This has come up plenty of times on Hacker News with plenty of examples. modersky generally just writes it off as being "harmful" to the community and other nonsense to avoid the issue. Harmful to his valuation is more like it.
You can have 100% type safety in a straight jacket, but scala pushes what it tries to type check to an extreme limit; "safe" but then also not as conservative as Haskell or ML. I see scala as the c++ of statically typed languages, filling that niche where you need more from your managed language and are willing to take a leap, but this is controversial and a personal opinion.