### What it does
Checks for bit masks that can be replaced by a call
to `trailing_zeros`

### Why is this bad?
`x.trailing_zeros() > 4` is much clearer than `x & 15
== 0`

### Known problems
llvm generates better code for `x & 15 == 0` on x86

### Example
```
if x & 0b1111 == 0 { }
```