anchor.diff:              with _ -> 
                   Debug.Assert(false, "couldn't update navigation items, ignoring")  
                   [| |]
  +
       member x.ParseTree = match infoOpt with
                            | Some (check,parse) -> parse.ParseTree
                            | None -> None    
  
positive.code:         | Some (checkResults, parseResults) -> 
              return! checkResults.GetSymbolUseAtLocation (line, col, lineStr, identIsland)
        }
      member x.GetUsesOfSymbolInFile(symbol) =
        async {
          match infoOpt with 
          | None -> return [| |]
          | Some (checkResults, parseResults) -> return! checkResults.GetUsesOfSymbolInFile(symbol)
        }
      member x.GetErrors() =
          match infoOpt with 
          | None -> None
  
negative.code:         | Some(colu, identIsland) ->
              return! checkResults.GetSymbolUseAtLocation(line, colu, lineStr, identIsland)
        }
  
      member x.GetSymbolAtLocation(line, col, lineStr, identIsland) =
        async {
          match infoOpt with 
  