CLI app for rustc lints

lints is a CLI application that parses the output of rustc -Whelp before writing the lints to stdout in a format that can be added to a TOML table, lints.rust, in Cargo.toml.

Why is this useful?

Unlike Clippy, many rustc lints are not members of at least one lint group which makes it easy for one to not enjoy the benefit of a lint they didn't know about it. rustc lints and lint groups change rather frequently, so it can be "annoying" to maintain a list of up-to-date lints.

Usage

lints [COMMAND] [OPTIONS]

Commands

• allow: Allows all lints.
• deny: Denies all lints.
• help: This message.
• version: Prints version info.

Options

• --all: Writes all individual lints even if they're already part of a lint group.
• --allow-undefined-lints: Lint groups that contain undefined lints are allowed.
• -: If the last argument, stdin is read instead of getting the output from rustc.

When nothing or deny is passed, all lint groups and allow-by-default lints that are not part of a group are set to deny. When allow is passed, "warnings" and all deny-by-default lints are set to allow. stdout is written to in the format of the TOML table, lints.rust, which can be added to Cargo.toml.

--allow-undefined-lints should rarely be necessary since the lints defined in a lint group per rustc -Whelp are almost always one of the lints listed. There have been exceptions though (e.g., rustc 1.48.0 lists the lint group "rustdoc" containing the lint "private-intra-doc-links" despite that lint not being in the table of lints).

lints in action

[zack@laptop ~]$ rustc -V
rustc 1.93.0 (254b59607 2026-01-19)
[zack@laptop ~]$ lints version
lints 0.3.0
[zack@laptop ~]$ lints
deprecated-safe = { level = "deny", priority = -1 }
future-incompatible = { level = "deny", priority = -1 }
keyword-idents = { level = "deny", priority = -1 }
let-underscore = { level = "deny", priority = -1 }
nonstandard-style = { level = "deny", priority = -1 }
refining-impl-trait = { level = "deny", priority = -1 }
rust-2018-compatibility = { level = "deny", priority = -1 }
rust-2018-idioms = { level = "deny", priority = -1 }
rust-2021-compatibility = { level = "deny", priority = -1 }
rust-2024-compatibility = { level = "deny", priority = -1 }
unknown-or-malformed-diagnostic-attributes = { level = "deny", priority = -1 }
unused = { level = "deny", priority = -1 }
warnings = { level = "deny", priority = -1 }
ambiguous-negative-literals = { level = "deny", priority = -1 }
closure-returning-async-block = { level = "deny", priority = -1 }
deprecated-in-future = { level = "deny", priority = -1 }
deref-into-dyn-supertrait = { level = "deny", priority = -1 }
ffi-unwind-calls = { level = "deny", priority = -1 }
fuzzy-provenance-casts = { level = "deny", priority = -1 }
impl-trait-redundant-captures = { level = "deny", priority = -1 }
linker-messages = { level = "deny", priority = -1 }
lossy-provenance-casts = { level = "deny", priority = -1 }
macro-use-extern-crate = { level = "deny", priority = -1 }
meta-variable-misuse = { level = "deny", priority = -1 }
missing-copy-implementations = { level = "deny", priority = -1 }
missing-debug-implementations = { level = "deny", priority = -1 }
missing-docs = { level = "deny", priority = -1 }
multiple-supertrait-upcastable = { level = "deny", priority = -1 }
must-not-suspend = { level = "deny", priority = -1 }
non-ascii-idents = { level = "deny", priority = -1 }
non-exhaustive-omitted-patterns = { level = "deny", priority = -1 }
redundant-imports = { level = "deny", priority = -1 }
redundant-lifetimes = { level = "deny", priority = -1 }
resolving-to-items-shadowing-supertrait-items = { level = "deny", priority = -1 }
shadowing-supertrait-items = { level = "deny", priority = -1 }
single-use-lifetimes = { level = "deny", priority = -1 }
trivial-casts = { level = "deny", priority = -1 }
trivial-numeric-casts = { level = "deny", priority = -1 }
unit-bindings = { level = "deny", priority = -1 }
unnameable-types = { level = "deny", priority = -1 }
unqualified-local-imports = { level = "deny", priority = -1 }
unreachable-pub = { level = "deny", priority = -1 }
unsafe-code = { level = "deny", priority = -1 }
unstable-features = { level = "deny", priority = -1 }
unused-crate-dependencies = { level = "deny", priority = -1 }
unused-import-braces = { level = "deny", priority = -1 }
unused-lifetimes = { level = "deny", priority = -1 }
unused-qualifications = { level = "deny", priority = -1 }
unused-results = { level = "deny", priority = -1 }
variant-size-differences = { level = "deny", priority = -1 }

Minimum Supported Rust Version (MSRV)

This will frequently be updated to be the same as stable. Specifically, any time stable is updated and that update has "useful" features or compilation no longer succeeds (e.g., due to new compiler lints), then MSRV will be updated.

MSRV changes will correspond to a SemVer patch version bump pre-1.0.0; otherwise a minor version bump.

SemVer Policy

• All on-by-default features of this library are covered by SemVer
• MSRV is considered exempt from SemVer as noted above

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Before any PR is sent, cargo clippy --all-targets and cargo test --all-targets should be run using the stable and MSRV toolchains. One easy way to achieve this is by invoking ci-cargo as ci-cargo clippy --all-targets test --benches --bins --examples --tests in the lints directory.

Last, cargo +nightly doc should be run to ensure documentation can be built.

Status

The crate is only tested on the x86_64-unknown-linux-gnu, x86_64-unknown-openbsd, and aarch64-apple-darwin targets; but it should work on most platforms.