anchor.diff:          else
               checker.StartBackgroundCompile options
               let newLazyUntypedInfo = getLazyUntypedInfo filename
  -            lazyUntypedInfos.[filename] = newLazyUntypedInfo |> ignore
  +            lazyUntypedInfos.[filename] <- newLazyUntypedInfo
               newLazyUntypedInfo.Force()
   
       member self.UntypedInfo filename =
  
positive.code:         let index = getIndex filename
          let filesAndContents = Array.copy filesAndContents
          Array.set filesAndContents index (filename, Some contents)
          new Project(currentFile, filesAndContents, Set.add filename updatedFiles)
      member self.UpdateCurrentFileContents contents =
          self.UpdateContents self.CurrentFile contents
          
  
negative.code:     { typedInfo : TypeCheckResults option
        contents : string }
  
  type ParseInfoCache(project:Project, initialLazyTypedInfos) as self =
      let checker, options = Ast.getCheckerAndOptions project.Files
      let lazyUntypedInfos = new Dictionary<string,Lazy<UntypedInfo>>()
      let lazyTypedInfos = new Dictionary<string,Lazy<TypedInfo>>()
  