Relevant video by Martin Odersky covering Scala 2.10:
http://www.youtube.com/watch?v=qqQNqIy5LdM
Slides:
http://mrkn.co/s/video_martin_odersky_what_s_next_for_scala,...
I especially recommend the part about how reflection is implemented in Scala 2.10. It explains the Cake pattern and how Scala self types enable dependency injection.
Good stuff