# Rust Clippy
* [rust_clippy](#rust_clippy)
* [rust_clippy_aspect](#rust_clippy_aspect)
## Overview
[Clippy][clippy] is a tool for catching common mistakes in Rust code and improving it. An
expansive list of lints and the justification can be found in their [documentation][docs].
[clippy]: https://github.com/rust-lang/rust-clippy#readme
[docs]: https://rust-lang.github.io/rust-clippy/
### Setup
Simply add the following to the `.bazelrc` file in the root of your workspace:
```text
build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect
build --output_groups=+clippy_checks
```
This will enable clippy on all [Rust targets](./defs.md).
Note that targets tagged with `no-clippy` will not perform clippy checks
To use a local clippy.toml, add the following flag to your `.bazelrc`. Note that due to
the upstream implementation of clippy, this file must be named either `.clippy.toml` or
`clippy.toml`. Using a custom config file requires Rust 1.34.0 or newer.
```text
build --@rules_rust//:clippy.toml=//:clippy.toml
```
## rust_clippy
rust_clippy(name, deps)
Executes the clippy checker on a specific target.
Similar to `rust_clippy_aspect`, but allows specifying a list of dependencies within the build system.
For example, given the following example targets:
```python
load("@rules_rust//rust:defs.bzl", "rust_library", "rust_test")
rust_library(
name = "hello_lib",
srcs = ["src/lib.rs"],
)
rust_test(
name = "greeting_test",
srcs = ["tests/greeting.rs"],
deps = [":hello_lib"],
)
```
Rust clippy can be set as a build target with the following:
```python
load("@rules_rust//rust:defs.bzl", "rust_clippy")
rust_clippy(
name = "hello_library_clippy",
testonly = True,
deps = [
":hello_lib",
":greeting_test",
],
)
```
**ATTRIBUTES**
| Name | Description | Type | Mandatory | Default |
| :------------- | :------------- | :------------- | :------------- | :------------- |
| name | A unique name for this target. | Name | required | |
| deps | Rust targets to run clippy on. | List of labels | optional | `[]` |
## rust_clippy_aspect
rust_clippy_aspect(name)
Executes the clippy checker on specified targets.
This aspect applies to existing rust_library, rust_test, and rust_binary rules.
As an example, if the following is defined in `examples/hello_lib/BUILD.bazel`:
```python
load("@rules_rust//rust:defs.bzl", "rust_library", "rust_test")
rust_library(
name = "hello_lib",
srcs = ["src/lib.rs"],
)
rust_test(
name = "greeting_test",
srcs = ["tests/greeting.rs"],
deps = [":hello_lib"],
)
```
Then the targets can be analyzed with clippy using the following command:
```output
$ bazel build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect --output_groups=clippy_checks //hello_lib:all
```
**ASPECT ATTRIBUTES**
**ATTRIBUTES**
| Name | Description | Type | Mandatory | Default |
| :------------- | :------------- | :------------- | :------------- | :------------- |
| name | A unique name for this target. | Name | required | |