Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::match_overlapping_arm: some ranges overlap
What it meansChecks for overlapping match arms. It is in the style group and warns by default.
What you see
warning: some ranges overlap --> main.rs:5:5 | 5 | 1..=10 => println!("1 ... 10"), | ^^^^^^ | note: overlaps with this --> main.rs:6:5 | 6 | 5..=15 => println!("5 ... 15"), | ^^^^^^ = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#match_overlapping_arm = note: `#[warn(clippy::match_overlapping_arm)]` on by default
Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.
Does it matter?
It is likely to be an error and if not, makes the code less obvious.
Code that works but is not idiomatic Rust. Warns by default.
How to fix it
Clippy does not fix this one automatically. Change the code by hand:
Flagged
let x = 5;
match x {
1..=10 => println!("1 ... 10"),
5..=15 => println!("5 ... 15"),
_ => (),
}
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_overlapping_arm)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
match_overlapping_arm = "allow"One run
cargo clippy -- -A clippy::match-overlapping-armThe [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 overlapping match arms.
Why is this bad?
It is likely to be an error and if not, makes the code less obvious.
Example
let x = 5;
match x {
1..=10 => println!("1 ... 10"),
5..=15 => println!("5 ... 15"),
_ => (),
}
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- needless_returnunneeded `return` statement
- new_without_defaultChecks for public types with a pub fn new() -> Self method and no implementation of Default
- len_zeroChecks for getting the length of something via .len() just to compare to zero, and suggests using .is_empty() where applicable
- map_cloneyou are using an explicit closure for copying elements
- map_collect_result_unit`.map().collect()` can be replaced with `.try_for_each()`
- match_like_matches_macromatch expression looks like `matches!` macro
- match_ref_patsChecks for matches where all arms match a reference, suggesting to remove the reference and deref the matched expression instead
- match_result_okChecks for unnecessary ok() in while let
- mem_replace_option_with_nonereplacing an `Option` with `None`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::needless_returnunneeded `return` statementRead it next →Did this answer your question?