anchor.diff:  type FSharpParsedDocument(fileName) = 
       inherit DefaultParsedDocument(fileName)
       member val Tokens = None with get,set
  -    member val AllSymbolUses = None with get,set
  +    member val AllSymbolsKeyed = Dictionary<_,_>() with get, set
   
   // An instance of this type is created by MonoDevelop (as defined in the .xml for the AddIn) 
   type FSharpParser() = 
  
positive.code:             cancellationToken = cancellationToken,
              computation = async {
              let shortFilename = Path.GetFileName fileName
  
              let curVersion = parseOptions.Content.Version
              let isObsolete =
  
negative.code: open MonoDevelop.Ide.Gui
  open MonoDevelop.Ide.Editor
  open MonoDevelop.Ide.TypeSystem
  open System
  open System.Collections.Generic
  open System.Diagnostics
  open System.IO
  open System.Text
  