anchor.diff:  module Helpers =
       let inline ni () = raise (new System.NotImplementedException ())
   
  +[<NoEquality>]
   type internal MetadataReference =
   | FileMetadataReference of string
   | ImageMetadataReference of string * byte array
  
positive.code: 
          let withTemp fn = fun () ->
              let path = getTempPath ()
              Directory.CreateDirectory path
              let result = fn path
              Directory.Delete (path, true)
              result
  
negative.code:         with get () =
              match r with
              | FileMetadataReference f -> f
              | ImageMetadataReference (p, _) -> p
              | ProjectMetadataReference (p, _) -> p
  
  [<CompilationRepresentationAttribute(CompilationRepresentationFlags.ModuleSuffix)>]
  module internal MetadataReference =
  