anchor.diff:          if JS.isDefined event then
               parseFile event
               |> Promise.bind (fun n ->
  -                LanguageService.projectsInBackground event.fileName
  +                match n with
  +                | Some _fileName -> LanguageService.projectsInBackground event.fileName
  +                | None -> Promise.lift ()
               )
           else
               Promise.lift ()
  
positive.code:         if JS.isDefined event then
              parseFile event.document
              |> Promise.bind (fun n ->
                  LanguageService.projectsInBackground event.document.fileName
              )
          else
              Promise.lift ()
  
negative.code:                 UnusedDeclarations.refresh.fire fileName
                  SimplifyName.refresh.fire fileName
                  CodeOutline.refresh.fire (undefined)
                  (Uri.file fileName, (mapResult result |> snd |> Seq.map fst |> ResizeArray)) |> currentDiagnostic.set
                  Some fileName
              else
                  None)
  
      let private parseFile (file : TextDocument) =
          match file with
  