anchor.diff:          let makeEmpty<'k, 'a when 'k : comparison> optCommitMultiplier =
               let map =
                   { Dict = Dictionary<'k, 'a> HashIdentity.Structural
  +                  DictOrigin = Dictionary<'k, 'a> HashIdentity.Structural
                     Logs = []
                     LogsLength = 0
                     Tmap = Unchecked.defaultof<Tmap<'k, 'a>>
  -                  CommitMultiplier = match optCommitMultiplier with Some cm -> cm | None -> 4 }
  +                  CommitMultiplier = match optCommitMultiplier with Some cm -> cm | None -> 2 }
               map.Tmap <- map
               map
   
  
positive.code:     module Tmap =
  
          let private commit map =
              let dict = Dictionary<'k, 'a> (map.Dict, HashIdentity.Structural)
              List.foldBack (fun log () ->
                  match log with
                  | Add (key, value) -> dict.[key] <- value
                  | Remove key -> ignore ^ dict.Remove(key))
                  map.Logs ()
              let map = { map with Dict = dict; Logs = []; LogsLength = 0 }
              map.Tmap <- map
              map
  
  
negative.code:     type [<NoEquality; NoComparison>] Tmap<'k, 'v when 'k : comparison> =
          private
              { Dict : Dictionary<'k, 'v>
                DictOrigin : Dictionary<'k, 'v>
                mutable Logs : Log<'k, 'v> list
                mutable LogsLength : int
                mutable Tmap : Tmap<'k, 'v>
  