rust-clippy
rust-clippy copied to clipboard
Use slices or arrays instead of vecs lint
What it does
The lint suggests to replace an allocated vec![] with a slice. In test blocks I see lot of vecs that aren't necessary.
Lint Name
use_slice_or_array
Category
perf
Advantage
It's more efficient.
Drawbacks
None, I think.
Example
#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]
fn append(mut items: Vec<i32>, suffix: &[i32]) -> Vec<i32> {
items.extend_from_slice(suffix);
items
}
fn main() {
assert_eq!(vec![1, 2, 3, 4], append(vec![1, 2], &[3, 4]));
}
Could be written as:
#![warn(clippy::all)]
#![warn(clippy::nursery)]
#![warn(clippy::pedantic)]
fn append(mut items: Vec<i32>, suffix: &[i32]) -> Vec<i32> {
items.extend_from_slice(suffix);
items
}
fn main() {
assert_eq!(&[1, 2, 3, 4][..], append(vec![1, 2], &[3, 4]));
}
This lint should suggest to use slices or arrays instead of probably-heap-allocated vecs. But only for short literals. Past a certain length better not to fire this lint.