development/index.html
+Did a compiler error message tell you to come here? If you want to create an ICE report,
+refer to [this section][contributing-bug-reports] and [open an issue][issue template].
-## High level approach
-
-1. Find something to fix/improve
-2. Change code (likely some file in `clippy_lints/src/`)
-3. Follow the instructions in the [Basics docs](book/src/development/basics.md)
- to get set up
-4. Run `cargo test` in the root directory and wiggle code until it passes
-5. Open a PR (also can be done after 2. if you run into problems)
-
-## Finding something to fix/improve
-
-All issues on Clippy are mentored, if you want help simply ask someone from the
-Clippy team directly by mentioning them in the issue or over on [Zulip]. All
-currently active team members can be found
-[here](https://github.com/rust-lang/highfive/blob/master/highfive/configs/rust-lang/rust-clippy.json#L3)
-
-Some issues are easier than others. The [`good-first-issue`] label can be used to find the easy
-issues. You can use `@rustbot claim` to assign the issue to yourself.
-
-There are also some abandoned PRs, marked with [`S-inactive-closed`].
-Pretty often these PRs are nearly completed and just need some extra steps
-(formatting, addressing review comments, ...) to be merged. If you want to
-complete such a PR, please leave a comment in the PR and open a new one based
-on it.
-
-Issues marked [`T-AST`] involve simple matching of the syntax tree structure,
-and are generally easier than [`T-middle`] issues, which involve types
-and resolved paths.
-
-[`T-AST`] issues will generally need you to match against a predefined syntax structure.
-To figure out how this syntax structure is encoded in the AST, it is recommended to run
-`rustc -Z unpretty=ast-tree` on an example of the structure and compare with the [nodes in the AST docs].
-Usually the lint will end up to be a nested series of matches and ifs, [like so][deep-nesting].
-But we can make it nest-less by using [let chains], [like this][nest-less].
-
-[`E-medium`] issues are generally pretty easy too, though it's recommended you work on an [`good-first-issue`]
-first. Sometimes they are only somewhat involved code wise, but not difficult per-se.
-Note that [`E-medium`] issues may require some knowledge of Clippy internals or some
-debugging to find the actual problem behind the issue.
-
-[`T-middle`] issues can be more involved and require verifying types. The [`ty`] module contains a
-lot of methods that are useful, though one of the most useful would be `expr_ty` (gives the type of
-an AST expression). `match_def_path()` in Clippy's `utils` module can also be useful.
-
-[`good-first-issue`]: https://github.com/rust-lang/rust-clippy/labels/good-first-issue
-[`S-inactive-closed`]: https://github.com/rust-lang/rust-clippy/pulls?q=is%3Aclosed+label%3AS-inactive-closed
-[`T-AST`]: https://github.com/rust-lang/rust-clippy/labels/T-AST
-[`T-middle`]: https://github.com/rust-lang/rust-clippy/labels/T-middle
-[`E-medium`]: https://github.com/rust-lang/rust-clippy/labels/E-medium
-[`ty`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty
-[nodes in the AST docs]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_ast/ast/
-[deep-nesting]: https://github.com/rust-lang/rust-clippy/blob/5e4f0922911536f80d9591180fa604229ac13939/clippy_lints/src/mem_forget.rs#L31-L45
-[let chains]: https://github.com/rust-lang/rust/pull/94927
-[nest-less]: https://github.com/rust-lang/rust-clippy/blob/5e4f0922911536f80d9591180fa604229ac13939/clippy_lints/src/bit_mask.rs#L133-L159
-
-## Getting code-completion for rustc internals to work
-
-### IntelliJ Rust
-Unfortunately, [`IntelliJ Rust`][IntelliJ_rust_homepage] does not (yet?) understand how Clippy uses compiler-internals
-using `extern crate` and it also needs to be able to read the source files of the rustc-compiler which are not
-available via a `rustup` component at the time of writing.
-To work around this, you need to have a copy of the [rustc-repo][rustc_repo] available which can be obtained via
-`git clone https://github.com/rust-lang/rust/`.
