java.lang.AssertionError: assertion failed: Should not happen!
   at scala.Predef$.assert(Predef.java:179)
   at scala.tools.nsc.Global.assert(Global.java:240)
   at org.netbeans.modules.scala.core.ast.ScalaAstVisitor$treeTraverser.getBoundsToken(ScalaAstVisitor.java:837)
   at org.netbeans.modules.scala.core.ast.ScalaAstVisitor$treeTraverser.getBoundsTokens(ScalaAstVisitor.java:819)
   at org.netbeans.modules.scala.core.ast.ScalaAstVisitor$treeTraverser.<init>(ScalaAstVisitor.java:94)
   at org.netbeans.modules.scala.core.ast.ScalaAstVisitor$class.astVisit(ScalaAstVisitor.java:73)
   at org.netbeans.modules.scala.core.ScalaGlobal.astVisit(ScalaGlobal.java:93)
   at org.netbeans.modules.scala.core.ScalaGlobal$$anonfun$askSemanticRoot$1.apply(ScalaGlobal.java:204)
   at org.netbeans.modules.scala.core.ScalaGlobal$$anonfun$askSemanticRoot$1.apply(ScalaGlobal.java:202)
   at scala.tools.nsc.util.InterruptReq.execute(InterruptReq.java:26)
   at scala.tools.nsc.interactive.Global.pollForWork(Global.java:346)
   at scala.tools.nsc.interactive.Global.checkForMoreWork(Global.java:407)
   at scala.tools.nsc.interactive.Global.signalDone(Global.java:259)
   at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.java:5646)
   at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.java:5704)
   at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.java:5712)
   at scala.tools.nsc.typechecker.Typers$Typer.typedPackageDef$1(Typers.java:5275)
   at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.java:5564)
   at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.java:5619)
   at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.java:5681)
   at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3.apply(Analyzer.java:99)
   at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.java:465)
   at scala.tools.nsc.interactive.Global$TyperRun$$anonfun$applyPhase$1.apply$mcV$sp(Global.java:1174)
   at scala.tools.nsc.interactive.Global$TyperRun$$anonfun$applyPhase$1.apply(Global.java:1174)
   at scala.tools.nsc.interactive.Global$TyperRun$$anonfun$applyPhase$1.apply(Global.java:1174)
   at scala.reflect.internal.SymbolTable.atPhase(SymbolTable.java:207)
   at scala.tools.nsc.interactive.Global$TyperRun.applyPhase(Global.java:1174)
   at scala.tools.nsc.interactive.Global$TyperRun.typeCheck(Global.java:1167)
   at scala.tools.nsc.interactive.Global.scala$tools$nsc$interactive$Global$$typeCheck(Global.java:592)
   at scala.tools.nsc.interactive.Global$$anonfun$backgroundCompile$5$$anonfun$apply$7.apply(Global.java:508)
   at scala.tools.nsc.interactive.Global$$anonfun$backgroundCompile$5$$anonfun$apply$7.apply(Global.java:504)
   at scala.Option.foreach(Option.java:236)
   at scala.tools.nsc.interactive.Global$$anonfun$backgroundCompile$5.apply(Global.java:504)
   at scala.tools.nsc.interactive.Global$$anonfun$backgroundCompile$5.apply(Global.java:504)
   at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.java:772)
   at scala.collection.immutable.List.foreach(List.java:318)
   at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.java:771)
   at scala.tools.nsc.interactive.Global.backgroundCompile(Global.java:504)
   at scala.tools.nsc.interactive.PresentationCompilerThread.run(PresentationCompilerThread.java:25)