Ah, now I found the hint that there will probably ...

# ios

[Christoph Schulte Moenting]

Ah, now I found the hint that there will probably be support in K/N 0.7: "Starting from 0.7-dev-1447 version, if method is marked with @Throws annotation, exceptions thrown out of this method are converted to NSError* when calling from Objective-C and thrown as errors when calling from Swift."