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Option::is_none_or: unnecessary_map_or lint doesn't work on references #14023

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Azkellas opened this issue Jan 18, 2025 · 2 comments · May be fixed by #14024
Open

Option::is_none_or: unnecessary_map_or lint doesn't work on references #14023

Azkellas opened this issue Jan 18, 2025 · 2 comments · May be fixed by #14024
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@samueltardieu
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C-bug Category: Clippy is not doing the correct thing I-false-negative Issue: The lint should have been triggered on code, but wasn't

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@Azkellas
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Azkellas commented Jan 18, 2025 •
edited by rustbot
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Summary

Using Option::map_or to emulates Option::is_none_or fails to generate a warning when dereferencing.

Lint Name

unnecessary_map_or

Reproducer

Running this code

fn test(a: Option<f32>) {
    println!("{}", a.map_or(true, |f| f < 0.0))
}

fn test_ref(a: &Option<f32>) {
    println!("{}", a.map_or(true, |f| f < 0.0))
}

fn test_ref_mut(a: &mut Option<f32>) {
    println!("{}", a.map_or(true, |f| f < 0.0))
}

fn main() {
    test(Some(1.0));
    test_ref(&Some(1.0));
    test_ref_mut(&mut Some(1.0));
}

link to the playground

I expected a warning for each case, so three in total

Instead, this happened:

Checking playground v0.0.1 (/playground)
warning: this `map_or` can be simplified
 --> src/main.rs:3:20
  |
3 |     println!("{}", a.map_or(true, |f| f < 0.0))
  |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use is_none_or instead: `a.is_none_or(|f| f < 0.0)`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
  = note: `#[warn(clippy::unnecessary_map_or)]` on by default

warning: `playground` (bin "playground") generated 1 warning (run `cargo clippy --fix --bin "playground"` to apply 1 suggestion)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.47s

Version

1.86.0-nightly

(2025-01-17 6067b36314ab5eb2eb47)
@Azkellas Azkellas added C-bug Category: Clippy is not doing the correct thing I-false-negative Issue: The lint should have been triggered on code, but wasn't labels Jan 18, 2025
@samueltardieu
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@rustbot claim

@samueltardieu samueltardieu linked a pull request Jan 18, 2025 that will close this issue
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@samueltardieu
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Thanks for the report @Azkellas.

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@samueltardieu samueltardieu

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C-bug Category: Clippy is not doing the correct thing I-false-negative Issue: The lint should have been triggered on code, but wasn't
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Make unnecessary_map_or work with ref and Deref to Option/Result samueltardieu/rust-clippy
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@samueltardieu @Azkellas