anchor.diff:  
   [<Extension;Sealed>]
   type Item4 =
  -    static member inline       Item4 (t :'a          ) = (^a : (member Item4: _ ) t)
       [<Extension>]static member Item4 ((_, _, _, d, _)) = d
       [<Extension>]static member Item4 ((_, _, _, d)   ) = d
   
  
positive.code: 
  [<Extension;Sealed>]
  type Item1 =
      static member inline       Item1 (t :'a          ) = (^a : (member Item1: _ ) t)
      [<Extension>]static member Item1 ((a, _, _, _, _)) = a
      [<Extension>]static member Item1 ((a, _, _, _)   ) = a
      [<Extension>]static member Item1 ((a, _, _)      ) = a
  
negative.code: 
  [<Extension;Sealed>]
  type Item5 =
      [<Extension>]static member Item5 ((_, _, _, _, e)) = e
  
      static member inline Invoke value = 
  