anchor.diff:  
           let len = vec.Length
           if len = 0 then
  -            invalidArg "array" "The array is empty."
  +            invalidArg "vec" "The vector is empty."
   
           let mutable acc = vec.[0]
           for i = 1 to len - 1 do
  
positive.code:         else
              Array.toList vec.Elements
  
      //
      [<CompiledName("ToSeq")>]
      let toSeq (vec : vector<'T>) : seq<'T> =
          // Preconditions
  
negative.code:                 | Choice3Of3 value ->
                      resultList3.Add value)
  
              // Convert the ResizeArrays to vectors and return them.
              resultList1.ToArray () |> vector.UnsafeCreate,
              resultList2.ToArray () |> vector.UnsafeCreate,
              resultList3.ToArray () |> vector.UnsafeCreate
  
      /// Applies a mapping function to each element of the vector, then repeatedly applies
      /// a reduction function to each pair of results until one (1) result value remains.
      [<CompiledName("MapReduce")>]
      let mapReduce (mapReduction : IMapReduction<'Key, 'T>) (vec : vector<'Key>) : 'T =
  