rust-lang/rust-clippy

Add an easy way to run clippy with high FPR / trivial lints disabled

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#5537 opened on Apr 27, 2020

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 (10 comments) (9 reactions) (0 assignees)Rust (10,406 stars) (1,391 forks)batch import
A-categoryC-enhancementE-help-wantedS-needs-discussiongood first issue

Description

Hi!

It often happens that users submit a "make clippy happier" PR to one of my projects. These PRs often contain quite a bunch of changes, of which a couple are undeniably great, but majority just shuffle code around. An example of good change would be a removal of (now useless) .into() or .clone(). A typical example of not really good change is .unwrap_or(xs.len()) -> .unwrap_or_else(|| xs.len()).

I've written at some length about this here: https://github.com/rust-analyzer/rowan/pull/57#discussion_r415676159.

I would really love the ability to run cargo clippy --conservative, and only get lints about the code which can be unambiguously improved across all dimensions. (that is, those lints that we probably want to lift eventually into the compiler).

I know that lint categories exists, but:

  • they seem to slice the lints across the different axis -- not the FPR range, but the, well, category
  • it's unclear how to actually make clippy run only specific category from the command line.

Contributor guide

Tech stack
rust
Domain
developer experiencecli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Rust programmingclippy command line interfacelint categorization
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
This issue requests a new flag to run clippy with high false positive rate lints disabled. The discussion in the issue and the linked PR comment provide insights into which lints are considered trivial. A newcomer should investigate clippy's flag parsing in `src/main.rs` and lint category filtering logic in `clippy lints/src/lib.rs`. The goal is to implement a ` conservative` flag that filters out lints like `unwrap or else` suggestions while keeping lints like unnecessary `clone`.