java.lang.NullPointerException
   at com.sun.tools.javac.code.Types$Subst.visitTypeVar(Types.java:2960)
   at com.sun.tools.javac.code.Types$Subst.visitTypeVar(Types.java:2898)
   at com.sun.tools.javac.code.Type$TypeVar.accept(Type.java:1289)
   at com.sun.tools.javac.code.Types$UnaryVisitor.visit(Types.java:4562)
   at com.sun.tools.javac.code.Types$Subst.subst(Types.java:2921)
   at com.sun.tools.javac.code.Types$Subst.subst(Types.java:2929)
   at com.sun.tools.javac.code.Types$Subst.subst(Types.java:2930)
   at com.sun.tools.javac.code.Types$Subst.visitClassType(Types.java:2970)
   at com.sun.tools.javac.code.Types$Subst.visitClassType(Types.java:2898)
   at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:778)
   at com.sun.tools.javac.code.Types$UnaryVisitor.visit(Types.java:4562)
   at com.sun.tools.javac.code.Types$Subst.subst(Types.java:2921)
   at com.sun.tools.javac.code.Types.subst(Types.java:2895)
   at org.netbeans.api.java.source.TypeUtilities.substitute(TypeUtilities.java:130)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.getMatchingArgumentTypes(JavaCompletionProvider.java:5385)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.getSmartTypes(JavaCompletionProvider.java:4901)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.access$2500(JavaCompletionProvider.java:145)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery$Env.getSmartTypes(JavaCompletionProvider.java:6038)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.addMembers(JavaCompletionProvider.java:3374)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.insideMemberSelect(JavaCompletionProvider.java:1857)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.resolveCompletion(JavaCompletionProvider.java:694)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.run(JavaCompletionProvider.java:448)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery$Task.run(JavaCompletionProvider.java:5902)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:598)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:155)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:139)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:206)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:203)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:74)
Caused: org.netbeans.modules.parsing.spi.ParseException
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:211)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:106)
   at org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.query(JavaCompletionProvider.java:320)
   at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:223)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)