clippy::useless_conversion suggested fix breaks code with lifetimes #14322
Description
Summary
clippy::useless_conversion is issued when Into is used to convert to the same type but with different lifetime. The suggested fix breaks the code.
Lint Name
useless_conversion
Reproducer
I tried this code:
pub trait MyTrait { type Borrowed<'a>; } pub fn make_static<T: MyTrait>(x: T::Borrowed<'_>) -> T::Borrowed<'static> where for<'a> T::Borrowed<'a>: Into<T::Borrowed<'static>>, { x.into() }I saw this happen:
| 9 | x.into() | ^^^^^^^^ help: consider removing `.into()`: `x` This breaks:
pub fn make_static<T: MyTrait>(x: T::Borrowed<'_>) -> T::Borrowed<'static> where for<'a> T::Borrowed<'a>: Into<T::Borrowed<'static>>, { x }9 | x | ^ returning this value requires that `'1` must outlive `'static` Version
rust stable 1.85.0 clippy 0.1.85 (2025-02-17 4d91de4e48) Additional Labels
@rustbot label +I-suggestion-causes-error