rust-lang / rust-lang/rust-clippy

lint generic type argument of a generic type that could be `: ?Sized`

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

struct A<T: Trait>(Box<T>);

should lint that one should write T: Trait + ?Sized.

Motivation: http://stackoverflow.com/questions/40846232/rust-compiler-does-not-see-structure-as-sized

To reduce false positives, this should only lint if the impl X for A and impl A, will continue working if they are also changed.

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Research direction

Start with the Rust snippet in the issue as the minimal reproduction, then investigate how Clippy tests and implements generic-type lints. Compare cases with impl X for A and impl A to verify the proposed change does not produce false positives. Done means the appropriate lint is emitted only when both impl forms remain valid after adding ?Sized.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
devtools
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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