Hello fellow Rustacean! Great to see your interest in compiler internals and lints!
-**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.
+**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.
-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` IRC channel on `irc.mozilla.org` or meet us in `#wg-clippy` on [Discord](https://discord.gg/rust-lang).
+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` IRC channel on `irc.mozilla.org` or meet us in
+`#clippy` on [Discord](https://discord.gg/rust-lang).
All contributors are expected to follow the [Rust Code of Conduct](http://www.rust-lang.org/conduct.html).
* [Getting started](#getting-started)
* [Finding something to fix/improve](#finding-something-to-fiximprove)
* [Writing code](#writing-code)
- * [Author lint](#author-lint)
- * [Documentation](#documentation)
- * [Running test suite](#running-test-suite)
- * [Running rustfmt](#running-rustfmt)
- * [Testing manually](#testing-manually)
* [How Clippy works](#how-clippy-works)
* [Fixing nightly build failures](#fixing-build-failures-caused-by-rust)
* [Issue and PR Triage](#issue-and-pr-triage)
[`T-middle`](https://github.com/rust-lang/rust-clippy/labels/T-middle) issues, which involve types
and resolved paths.
-[`T-AST`](https://github.com/rust-lang/rust-clippy/labels/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 ast-json` on an
-example of the structure and compare with the
-[nodes in the AST docs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast). Usually
-the lint will end up to be a nested series of matches and ifs,
-[like so](https://github.com/rust-lang/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
+[`T-AST`](https://github.com/rust-lang/rust-clippy/labels/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 ast-json` on an example of the structure and compare with the [nodes in the AST
+docs](https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ast). Usually the lint will end up to be a nested series of
+matches and ifs, [like
+so](https://github.com/rust-lang/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
[`E-medium`](https://github.com/rust-lang/rust-clippy/labels/E-medium) issues are generally
pretty easy too, though it's recommended you work on an E-easy issue first. They are mostly classified
## Writing code
-Clippy depends on the current git master version of rustc, which can change rapidly. Make sure you're
-working near rust-clippy's master, and use the `setup-toolchain.sh` script to configure the appropriate
-toolchain for this directory.
-
-[Llogiq's blog post on lints](https://llogiq.github.io/2015/06/04/workflows.html) is a nice primer
-to lint-writing, though it does get into advanced stuff. Most lints consist of an implementation of
-`LintPass` with one or more of its default methods overridden. See the existing lints for examples
-of this.
+Have a look at the [docs for writing lints](doc/adding_lints.md) for more details. [Llogiq's blog post on
+lints](https://llogiq.github.io/2015/06/04/workflows.html) is also a nice primer to lint-writing, though it does get
+into advanced stuff and may be a bit outdated.
If you want to add a new lint or change existing ones apart from bugfixing, it's
also a good idea to give the [stability guarantees][rfc_stability] and
[lint categories][rfc_lint_cats] sections of the [Clippy 1.0 RFC][clippy_rfc] a
quick read.
-### Author lint
-
-There is also the internal `author` lint to generate Clippy code that detects the offending pattern. It does not work for all of the Rust syntax, but can give a good starting point.
-
-First, create a new UI test file in the `tests/ui/` directory with the pattern you want to match:
-
-```rust
-// ./tests/ui/my_lint.rs
-fn main() {
- #[clippy::author]
- let arr: [i32; 1] = [7]; // Replace line with the code you want to match
-}
-```
-
-Now you run `TESTNAME=ui/my_lint cargo uitest` to produce
-a `.stdout` file with the generated code:
-
-```rust
-// ./tests/ui/my_lint.stdout
-
-if_chain! {
- if let ExprKind::Array(ref elements) = stmt.node;
- if elements.len() == 1;
- if let ExprKind::Lit(ref lit) = elements[0].node;
- if let LitKind::Int(7, _) = lit.node;
- then {
- // report your lint here
- }
-}
-```
-
-If the command was executed successfully, you can copy the code over to where you are implementing your lint.
