anchor.diff:          checkNonNull "list" list
   
           let rec lengthAux acc (list : LazyList<'T>) =
  -            match getCell list with
  +            match list.Value with
               | Empty ->
                   int acc
               | Cons (_, tl) ->
  
positive.code: 
      let rec private skipCell count (list : LazyList<'T>) =
          if count = 0 then
              getCell list
          else
              match list.Value with
              | Cons (_, tl) ->
  
negative.code:         assert (not <| isNull list)
          Cons (value, list)
  
      /// Alias for LazyList.CreateLazy.
      let inline private lzy cellCreator : LazyList<'T> =
          LazyList<_>.CreateLazy cellCreator
  
      /// Apply the given function to successive elements of the list, returning the first
      /// result where function returns <c>Some(x)</c> for some x.
  