### What it does
Checks for overlapping match arms.

### Why is this bad?
It is likely to be an error and if not, makes the code
less obvious.

### Example
```
let x = 5;
match x {
    1..=10 => println!("1 ... 10"),
    5..=15 => println!("5 ... 15"),
    _ => (),
}
```