diff --git a/benchmark/bench_actor.cpp b/benchmark/bench_actor.cpp
index 6f49c7aad..63cc1fca3 100644
--- a/benchmark/bench_actor.cpp
+++ b/benchmark/bench_actor.cpp
@@ -58,8 +58,7 @@ class RingBench final : public td::Benchmark {
           } else {
             // TODO: it is three times faster than send_event
             // maybe send event could be further optimized?
-            ::td::Scheduler::instance()->hack(static_cast<td::ActorId<Actor>>(next_actor),
-                                              td::Event::raw(static_cast<td::uint32>(n - 1)));
+            next_actor.get_actor_unsafe()->raw_event(td::Event::raw(static_cast<td::uint32>(n - 1)).data);
           }
         } else if (type == 4) {
           send_lambda(next_actor, [n, ptr = next_actor.get_actor_unsafe()] { ptr->pass(n - 1); });
diff --git a/td/mtproto/AuthData.cpp b/td/mtproto/AuthData.cpp
index aede7d3b6..dedca5031 100644
--- a/td/mtproto/AuthData.cpp
+++ b/td/mtproto/AuthData.cpp
@@ -100,7 +100,7 @@ std::vector<ServerSalt> AuthData::get_future_salts() const {
 
 int64 AuthData::next_message_id(double now) {
   double server_time = get_server_time(now);
-  int64 t = static_cast<int64>(server_time * (1ll << 32));
+  auto t = static_cast<int64>(server_time * (1ll << 32));
 
   // randomize lower bits for clocks with low precision
   // TODO(perf) do not do this for systems with good precision?..
diff --git a/td/mtproto/CryptoStorer.h b/td/mtproto/CryptoStorer.h
index 67763c6dc..ead442f7f 100644
--- a/td/mtproto/CryptoStorer.h
+++ b/td/mtproto/CryptoStorer.h
@@ -192,8 +192,9 @@ class CryptoImpl {
  public:
   CryptoImpl(const vector<MtprotoQuery> &to_send, Slice header, vector<int64> &&to_ack, int64 ping_id, int ping_timeout,
              int max_delay, int max_after, int max_wait, int future_salt_n, vector<int64> get_info,
-             vector<int64> resend, vector<int64> cancel, bool destroy_key, AuthData *auth_data, uint64 *container_id,
-             uint64 *get_info_id, uint64 *resend_id, uint64 *ping_message_id, uint64 *parent_message_id)
+             vector<int64> resend, const vector<int64> &cancel, bool destroy_key, AuthData *auth_data,
+             uint64 *container_id, uint64 *get_info_id, uint64 *resend_id, uint64 *ping_message_id,
+             uint64 *parent_message_id)
       : query_storer_(to_send, header)
       , ack_empty_(to_ack.empty())
       , ack_storer_(!ack_empty_, mtproto_api::msgs_ack(std::move(to_ack)), auth_data)
@@ -206,7 +207,7 @@ class CryptoImpl {
       , resend_storer_(resend_not_empty_, mtproto_api::msg_resend_req(std::move(resend)), auth_data, true)
       , cancel_not_empty_(!cancel.empty())
       , cancel_cnt_(static_cast<int32>(cancel.size()))
-      , cancel_storer_(cancel_not_empty_, std::move(cancel), auth_data, true)
+      , cancel_storer_(cancel_not_empty_, cancel, auth_data, true)
       , destroy_key_storer_(destroy_key, mtproto_api::destroy_auth_key(), auth_data, true)
       , tmp_storer_(query_storer_, ack_storer_)
       , tmp2_storer_(tmp_storer_, http_wait_storer_)
diff --git a/td/mtproto/Handshake.cpp b/td/mtproto/Handshake.cpp
index 23b32e758..79fd9a716 100644
--- a/td/mtproto/Handshake.cpp
+++ b/td/mtproto/Handshake.cpp
@@ -95,7 +95,8 @@ Status AuthKeyHandshake::on_res_pq(Slice message, Callback *connection, PublicRs
   }
   auto rsa_key = r_rsa_key.move_as_ok();
 
-  string p, q;
+  string p;
+  string q;
   if (pq_factorize(res_pq->pq_, &p, &q) == -1) {
     return Status::Error("Failed to factorize");
   }
@@ -129,7 +130,7 @@ Status AuthKeyHandshake::on_res_pq(Slice message, Callback *connection, PublicRs
     string aes_key(32, '\0');
     Random::secure_bytes(MutableSlice(aes_key));
 
-    string data_with_hash = data + sha256(aes_key + data);
+    string data_with_hash = PSTRING() << data << sha256(aes_key + data);
     std::reverse(data_with_hash.begin(), data_with_hash.begin() + data.size());
 
     string decrypted_data(256, '\0');
diff --git a/td/mtproto/Handshake.h b/td/mtproto/Handshake.h
index 435350d94..b3979ed20 100644
--- a/td/mtproto/Handshake.h
+++ b/td/mtproto/Handshake.h
@@ -97,7 +97,7 @@ class AuthKeyHandshake {
   static string store_object(const mtproto_api::Object &object);
 
   void send(Callback *connection, const Storer &storer);
-  void do_send(Callback *connection, const Storer &storer);
+  static void do_send(Callback *connection, const Storer &storer);
 
   Status on_start(Callback *connection) TD_WARN_UNUSED_RESULT;
   Status on_res_pq(Slice message, Callback *connection, PublicRsaKeyInterface *public_rsa_key) TD_WARN_UNUSED_RESULT;
diff --git a/td/mtproto/HandshakeConnection.h b/td/mtproto/HandshakeConnection.h
index f7760ce05..49ef722b0 100644
--- a/td/mtproto/HandshakeConnection.h
+++ b/td/mtproto/HandshakeConnection.h
@@ -65,7 +65,7 @@ class HandshakeConnection final
   }
 
   Status on_raw_packet(const PacketInfo &packet_info, BufferSlice packet) final {
-    if (packet_info.no_crypto_flag == false) {
+    if (!packet_info.no_crypto_flag) {
       return Status::Error("Expected not encrypted packet");
     }
 
diff --git a/td/mtproto/Ping.cpp b/td/mtproto/Ping.cpp
index b3dadcc7c..f92368c50 100644
--- a/td/mtproto/Ping.cpp
+++ b/td/mtproto/Ping.cpp
@@ -19,7 +19,7 @@
 namespace td {
 namespace mtproto {
 
