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fix unnecessary_to_owned about msrv by kyoto7250 · Pull Request #8692 · rust-lan...

 2 years ago
source link: https://github.com/rust-lang/rust-clippy/pull/8692
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kyoto7250 commented 10 days ago •

edited by giraffate

This PR fixes [`unnecessary_owned`].

# sample code
fn _msrv_1_35() {
    #![clippy::msrv = "1.35"]
    let _ = &["x"][..].to_vec().into_iter();
}

fn _msrv_1_36() {
    #![clippy::msrv = "1.36"]
    let _ = &["x"][..].to_vec().into_iter();
}

If we will check this code using clippy, [`unnecessary_owned`] will modify the code as follows.

error: unnecessary use of `to_vec`
  --> $DIR/unnecessary_to_owned.rs:219:14
   |
LL |     let _ = &["x"][..].to_vec().into_iter();
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `["x"][..].iter().copied()`

error: unnecessary use of `to_vec`
  --> $DIR/unnecessary_to_owned.rs:224:14
   |
LL |     let _ = &["x"][..].to_vec().into_iter();
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `["x"][..].iter().copied()`

This is incorrect. Because Iterator::copied was estabilished in 1.36.

This bug was caused by not separating "copied" and "clone" by reference to msrv.

let cloned_or_copied = if is_copy(cx, item_ty) { "copied" } else { "cloned" };

So, I added a conditional branch and described the corresponding test.

Thank you in advance.

changelog: fix wrong suggestions about msrv in [unnecessary_to_owned]

r! @giraffate


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