message: Restrict merge_rows to requirement of empty linklists in AFL.
diff: @@ -617,7 +617,19 @@ void parse_and_apply_instructions(std::string& in, const std::string& path, util
  if (row_ndx1 == row_ndx2) {
  row_ndx2 = (row_ndx2 + 1) % t->size();
  }
  -
  + // A restriction of merge_rows is that any linklists in the
  + // "to" row must be empty because merging lists is not defined.
  + for (size_t col_ndx = 0; col_ndx != t->get_column_count(); ++col_ndx) {
  + if (t->get_column_type(col_ndx) == DataType::type_LinkList) {
  + if (!t->get_linklist(col_ndx, row_ndx2)->is_empty()) {
  + if (log) {
  + *log << "g.get_table(" << table_ndx << ")->get_linklist("
  + << col_ndx << ", " << row_ndx2 << ")->clear();";
  + }
  + t->get_linklist(col_ndx, row_ndx2)->clear();
  + }
  + }
  + }
  if (log) {
  *log << "g.get_table(" << table_ndx << ")->merge_rows(" << row_ndx1 << ", " << row_ndx2 << ");\n";
  }
  