message: Add method dedup map lookup safety check
diff: @@ -499,11 +499,13 @@ void write_out_type_mapping(
  auto merger = pair.second;
  out << SHOW(mergeable) << " -> " << SHOW(merger) << std::endl;
  + if (method_dedup_map.count(mergeable)) {
  for (auto& symbol_map : method_dedup_map.at(mergeable)) {
  out << " " << symbol_map.first << " -> " << SHOW(symbol_map.second)
  << std::endl;
  }
  }
  + }
  out << std::endl;
  os << out.str();
  