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.Annotate.fromAnnotations(Annotate.java:149)
   at com.sun.tools.javac.comp.Annotate$6.run(Annotate.java:1020)
   at com.sun.tools.javac.comp.Annotate.flush(Annotate.java:176)
   at com.sun.tools.javac.code.ClassFinder.complete(ClassFinder.java:311)
   at com.sun.tools.javac.code.ClassFinder.access$000(ClassFinder.java:75)
   at com.sun.tools.javac.code.ClassFinder$1.complete(ClassFinder.java:169)
   at com.sun.tools.javac.code.Symbol.complete(Symbol.java:592)
   at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1107)
   at com.sun.tools.javac.code.Symbol$ClassSymbol.flags(Symbol.java:1032)
   at com.sun.tools.javac.comp.Check.importAccessible(Check.java:3711)
   at com.sun.tools.javac.comp.TypeEnter$ImportsPhase.lambda$resolveImports$86(TypeEnter.java:350)
   at com.sun.tools.javac.code.Scope$FilterImportScope$SymbolImporter.lambda$importFrom$7(Scope.java:940)
   at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
   at java.util.Spliterators$IteratorSpliterator.tryAdvance(Spliterators.java:1812)
   at java.util.stream.StreamSpliterators$WrappingSpliterator.lambda$initPartialTraversalState$0(StreamSpliterators.java:294)
   at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.fillBuffer(StreamSpliterators.java:206)
   at java.util.stream.StreamSpliterators$AbstractWrappingSpliterator.doAdvance(StreamSpliterators.java:161)
   at java.util.stream.StreamSpliterators$WrappingSpliterator.tryAdvance(StreamSpliterators.java:300)
   at java.util.stream.Streams$ConcatSpliterator.tryAdvance(Streams.java:728)
   at java.util.Spliterators$1Adapter.hasNext(Spliterators.java:681)
   at com.sun.tools.javac.util.Iterators$CompoundIterator.hasNext(Iterators.java:56)
   at org.netbeans.api.java.source.ElementUtilities.getLocalMembersAndVars(ElementUtilities.java:465)
   at org.netbeans.modules.java.completion.JavaCompletionTask.getLocalMembersAndVars(JavaCompletionTask.java:2969)
   at org.netbeans.modules.java.completion.JavaCompletionTask.addLocalMembersAndVars(JavaCompletionTask.java:2774)
   at org.netbeans.modules.java.completion.JavaCompletionTask.localResult(JavaCompletionTask.java:2683)
   at org.netbeans.modules.java.completion.JavaCompletionTask.insideVariable(JavaCompletionTask.java:707)
   at org.netbeans.modules.java.completion.JavaCompletionTask.resolve(JavaCompletionTask.java:296)
   at org.netbeans.modules.java.completion.BaseTask.run(BaseTask.java:93)
   at org.netbeans.modules.java.completion.JavaCompletionTask.run(JavaCompletionTask.java:80)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:609)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:153)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:137)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:204)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:201)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:88)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:201)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:104)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.query(JavaCompletionProvider.java:234)
   at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)
   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)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to: java.lang.AssertionError