error: this lifetime isn't used in the function definition
  --> $DIR/unused_lt.rs:16:14
   |
16 | fn unused_lt<'a>(x: u8) {
   |              ^^
   |
   = note: `-D extra-unused-lifetimes` implied by `-D warnings`

error: this lifetime isn't used in the function definition
  --> $DIR/unused_lt.rs:20:25
   |
20 | fn unused_lt_transitive<'a, 'b: 'a>(x: &'b u8) {
   |                         ^^

error: this lifetime isn't used in the function definition
  --> $DIR/unused_lt.rs:50:10
   |
50 |     fn x<'a>(&self) {}
   |          ^^

error: aborting due to 3 previous errors