Alas, the archives are private, so:

Alice: I am guessing there is a good reason for Fortress to be implemented using a mix of Scala and Java rather than just one of them?

Bob: There is. Scala’s a much better language for writing type-checker-like code in, and Fortress makes amusing demands on type inference and checking.

Alice: Perhaps Scala is the language that Java should have been ? (Or is that just too contentious :-)