-Then you can run a `cargo dev` command to automatically make Clippy use the rustc-repo via path-dependencies
-which `IntelliJ Rust` will be able to understand.
-Run `cargo dev setup intellij --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
-you just cloned.
-The command will add path-dependencies pointing towards rustc-crates inside the rustc repo to
-Clippy's `Cargo.toml`s and should allow `IntelliJ Rust` to understand most of the types that Clippy uses.
-Just make sure to remove the dependencies again before finally making a pull request!
-
-[rustc_repo]: https://github.com/rust-lang/rust/
-[IntelliJ_rust_homepage]: https://intellij-rust.github.io/
-
-### Rust Analyzer
-For [`rust-analyzer`][ra_homepage] to work correctly make sure that in the `rust-analyzer` configuration you set
-
-```json
-{ "rust-analyzer.rustc.source": "discover" }
-```
-
-You should be able to see information on things like `Expr` or `EarlyContext` now if you hover them, also
-a lot more type hints.
-
-To have `rust-analyzer` also work in the `clippy_dev` and `lintcheck` crates, add the following configuration
-
-```json
-{
- "rust-analyzer.linkedProjects": [
- "./Cargo.toml",
- "clippy_dev/Cargo.toml",
- "lintcheck/Cargo.toml",
- ]
-}
-```
-
-[ra_homepage]: https://rust-analyzer.github.io/
-
-## How Clippy works
-
-[`clippy_lints/src/lib.rs`][lint_crate_entry] imports all the different lint modules and registers in the [`LintStore`].
-For example, the [`else_if_without_else`][else_if_without_else] lint is registered like this:
-
-```rust
-// ./clippy_lints/src/lib.rs
-
-// ...
-pub mod else_if_without_else;
-// ...
-
-pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &Conf) {
- // ...
- store.register_early_pass(|| box else_if_without_else::ElseIfWithoutElse);
- // ...
-
- store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
- // ...
- LintId::of(&else_if_without_else::ELSE_IF_WITHOUT_ELSE),
- // ...
- ]);
-}
-```
-
-The [`rustc_lint::LintStore`][`LintStore`] provides two methods to register lints:
-[register_early_pass][reg_early_pass] and [register_late_pass][reg_late_pass]. Both take an object
-that implements an [`EarlyLintPass`][early_lint_pass] or [`LateLintPass`][late_lint_pass] respectively. This is done in
-every single lint. It's worth noting that the majority of `clippy_lints/src/lib.rs` is autogenerated by `cargo dev
-update_lints`. When you are writing your own lint, you can use that script to save you some time.
-
-```rust
-// ./clippy_lints/src/else_if_without_else.rs
-
-use rustc_lint::{EarlyLintPass, EarlyContext};
-
-// ...
-
-pub struct ElseIfWithoutElse;
-
-// ...
-
-impl EarlyLintPass for ElseIfWithoutElse {
- // ... the functions needed, to make the lint work
-}
-```
-
-The difference between `EarlyLintPass` and `LateLintPass` is that the methods of the `EarlyLintPass` trait only provide
-AST information. The methods of the `LateLintPass` trait are executed after type checking and contain type information
-via the `LateContext` parameter.
-
-That's why the `else_if_without_else` example uses the `register_early_pass` function. Because the
-[actual lint logic][else_if_without_else] does not depend on any type information.
-
-[lint_crate_entry]: https://github.com/rust-lang/rust-clippy/blob/master/clippy_lints/src/lib.rs
-[else_if_without_else]: https://github.com/rust-lang/rust-clippy/blob/4253aa7137cb7378acc96133c787e49a345c2b3c/clippy_lints/src/else_if_without_else.rs
-[`LintStore`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html
-[reg_early_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html#method.register_early_pass
-[reg_late_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/struct.LintStore.html#method.register_late_pass
-[early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/trait.EarlyLintPass.html
-[late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint/trait.LateLintPass.html
-
-## Issue and PR triage
-
-Clippy is following the [Rust triage procedure][triage] for issues and pull
-requests.
-
-However, we are a smaller project with all contributors being volunteers
-currently. Between writing new lints, fixing issues, reviewing pull requests and
-responding to issues there may not always be enough time to stay on top of it
-all.
