Swift: a compiler crash

Here is a sample project to reproduce a crash in the Swift compiler.

Don't know how to fix this. Issue seems to be tied to the closure parameter, but not really sure about this.

Any idea?

internal func changeCounter(
    atIndexPath indexPath: NSIndexPath,
    withUnary operation: ( Int ) -> Int
    )
{
    let section = Sections(rawValue: indexPath.section)
    if ( .counters == section )
    {
      value = operation(value)
    }
}