error: unused variable: `y`
  --> $DIR/lint-match-arms.rs:5:9
   |
LL |         y => (),
   |         ^ help: if this is intentional, prefix it with an underscore: `_y`
   |
note: the lint level is defined here
  --> $DIR/lint-match-arms.rs:3:16
   |
LL |         #[deny(unused_variables)]
   |                ^^^^^^^^^^^^^^^^

error: aborting due to previous error