anchor.diff:            }
           }
           if (!empty) {
  -          patches.insertRange(++x, 1, patch);
  +          patches.insert(++x, patch);
           }
         }
       }
  
positive.code:             && ((pre_ins ? 1 : 0) + (pre_del ? 1 : 0) + (post_ins ? 1 : 0)
                  + (post_del ? 1 : 0)) == 3))) {
            // Duplicate record.
            diffs.insertRange(equalities.last, 1,
                              new Diff(DIFF_DELETE, lastequality));
            // Change second copy to insert.
            diffs[equalities.last + 1].operation = DIFF_INSERT;
  
negative.code:             && (lastequality.length <= max(length_insertions2,
                                                  length_deletions2))) {
            // Duplicate record.
            diffs.insert(equalities.last,
                              new Diff(DIFF_DELETE, lastequality));
            // Change second copy to insert.
            diffs[equalities.last + 1].operation = DIFF_INSERT;
  