message: Issue Fix self assignment
  It appears that tidy only understands one
  type of guard...
diff: @@ -15,13 +15,14 @@ struct EntropyState {
  DistinctMap *distinct;
  EntropyState &operator=(const EntropyState &other) {
  - if (this != &other) {
  + if (this == &other) {
  + return *this;
  + }
  if (distinct) {
  delete distinct;
  }
  distinct = new DistinctMap(*other.distinct);
  count = other.count;
  - }
  return *this;
  }
  };
  