catch manual next_multiple_of

[nyurik]

What it does

detect manual implementation of the next_multiple_of, e.g. a.div_ceil(b) * b. Note that this may combine clippy::manual_div_ceil detection as well, e.g. (x + (y - 1)) / y * y.

Make sure to include checked_next_multiple_of variant detection

Advantage

• shows clear intent rather
• reduces code complexity
• prevents accidental bugs

Drawbacks

No response

Example

use std::ops::Mul;

fn mult1(a: u32, b: u32) -> u32 {
    a.div_ceil(b) * b
}

fn mult2(a: u32, b: u32) -> u32 {
    a.div_ceil(b).mul(b)
}

fn mult3(a: u32, b: u32) -> u32 {
    (a + (b - 1)) / b * b
}

Could be written as:

a.next_multiple_of(b)

Comparison with existing lints

manual_div_ceil does something similar

Additional Context

No response

[nyurik]

possible dup: #16728, #14543, #14144