anchor.diff:  type FrameworkVersion = FrameworkVersion of string
   with
       member this.Value = (fun (FrameworkVersion x) -> x)this
  +
  +type ProjectRef = ProjectRef of Guid
  +with
  +    member this.Value = (fun (ProjectRef x) -> x)this
  +    static member Bind(guid : Guid) = ProjectRef guid
   
   type Project = 
       { Repository : RepositoryName
  
positive.code:     static member Bind (file : FileInfo) =  AssemblyRef.Bind (Path.GetFileNameWithoutExtension(file.Name))
  
  type BookmarkName = BookmarkName of string
  type BookmarkVersion = BookmarkVersion of string
  
  type Bookmark = { Name : BookmarkName
                    Version : BookmarkVersion }
  
  type PackageVersion = PackageVersion of string
  with
  
negative.code:     | Exe
      | Dll
  
  type AssemblyRef = private AssemblyRef of string
  with
      member this.Value = (fun (AssemblyRef x) -> x)this
  