rust-lang / rust-lang/rust-clippy

New Lint: suggest using a custom `std::error::Error` type instead of a static str for `io::Error::new`

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A-lint E-medium L-unnecessary T-middle
Dominant language
Rust
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Description

Using a custom io::Error with a string results in boxing the description, even when used with a static string. It would probably be worth (pedantically) warning that using a custom type would reduce the allocation/copy of the description.

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  3. Fork the repository and make your change on a branch.
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Research direction

Review existing rust-clippy lint implementations and tests for io::Error::new handling. Confirm the allocation concern and define the lint's trigger and suggested replacement for static strings, then add coverage and run the relevant lint tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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