wish: disabling check (by special formatted comment?)

``` d
auto inner = args.length - 1;
```

```
./src/dpq2/answer.d(432:27)[warn]: Avoid subtracting from '.length' as it may be unsigned.
```

But I am sure that at this point .length > 0 (by assert/enforce) and it will be cool if this check on this line can be disabled by any way
