anchor.diff:  
   let arrayEncoder dE (t: System.Type) =
       let e = dE (t.GetElementType())
  -    fun (i: M.Info) (x: obj) ->
  +    fun (i: FormatSettings) (x: obj) ->
           match x with
           | null ->
               EncodedNull
  
positive.code:     let dV = dD tg.[1]
      let tt = typedefof<System.Tuple<_,_>>.MakeGenericType(tg.[0], tg.[1])
      let cT = FSV.PreComputeTupleConstructor(tt)
      fun (i: M.Info) (x: Value) ->
          let rec walk fields =
              seq {
                  for f in fields do
  
negative.code:     let fs = getObjectFields t
      let ms = fs |> Array.map (fun x -> x :> System.Reflection.MemberInfo)
      let es = fs |> Array.map (fun f -> (f.Name, dE f.FieldType))
      fun (i: FormatSettings) (x: obj) ->
          match x with
          | null ->
              EncodedNull
  