Starting with Rust version 1.82.0, the compiler generates similar code
with and without the `with_ref` cfg:
```rust
fn f(x: impl IntoIterator<Item = String>) {
for y in x { println!("{y}"); }
}
fn main() {
#[cfg(with_ref)]
let a = ["foo", "bar"].iter().map(|&s| s.to_string());
#[cfg(not(with_ref))]
let a = ["foo", "bar"].iter().map(|s| s.to_string());
f(a);
}
```
The generated code is strictly identical with `-O`, and identical modulo
some minor reordering without.
changelog: [`inefficient_to_string`]: do not trigger for Rust ≥ 1.82.0
|
||
|---|---|---|
| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||
clippy-utils
Helpful tools for writing lints, provided as they are used in Clippy.
Usage
This crate is only guaranteed to build with this nightly toolchain:
nightly-2025-09-18
To use clippy-utils in your lint, add the following to your Cargo.toml:
clippy_utils = "0.1.XY"
XY is the version of the nightly toolchain above and can be determined with rustc +nightly-YYYY-MM-DD -V.
⚠️ Stability ⚠️
No stability guarantees are made for this crate! Use at your own risk.
Function signatures can change or be removed without replacement without any prior notice.
LICENSE
Copyright 2014-2025 The Rust Project Developers
Licensed under the Apache License, Version 2.0 <https://www.apache.org/licenses/LICENSE-2.0> or the MIT license <https://opensource.org/licenses/MIT>, at your option. Files in the project may not be copied, modified, or distributed except according to those terms.