rust-lang/rust-clippy

Lint functions taking references as arguments but only use them to create an owned value

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#1,563 opened on Feb 21, 2017

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A-lintE-hardL-unnecessaryT-middlegood first issue

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Description

A function that takes a &str and always converts it to a String, should be taking a String argument instead. This is hard to generalize, but we could start with anything implementing to_owned and only calling to_owned.

Contributor guide

Research direction
Implement a new lint that detects functions taking a &str and immediately converting to String via to owned(). The lint should check for methods that accept &str and only use it to call to owned() once. Use Clippy's existing infrastructure for pattern matching. See examples like 'single char pattern' for reference.
Tech stack
rust
Domain
tooling
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.
3-5 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.
Clear
Prerequisites
RustClippy internalsGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70