Clippy lints / Style
Clippy lint · Style · checked with Clippy 0.1.99
clippy::manual_slice_fill: manually filling a slice
What it meansChecks for manually filling a slice with a value. It is in the style group and warns by default.
What you see
warning: manually filling a slice --> main.rs:4:1 | 4 | / for i in 0..some_slice.len() { 5 | | some_slice[i] = 0; 6 | | } | |_^ help: try: `some_slice.fill(0);` | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#manual_slice_fill = note: `#[warn(clippy::manual_slice_fill)]` 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?
Using the fill method is more idiomatic and concise.
Code that works but is not idiomatic Rust. Warns by default.
How to fix it
Clippy does not fix this one automatically (its suggestion may change behaviour, so it only shows it). Change the code by hand:
Flagged
let mut some_slice = [1, 2, 3, 4, 5];
for i in 0..some_slice.len() {
some_slice[i] = 0;
}
Write this instead
let mut some_slice = [1, 2, 3, 4, 5];
some_slice.fill(0);
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::manual_slice_fill)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
manual_slice_fill = "allow"One run
cargo clippy -- -A clippy::manual-slice-fillThe [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.
Settings in clippy.toml
msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml
Clippy's own documentation
What it does
Checks for manually filling a slice with a value.
Why is this bad?
Using the fill method is more idiomatic and concise.
Example
let mut some_slice = [1, 2, 3, 4, 5];
for i in 0..some_slice.len() {
some_slice[i] = 0;
}
Use instead:
let mut some_slice = [1, 2, 3, 4, 5];
some_slice.fill(0);
Configuration
-
msrv: The minimum rust version that the project supports. Defaults to therust-versionfield inCargo.toml(default:
current version)
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
- manual_repeat_nthis `repeat().take()` can be written more concisely
- manual_rotatethere is no need to manually implement bit rotation
- manual_saturating_arithmeticChecks for .checked_add/sub(x).unwrap_or(MAX/MIN)
- manual_while_let_someyou seem to be trying to pop elements from a `Vec` in a loop
- map_cloneyou are using an explicit closure for copying elements
- map_collect_result_unit`.map().collect()` can be replaced with `.try_for_each()`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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