### What it does
Checks for nested `if` statements which can be collapsed
by `&&`-combining their conditions.

### Why is this bad?
Each `if`-statement adds one level of nesting, which
makes code look more complex than it really is.

### Example
```
if x {
    if y {
        // …
    }
}
```

Use instead:
```
if x && y {
    // …
}
```