java.util.ConcurrentModificationException
   at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
   at java.util.AbstractList$Itr.next(AbstractList.java:343)
   at scala.collection.JavaConversions$JIteratorWrapper.next(JavaConversions.java:476)
   at scala.collection.Iterator$class.foreach(Iterator.java:631)
   at scala.collection.JavaConversions$JIteratorWrapper.foreach(JavaConversions.java:474)
   at scala.collection.IterableLike$class.foreach(IterableLike.java:79)
   at scala.collection.JavaConversions$JListWrapper.foreach(JavaConversions.java:521)
   at scala.collection.TraversableLike$class.filter(TraversableLike.java:237)
   at scala.collection.JavaConversions$JListWrapper.filter(JavaConversions.java:521)
   at org.netbeans.modules.scala.hints.ScalaHintsProvider.computeErrors(ScalaHintsProvider.java:128)
   at org.netbeans.modules.csl.hints.GsfHintsProvider$2.run(GsfHintsProvider.java:323)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:154)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:138)
   at org.netbeans.modules.parsing.impl.TaskProcessor$1.call(TaskProcessor.java:199)
   at org.netbeans.modules.parsing.impl.TaskProcessor$1.call(TaskProcessor.java:196)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:167)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:323)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:66)
Caused: org.netbeans.modules.parsing.spi.ParseException
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:204)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:106)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.run(GsfHintsProvider.java:297)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.run(GsfHintsProvider.java:101)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:675)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
   at java.util.concurrent.FutureTask.run(FutureTask.java:138)
   at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   at java.lang.Thread.run(Thread.java:619)