-
-### Documentation
-
-Please document your lint with a doc comment akin to the following:
-
-```rust
-/// **What it does:** Checks for ... (describe what the lint matches).
-///
-/// **Why is this bad?** Supply the reason for linting the code.
-///
-/// **Known problems:** None. (Or describe where it could go wrong.)
-///
-/// **Example:**
-///
-/// ```rust
-/// // Bad
-/// Insert a short example of code that triggers the lint
-///
-/// // Good
-/// Insert a short example of improved code that doesn't trigger the lint
-/// ```
-```
-
-Once your lint is merged it will show up in the [lint list](https://rust-lang.github.io/rust-clippy/master/index.html)
-
-### Running test suite
-
-Use `cargo test` to run the whole testsuite.
-
-If you don't want to wait for all tests to finish, you can also execute a single test file by using `TESTNAME` to specify the test to run:
-
-```bash
-TESTNAME=ui/empty_line_after_outer_attr cargo uitest
-```
-
-Clippy uses UI tests. UI tests check that the output of the compiler is exactly as expected.
-Of course there's little sense in writing the output yourself or copying it around.
-Therefore you should use `tests/ui/update-all-references.sh` (after running
-`cargo test`) and check whether the output looks as you expect with `git diff`. Commit all
-`*.stderr` files, too.
-
-If the lint you are working on is making use of structured suggestions, the
-test file should include a `// run-rustfix` comment at the top. This will
-additionally run [rustfix](https://github.com/rust-lang-nursery/rustfix) for
-that test. Rustfix will apply the suggestions from the lint to the code of the
-test file and compare that to the contents of a `.fixed` file.
-
-Use `tests/ui/update-all-references.sh` to automatically generate the
-`.fixed` file after running `cargo test`.
-
-### Running rustfmt
-
-[Rustfmt](https://github.com/rust-lang/rustfmt) is a tool for formatting Rust code according
-to style guidelines. The code has to be formatted by `rustfmt` before a PR will be merged.
-
-It can be installed via `rustup`:
-```bash
-rustup component add rustfmt
-```
-
-Use `cargo fmt --all` to format the whole codebase.
-
-### Testing manually
-
-Manually testing against an example file is useful if you have added some
-`println!`s and test suite output becomes unreadable. To try Clippy with your
-local modifications, run `env CLIPPY_TESTS=true cargo run --bin clippy-driver -- -L ./target/debug input.rs`
-from the working copy root.
-
## How Clippy works
-Clippy is a [rustc compiler plugin][compiler_plugin]. The main entry point is at [`src/lib.rs`][main_entry]. In there, the lint registration is delegated to the [`clippy_lints`][lint_crate] crate.
+Clippy is a [rustc compiler plugin][compiler_plugin]. The main entry point is at [`src/lib.rs`][main_entry]. In there,
+the lint registration is delegated to the [`clippy_lints`][lint_crate] crate.
-[`clippy_lints/src/lib.rs`][lint_crate_entry] imports all the different lint modules and registers them with the rustc plugin registry. For example, the [`else_if_without_else`][else_if_without_else] lint is registered like this:
+[`clippy_lints/src/lib.rs`][lint_crate_entry] imports all the different lint modules and registers them with the rustc
+plugin registry. 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(reg: &mut rustc_plugin::Registry) {
+pub fn register_plugins(reg: &mut rustc_driver::plugin::Registry) {
// ...
reg.register_early_lint_pass(box else_if_without_else::ElseIfWithoutElse);
// ...
}
```
-The [`rustc_plugin::PluginRegistry`][plugin_registry] provides two methods to register lints: [register_early_lint_pass][reg_early_lint_pass] and [register_late_lint_pass][reg_late_lint_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 `util/dev update_lints` and you don't have to add anything by hand. When you are writing your own lint, you can use that script to save you some time.
+The [`plugin::PluginRegistry`][plugin_registry] provides two methods to register lints:
+[register_early_lint_pass][reg_early_lint_pass] and [register_late_lint_pass][reg_late_lint_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` and you don't have to add anything by hand. 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, LintArray, LintPass};
+use rustc_lint::{EarlyLintPass, EarlyContext};
// ...