-
-Our highest priority is fixing [crashes][l-crash] and [bugs][l-bug], for example
-an ICE in a popular crate that many other crates depend on. We don't
-want Clippy to crash on your code and we want it to be as reliable as the
-suggestions from Rust compiler errors.
-
-We have prioritization labels and a sync-blocker label, which are described below.
-- [P-low][p-low]: Requires attention (fix/response/evaluation) by a team member but isn't urgent.
-- [P-medium][p-medium]: Should be addressed by a team member until the next sync.
-- [P-high][p-high]: Should be immediately addressed and will require an out-of-cycle sync or a backport.
-- [L-sync-blocker][l-sync-blocker]: An issue that "blocks" a sync.
-Or rather: before the sync this should be addressed,
-e.g. by removing a lint again, so it doesn't hit beta/stable.
-
-## Bors and Homu
-
-We use a bot powered by [Homu][homu] to help automate testing and landing of pull
-requests in Clippy. The bot's username is @bors.
-
-You can find the Clippy bors queue [here][homu_queue].
-
-If you have @bors permissions, you can find an overview of the available
-commands [here][homu_instructions].
-
-[triage]: https://forge.rust-lang.org/release/triage-procedure.html
-[l-crash]: https://github.com/rust-lang/rust-clippy/labels/L-crash
-[l-bug]: https://github.com/rust-lang/rust-clippy/labels/L-bug
-[p-low]: https://github.com/rust-lang/rust-clippy/labels/P-low
-[p-medium]: https://github.com/rust-lang/rust-clippy/labels/P-medium
-[p-high]: https://github.com/rust-lang/rust-clippy/labels/P-high
-[l-sync-blocker]: https://github.com/rust-lang/rust-clippy/labels/L-sync-blocker
-[homu]: https://github.com/rust-lang/homu
-[homu_instructions]: https://bors.rust-lang.org/
-[homu_queue]: https://bors.rust-lang.org/queue/clippy
-
-## Contributions
-
-Contributions to Clippy should be made in the form of GitHub pull requests. Each pull request will
-be reviewed by a core contributor (someone with permission to land patches) and either landed in the
-main tree or given feedback for changes that would be required.
-
-All PRs should include a `changelog` entry with a short comment explaining the change. The rule of thumb is basically,
-"what do you believe is important from an outsider's perspective?" Often, PRs are only related to a single property of a
-lint, and then it's good to mention that one. Otherwise, it's better to include too much detail than too little.
-
-Clippy's [changelog] is created from these comments. Every release, someone gets all commits from bors with a
-`changelog: XYZ` entry and combines them into the changelog. This is a manual process.
-
-Examples:
-- New lint
- ```
- changelog: new lint: [`missing_trait_methods`]
- ```
-- False positive fix
- ```
- changelog: Fix [`unused_peekable`] false positive when peeked in a closure or called as `f(&mut peekable)`
- ```
-- Purely internal change
- ```
- changelog: none
- ```
-
-Note this it is fine for a PR to include multiple `changelog` entries, e.g.:
-```
-changelog: Something 1
-changelog: Something 2
-changelog: Something 3
-```
-
-[changelog]: CHANGELOG.md
-
-## License
-
-All code in this repository is under the [Apache-2.0] or the [MIT] license.
-
-<!-- adapted from https://github.com/servo/servo/blob/master/CONTRIBUTING.md -->
-
-[Apache-2.0]: https://www.apache.org/licenses/LICENSE-2.0
-[MIT]: https://opensource.org/licenses/MIT
+[Contributing to Rust]: https://rustc-dev-guide.rust-lang.org/contributing.html#contributing-to-rust
+[rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org/
+[std-dev-guide]: https://std-dev-guide.rust-lang.org/
+[contributing-bug-reports]: https://rustc-dev-guide.rust-lang.org/contributing.html#bug-reports
+[issue template]: https://github.com/rust-lang/rust/issues/new/choose
+[internals]: https://internals.rust-lang.org
+[rust-discord]: http://discord.gg/rust-lang
+[rust-zulip]: https://rust-lang.zulipchat.com
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