anchor.diff:                  .ToString()
           | [KeyValue h1; KeyValue h2; KeyValue h3] ->
               System.Text.StringBuilder()
  -                .Append("hashMap [")
  +                .Append("intMap [")
                   .Append(IntMap<_>.ElementString h1)
                   .Append("; ")
                   .Append(IntMap<_>.ElementString h2)
  
positive.code:                 .ToString()
          | KeyValue h1 :: KeyValue h2 :: KeyValue h3 :: _ ->
              System.Text.StringBuilder()
                  .Append("hashMap [")
                  .Append(IntMap<_>.ElementString h1)
                  .Append("; ")
                  .Append(IntMap<_>.ElementString h2)
  
negative.code:     override this.ToString () =
          (* NOTE :   Like Map, we have specific cases for 0, 1, 2, 3, and 4+ elements. *)
          match List.ofSeq (Seq.truncate 4 this) with
          | [] -> "intMap []"
          | [KeyValue h1] ->
              System.Text.StringBuilder()
                  .Append("intMap [")
                  .Append(IntMap<_>.ElementString h1)
                  .Append("]")
                  .ToString()
          | [KeyValue h1; KeyValue h2] ->
              System.Text.StringBuilder()
                  .Append("intMap [")
                  .Append(IntMap<_>.ElementString h1)
                  .Append("; ")
                  .Append(IntMap<_>.ElementString h2)
  