}
```
-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.
+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_lint_pass` function. Because the [actual lint logic][else_if_without_else] does not depend on any type information.
+That's why the `else_if_without_else` example uses the `register_early_lint_pass` function. Because the [actual lint
+logic][else_if_without_else] does not depend on any type information.
## Fixing build failures caused by Rust
-Clippy will sometimes fail to build from source because building it depends on unstable internal Rust features. Most of the times we have to adapt to the changes and only very rarely there's an actual bug in Rust. Fixing build failures caused by Rust updates, can be a good way to learn about Rust internals.
+Clippy will sometimes fail to build from source because building it depends on unstable internal Rust features. Most of
+the times we have to adapt to the changes and only very rarely there's an actual bug in Rust. Fixing build failures
+caused by Rust updates, can be a good way to learn about Rust internals.
-In order to find out why Clippy does not work properly with a new Rust commit, you can use the [rust-toolstate commit history][toolstate_commit_history].
-You will then have to look for the last commit that contains `test-pass -> build-fail` or `test-pass` -> `test-fail` for the `clippy-driver` component. [Here][toolstate_commit] is an example.
+In order to find out why Clippy does not work properly with a new Rust commit, you can use the [rust-toolstate commit
+history][toolstate_commit_history]. You will then have to look for the last commit that contains `test-pass ->
+build-fail` or `test-pass` -> `test-fail` for the `clippy-driver` component. [Here][toolstate_commit] is an example.
-The commit message contains a link to the PR. The PRs are usually small enough to discover the breaking API change and if they are bigger, they likely include some discussion that may help you to fix Clippy.
+The commit message contains a link to the PR. The PRs are usually small enough to discover the breaking API change and
+if they are bigger, they likely include some discussion that may help you to fix Clippy.
To check if Clippy is available for a specific target platform, you can check
the [rustup component history][rustup_component_history].
You can use [rustup-toolchain-install-master][rtim] to do that:
-```
+```bash
cargo install rustup-toolchain-install-master
-rustup-toolchain-install-master -n master --force
+rustup-toolchain-install-master --force -n master -c rustc-dev
rustup override set master
cargo test
```
+After fixing the build failure on this repository, we can submit a pull request
+to [`rust-lang/rust`] to fix the toolstate.
+
+To submit a pull request, you should follow these steps:
+
+```bash
+# Assuming you already cloned the rust-lang/rust repo and you're in the correct directory
+git submodule update --remote src/tools/clippy
+cargo update -p clippy
+git add -u
+git commit -m "Update Clippy"
+./x.py test -i --stage 1 src/tools/clippy # This is optional and should succeed anyway
+# Open a PR in rust-lang/rust
+```
+
## Issue and PR triage
Clippy is following the [Rust triage procedure][triage] for issues and pull
[lint_crate_entry]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/lib.rs
[else_if_without_else]: https://github.com/rust-lang/rust-clippy/blob/c5b39a5917ffc0f1349b6e414fa3b874fdcf8429/clippy_lints/src/else_if_without_else.rs
[compiler_plugin]: https://doc.rust-lang.org/unstable-book/language-features/plugin.html#lint-plugins
-[plugin_registry]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin/registry/struct.Registry.html
-[reg_early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin/registry/struct.Registry.html#method.register_early_lint_pass
-[reg_late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin/registry/struct.Registry.html#method.register_late_lint_pass
+[plugin_registry]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html
+[reg_early_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html#method.register_early_lint_pass
+[reg_late_lint_pass]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc_plugin_impl/registry/struct.Registry.html#method.register_late_lint_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
[toolstate_commit_history]: https://github.com/rust-lang-nursery/rust-toolstate/commits/master
[homu]: https://github.com/servo/homu
[homu_instructions]: https://buildbot2.rust-lang.org/homu/
[homu_queue]: https://buildbot2.rust-lang.org/homu/queue/clippy
+[`rust-lang/rust`]: https://github.com/rust-lang/rust
projects / rust.git / blobdiff