1 We are currently in the process of discussing Clippy 1.0 via the RFC process in https://github.com/rust-lang/rfcs/pull/2476 . The RFC's goal is to clarify policies around lint categorizations and the policy around which lints should be in the compiler and which lints should be in Clippy. Please leave your thoughts on the RFC PR.
5 [![Build Status](https://travis-ci.org/rust-lang-nursery/rust-clippy.svg?branch=master)](https://travis-ci.org/rust-lang-nursery/rust-clippy)
6 [![Windows Build status](https://ci.appveyor.com/api/projects/status/id677xpw1dguo7iw?svg=true)](https://ci.appveyor.com/project/rust-lang-libs/rust-clippy)
7 [![Current Version](https://meritbadge.herokuapp.com/clippy)](https://crates.io/crates/clippy)
8 [![License: MPL-2.0](https://img.shields.io/crates/l/clippy.svg)](#license)
10 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
12 [There are 273 lints included in this crate!](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
14 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
16 * `clippy` (everything that has no false positives)
17 * `clippy_pedantic` (everything)
18 * `clippy_nursery` (new lints that aren't quite ready yet)
19 * `clippy_style` (code that should be written in a more idiomatic way)
20 * `clippy_complexity` (code that does something simple but in a complex way)
21 * `clippy_perf` (code that can be written in a faster way)
22 * `clippy_cargo` (checks against the cargo manifest)
23 * **`clippy_correctness`** (code that is just outright wrong or very very useless)
25 More to come, please [file an issue](https://github.com/rust-lang-nursery/rust-clippy/issues) if you have ideas!
29 * [Usage instructions](#usage)
30 * [Configuration](#configuration)
35 Since this is a tool for helping the developer of a library or application
36 write better code, it is recommended not to include Clippy as a hard dependency.
37 Options include using it as an optional dependency, as a cargo subcommand, or
38 as an included feature during build. These options are detailed below.
40 ### As a cargo subcommand (`cargo clippy`)
42 One way to use Clippy is by installing Clippy through rustup as a cargo
45 #### Step 1: Install rustup
47 You can install [rustup](http://rustup.rs/) on supported platforms. This will help
48 us install clippy and its dependencies.
50 If you already have rustup installed, update to ensure you have the latest
57 #### Step 2: Install nightly toolchain
59 Rustup integration is still new, you will need a relatively new nightly (2018-07-15 or later).
61 To install Rust nightly with [rustup](https://rustup.rs/):
64 rustup install nightly
67 #### Step 3: Install clippy
69 Once you have rustup and the nightly toolchain installed, run the following command:
72 rustup component add clippy-preview --toolchain=nightly
75 Now you can run Clippy by invoking `cargo +nightly clippy`. If nightly is your
76 default toolchain in rustup, `cargo clippy` will work fine.
78 ### Running Clippy from the command line without installing it
80 To have cargo compile your crate with Clippy without Clippy installation
81 in your code, you can use:
84 cargo run --bin cargo-clippy --manifest-path=path_to_clippys_Cargo.toml
87 *[Note](https://github.com/rust-lang-nursery/rust-clippy/wiki#a-word-of-warning):*
88 Be sure that Clippy was compiled with the same version of rustc that cargo invokes here!
92 Some lints can be configured in a TOML file named with `clippy.toml` or `.clippy.toml`. It contains basic `variable = value` mapping eg.
95 blacklisted-names = ["toto", "tata", "titi"]
96 cyclomatic-complexity-threshold = 30
99 See the [list of lints](https://rust-lang-nursery.github.io/rust-clippy/master/index.html) for more information about which lints can be configured and the
100 meaning of the variables.
102 To deactivate the “for further information visit *lint-link*” message you can
103 define the `CLIPPY_DISABLE_DOCS_LINKS` environment variable.
105 ### Allowing/denying lints
107 You can add options to `allow`/`warn`/`deny`:
109 * the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy)]`)
111 * all lints using both the `clippy` and `clippy_pedantic` lint groups (`#![deny(clippy)]`,
112 `#![deny(clippy_pedantic)]`). Note that `clippy_pedantic` contains some very aggressive
113 lints prone to false positives.
115 * only some lints (`#![deny(single_match, box_vec)]`, etc)
117 * `allow`/`warn`/`deny` can be limited to a single function or module using `#[allow(...)]`, etc
119 Note: `deny` produces errors instead of warnings.
121 For convenience, `cargo clippy` automatically defines a `cargo-clippy`
122 feature. This lets you set lint levels and compile with or without Clippy
126 #[cfg_attr(feature = "cargo-clippy", allow(needless_lifetimes))]
131 Sometimes, rustc moves forward without Clippy catching up. Therefore updating
132 rustc may leave Clippy a non-functional state until we fix the resulting
135 You can use the [rust-update](rust-update) script to update rustc only if
136 Clippy would also update correctly.
140 Licensed under [MPL](https://www.mozilla.org/MPL/2.0/).
141 If you're having issues with the license, let me know and I'll try to change it to something more permissive.