$ scala -version
Scala code runner version 2.10.0 -- Copyright 2002-2012, LAMP/EPFL
$ scala -X
-Xmigration Warn about constructs whose behavior may have changed between 2.7 and 2.8.
Adding a version number argument should clean that up
The deprecation is now in 2.10.x. To avoid a merge conflict I'll wait until that's in master and then remove the entire switch.
New plan is to add a version parameter to -Xmigration in 2.11. Then it would only print a warning on things that changed after that version number.