rust-lang / rust-lang/rust-clippy
New lint: prevent dropping Results (and other must_use types)
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A-lint
L-style
S-needs-discussion
- Dominant language
- Rust
- Stars
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- Avg merge
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- Merged PRs (30d)
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Description
What it does
I just found the following code:
drop(env_logger::try_init());
Basically someone got a warning on an unused must_use type (in this case a Result), and thus "used" it … by dropping it. Tada, the warning's gone 🎉.
Categories (optional)
- Kind:
clippy::correctness
Drawbacks
None.
Example
drop(crate::try_do_stuff());
Could be written as:
crate::try_do_stuff().unwrap();
If the drop was intentional, it should be:
drop(crate::try_do_stuff().unwrap());
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start from the issue's Rust examples and inspect Clippy's existing lint implementations for drop calls and must_use types. Determine how the lint should distinguish intentional dropping from suppressing a warning, then add coverage for both example forms. Done means the lint reports the problematic calls without rejecting intentional drops.
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