anchor.diff:            let isWindows = System.Environment.OSVersion.Platform = System.PlatformID.Win32NT
             let loc =
                 if isWindows && assembly.GetName().Name = "FSharp.Core" then
  +                  FSharpAssemblyHelper.fsCore4300()
                     // TODO: handle more cases / versions.
                     // file references only valid on Windows 
                     // NOTE: we use 4.3.0.0 as even when you specify 4.3.1.0 you will get a 4.3.0.0 reference as result 
                     // (this will break above when we try to find for every file its reference)
  -                  sprintf @"C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp\.NETFramework\v4.0\4.3.0.0\FSharp.Core.dll"
  +                  //sprintf @"C:\Program Files (x86)\Reference Assemblies\Microsoft\FSharp\.NETFramework\v4.0\4.3.0.0\FSharp.Core.dll"
                 else
                     assembly.Location
             if loc = null then None
  
positive.code:   module internal FSharpAssemblyHelper =
        open System.IO
        let checker = FSharpChecker.Create()
            
        let getProjectReferences otherFlags libDirs dllFiles = 
            let dllFiles, hasCoreLib =
              dllFiles
              |> Seq.fold (fun (files, hasCoreLib) dllFile -> 
                 dllFile :: files, 
                 hasCoreLib || 
                 let name = (Path.GetFileName dllFile).ToLowerInvariant()
                 let iscorelib = name = "fsharp.core.dll" || name = "mscorlib.dll" 
                 printfn "%s is corlib: %b" dllFile iscorelib
                 iscorelib
              ) ([], false)
  
            let otherFlags = defaultArg otherFlags Seq.empty
            let libDirs = defaultArg libDirs Seq.empty
            let base1 = Path.GetTempFileName()
  
negative.code:                       yield "--define:DEBUG" 
                        //yield "--optimize-" 
                        yield "--nooptimizationdata"
                        yield "--noframework"
                        if msCoreLib.IsSome then
                          yield sprintf "-r:%s" msCoreLib.Value
                        if fsCoreLib.IsSome then
                          yield sprintf "-r:%s" fsCoreLib.Value
                        yield "--out:" + dllName
                        yield "--doc:" + xmlName
                        yield "--warn:3" 
  