java.lang.AssertionError
   at com.sun.tools.javac.util.Assert.error(Assert.java:155)
   at com.sun.tools.javac.util.Assert.checkNonNull(Assert.java:62)
   at com.sun.tools.javac.comp.Modules.completeModule(Modules.java:960)
   at com.sun.tools.javac.comp.Modules.access$000(Modules.java:117)
   at com.sun.tools.javac.comp.Modules$1.complete(Modules.java:376)
   at com.sun.tools.javac.code.Symbol.complete(Symbol.java:604)
   at com.sun.tools.javac.comp.Modules.enter(Modules.java:214)
   at com.sun.tools.javac.main.JavaCompiler.initModules(JavaCompiler.java:1053)
   at com.sun.tools.javac.main.JavaCompiler.initModules(JavaCompiler.java:1045)
   at com.sun.tools.javac.api.JavacTaskImpl.enter(JavacTaskImpl.java:376)
   at com.sun.tools.javac.api.JavacTaskImpl.enterTrees(JavacTaskImpl.java:433)
   at org.netbeans.modules.java.source.indexing.MultiPassCompileWorker.compile(MultiPassCompileWorker.java:217)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer.index(JavaCustomIndexer.java:271)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor$2.run(Indexable.java:161)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runIndexer(RepositoryUpdater.java:296)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:159)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doIndex(RepositoryUpdater.java:2753)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.access$500(RepositoryUpdater.java:2157)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2639)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2637)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.refreshTransaction(TaskCache.java:565)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:2637)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork$4.call(RepositoryUpdater.java:5701)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork$4.call(RepositoryUpdater.java:5609)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$4.run(RepositoryUpdater.java:2130)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2126)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2107)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.access$1200(RepositoryUpdater.java:157)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSource(RepositoryUpdater.java:5736)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$AbstractRootsWork.scanSources(RepositoryUpdater.java:5406)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$RootsWork.getDone(RepositoryUpdater.java:5025)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$InitialRootsWork.getDone(RepositoryUpdater.java:5808)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:3407)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:6170)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.access$4300(RepositoryUpdater.java:5821)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2$1.run(RepositoryUpdater.java:6086)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.RunWhenScanFinishedSupport.performScan(RunWhenScanFinishedSupport.java:106)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6082)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6078)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:90)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:6078)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)