error: unknown lint: `unit_expr`
 --> $DIR/is_unit_expr.rs:4:8
  |
4 | #[warn(unit_expr)]
  |        ^^^^^^^^^
  |
  = note: `-D unknown-lints` implied by `-D warnings`

error: unknown lint: `no_effect`
 --> $DIR/is_unit_expr.rs:6:9
  |
6 | #[allow(no_effect)]
  |         ^^^^^^^^^

error: aborting due to 2 previous errors