anchor.diff:                                                       fn.EndsWith(assumedFile, true, CultureInfo.InvariantCulture))
         match coreRef with
         | None ->
  -        let dirs = FSharpEnvironment.getDefaultDirectories(langVersion, targetFramework) 
  -        match FSharpEnvironment.resolveAssembly dirs assumedFile with
  +        let fullName = project.AssemblyContext.GetAssemblyFullName (assumedFile, project.TargetFramework);
  +        let fxCoreRef = Some(project.AssemblyContext.GetAssemblyLocation(fullName, project.TargetFramework))
  +        match fxCoreRef with
           | Some fn -> yield "-r:" + wrapf(fn)
  -        | None -> Debug.WriteLine(sprintf "Resolution: Assembly resolution failed when trying to find default reference for '%s'!" assumedFile)
  +        | None ->
  +          let dirs = FSharpEnvironment.getDefaultDirectories(langVersion, targetFramework) 
  +          match FSharpEnvironment.resolveAssembly dirs assumedFile with
  +          | Some fn -> yield "-r:" + wrapf(fn)
  +          | None -> Debug.WriteLine(sprintf "Resolution: Assembly resolution failed when trying to find default reference for '%s'!" assumedFile)
         | Some r -> 
           Debug.WriteLine(sprintf "Resolution: Found '%s' reference '%s'" assumedFile r)
         
  
positive.code:   /// F# compiler options (debugging, tail-calls etc.), custom command line
    /// parameters and assemblies referenced by the project ("-r" options)
    let generateCompilerOptions (fsconfig:FSharpCompilerParameters, reqLangVersion, targetFramework, items, configSelector, shouldWrap) =
      let dashr = generateReferences (items, reqLangVersion, targetFramework, configSelector, shouldWrap) |> Array.ofSeq
      let defines = fsconfig.DefineConstants.Split([| ';'; ','; ' ' |], StringSplitOptions.RemoveEmptyEntries)
      [  yield "--noframework"
         for symbol in defines do yield "--define:" + symbol
  
negative.code: 
    /// Generates references for the current project & configuration as a 
    /// list of strings of the form [ "-r:<full-path>"; ... ]
    let private generateReferences (project:DotNetProject, items:ProjectItemCollection, langVersion, targetFramework, configSelector, shouldWrap) = 
     [ // Should we wrap references in "..."
      let wrapf = if shouldWrap then wrapFile else id
      let files = 
  