anchor.diff:                  | Some i ->
                       CharDiet.Join (comparer, result, stream'', i)
   
  -            Debug.Assert (
  -                dietInvariant result,
  -                "The DIET invariant does not hold for the result.")
  -            Debug.Assert (
  -                intervalsDisjoint result,
  -                "The intervals in the DIET are not disjoint.")
  -
  -            #if DEBUG
  -            let resultCount = count result
  -            Debug.Assert (
  -                resultCount >= minPossibleResultCount,
  -                sprintf "The result set should not contain fewer than %i elements, but it contains only %i elements."
  -                    minPossibleResultCount resultCount)
  -            Debug.Assert (
  -                resultCount <= maxPossibleResultCount,
  -                sprintf "The result set should not contain more than %i elements, but it contains %i elements."
  -                    maxPossibleResultCount resultCount)
  -            #endif
  +//            Debug.Assert (
  +//                dietInvariant result,
  +//                "The DIET invariant does not hold for the result.")
  +//            Debug.Assert (
  +//                intervalsDisjoint result,
  +//                "The intervals in the DIET are not disjoint.")
  +
  +//            #if DEBUG
  +//            let resultCount = count result
  +//            Debug.Assert (
  +//                resultCount >= minPossibleResultCount,
  +//                sprintf "The result set should not contain fewer than %i elements, but it contains only %i elements."
  +//                    minPossibleResultCount resultCount)
  +//            Debug.Assert (
  +//                resultCount <= maxPossibleResultCount,
  +//                sprintf "The result set should not contain more than %i elements, but it contains %i elements."
  +//                    maxPossibleResultCount resultCount)
  +//            #endif
               result
   
       /// Recursive implementation function for computing the intersection of two sets.
  
positive.code:             && dietInvariant r
              // Check that the intervals are disjoint.
              //&& (intervalsDisjoint tree Set.empty |> fst)
  
      //
      // NOTE : This function is only called by 'addRange'.
  
negative.code:             when streamHeight > inputHeight ->
              union stream input
          | _, _ ->
  //            #if DEBUG
  //            let inputCount = count input
  //            let streamCount = count stream
  //            /// The minimum possible number of elements in the resulting set.
  //            let minPossibleResultCount =
  //                max inputCount streamCount
  //            /// The maximum possible number of elements in the resulting set.
  //            let maxPossibleResultCount =
  //                inputCount + streamCount
  //            #endif
  
              let result =
                  let result, head', stream'' =
  