java.lang.AssertionError: receiverNode is not null
        at org.jruby.nb.ast.CallNode.<init>(CallNode.java:75)
        at org.jruby.nb.ast.CallOneArgNode.<init>(CallOneArgNode.java:48)
        at org.jruby.nb.parser.ParserSupport.new_call(ParserSupport.java:908)
        at org.jruby.nb.parser.DefaultRubyParser.yyparse(DefaultRubyParser.java:2553)
        at org.jruby.nb.parser.DefaultRubyParser.yyparse(DefaultRubyParser.java:829)
        at org.jruby.nb.parser.DefaultRubyParser.parse(DefaultRubyParser.java:3334)
        at org.netbeans.modules.ruby.RubyParser.parseBuffer(RubyParser.java:596)
        at org.netbeans.modules.ruby.RubyParser.parse(RubyParser.java:118)
        at org.netbeans.modules.parsing.impl.SourceCache.getResult(SourceCache.java:194)
        at org.netbeans.modules.parsing.api.ResultIterator.getParserResult(ResultIterator.java:134)
        at org.netbeans.modules.parsing.impl.indexing.SourceIndexer$1.visit(SourceIndexer.java:119)
        at org.netbeans.modules.parsing.impl.indexing.SourceIndexer$1.run(SourceIndexer.java:105)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:131)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:115)
        at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:188)
        at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:101)
        at org.netbeans.modules.parsing.impl.indexing.SourceIndexer.index(SourceIndexer.java:99)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.index(RepositoryUpdater.java:685)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$FileListWork.getDone(RepositoryUpdater.java:765)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Work.doTheWork(RepositoryUpdater.java:704)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task._run(RepositoryUpdater.java:1175)
        at org.netbeans.modules.parsing.impl.indexing.RepositoryUpdater$Task.run(RepositoryUpdater.java:1150)
        at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:601)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
        at java.lang.Thread.run(Thread.java:619)