-ActorOwn<> create_ping_actor(string debug, unique_ptr<RawConnection> raw_connection, unique_ptr<AuthData> auth_data,
+ActorOwn<> create_ping_actor(Slice actor_name, unique_ptr<RawConnection> raw_connection, unique_ptr<AuthData> auth_data,
                              Promise<unique_ptr<RawConnection>> promise, ActorShared<> parent) {
   class PingActor final : public Actor {
    public:
@@ -99,7 +99,7 @@ ActorOwn<> create_ping_actor(string debug, unique_ptr<RawConnection> raw_connect
       }
     }
   };
-  return ActorOwn<>(create_actor<PingActor>(PSLICE() << "PingActor<" << debug << ">", std::move(raw_connection),
+  return ActorOwn<>(create_actor<PingActor>(PSLICE() << "PingActor<" << actor_name << ">", std::move(raw_connection),
                                             std::move(auth_data), std::move(promise), std::move(parent)));
 }
 
diff --git a/td/mtproto/Ping.h b/td/mtproto/Ping.h
index 7dc9aa4e0..25aded068 100644
--- a/td/mtproto/Ping.h
+++ b/td/mtproto/Ping.h
@@ -17,7 +17,7 @@
 namespace td {
 namespace mtproto {
 
-ActorOwn<> create_ping_actor(string debug, unique_ptr<RawConnection> raw_connection, unique_ptr<AuthData> auth_data,
+ActorOwn<> create_ping_actor(Slice actor_name, unique_ptr<RawConnection> raw_connection, unique_ptr<AuthData> auth_data,
                              Promise<unique_ptr<RawConnection>> promise, ActorShared<> parent);
 
 }  // namespace mtproto
diff --git a/td/mtproto/RawConnection.cpp b/td/mtproto/RawConnection.cpp
index d26f48a1d..2e4ec5dad 100644
--- a/td/mtproto/RawConnection.cpp
+++ b/td/mtproto/RawConnection.cpp
@@ -37,7 +37,7 @@ class RawConnectionDefault final : public RawConnection {
  public:
   RawConnectionDefault(SocketFd socket_fd, TransportType transport_type, unique_ptr<StatsCallback> stats_callback)
       : socket_fd_(std::move(socket_fd))
-      , transport_(create_transport(transport_type))
+      , transport_(create_transport(std::move(transport_type)))
       , stats_callback_(std::move(stats_callback)) {
     transport_->init(&socket_fd_.input_buffer(), &socket_fd_.output_buffer());
   }
diff --git a/td/mtproto/RawConnection.h b/td/mtproto/RawConnection.h
index 1afd78372..98cee88e0 100644
--- a/td/mtproto/RawConnection.h
+++ b/td/mtproto/RawConnection.h
@@ -48,7 +48,7 @@ class RawConnection {
   virtual bool can_send() const = 0;
   virtual TransportType get_transport_type() const = 0;
   virtual void send_crypto(const Storer &storer, int64 session_id, int64 salt, const AuthKey &auth_key,
-                           uint64 quick_ack_token = 0) = 0;
+                           uint64 quick_ack_token) = 0;
   virtual uint64 send_no_crypto(const Storer &storer) = 0;
 
   virtual PollableFdInfo &get_poll_info() = 0;
diff --git a/td/mtproto/SessionConnection.cpp b/td/mtproto/SessionConnection.cpp
index 228edae56..f69d01c11 100644
--- a/td/mtproto/SessionConnection.cpp
+++ b/td/mtproto/SessionConnection.cpp
@@ -893,7 +893,8 @@ void SessionConnection::flush_packet() {
     }
   }
 
-  size_t send_till = 0, send_size = 0;
+  size_t send_till = 0;
+  size_t send_size = 0;
   // send at most 1020 queries, of total size 2^15
   // don't send anything if have no salt
   if (has_salt) {
diff --git a/td/mtproto/SessionConnection.h b/td/mtproto/SessionConnection.h
index 3da23a4fc..3661378b5 100644
--- a/td/mtproto/SessionConnection.h
+++ b/td/mtproto/SessionConnection.h
@@ -212,7 +212,8 @@ class SessionConnection final
     };
   }
 
-  Status parse_message(TlParser &parser, MsgInfo *info, Slice *packet, bool crypto_flag = true) TD_WARN_UNUSED_RESULT;
+  static Status parse_message(TlParser &parser, MsgInfo *info, Slice *packet,
+                              bool crypto_flag = true) TD_WARN_UNUSED_RESULT;
   Status parse_packet(TlParser &parser) TD_WARN_UNUSED_RESULT;
   Status on_packet_container(const MsgInfo &info, Slice packet) TD_WARN_UNUSED_RESULT;
   Status on_packet_rpc_result(const MsgInfo &info, Slice packet) TD_WARN_UNUSED_RESULT;
diff --git a/td/mtproto/TcpTransport.cpp b/td/mtproto/TcpTransport.cpp
index 98760aa1e..2570403dd 100644
--- a/td/mtproto/TcpTransport.cpp
+++ b/td/mtproto/TcpTransport.cpp
@@ -272,8 +272,8 @@ void ObfuscatedTransport::do_write_tls(BufferBuilder &&builder) {
   do_write(builder.extract());
 }
 
-void ObfuscatedTransport::do_write(BufferSlice &&slice) {
-  output_->append(std::move(slice));
+void ObfuscatedTransport::do_write(BufferSlice &&message) {
+  output_->append(std::move(message));
 }
 
 }  // namespace tcp
diff --git a/td/mtproto/TcpTransport.h b/td/mtproto/TcpTransport.h
index 2d188bbd8..4a2b918d9 100644
--- a/td/mtproto/TcpTransport.h
+++ b/td/mtproto/TcpTransport.h
@@ -128,8 +128,8 @@ class OldTransport final : public IStreamTransport {
 
 class ObfuscatedTransport final : public IStreamTransport {
  public:
-  ObfuscatedTransport(int16 dc_id, const ProxySecret &secret)
-      : dc_id_(dc_id), secret_(secret), impl_(secret_.use_random_padding()) {
+  ObfuscatedTransport(int16 dc_id, ProxySecret secret)
+      : dc_id_(dc_id), secret_(std::move(secret)), impl_(secret_.use_random_padding()) {
   }
 
