anchor.diff:      member __.OnDeserialized(context: System.Runtime.Serialization.StreamingContext) =
           ignore context
           comparer <- LanguagePrimitives.FastGenericComparer<'Key>
  -        tree <- serializedData |> Array.map (fun (KeyValue(k, v)) -> (k, v)) |> MapTree.ofArray comparer
  +        tree <- serializedData |> Array.map (fun kvp -> kvp.Key, kvp.Value) |> MapTree.ofArray comparer
           serializedData <- null
   
       static member Empty : Map<'Key, 'Value> =
  
positive.code: 
      [<CompiledName("FoldBack")>]
      let foldBack<'Key, 'T, 'State  when 'Key : comparison> folder (table: Map<'Key, 'T>) (state:'State) =
          MapTree.foldBack  folder table.Tree state
  
      [<CompiledName("ToSeq")>]
      let toSeq (table: Map<_, _>) =
  
negative.code:                 let m1 = e1.MoveNext() 
                  let m2 = e2.MoveNext()
                  (m1 = m2) && (not m1 || 
                                   (let e1c = e1.Current
                                    let e2c = e2.Current
                                    ((e1c.Key = e2c.Key) && (Unchecked.equals e1c.Value e2c.Value) && loop())))
              loop()
          | _ -> false
  