Perhaps I should post a bug, but I've been using the nightly, and started seeing this after the last update or so:
2016-10-14 18:59:41,626 INFO [Worker-2] - CompilerBridgeStore - '2.10.5' not yet compiled for Scala 2.10.5. Compiling...
2016-10-14 18:59:45,579 ERROR [Worker-2] - System.err - /tmp/sbt_2f6dfeab/xsbt/ClassName.scala:16: error: not found: value enteringPhase
enteringPhase(currentRun.flattenPhase.next) { s fullName separator }
^
2016-10-14 18:59:45,588 ERROR [Worker-2] - System.err - /tmp/sbt_2f6dfeab/xsbt/ClassName.scala:29: error: not found: value enteringPhase
protected def classNameAsSeenIn(in: Symbol, s: Symbol): String = enteringPhase(currentRun.picklerPhase.next) {
^
2016-10-14 18:59:45,590 ERROR [Worker-2] - System.err - /tmp/sbt_2f6dfeab/xsbt/ClassName.scala:39: error: not found: value enteringPhase
enteringPhase(currentRun.picklerPhase.next) { s.fullName }
^
2016-10-14 18:59:45,592 ERROR [Worker-2] - System.err - /tmp/sbt_2f6dfeab/xsbt/ClassName.scala:42: error: not found: value enteringPhase
enteringPhase(currentRun.picklerPhase.next) {
^
2016-10-14 18:59:46,972 ERROR [Worker-2] - System.err - /tmp/sbt_2f6dfeab/xsbt/DelegatingReporter.scala:48: error: value finalPosition is not a member of scala.reflect.internal.util.Position
posIn.finalPosition
^
Apologies if this is a known issue.