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.allModules(Modules.java:879)
   at com.sun.tools.javac.comp.Modules.getObservableModule(Modules.java:1002)
   at com.sun.tools.javac.model.JavacElements.getModuleElement(JavacElements.java:109)
   at java.util.Optional.map(Optional.java:215)
   at org.netbeans.api.java.source.CompilationInfo.getTopLevelElements(CompilationInfo.java:246)
   at org.netbeans.modules.java.navigation.ElementScanningTask.runImpl(ElementScanningTask.java:170)
   at org.netbeans.modules.java.navigation.ElementScanningTask.run(ElementScanningTask.java:119)
   at org.netbeans.modules.java.navigation.ElementScanningTask.run(ElementScanningTask.java:100)
   at org.netbeans.modules.java.source.JavaSourceAccessor$CancelableTaskWrapper.run(JavaSourceAccessor.java:297)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callParserResultTask(TaskProcessor.java:584)
   at org.netbeans.modules.parsing.impl.TaskProcessor$RequestPerformer.run(TaskProcessor.java:809)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.TaskProcessor$RequestPerformer.execute(TaskProcessor.java:725)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:686)
   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)