error: unused return value of `foo` that must be used --> $DIR/must_use-unit.rs:13:5 | LL | foo(); | ^^^^^^ | note: the lint level is defined here --> $DIR/must_use-unit.rs:2:9 | LL | #![deny(unused_must_use)] | ^^^^^^^^^^^^^^^ error: unused return value of `bar` that must be used --> $DIR/must_use-unit.rs:15:5 | LL | bar(); | ^^^^^^ error: aborting due to 2 previous errors