java.lang.AssertionError
        at org.netbeans.modules.scala.editing.ast.ScalaElement.paramNames(ScalaElement.java:342)
        at org.netbeans.modules.scala.editing.ScalaCompletionProposal$FunctionProposal.getLhsHtml(ScalaCompletionProposal.java:243)
        at org.netbeans.modules.csl.editor.completion.GsfCompletionItem$DelegatedItem.getLeftHtmlText(GsfCompletionItem.java:171)
        at org.netbeans.modules.csl.editor.completion.GsfCompletionItem.getPreferredWidth(GsfCompletionItem.java:498)
        at org.netbeans.modules.editor.completion.CompletionJList$RenderComponent.getPreferredSize(CompletionJList.java:325)
        at org.netbeans.modules.editor.completion.CompletionJList.setData(CompletionJList.java:160)
        at org.netbeans.modules.editor.completion.CompletionScrollPane.setData(CompletionScrollPane.java:124)
        at org.netbeans.modules.editor.completion.CompletionLayout$CompletionPopup.show(CompletionLayout.java:363)
        at org.netbeans.modules.editor.completion.CompletionLayout.showCompletion(CompletionLayout.java:137)
        at org.netbeans.modules.editor.completion.CompletionImpl$7.run(CompletionImpl.java:914)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:633)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)