clippy 0.0.208

A bunch of helpful lints to avoid common pitfalls in Rust
error: unused label `'label`
  --> $DIR/unused_labels.rs:8:5
   |
8  | /     'label: for i in 1..2 {
9  | |         if i > 4 { continue }
10 | |     }
   | |_____^
   |
   = note: `-D unused-label` implied by `-D warnings`

error: unused label `'a`
  --> $DIR/unused_labels.rs:21:5
   |
21 |     'a: loop { break }
   |     ^^^^^^^^^^^^^^^^^^

error: unused label `'same_label_in_two_fns`
  --> $DIR/unused_labels.rs:32:5
   |
32 | /     'same_label_in_two_fns: loop {
33 | |         let _ = 1;
34 | |     }
   | |_____^

error: aborting due to 3 previous errors