Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::match_ref_pats: Checks for matches where all arms match a reference, suggesting to remove the reference and deref the matched expression instead
What it meansChecks for matches where all arms match a reference, suggesting to remove the reference and deref the matched expression instead. It also checks for if let &foo = bar blocks. It is in the style group and warns by default.
Does it matter?
It just makes the code less readable. That reference destructuring adds nothing to the code.
Code that works but is not idiomatic Rust. Warns by default.
How to fix it
Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.
Flagged
match x {
&A(ref y) => foo(y),
&B => bar(),
_ => frob(&x),
}
Write this instead
match *x {
A(ref y) => foo(y),
B => bar(),
_ => frob(x),
}
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::match_ref_pats)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
match_ref_pats = "allow"One run
cargo clippy -- -A clippy::match-ref-patsThe [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.
Clippy's own documentation
What it does
Checks for matches where all arms match a reference,
suggesting to remove the reference and deref the matched expression
instead. It also checks for if let &foo = bar blocks.
Why is this bad?
It just makes the code less readable. That reference destructuring adds nothing to the code.
Example
match x {
&A(ref y) => foo(y),
&B => bar(),
_ => frob(&x),
}
Use instead:
match *x {
A(ref y) => foo(y),
B => bar(),
_ => frob(x),
}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
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- map_collect_result_unit`.map().collect()` can be replaced with `.try_for_each()`
- match_like_matches_macromatch expression looks like `matches!` macro
- match_overlapping_armsome ranges overlap
- match_result_okChecks for unnecessary ok() in while let
- mem_replace_option_with_nonereplacing an `Option` with `None`
- mem_replace_option_with_somereplacing an `Option` with `Some(..)`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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