   Result<size_t> read_next(BufferSlice *message, uint32 *quick_ack) final TD_WARN_UNUSED_RESULT;
@@ -172,6 +172,7 @@ class ObfuscatedTransport final : public IStreamTransport {
   TransportType get_type() const final {
     return TransportType{TransportType::ObfuscatedTcp, dc_id_, secret_};
   }
+
   bool use_random_padding() const final {
     return secret_.use_random_padding();
   }
diff --git a/td/telegram/net/ConnectionCreator.cpp b/td/telegram/net/ConnectionCreator.cpp
index c10c22acf..08b4e439c 100644
--- a/td/telegram/net/ConnectionCreator.cpp
+++ b/td/telegram/net/ConnectionCreator.cpp
@@ -396,7 +396,7 @@ void ConnectionCreator::ping_proxy_socket_fd(IPAddress ip_address, SocketFd sock
   auto raw_connection =
       mtproto::RawConnection::create(ip_address, std::move(socket_fd), std::move(transport_type), nullptr);
   children_[token] = {
-      false, create_ping_actor(std::move(debug_str), std::move(raw_connection), nullptr,
+      false, create_ping_actor(debug_str, std::move(raw_connection), nullptr,
                                PromiseCreator::lambda([promise = std::move(promise)](
                                                           Result<unique_ptr<mtproto::RawConnection>> result) mutable {
                                  if (result.is_error()) {
diff --git a/tdactor/td/actor/PromiseFuture.h b/tdactor/td/actor/PromiseFuture.h
index 938267eb3..ba474cc9e 100644
--- a/tdactor/td/actor/PromiseFuture.h
+++ b/tdactor/td/actor/PromiseFuture.h
@@ -184,35 +184,29 @@ class SafePromise;
 template <class T = Unit>
 class Promise;
 
-constexpr std::false_type is_promise_interface(...) {
-  return {};
-}
+constexpr std::false_type is_promise_interface(...);
+
 template <class T>
-constexpr std::true_type is_promise_interface(const PromiseInterface<T> &promise) {
-  return {};
-}
+constexpr std::true_type is_promise_interface(const PromiseInterface<T> &promise);
+
 template <class T>
-constexpr std::true_type is_promise_interface(const Promise<T> &promise) {
-  return {};
-}
+constexpr std::true_type is_promise_interface(const Promise<T> &promise);
 
 template <class F>
 constexpr bool is_promise_interface() {
   return decltype(is_promise_interface(std::declval<F>()))::value;
 }
 
-constexpr std::false_type is_promise_interface_ptr(...) {
-  return {};
-}
+constexpr std::false_type is_promise_interface_ptr(...);
+
 template <class T>
-constexpr std::true_type is_promise_interface_ptr(const unique_ptr<T> &promise) {
-  return {};
-}
+constexpr std::true_type is_promise_interface_ptr(const unique_ptr<T> &promise);
 
 template <class F>
 constexpr bool is_promise_interface_ptr() {
   return decltype(is_promise_interface_ptr(std::declval<F>()))::value;
 }
+
 template <class T = void, class F = void, std::enable_if_t<std::is_same<T, void>::value, bool> has_t = false>
 auto lambda_promise(F &&f) {
   return detail::LambdaPromise<detail::drop_result_t<detail::get_arg_t<std::decay_t<F>>>, std::decay_t<F>>(
diff --git a/tdactor/td/actor/impl/Actor.h b/tdactor/td/actor/impl/Actor.h
index b29ee5452..4cf204ffe 100644
--- a/tdactor/td/actor/impl/Actor.h
+++ b/tdactor/td/actor/impl/Actor.h
@@ -52,7 +52,7 @@ inline void Actor::do_stop() {
   CHECK(empty());
 }
 inline bool Actor::has_timeout() const {
-  return Scheduler::instance()->has_actor_timeout(this);
+  return get_info()->get_heap_node()->in_heap();
 }
 inline double Actor::get_timeout() const {
   return Scheduler::instance()->get_actor_timeout(this);
diff --git a/tdactor/td/actor/impl/EventFull-decl.h b/tdactor/td/actor/impl/EventFull-decl.h
index f270ee857..a3d41c3a0 100644
--- a/tdactor/td/actor/impl/EventFull-decl.h
+++ b/tdactor/td/actor/impl/EventFull-decl.h
@@ -45,7 +45,7 @@ class EventFull {
     data_.link_token = actor_ref.token();
   }
   template <class T>
-  EventFull(ActorId<T> actor_id, Event &&data) : actor_id_(actor_id), data_(std::move(data)) {
+  EventFull(ActorId<T> actor_id, Event &&data) : actor_id_(std::move(actor_id)), data_(std::move(data)) {
   }
 
   ActorId<> actor_id_;
diff --git a/tdactor/td/actor/impl/Scheduler-decl.h b/tdactor/td/actor/impl/Scheduler-decl.h
index 0e3fa3b03..daa988580 100644
--- a/tdactor/td/actor/impl/Scheduler-decl.h
+++ b/tdactor/td/actor/impl/Scheduler-decl.h
@@ -107,9 +107,6 @@ class Scheduler {
   template <ActorSendType send_type>
   void send(ActorRef actor_ref, Event &&event);
 
-  void hack(const ActorId<> &actor_id, Event &&event) {
-    actor_id.get_actor_unsafe()->raw_event(event.data);
-  }
   void before_tail_send(const ActorId<> &actor_id);
 
   static void subscribe(PollableFd fd, PollFlags flags = PollFlags::ReadWrite());
@@ -125,7 +122,6 @@ class Scheduler {
   void start_migrate_actor(Actor *actor, int32 dest_sched_id);
   void finish_migrate_actor(Actor *actor);
 
-  bool has_actor_timeout(const Actor *actor) const;
   double get_actor_timeout(const Actor *actor) const;
   void set_actor_timeout_in(Actor *actor, double timeout);
   void set_actor_timeout_at(Actor *actor, double timeout_at);
@@ -176,7 +172,6 @@ class Scheduler {
   void do_migrate_actor(ActorInfo *actor_info, int32 dest_sched_id);
   void start_migrate_actor(ActorInfo *actor_info, int32 dest_sched_id);
 
