#![feature(tool_lints)] #![warn(clippy::neg_multiply)] #![allow(clippy::no_effect, clippy::unnecessary_operation)] use std::ops::Mul; struct X; impl Mul for X { type Output = X; fn mul(self, _r: isize) -> Self { self } } impl Mul for isize { type Output = X; fn mul(self, _r: X) -> X { X } } fn main() { let x = 0; x * -1; -1 * x; -1 * -1; // should be ok X * -1; // should be ok -1 * X; // should also be ok }