clippy 0.0.208

A bunch of helpful lints to avoid common pitfalls in Rust
error: use of `unwrap_or` followed by a function call
 --> $DIR/unwrap_or.rs:4:47
  |
4 |     let s = Some(String::from("test string")).unwrap_or("Fail".to_string()).len();
  |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "Fail".to_string())`
  |
  = note: `-D or-fun-call` implied by `-D warnings`

error: use of `unwrap_or` followed by a function call
 --> $DIR/unwrap_or.rs:9:10
  |
9 |         .unwrap_or("Fail".to_string())
  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "Fail".to_string())`

error: aborting due to 2 previous errors