-  bool has_actor_timeout(const ActorInfo *actor_info) const;
   double get_actor_timeout(const ActorInfo *actor_info) const;
   void set_actor_timeout_in(ActorInfo *actor_info, double timeout);
   void set_actor_timeout_at(ActorInfo *actor_info, double timeout_at);
diff --git a/tdactor/td/actor/impl/Scheduler.h b/tdactor/td/actor/impl/Scheduler.h
index 2356f6d1c..47780e760 100644
--- a/tdactor/td/actor/impl/Scheduler.h
+++ b/tdactor/td/actor/impl/Scheduler.h
@@ -299,9 +299,6 @@ inline void Scheduler::finish_migrate_actor(Actor *actor) {
   register_migrated_actor(actor->get_info());
 }
 
-inline bool Scheduler::has_actor_timeout(const Actor *actor) const {
-  return has_actor_timeout(actor->get_info());
-}
 inline double Scheduler::get_actor_timeout(const Actor *actor) const {
   return get_actor_timeout(actor->get_info());
 }
@@ -315,11 +312,6 @@ inline void Scheduler::cancel_actor_timeout(Actor *actor) {
   cancel_actor_timeout(actor->get_info());
 }
 
-inline bool Scheduler::has_actor_timeout(const ActorInfo *actor_info) const {
-  const HeapNode *heap_node = actor_info->get_heap_node();
-  return heap_node->in_heap();
-}
-
 inline void Scheduler::cancel_actor_timeout(ActorInfo *actor_info) {
   HeapNode *heap_node = actor_info->get_heap_node();
   if (heap_node->in_heap()) {
diff --git a/tddb/td/db/SqliteKeyValue.h b/tddb/td/db/SqliteKeyValue.h
index b44537d48..1d920aaa0 100644
--- a/tddb/td/db/SqliteKeyValue.h
+++ b/tddb/td/db/SqliteKeyValue.h
@@ -35,10 +35,6 @@ class SqliteKeyValue {
 
   Status init_with_connection(SqliteDb connection, string table_name) TD_WARN_UNUSED_RESULT;
 
-  Result<bool> try_regenerate_index() TD_WARN_UNUSED_RESULT {
-    return false;
-  }
-
   void close() {
     *this = SqliteKeyValue();
   }
@@ -118,7 +114,7 @@ class SqliteKeyValue {
   SqliteStatement get_by_prefix_stmt_;
   SqliteStatement get_by_prefix_rare_stmt_;
 
-  string next_prefix(Slice prefix);
+  static string next_prefix(Slice prefix);
 };
 
 }  // namespace td
diff --git a/tddb/td/db/SqliteKeyValueAsync.cpp b/tddb/td/db/SqliteKeyValueAsync.cpp
index 3f59b2b81..796d02282 100644
--- a/tddb/td/db/SqliteKeyValueAsync.cpp
+++ b/tddb/td/db/SqliteKeyValueAsync.cpp
@@ -44,6 +44,7 @@ class SqliteKeyValueAsync final : public SqliteKeyValueAsyncInterface {
    public:
     explicit Impl(std::shared_ptr<SqliteKeyValueSafe> kv_safe) : kv_safe_(std::move(kv_safe)) {
     }
+
     void set(string key, string value, Promise<> promise) {
       auto it = buffer_.find(key);
       if (it != buffer_.end()) {
@@ -57,6 +58,7 @@ class SqliteKeyValueAsync final : public SqliteKeyValueAsyncInterface {
       cnt_++;
       do_flush(false /*force*/);
     }
+
     void erase(string key, Promise<> promise) {
       auto it = buffer_.find(key);
       if (it != buffer_.end()) {
@@ -70,6 +72,7 @@ class SqliteKeyValueAsync final : public SqliteKeyValueAsyncInterface {
       cnt_++;
       do_flush(false /*force*/);
     }
+
     void erase_by_prefix(string key_prefix, Promise<> promise) {
       do_flush(true /*force*/);
       kv_->erase_by_prefix(key_prefix);
diff --git a/tddb/td/db/TQueue.cpp b/tddb/td/db/TQueue.cpp
index 70095eb93..52335504a 100644
--- a/tddb/td/db/TQueue.cpp
+++ b/tddb/td/db/TQueue.cpp
@@ -68,7 +68,7 @@ bool EventId::operator<(const EventId &other) const {
   return id_ < other.id_;
 }
 
-StringBuilder &operator<<(StringBuilder &string_builder, const EventId id) {
+StringBuilder &operator<<(StringBuilder &string_builder, EventId id) {
   return string_builder << "EventId{" << id.value() << "}";
 }
 
diff --git a/tddb/td/db/TQueue.h b/tddb/td/db/TQueue.h
index 6301e20ba..8e84ae9a9 100644
--- a/tddb/td/db/TQueue.h
+++ b/tddb/td/db/TQueue.h
@@ -117,7 +117,7 @@ class TQueue {
   virtual void close(Promise<> promise) = 0;
 };
 
-StringBuilder &operator<<(StringBuilder &string_builder, const TQueue::EventId id);
+StringBuilder &operator<<(StringBuilder &string_builder, TQueue::EventId id);
 
 struct BinlogEvent;
 
@@ -131,7 +131,7 @@ class TQueueBinlog final : public TQueue::StorageCallback {
   void set_binlog(std::shared_ptr<BinlogT> binlog) {
     binlog_ = std::move(binlog);
   }
-  virtual void close(Promise<> promise) final;
+  void close(Promise<> promise) final;
 
  private:
   std::shared_ptr<BinlogT> binlog_;
@@ -143,7 +143,7 @@ class TQueueMemoryStorage final : public TQueue::StorageCallback {
   uint64 push(QueueId queue_id, const RawEvent &event) final;
   void pop(uint64 log_event_id) final;
   void replay(TQueue &q) const;
-  virtual void close(Promise<> promise) final;
+  void close(Promise<> promise) final;
 
  private:
   uint64 next_log_event_id_{1};
diff --git a/tddb/td/db/binlog/Binlog.cpp b/tddb/td/db/binlog/Binlog.cpp
index fb2e4bcab..9e5215ca8 100644
--- a/tddb/td/db/binlog/Binlog.cpp
+++ b/tddb/td/db/binlog/Binlog.cpp
@@ -54,7 +54,7 @@ struct AesCtrEncryptionEvent {
   BufferSlice iv_;
   BufferSlice key_hash_;
 
