### What it does
Checks for casts between numerical types that may
truncate large values. This is expected behavior, so the cast is `Allow` by
default.

### Why is this bad?
In some problem domains, it is good practice to avoid
truncation. This lint can be activated to help assess where additional
checks could be beneficial.

### Example
```
fn as_u8(x: u64) -> u8 {
    x as u8
}
```