anchor.diff:          | None -> None
       with e -> 
         System.Diagnostics.Debug.Assert(false, "Error while determining default location of F# compiler")
  +      Debug.tracef "Resolution" "BinFolderOfDefaultFSharpCore: error %s" (e.ToString())
         None
   
   
  
positive.code:   let internal tryFsharpiScript(url:string) =
      try
        let str = File.ReadAllText(url)
        let reg = new Regex("mono (\/.*)\/fsi\.exe")
        let res = reg.Match(str)
        if res.Success then Some(res.Groups.[1].Value) else None
      with e -> 
  
negative.code:         match result with 
          | Some _ -> result
          | None -> 
  
          let result = 
              BackupInstallationProbePoints |> List.tryPick (fun x -> 
                 Debug.tracef "Resolution" "BinFolderOfDefaultFSharpCore: Probing %s" x
                 let safeExists f = (try File.Exists(f) with _ -> false)
                 let file f = Path.Combine(Path.Combine(x,"bin"),f)
                 let exists f = safeExists(file f)
  