### What it does
Checks for usage of `.as_ref()` or `.as_mut()` where the
types before and after the call are the same.

### Why is this bad?
The call is unnecessary.

### Example
```
let x: &[i32] = &[1, 2, 3, 4, 5];
do_stuff(x.as_ref());
```
The correct use would be:
```
let x: &[i32] = &[1, 2, 3, 4, 5];
do_stuff(x);
```