-  BufferSlice generate_key(const DbKey &db_key) {
+  BufferSlice generate_key(const DbKey &db_key) const {
     CHECK(!db_key.is_empty());
     BufferSlice key(key_size());
     size_t iteration_count = kdf_iteration_count();
@@ -64,7 +64,8 @@ struct AesCtrEncryptionEvent {
     pbkdf2_sha256(db_key.data(), key_salt_.as_slice(), narrow_cast<int>(iteration_count), key.as_slice());
     return key;
   }
-  BufferSlice generate_hash(Slice key) {
+
+  static BufferSlice generate_hash(Slice key) {
     BufferSlice hash(hash_size());
     hmac_sha256(key, "cucumbers everywhere", hash.as_slice());
     return hash;
@@ -354,11 +355,13 @@ void Binlog::do_event(BinlogEvent &&event) {
         key = encryption_event.generate_key(db_key_);
       }
 
-      if (encryption_event.generate_hash(key.as_slice()).as_slice() != encryption_event.key_hash_.as_slice()) {
+      if (detail::AesCtrEncryptionEvent::generate_hash(key.as_slice()).as_slice() !=
+          encryption_event.key_hash_.as_slice()) {
         CHECK(state_ == State::Load);
         if (!old_db_key_.is_empty()) {
           key = encryption_event.generate_key(old_db_key_);
-          if (encryption_event.generate_hash(key.as_slice()).as_slice() != encryption_event.key_hash_.as_slice()) {
+          if (detail::AesCtrEncryptionEvent::generate_hash(key.as_slice()).as_slice() !=
+              encryption_event.key_hash_.as_slice()) {
             info_.wrong_password = true;
           }
         } else {
@@ -610,7 +613,7 @@ void Binlog::reset_encryption() {
     key = event.generate_key(db_key_);
   }
 
-  event.key_hash_ = event.generate_hash(key.as_slice());
+  event.key_hash_ = EncryptionEvent::generate_hash(key.as_slice());
 
   do_event(BinlogEvent(
       BinlogEvent::create_raw(0, BinlogEvent::ServiceTypes::AesCtrEncryption, 0, create_default_storer(event)),
@@ -722,7 +725,7 @@ string Binlog::debug_get_binlog_data(int64 begin_offset, int64 end_offset) {
   SCOPE_EXIT {
     fd_.lock(FileFd::LockFlags::Write, path_, 1).ensure();
   };
-  size_t expected_data_length = narrow_cast<size_t>(end_offset - begin_offset);
+  auto expected_data_length = narrow_cast<size_t>(end_offset - begin_offset);
   string data(expected_data_length, '\0');
   auto r_data_size = fd.pread(data, begin_offset);
   if (r_data_size.is_error()) {
diff --git a/tddb/td/db/binlog/Binlog.h b/tddb/td/db/binlog/Binlog.h
index d9ebe1038..1cc50c13e 100644
--- a/tddb/td/db/binlog/Binlog.h
+++ b/tddb/td/db/binlog/Binlog.h
@@ -154,7 +154,7 @@ class Binlog {
   bool need_sync_{false};
   enum class State { Empty, Load, Reindex, Run } state_{State::Empty};
 
-  Result<FileFd> open_binlog(const string &path, int32 flags);
+  static Result<FileFd> open_binlog(const string &path, int32 flags);
   size_t flush_events_buffer(bool force);
   void do_add_event(BinlogEvent &&event);
   void do_event(BinlogEvent &&event);
diff --git a/tddb/td/db/binlog/BinlogInterface.h b/tddb/td/db/binlog/BinlogInterface.h
index 21fe53451..20d156661 100644
--- a/tddb/td/db/binlog/BinlogInterface.h
+++ b/tddb/td/db/binlog/BinlogInterface.h
@@ -66,7 +66,7 @@ class BinlogInterface {
 
   virtual void force_sync(Promise<> promise) = 0;
   virtual void force_flush() = 0;
-  virtual void change_key(DbKey db_key, Promise<> promise = Promise<>()) = 0;
+  virtual void change_key(DbKey db_key, Promise<> promise) = 0;
 
   virtual uint64 next_id() = 0;
   virtual uint64 next_id(int32 shift) = 0;
diff --git a/tdnet/td/net/GetHostByNameActor.cpp b/tdnet/td/net/GetHostByNameActor.cpp
index 227780287..c966103c9 100644
--- a/tdnet/td/net/GetHostByNameActor.cpp
+++ b/tdnet/td/net/GetHostByNameActor.cpp
@@ -62,7 +62,7 @@ class GoogleDnsResolver final : public Actor {
     }
     TRY_RESULT(answer, get_json_object_field(json_value.get_object(), "Answer", JsonValue::Type::Array, false));
     auto &array = answer.get_array();
-    if (array.size() == 0) {
+    if (array.empty()) {
       return Status::Error("Failed to parse DNS result: Answer is an empty array");
     }
     if (array[0].type() != JsonValue::Type::Object) {
diff --git a/tdnet/td/net/HttpChunkedByteFlow.cpp b/tdnet/td/net/HttpChunkedByteFlow.cpp
index c56fb2d87..7123c1727 100644
--- a/tdnet/td/net/HttpChunkedByteFlow.cpp
+++ b/tdnet/td/net/HttpChunkedByteFlow.cpp
@@ -62,7 +62,7 @@ bool HttpChunkedByteFlow::loop() {
 
     if (len_ == 0) {
       if (input_->size() < 2) {
-        need_size = 2;
+        set_need_size(2);
         break;
       }
       input_->advance(2);
diff --git a/tdnet/td/net/HttpConnectionBase.cpp b/tdnet/td/net/HttpConnectionBase.cpp
index c12782b2d..ff61ee9ab 100644
--- a/tdnet/td/net/HttpConnectionBase.cpp
+++ b/tdnet/td/net/HttpConnectionBase.cpp
@@ -184,7 +184,7 @@ void HttpConnectionBase::loop() {
   }
   if (state_ == State::Close) {
     LOG_IF(INFO, fd_.need_flush_write()) << "Close nonempty connection";
-    LOG_IF(INFO, want_read && (fd_.input_buffer().size() > 0 || current_query_->type_ != HttpQuery::Type::Empty))
+    LOG_IF(INFO, want_read && (!fd_.input_buffer().empty() || current_query_->type_ != HttpQuery::Type::Empty))
         << "Close connection while reading request/response";
     return stop();
   }
diff --git a/tdnet/td/net/SslStream.h b/tdnet/td/net/SslStream.h
index c3e9bbd3d..5a1a40671 100644
--- a/tdnet/td/net/SslStream.h
+++ b/tdnet/td/net/SslStream.h
@@ -26,7 +26,7 @@ class SslStream {
   enum class VerifyPeer { On, Off };
 
   static Result<SslStream> create(CSlice host, CSlice cert_file = CSlice(), VerifyPeer verify_peer = VerifyPeer::On,
-                                  bool check_ip_address_as_host = false);
+                                  bool use_ip_address_as_host = false);
 
