Hello fellow Rustacean! Great to see your interest in compiler internals and lints!
+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`.
+
+All contributors are expected to follow the [Rust Code of Conduct](http://www.rust-lang.org/conduct.html).
+
## Getting started
High level approach:
[`T-AST`](https://github.com/rust-lang-nursery/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](http://manishearth.github.io/rust-internals-docs/syntax/ast/). Usually
+[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-nursery/rust-clippy/blob/de5ccdfab68a5e37689f3c950ed1532ba9d652a0/src/misc.rs#L34).
[`T-middle`](https://github.com/rust-lang-nursery/rust-clippy/labels/T-middle) issues can
be more involved and require verifying types. The
-[`ty`](http://manishearth.github.io/rust-internals-docs/rustc/ty) module contains a
+[`ty`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc/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.
`LintPass` with one or more of its default methods overridden. See the existing lints for examples
of this.
+
+#### 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
+
+// The custom_attribute needs to be enabled for the author lint to work
+#![feature(plugin, custom_attribute)]
+
+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 test --test compile-test` to produce
+a `.stdout` file with the generated code:
+
+```rust
+// ./tests/ui/my_lint.stdout
+
+if_chain! {
+ if let Expr_::ExprArray(ref elements) = stmt.node;
+ if elements.len() == 1;
+ if let Expr_::ExprLit(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
/// ```
```
+Once your lint is merged it will show up in the [lint list](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
+
### Running test suite
Clippy uses UI tests. UI tests check that the output of the compiler is exactly as expected.
## Contributions
-Clippy welcomes contributions from everyone.
-
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 code in this repository is under the [Mozilla Public License, 2.0](https://www.mozilla.org/MPL/2.0/)
-## Conduct
-
-We follow the [Rust Code of Conduct](http://www.rust-lang.org/conduct.html).
-
-
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