message: Issue Const aggregate Combine
  Replace assignment with named method to avoid
  incomprehensible clang-tidy whinging.
  Also delete assignment to prevent Bad Things.
diff: @@ -14,8 +14,9 @@ struct EntropyState {
  idx_t count;
  DistinctMap *distinct;
  - // NOLINTNEXTLINE(bugprone-unhandled-self-assignment)
  - EntropyState &operator=(const EntropyState &other) {
  + EntropyState &operator=(const EntropyState &other) = delete;
  +
  + EntropyState &Assign(const EntropyState &other) {
  if (this == &other) {
  return *this;
  }
  @@ -41,7 +42,7 @@ struct EntropyFunctionBase {
  return;
  }
  if (!target->distinct) {
  - *target = source;
  + target->Assign(source);
  return;
  }
  for (auto &val : *source.distinct) {
  