Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::iter_nth: called `.iter().nth()` on a `Vec`
What it meansChecks for usage of .iter().nth()/.iter_mut().nth() on standard library types that have equivalent .get()/.get_mut() methods. It is in the style group and warns by default.
What you see
warning: called `.iter().nth()` on a `Vec` --> main.rs:4:15 | 4 | let bad_vec = some_vec.iter().nth(3); | ^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#iter_nth = note: `#[warn(clippy::iter_nth)]` on by default help: `get` is equivalent but more concise | 4 - let bad_vec = some_vec.iter().nth(3); 4 + let bad_vec = some_vec.get(3); |
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?
.get() and .get_mut() are equivalent but more concise.
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
let some_vec = vec![0, 1, 2, 3];
let bad_vec = some_vec.iter().nth(3);
let bad_slice = &some_vec[..].iter().nth(3);
Write this instead
let some_vec = vec![0, 1, 2, 3];
let bad_vec = some_vec.get(3);
let bad_slice = &some_vec[..].get(3);
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_nth)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
iter_nth = "allow"One run
cargo clippy -- -A clippy::iter-nthThe [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().nth()/.iter_mut().nth() on standard library types that have
equivalent .get()/.get_mut() methods.
Why is this bad?
.get() and .get_mut() are equivalent but more concise.
Example
let some_vec = vec![0, 1, 2, 3];
let bad_vec = some_vec.iter().nth(3);
let bad_slice = &some_vec[..].iter().nth(3);
The correct use would be:
let some_vec = vec![0, 1, 2, 3];
let bad_vec = some_vec.get(3);
let bad_slice = &some_vec[..].get(3);
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
- 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_next_sliceChecks for usage of iter().next() or iter_mut().next() on a Slice or an Array
- iter_nth_zeroChecks for the use of iter.nth(0)
- iter_skip_nextcalled `skip(..).next()` on an iterator
- just_underscores_and_digitsconsider choosing a more descriptive name
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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