rust-lang/rust-clippy

Add utils helper for filtering out type/lifetime parameters on generics

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#3787 opened on Feb 19, 2019

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 (4 comments) (0 reactions) (0 assignees)Rust (10,406 stars) (1,391 forks)batch import
C-enhancementgood first issue

Description

See https://github.com/rust-lang/rust-clippy/pull/3786/files , we have a lot of code that does something like params.args.iter().filter_map(|arg| match arg { GenericArg::Lifetime(lt) => Some(lt), _ => None }

We should probably have a helper function that returns an iterator for these, placed in utils. Probably something like:

fn types_of_generics(generics: &Generics) -> impl Iterator<Type> {...}
fn lifetimes_of_generics(generics: &Generics) -> impl Iterator<Lifetime> {...}

Contributor guide

Tech stack
rust
Domain
developer experiencetooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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.
clear
Prerequisites
Rust genericsIterator patternClippy codebase structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The issue references a previous PR (https://github.com/rust lang/rust clippy/pull/3786) that contains similar code. The proposed helper functions should be placed in the `utils` module. Review existing iterator patterns in Clippy's source, particularly how `GenericArg` variants are filtered. The functions should return `impl Iterator<Type>` and `impl Iterator<Lifetime>`. No current assignees or linked PRs.