// check-pass #![warn(unused_must_use)] #![feature(never_type)] use std::ops::Add; use std::ops::Sub; use std::ops::Mul; use std::ops::Div; use std::ops::Rem; fn main() { let x = 2_u32; (x.add(4), x.sub(4), x.mul(4), x.div(4), x.rem(4)); x.add(4); //~ WARN unused return value of `add` that must be used x.sub(4); //~ WARN unused return value of `sub` that must be used x.mul(4); //~ WARN unused return value of `mul` that must be used x.div(4); //~ WARN unused return value of `div` that must be used x.rem(4); //~ WARN unused return value of `rem` that must be used println!("{}", x); }