   ByteFlowInterface &read_byte_flow();
   ByteFlowInterface &write_byte_flow();
diff --git a/tdutils/generate/generate_mime_types_gperf.cpp b/tdutils/generate/generate_mime_types_gperf.cpp
index 4a424814e..6bb64903b 100644
--- a/tdutils/generate/generate_mime_types_gperf.cpp
+++ b/tdutils/generate/generate_mime_types_gperf.cpp
@@ -116,7 +116,7 @@ int main(int argc, char *argv[]) {
 
     std::vector<std::string> extensions;
     while (!extensions_string.empty()) {
-      extensions.push_back("");
+      extensions.emplace_back();
       std::tie(extensions.back(), extensions_string) = split(extensions_string);
     }
     assert(!extensions.empty());
diff --git a/tdutils/td/utils/BigNum.cpp b/tdutils/td/utils/BigNum.cpp
index 09612aacb..adf70c53c 100644
--- a/tdutils/td/utils/BigNum.cpp
+++ b/tdutils/td/utils/BigNum.cpp
@@ -70,6 +70,9 @@ BigNum::BigNum(const BigNum &other) : BigNum() {
 }
 
 BigNum &BigNum::operator=(const BigNum &other) {
+  if (this == &other) {
+    return *this;
+  }
   CHECK(impl_ != nullptr);
   CHECK(other.impl_ != nullptr);
   BIGNUM *result = BN_copy(impl_->big_num, other.impl_->big_num);
diff --git a/tdutils/td/utils/BufferedUdp.h b/tdutils/td/utils/BufferedUdp.h
index 924ba791d..6e70b6832 100644
--- a/tdutils/td/utils/BufferedUdp.h
+++ b/tdutils/td/utils/BufferedUdp.h
@@ -79,8 +79,8 @@ class UdpReader {
     }
   }
   Status read_once(UdpSocketFd &fd, VectorQueue<UdpMessage> &queue) TD_WARN_UNUSED_RESULT {
-    for (size_t i = 0; i < messages_.size(); i++) {
-      CHECK(messages_[i].data.size() == 2048);
+    for (auto &message : messages_) {
+      CHECK(message.data.size() == 2048);
     }
     size_t cnt = 0;
     auto status = fd.receive_messages(messages_, cnt);
diff --git a/tdutils/td/utils/Gzip.cpp b/tdutils/td/utils/Gzip.cpp
index 3281e5849..a2fc6037d 100644
--- a/tdutils/td/utils/Gzip.cpp
+++ b/tdutils/td/utils/Gzip.cpp
@@ -189,7 +189,7 @@ BufferSlice gzencode(Slice s, double max_compression_ratio) {
   gzip.init_encode().ensure();
   gzip.set_input(s);
   gzip.close_input();
-  size_t max_size = static_cast<size_t>(static_cast<double>(s.size()) * max_compression_ratio);
+  auto max_size = static_cast<size_t>(static_cast<double>(s.size()) * max_compression_ratio);
   BufferWriter message{max_size};
   gzip.set_output(message.prepare_append());
   auto r_state = gzip.run();
diff --git a/tdutils/td/utils/Heap.h b/tdutils/td/utils/Heap.h
index c9bbbd901..68f557705 100644
--- a/tdutils/td/utils/Heap.h
+++ b/tdutils/td/utils/Heap.h
@@ -38,7 +38,7 @@ class KHeap {
   }
 
   KeyT get_key(const HeapNode *node) const {
-    size_t pos = static_cast<size_t>(node->pos_);
+    auto pos = static_cast<size_t>(node->pos_);
     CHECK(pos < array_.size());
     return array_[pos].key_;
   }
@@ -62,7 +62,7 @@ class KHeap {
   }
 
   void fix(KeyT key, HeapNode *node) {
-    size_t pos = static_cast<size_t>(node->pos_);
+    auto pos = static_cast<size_t>(node->pos_);
     CHECK(pos < array_.size());
     KeyT old_key = array_[pos].key_;
     array_[pos].key_ = key;
@@ -74,7 +74,7 @@ class KHeap {
   }
 
   void erase(HeapNode *node) {
-    size_t pos = static_cast<size_t>(node->pos_);
+    auto pos = static_cast<size_t>(node->pos_);
     node->remove();
     CHECK(pos < array_.size());
     erase(pos);
diff --git a/tdutils/td/utils/Hints.cpp b/tdutils/td/utils/Hints.cpp
index a583fb483..e5c03954e 100644
--- a/tdutils/td/utils/Hints.cpp
+++ b/tdutils/td/utils/Hints.cpp
@@ -150,7 +150,7 @@ void Hints::add_search_results(vector<KeyT> &results, const string &word,
 vector<Hints::KeyT> Hints::search_word(const string &word) const {
   vector<KeyT> results;
   add_search_results(results, word, translit_word_to_keys_);
-  for (auto w : get_word_transliterations(word, true)) {
+  for (const auto &w : get_word_transliterations(word, true)) {
     add_search_results(results, w, word_to_keys_);
   }
 
diff --git a/tdutils/td/utils/HttpUrl.cpp b/tdutils/td/utils/HttpUrl.cpp
index 0b8f4f21b..f30497257 100644
--- a/tdutils/td/utils/HttpUrl.cpp
+++ b/tdutils/td/utils/HttpUrl.cpp
@@ -168,7 +168,7 @@ Result<HttpUrl> parse_url(Slice url, HttpUrl::Protocol default_protocol) {
     }
 
