java.lang.AssertionError
   at com.sun.tools.javac.util.Assert.error(Assert.java:155)
   at com.sun.tools.javac.util.Assert.check(Assert.java:46)
   at com.sun.tools.javac.code.Types.merge(Types.java:3778)
   at com.sun.tools.javac.code.Types.intersect(Types.java:3707)
   at com.sun.tools.javac.code.Types.lub(Types.java:3936)
   at com.sun.tools.javac.comp.Infer.getParameterizedSupers(Infer.java:1150)
   at com.sun.tools.javac.comp.Infer.access$200(Infer.java:76)
   at com.sun.tools.javac.comp.Infer$CheckUpperBounds.apply(Infer.java:952)
   at com.sun.tools.javac.comp.Infer.doIncorporation(Infer.java:1124)
   at com.sun.tools.javac.comp.Infer$GraphSolver.solve(Infer.java:1658)
   at com.sun.tools.javac.comp.InferenceContext.solve(InferenceContext.java:475)
   at com.sun.tools.javac.comp.InferenceContext.solve(InferenceContext.java:482)
   at com.sun.tools.javac.comp.Infer.instantiateMethod(Infer.java:226)
   at com.sun.tools.javac.comp.Resolve.rawInstantiate(Resolve.java:607)
   at com.sun.tools.javac.comp.Resolve.checkMethod(Resolve.java:646)
   at com.sun.tools.javac.comp.Attr.checkMethod(Attr.java:4237)
   at com.sun.tools.javac.comp.Attr.checkIdInternal(Attr.java:4025)
   at com.sun.tools.javac.comp.Attr.checkMethodIdInternal(Attr.java:3936)
   at com.sun.tools.javac.comp.Attr.checkMethodId(Attr.java:3911)
   at com.sun.tools.javac.comp.Attr.checkId(Attr.java:3898)
   at com.sun.tools.javac.comp.Attr.visitIdent(Attr.java:3637)
   at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:2243)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:658)
   at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1970)
   at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1634)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:658)
   at com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:704)
   at com.sun.tools.javac.comp.Attr.visitVarDef(Attr.java:1197)
   at com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:956)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:658)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:734)
   at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:758)
   at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1245)
   at org.netbeans.lib.nbjavac.services.NBAttr.visitBlock(NBAttr.java:82)
   at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1020)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:658)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:734)
   at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1131)
   at org.netbeans.lib.nbjavac.services.NBAttr.visitMethodDef(NBAttr.java:76)
   at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:872)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:658)
   at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:734)
   at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4815)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4699)
   at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4627)
   at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4572)
   at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1416)
   at com.sun.tools.javac.api.JavacTaskImpl$1.process(JavacTaskImpl.java:497)
   at com.sun.tools.javac.api.JavacTaskImpl$Filter.run(JavacTaskImpl.java:638)
   at com.sun.tools.javac.api.JavacTaskImpl.analyze(JavacTaskImpl.java:500)
   at org.netbeans.modules.java.source.indexing.MultiPassCompileWorker.compile(MultiPassCompileWorker.java:277)
   at org.netbeans.modules.java.source.indexing.JavaCustomIndexer.index(JavaCustomIndexer.java:297)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor$2.run(Indexable.java:161)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runIndexer(RepositoryUpdater.java:298)
   at org.netbeans.modules.parsing.spi.indexing.Indexable$MyAccessor.index(Indexable.java:159)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doIndex(RepositoryUpdater.java:2773)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.access$800(RepositoryUpdater.java:2177)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2659)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$1.run(RepositoryUpdater.java:2657)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.refreshTransaction(TaskCache.java:565)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:2657)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$3.call(RepositoryUpdater.java:3323)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work$3.call(RepositoryUpdater.java:3278)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$4.run(RepositoryUpdater.java:2150)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2146)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.runInContext(RepositoryUpdater.java:2127)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater.access$1500(RepositoryUpdater.java:159)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.scanFiles(RepositoryUpdater.java:3278)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$FileListWork.getDone(RepositoryUpdater.java:3808)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:3443)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:6206)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.access$4300(RepositoryUpdater.java:5857)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2$1.run(RepositoryUpdater.java:6122)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:304)
   at org.netbeans.modules.parsing.impl.RunWhenScanFinishedSupport.performScan(RunWhenScanFinishedSupport.java:106)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6118)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task$2.call(RepositoryUpdater.java:6114)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:90)
   at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:6114)
   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)