Use td::append if possible.

td/telegram/PollManager.cpp

@@ -1157,7 +1157,7 @@ void PollManager::on_get_poll_voters(PollId poll_id, int32 option_id, string off
       LOG(ERROR) << "Receive " << user_id << " as voter in " << poll_id;
     }
   }
-  voters.voter_user_ids_.insert(voters.voter_user_ids_.end(), user_ids.begin(), user_ids.end());
+  append(voters.voter_user_ids_, user_ids);
   if (static_cast<int32>(user_ids.size()) > limit) {
     user_ids.resize(limit);
   }

td/telegram/files/FileManager.cpp

@@ -1777,7 +1777,7 @@ Status FileManager::merge(FileId x_file_id, FileId y_file_id, bool no_sync) {
 
   bool send_updates_flag = false;
   auto other_pmc_id = other_node->pmc_id_;
-  node->file_ids_.insert(node->file_ids_.end(), other_node->file_ids_.begin(), other_node->file_ids_.end());
+  append(node->file_ids_, other_node->file_ids_);
 
   for (auto file_id : other_node->file_ids_) {
     auto file_id_info = get_file_id_info(file_id);

tdactor/td/actor/impl/Scheduler.cpp

@@ -12,6 +12,7 @@
 #include "td/actor/impl/Event.h"
 #include "td/actor/impl/EventFull.h"
 
+#include "td/utils/algorithm.h"
 #include "td/utils/common.h"
 #include "td/utils/ExitGuard.h"
 #include "td/utils/format.h"
@@ -26,7 +27,6 @@
 #include "td/utils/Time.h"
 
 #include <functional>
-#include <iterator>
 #include <memory>
 #include <utility>
 
@@ -314,8 +314,7 @@ void Scheduler::register_migrated_actor(ActorInfo *actor_info) {
   }
   auto it = pending_events_.find(actor_info);
   if (it != pending_events_.end()) {
-    actor_info->mailbox_.insert(actor_info->mailbox_.end(), std::make_move_iterator(it->second.begin()),
-                                std::make_move_iterator(it->second.end()));
+    append(actor_info->mailbox_, std::move(it->second));
     pending_events_.erase(it);
   }
   if (actor_info->mailbox_.empty()) {

tdutils/td/utils/Hints.cpp

@@ -115,7 +115,7 @@ void Hints::add_search_results(vector<KeyT> &results, const string &word,
   LOG(DEBUG) << "Search for word " << word;
   auto it = word_to_keys.lower_bound(word);
   while (it != word_to_keys.end() && begins_with(it->first, word)) {
-    results.insert(results.end(), it->second.begin(), it->second.end());
+    append(results, it->second);
     ++it;
   }
 }