     // all other symbols aren't allowed
-    unsigned char uc = static_cast<unsigned char>(c);
+    auto uc = static_cast<unsigned char>(c);
     if (uc >= 128) {
       // but we allow plain UTF-8 symbols
       continue;
diff --git a/tdutils/td/utils/JsonBuilder.cpp b/tdutils/td/utils/JsonBuilder.cpp
index c0ac51776..2872b50a1 100644
--- a/tdutils/td/utils/JsonBuilder.cpp
+++ b/tdutils/td/utils/JsonBuilder.cpp
@@ -394,7 +394,7 @@ Result<JsonValue> do_json_decode(Parser &parser, int32 max_depth) {
     case '{': {
       parser.skip('{');
       parser.skip_whitespaces();
-      std::vector<std::pair<MutableSlice, JsonValue> > res;
+      std::vector<std::pair<MutableSlice, JsonValue>> res;
       if (parser.try_skip('}')) {
         return JsonValue::make_object(std::move(res));
       }
@@ -408,7 +408,7 @@ Result<JsonValue> do_json_decode(Parser &parser, int32 max_depth) {
           return Status::Error("':' expected");
         }
         TRY_RESULT(value, do_json_decode(parser, max_depth - 1));
-        res.emplace_back(std::move(key), std::move(value));
+        res.emplace_back(key, std::move(value));
 
         parser.skip_whitespaces();
         if (parser.try_skip('}')) {
diff --git a/tdutils/td/utils/ScopeGuard.h b/tdutils/td/utils/ScopeGuard.h
index 30d964972..900906b20 100644
--- a/tdutils/td/utils/ScopeGuard.h
+++ b/tdutils/td/utils/ScopeGuard.h
@@ -42,11 +42,11 @@ class LambdaGuard final : public Guard {
   }
   LambdaGuard &operator=(LambdaGuard &&other) = delete;
 
-  void dismiss() override {
+  void dismiss() final {
     dismissed_ = true;
   }
 
-  ~LambdaGuard() override {
+  ~LambdaGuard() final {
     if (!dismissed_) {
       func_();
     }
diff --git a/tdutils/td/utils/TsCerr.h b/tdutils/td/utils/TsCerr.h
index 8ef4942e3..06416e49a 100644
--- a/tdutils/td/utils/TsCerr.h
+++ b/tdutils/td/utils/TsCerr.h
@@ -26,8 +26,8 @@ class TsCerr {
  private:
   static std::atomic_flag lock_;
 
-  void enterCritical();
-  void exitCritical();
+  static void enterCritical();
+  static void exitCritical();
 };
 
 }  // namespace td
diff --git a/tdutils/td/utils/TsFileLog.cpp b/tdutils/td/utils/TsFileLog.cpp
index 51ca4d54e..bdb54e5a1 100644
--- a/tdutils/td/utils/TsFileLog.cpp
+++ b/tdutils/td/utils/TsFileLog.cpp
@@ -99,7 +99,7 @@ class TsFileLog final : public LogInterface {
 
 Result<unique_ptr<LogInterface>> TsFileLog::create(string path, int64 rotate_threshold, bool redirect_stderr) {
   auto res = make_unique<detail::TsFileLog>();
-  TRY_STATUS(res->init(path, rotate_threshold, redirect_stderr));
+  TRY_STATUS(res->init(std::move(path), rotate_threshold, redirect_stderr));
   return std::move(res);
 }
 
diff --git a/tdutils/td/utils/Variant.h b/tdutils/td/utils/Variant.h
index d1e7fc6fa..502c7df03 100644
--- a/tdutils/td/utils/Variant.h
+++ b/tdutils/td/utils/Variant.h
@@ -121,6 +121,9 @@ class Variant {
     return *this;
   }
   Variant &operator=(const Variant &other) {
+    if (this == &other) {
+      return *this;
+    }
     clear();
     other.visit([&](auto &&value) { this->init_empty(std::forward<decltype(value)>(value)); });
     return *this;
diff --git a/tdutils/td/utils/crypto.h b/tdutils/td/utils/crypto.h
index 0fc608c11..714620060 100644
--- a/tdutils/td/utils/crypto.h
+++ b/tdutils/td/utils/crypto.h
@@ -139,7 +139,7 @@ class Sha256State {
 
   void feed(Slice data);
 
-  void extract(MutableSlice dest, bool destroy = false);
+  void extract(MutableSlice output, bool destroy = false);
 
  private:
   class Impl;
diff --git a/tdutils/td/utils/logging.cpp b/tdutils/td/utils/logging.cpp
index 87920dcbe..ebb528df8 100644
--- a/tdutils/td/utils/logging.cpp
+++ b/tdutils/td/utils/logging.cpp
@@ -219,6 +219,9 @@ class DefaultLog final : public LogInterface {
       case VERBOSITY_NAME(INFO):
         color = Slice("\x1b[1;36m");  // cyan
         break;
+      default:
+        // no color
+        break;
     }
     Slice no_color("\x1b[0m");
     if (!slice.empty() && slice.back() == '\n') {
diff --git a/tdutils/td/utils/misc.cpp b/tdutils/td/utils/misc.cpp
index fc33710f1..98dd015a4 100644
--- a/tdutils/td/utils/misc.cpp
+++ b/tdutils/td/utils/misc.cpp
@@ -16,7 +16,7 @@
 namespace td {
 
