rust-clippy/book/src/README.md

Clippy

A collection of lints to catch common mistakes and improve your Rust code.

There are over 700 lints included in this crate!

Lints are divided into categories, each with a default lint level. You can choose how much Clippy is supposed to annoy help you by changing the lint level by category.

Category	Description	Default level
clippy::all	all lints that are on by default (correctness, suspicious, style, complexity, perf)	warn/deny
clippy::correctness	code that is outright wrong or useless	deny
clippy::suspicious	code that is most likely wrong or useless	warn
clippy::style	code that should be written in a more idiomatic way	warn
clippy::complexity	code that does something simple but in a complex way	warn
clippy::perf	code that can be written to run faster	warn
clippy::pedantic	lints which are rather strict or have occasional false positives	allow
clippy::restriction	lints which prevent the use of language and library features1	allow
clippy::nursery	new lints that are still under development	allow
clippy::cargo	lints for the cargo manifest	allow

More to come, please file an issue if you have ideas!

The restriction category should, emphatically, not be enabled as a whole. The contained lints may lint against perfectly reasonable code, may not have an alternative suggestion, and may contradict any other lints (including other categories). Lints should be considered on a case-by-case basis before enabling.

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1. Some use cases for restriction lints include:

   • Strict coding styles (e.g. clippy::else_if_without_else).
   • Additional restrictions on CI (e.g. clippy::todo).
   • Preventing panicking in certain functions (e.g. clippy::unwrap_used).
   • Running a lint only on a subset of code (e.g. #[forbid(clippy::float_arithmetic)] on a module).
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