anchor.diff:                        (word.GetText()) endLine endCol framework (String.concat " " args)
               
                   return! 
  -                    getInstance().GetUsesOfSymbolInProjectAtLocationInFile
  +                    instance.GetUsesOfSymbolInProjectAtLocationInFile
                           (projectFileName, currentFile, source, sourceFiles, endLine, endCol, currentLine, 
                           args, framework, buildQueryLexState word.Snapshot.TextBuffer)
               with e ->
  
positive.code:      editorFactory: IVsEditorAdaptersFactoryService,
       fsharpLanguageService: FSharpLanguageService) =
  
      let instance = Atom None
      
      let getInstance() = 
          match instance.Value with
          | Some x -> x
          | None -> 
              instance.Swap (fun _ -> Some (LanguageService (fun _ -> ()))) |> ignore
              debug "Checker created."
              instance.Value.Value
  
      let invalidateProject (projectItem: EnvDTE.ProjectItem) =
          let project = projectItem.ContainingProject
          if box project <> null && isFSharpProject project then
              let p = ProjectProvider.createForProject project
              debug "[Language Service] InteractiveChecker.InvalidateConfiguration for %s" p.ProjectFileName
              let opts = getInstance().GetCheckerOptions (null, p.ProjectFileName, null, p.SourceFiles, 
                                                     p.CompilerOptions, p.TargetFramework)
              getInstance().InvalidateConfiguration(opts)
  
      let dte = serviceProvider.GetService<EnvDTE.DTE, Interop.SDTE>()
      let events = dte.Events :?> EnvDTE80.Events2
  
negative.code:                     snapshot.GetLineFromLineNumber(lineNumber).GetText() 
                  SymbolParser.getSymbol source line col (getLineStr line) args (buildQueryLexState snapshot.TextBuffer)
  
              let! symbolUses = instance.GetAllUsesOfAllSymbolsInFile(
                                  projectFileName, currentFile, source, sourceFiles, args, framework, stale)
              return symbolUses, getLexerSymbol
          }
  
      member x.Checker = instance.Checker
  