rust/tests/compile-fail/neg_multiply.rs

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#![feature(plugin)]
#![plugin(clippy)]
#![deny(neg_multiply)]
#![allow(no_effect)]
use std::ops::Mul;
struct X;
impl Mul<isize> for X {
type Output = X;
fn mul(self, _r: isize) -> Self {
self
}
}
impl Mul<X> for isize {
type Output = X;
fn mul(self, _r: X) -> X {
X
}
}
fn main() {
let x = 0;
x * -1;
//~^ ERROR Negation by multiplying with -1
-1 * x;
//~^ ERROR Negation by multiplying with -1
-1 * -1; // should be ok
X * -1; // should be ok
-1 * X; // should also be ok
}