rust-lang/rust-clippy

Lint suggesting from_fn instead of while let Some(x)

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#3,940 opened on Apr 11, 2019

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A-lintL-styleL-suggestiongood first issue

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Description

With the release of 1.34 with the from_fn function, I'd like to propose a new lint that matches: while let Some(x) = expr and suggests replacing it with for x in from_fn(|| expr). (With a special-case for while let Some(x) = fn() that suggests for x in from_fn(fn) if possible.)

Contributor guide

Research direction
Study existing clippy lints for while loops and iterators, trace how AST is parsed, and implement a new lint using the Clippy lint creation guide.
Tech stack
rust
Domain
cli
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Rust
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65