Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::iter_next_slice: Checks for usage of iter().next() or iter_mut().next() on a Slice or an Array
What it meansChecks for usage of iter().next() or iter_mut().next() on a Slice or an Array It is in the style group and warns by default.
Does it matter?
These can be shortened into .first() or .first_mut()
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
a[2..].iter().next();
b.iter().next();
c.iter_mut().next();
Write this instead
a.get(2);
b.first();
c.first_mut();
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::iter_next_slice)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
iter_next_slice = "allow"One run
cargo clippy -- -A clippy::iter-next-sliceThe [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 usage of iter().next() or iter_mut().next() on a Slice or an Array
Why is this bad?
These can be shortened into .first() or .first_mut()
Example
a[2..].iter().next();
b.iter().next();
c.iter_mut().next();
should be written as:
a.get(2);
b.first();
c.first_mut();
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
- is_digit_ascii_radixuse of `char::is_digit` with literal radix of 10
- items_after_test_moduleTriggers if an item is declared after the testing module marked with #[cfg(test)]
- iter_cloned_collectcalled `.iter().cloned().collect()` on a slice to create a `Vec`
- iter_nthcalled `.iter().nth()` on a `Vec`
- iter_nth_zeroChecks for the use of iter.nth(0)
- iter_skip_nextcalled `skip(..).next()` on an iterator
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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