RS.CLIPPY.SAME_ITEM_PUSH

The same item is pushed inside of a for loop

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: same_item_push. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks whether a for loop is being used to push a constant value into a Vec.

Why is this bad?

This kind of operation can be expressed more succinctly with vec![item; SIZE] or vec.resize(NEW_SIZE, item) and using these alternatives may also have better performance.

Example

let item1 = 2;
let item2 = 3;
let mut vec: Vec<u8> = Vec::new();
for _ in 0..20 {
    vec.push(item1);
}
for _ in 0..30 {
    vec.push(item2);
}

Use instead:

let item1 = 2;
let item2 = 3;
let mut vec: Vec<u8> = vec![item1; 20];
vec.resize(20 + 30, item2);

Configuration

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

(default: current version)