clippy::modulo_arithmetic: you are using modulo operator on constants with different signs: `-17 % 3`

What you see

warning: you are using modulo operator on constants with different signs: `-17 % 3`
 --> main.rs:3:9
  |
3 | let x = -17 % 3;
  |         ^^^^^^^
  |
  = note: double check for expected result especially when interoperating with different languages
  = note: or consider using `rem_euclid` or similar function
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#modulo_arithmetic
  = note: requested on the command line with `-W clippy::modulo-arithmetic`

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?

The results of modulo (%) operation might differ depending on the language, when negative numbers are involved. If you interop with different languages it might be beneficial to double check all places that use modulo arithmetic. For example, in Rust 17 % -3 = 2, but in Python 17 % -3 = -1.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

let x = -17 % 3;

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

[lints.clippy]
modulo_arithmetic = "warn"

#![warn(clippy::modulo_arithmetic)]

cargo clippy -- -W clippy::modulo-arithmetic

The [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

• allow-comparison-to-zero: Don’t lint when comparing the result of a modulo operation to zero.