 char *str_dup(Slice str) {
-  char *res = static_cast<char *>(std::malloc(str.size() + 1));
+  auto *res = static_cast<char *>(std::malloc(str.size() + 1));
   if (res == nullptr) {
     return nullptr;
   }
diff --git a/tdutils/td/utils/port/UdpSocketFd.cpp b/tdutils/td/utils/port/UdpSocketFd.cpp
index 971dcbf70..2c65c459d 100644
--- a/tdutils/td/utils/port/UdpSocketFd.cpp
+++ b/tdutils/td/utils/port/UdpSocketFd.cpp
@@ -79,6 +79,7 @@ class UdpSocketReceiveHelper {
   sockaddr_storage addr_;
   WSABUF buf_;
 };
+
 class UdpSocketSendHelper {
  public:
   void to_native(const UdpMessage &message, WSAMSG &message_header) {
@@ -295,7 +296,7 @@ class UdpSocketFdImpl final : private Iocp::Callback {
     VLOG(fd) << get_native_fd() << " on receive " << size;
     CHECK(is_receive_active_);
     is_receive_active_ = false;
-    receive_helper_.from_native(receive_message_, size, to_receive_);
+    UdpSocketReceiveHelper::from_native(receive_message_, size, to_receive_);
     receive_buffer_.confirm_read((to_receive_.data.size() + 7) & ~7);
     {
       auto lock = lock_.lock();
@@ -502,7 +503,7 @@ class UdpSocketFdImpl {
     auto recvmsg_res = detail::skip_eintr([&] { return recvmsg(native_fd, &message_header, flags); });
     auto recvmsg_errno = errno;
     if (recvmsg_res >= 0) {
-      helper.from_native(message_header, recvmsg_res, message);
+      UdpSocketReceiveHelper::from_native(message_header, recvmsg_res, message);
       is_received = true;
       return Status::OK();
     }
@@ -719,7 +720,7 @@ class UdpSocketFdImpl {
     if (recvmmsg_res >= 0) {
       cnt = narrow_cast<size_t>(recvmmsg_res);
       for (size_t i = 0; i < cnt; i++) {
-        helpers[i].from_native(headers[i].msg_hdr, headers[i].msg_len, messages[i]);
+        UdpSocketReceiveHelper::from_native(headers[i].msg_hdr, headers[i].msg_len, messages[i]);
       }
       return Status::OK();
     }
diff --git a/tdutils/td/utils/port/uname.cpp b/tdutils/td/utils/port/uname.cpp
index 6aa8a01d0..34a5c7525 100644
--- a/tdutils/td/utils/port/uname.cpp
+++ b/tdutils/td/utils/port/uname.cpp
@@ -49,7 +49,7 @@ static string read_os_name(CSlice os_version_file_path, CSlice prefix, CSlice su
         auto end_pos = r_file.ok().find(suffix.c_str(), begin_pos);
         if (end_pos != string::npos) {
           auto os_version = trim(r_file.ok().substr(begin_pos, end_pos - begin_pos));
-          if (os_version.find("\n") == string::npos) {
+          if (os_version.find('\n') == string::npos) {
             return os_version;
           }
         }
diff --git a/tdutils/td/utils/queue.h b/tdutils/td/utils/queue.h
index c0f419084..4d3f336eb 100644
--- a/tdutils/td/utils/queue.h
+++ b/tdutils/td/utils/queue.h
@@ -150,7 +150,7 @@ class SPSCBlockQueue {
   }
 };
 
-template <class T, class BlockQueueT = SPSCBlockQueue<T> >
+template <class T, class BlockQueueT = SPSCBlockQueue<T>>
 class SPSCChainQueue {
  public:
   using ValueType = T;
@@ -308,10 +308,10 @@ class BackoffQueue : public QueueT {
   }
 };
 
-template <class T, class QueueT = SPSCChainQueue<T> >
+template <class T, class QueueT = SPSCChainQueue<T>>
 using InfBackoffQueue = BackoffQueue<T, QueueT, detail::InfBackoff>;
 
-template <class T, class QueueT = BackoffQueue<T> >
+template <class T, class QueueT = BackoffQueue<T>>
 class PollQueue final : public QueueT {
  public:
   using ValueType = T;
diff --git a/tdutils/td/utils/tests.cpp b/tdutils/td/utils/tests.cpp
index ecb14a968..dddad7c75 100644
--- a/tdutils/td/utils/tests.cpp
+++ b/tdutils/td/utils/tests.cpp
@@ -64,10 +64,11 @@ class RegressionTesterImpl final : public RegressionTester {
     unlink(db_path).ignore();
   }
 
-  RegressionTesterImpl(string db_path, string db_cache_dir) : db_path_(db_path), db_cache_dir_(db_cache_dir) {
-    load_db(db_path).ignore();
+  RegressionTesterImpl(string db_path, string db_cache_dir)
+      : db_path_(std::move(db_path)), db_cache_dir_(std::move(db_cache_dir)) {
+    load_db(db_path_).ignore();
     if (db_cache_dir_.empty()) {
-      db_cache_dir_ = PathView(db_path).without_extension().str() + ".cache/";
+      db_cache_dir_ = PathView(db_path_).without_extension().str() + ".cache/";
     }
     mkdir(db_cache_dir_).ensure();
   }
@@ -120,7 +121,7 @@ class RegressionTesterImpl final : public RegressionTester {
 
   void save_db(StringBuilder &sb) {
     sb << magic() << "\n";
-    for (auto it : tests_) {
+    for (const auto &it : tests_) {
       sb << it.second;
     }
   }
@@ -171,7 +172,7 @@ void TestsRunner::add_test(string name, std::function<unique_ptr<Test>()> test)
       LOG(FATAL) << "Test name collision " << name;
     }
   }
-  tests_.emplace_back(name, TestInfo{std::move(test), nullptr});
+  tests_.emplace_back(std::move(name), TestInfo{std::move(test), nullptr});
 }
 
 void TestsRunner::add_substr_filter(string str) {
diff --git a/tdutils/td/utils/tests.h b/tdutils/td/utils/tests.h
index ec8377db5..10bca6010 100644
--- a/tdutils/td/utils/tests.h
+++ b/tdutils/td/utils/tests.h
@@ -122,7 +122,7 @@ template <class T>
 class RegisterTest {
  public:
   explicit RegisterTest(string name, TestsRunner &runner = TestsRunner::get_default()) {
-    runner.add_test(name, [] { return make_unique<T>(); });
+    runner.add_test(std::move(name), [] { return make_unique<T>(); });
   }
 };
 
diff --git a/tdutils/td/utils/unicode.cpp b/tdutils/td/utils/unicode.cpp
index 42bbf62c4..b5e7892fa 100644
--- a/tdutils/td/utils/unicode.cpp
+++ b/tdutils/td/utils/unicode.cpp
@@ -1200,8 +1200,9 @@ static uint32 binary_search_ranges(const int32 (&ranges)[N], uint32 code) {
     return 0;
   }
 
-  int32 code_int = static_cast<int32>(code);
-  size_t l = 0, r = N;
+  auto code_int = static_cast<int32>(code);
+  size_t l = 0;
+  size_t r = N;
   while (l < r) {
     size_t m = ((l + r + 2) >> 2) << 1;
     if (ranges[m] <= code_int) {
diff --git a/test/mtproto.cpp b/test/mtproto.cpp
index c0b66e126..7bee6b377 100644
--- a/test/mtproto.cpp
+++ b/test/mtproto.cpp
@@ -612,7 +612,7 @@ class FastPingTestActor final : public Actor {
       }
       iteration_++;
       fast_ping_ = create_ping_actor(
-          "", std::move(connection_), std::move(auth_data),
+          td::Slice(), std::move(connection_), std::move(auth_data),
           PromiseCreator::lambda([self = actor_id(this)](Result<unique_ptr<mtproto::RawConnection>> r_raw_connection) {
             send_closure(self, &FastPingTestActor::got_raw_connection, std::move(r_raw_connection));
           }),