anchor.diff:  
       /// <summary>Builds a non empty sequence from the given array.</summary>
       /// <param name="array">The input array.</param>
  -    /// <returns>Non empty sequence containing the elements of the list.</returns>
  +    /// <returns>Non empty sequence containing the elements of the array.</returns>
       /// <exception cref="System.ArgumentException">Thrown when the input array is empty.</exception>
       /// <remarks>Throws exception for empty array</remarks>
       let ofArray (array: _[]) =
  
positive.code:     /// <returns>The result sequence.</returns>
      let zip (source1: NonEmptySeq<_>) (source2: NonEmptySeq<_>) = Seq.zip source1 source2 |> unsafeOfSeq
  
      /// <summary>Combines the three sequences into a list of triples. The sequences need not have equal lengths:
      /// when one sequence is exhausted any remaining elements in the other
      /// sequences are ignored.</summary>
      ///
  
negative.code:             }
          go head state |> unsafeOfSeq
  
      /// <summary>Combines the two sequences into a sequence of pairs. The two sequences need not have equal lengths:
      /// when one sequence is exhausted any remaining elements in the other
      /// sequence are ignored.</summary>
      ///
  