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)
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8 [![License: MIT/Apache-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 279 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::all` (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 Clippy
59 Once you have rustup and the latest stable release (at least Rust 1.29) installed, run the following command:
62 rustup component add clippy-preview
65 Now you can run Clippy by invoking `cargo clippy`.
67 If it says that it can't find the `clippy` subcommand, please run `rustup self update`
69 ### Running Clippy from the command line without installing it
71 To have cargo compile your crate with Clippy without Clippy installation
72 in your code, you can use:
75 cargo run --bin cargo-clippy --manifest-path=path_to_clippys_Cargo.toml
78 *[Note](https://github.com/rust-lang-nursery/rust-clippy/wiki#a-word-of-warning):*
79 Be sure that Clippy was compiled with the same version of rustc that cargo invokes here!
83 You can add Clippy to Travis CI in the same way you use it locally:
91 - rustup component add clippy-preview
94 # if you want the build job to fail when encountering warnings, use
95 - cargo clippy -- -D warnings
96 # in order to also check tests and none-default crate features, use
97 - cargo clippy --all-targets --all-features -- -D warnings
104 Some lints can be configured in a TOML file named `clippy.toml` or `.clippy.toml`. It contains a basic `variable = value` mapping eg.
107 blacklisted-names = ["toto", "tata", "titi"]
108 cyclomatic-complexity-threshold = 30
111 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
112 meaning of the variables.
114 To deactivate the “for further information visit *lint-link*” message you can
115 define the `CLIPPY_DISABLE_DOCS_LINKS` environment variable.
117 ### Allowing/denying lints
119 You can add options to your code to `allow`/`warn`/`deny` Clippy lints:
121 * the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy::all)]`)
123 * all lints using both the `clippy` and `clippy::pedantic` lint groups (`#![deny(clippy::all)]`,
124 `#![deny(clippy::pedantic)]`). Note that `clippy::pedantic` contains some very aggressive
125 lints prone to false positives.
127 * only some lints (`#![deny(clippy::single_match, clippy::box_vec)]`, etc)
129 * `allow`/`warn`/`deny` can be limited to a single function or module using `#[allow(...)]`, etc
131 Note: `deny` produces errors instead of warnings.
133 Note: To use the new `clippy::lint_name` syntax, `#![feature(tool_lints)]` has to be activated
134 currently. If you want to compile your code with the stable toolchain you can use a `cfg_attr` to
135 activate the `tool_lints` feature:
137 #![cfg_attr(feature = "cargo-clippy", feature(tool_lints))]
138 #![cfg_attr(feature = "cargo-clippy", allow(clippy::lint_name))]
141 For this to work you have to use Clippy on the nightly toolchain: `cargo +nightly clippy`. If you
142 want to use Clippy with the stable toolchain, you can stick to the old unscoped method to
143 enable/disable Clippy lints until `tool_lints` are stable:
145 #![cfg_attr(feature = "cargo-clippy", allow(clippy_lint))]
148 If you do not want to include your lint levels in your code, you can globally enable/disable lints by passing extra flags to clippy during the run: `cargo clippy -- -A lint_name` will run clippy with `lint_name` disabled and `cargo clippy -- -W lint_name` will run it with that enabled. On newer compilers you may need to use `clippy::lint_name` instead.
152 Copyright 2014-2018 The Rust Project Developers
154 Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
155 http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
156 <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
157 option. All files in the project carrying such notice may not be
158 copied, modified, or distributed except according to those terms.