We plan to release the software in early June, but the article was published in advance of the release.

I've put a public repository at the location to make this clear, we'll update it soon.

The string concatenation API for Java IS terrible, but see modersky's post for the reasoning.

Just don't mistake a bad API for some kind of belief that Scala in general idly converts between types. The weakest point is APIs that use methods defined in java.lang.Object (e.g. toString and equals); they can universally use these methods without restricting the type.

Note that if you define a type as a knowledge of what actions can be performed on an object, then no type safety has been lost; toString() is universally available, though it may not do exactly what you want.