diff --git a/td/telegram/MessageContent.cpp b/td/telegram/MessageContent.cpp
index 98c839010..150258ff6 100644
--- a/td/telegram/MessageContent.cpp
+++ b/td/telegram/MessageContent.cpp
@@ -5975,14 +5975,14 @@ void update_used_hashtags(Td *td, const MessageContent *content) {
     }
     while (utf16_pos < entity.offset && ptr < end) {
       utf16_pos += 1 + (ptr[0] >= 0xf0);
-      ptr = next_utf8_unsafe(ptr, &skipped_code, "update_used_hashtags");
+      ptr = next_utf8_unsafe(ptr, &skipped_code);
     }
     CHECK(utf16_pos == entity.offset);
     auto from = ptr;
 
     while (utf16_pos < entity.offset + entity.length && ptr < end) {
       utf16_pos += 1 + (ptr[0] >= 0xf0);
-      ptr = next_utf8_unsafe(ptr, &skipped_code, "update_used_hashtags 2");
+      ptr = next_utf8_unsafe(ptr, &skipped_code);
     }
     CHECK(utf16_pos == entity.offset + entity.length);
     auto to = ptr;
diff --git a/td/telegram/MessageEntity.cpp b/td/telegram/MessageEntity.cpp
index e0ad2b291..312a14c23 100644
--- a/td/telegram/MessageEntity.cpp
+++ b/td/telegram/MessageEntity.cpp
@@ -262,7 +262,7 @@ static vector<Slice> match_mentions(Slice str) {
 
     if (ptr != begin) {
       uint32 prev;
-      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev, "match_mentions");
+      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev);
 
       if (is_word_character(prev)) {
         ptr++;
@@ -280,7 +280,7 @@ static vector<Slice> match_mentions(Slice str) {
     }
     uint32 next = 0;
     if (ptr != end) {
-      next_utf8_unsafe(ptr, &next, "match_mentions 2");
+      next_utf8_unsafe(ptr, &next);
     }
     if (is_word_character(next)) {
       continue;
@@ -306,7 +306,7 @@ static vector<Slice> match_bot_commands(Slice str) {
 
     if (ptr != begin) {
       uint32 prev;
-      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev, "match_bot_commands");
+      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev);
 
       if (is_word_character(prev) || prev == '/' || prev == '<' || prev == '>') {
         ptr++;
@@ -339,7 +339,7 @@ static vector<Slice> match_bot_commands(Slice str) {
 
     uint32 next = 0;
     if (ptr != end) {
-      next_utf8_unsafe(ptr, &next, "match_bot_commands 2");
+      next_utf8_unsafe(ptr, &next);
     }
     if (is_word_character(next) || next == '/' || next == '<' || next == '>') {
       continue;
@@ -382,7 +382,7 @@ static vector<Slice> match_hashtags(Slice str) {
 
     if (ptr != begin) {
       uint32 prev;
-      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev, "match_hashtags");
+      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev);
 
       if (is_hashtag_letter(prev, category)) {
         ptr++;
@@ -395,7 +395,7 @@ static vector<Slice> match_hashtags(Slice str) {
     bool was_letter = false;
     while (ptr != end) {
       uint32 code;
-      auto next_ptr = next_utf8_unsafe(ptr, &code, "match_hashtags 2");
+      auto next_ptr = next_utf8_unsafe(ptr, &code);
       if (!is_hashtag_letter(code, category)) {
         break;
       }
@@ -443,7 +443,7 @@ static vector<Slice> match_cashtags(Slice str) {
 
     if (ptr != begin) {
       uint32 prev;
-      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev, "match_cashtags");
+      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev);
 
       if (is_hashtag_letter(prev, category) || prev == '$') {
         ptr++;
@@ -467,7 +467,7 @@ static vector<Slice> match_cashtags(Slice str) {
 
     if (cashtag_end != end) {
       uint32 code;
-      next_utf8_unsafe(ptr, &code, "match_cashtags 2");
+      next_utf8_unsafe(ptr, &code);
       if (is_hashtag_letter(code, category) || code == '$') {
         continue;
       }
@@ -506,7 +506,7 @@ static vector<Slice> match_media_timestamps(Slice str) {
 
       if (media_timestamp_begin != begin) {
         uint32 prev;
-        next_utf8_unsafe(prev_utf8_unsafe(media_timestamp_begin), &prev, "match_media_timestamps 1");
+        next_utf8_unsafe(prev_utf8_unsafe(media_timestamp_begin), &prev);
 
         if (is_word_character(prev)) {
           continue;
@@ -514,7 +514,7 @@ static vector<Slice> match_media_timestamps(Slice str) {
       }
       if (media_timestamp_end != end) {
         uint32 next;
-        next_utf8_unsafe(media_timestamp_end, &next, "match_media_timestamps 2");
+        next_utf8_unsafe(media_timestamp_end, &next);
 
         if (is_word_character(next)) {
           continue;
@@ -546,7 +546,7 @@ static vector<Slice> match_bank_card_numbers(Slice str) {
     }
     if (ptr != begin) {
       uint32 prev;
-      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev, "match_bank_card_numbers");
+      next_utf8_unsafe(prev_utf8_unsafe(ptr), &prev);
 
       if (prev == '.' || prev == ',' || prev == '+' || prev == '-' || prev == '_' ||
           get_unicode_simple_category(prev) == UnicodeSimpleCategory::Letter) {
@@ -582,7 +582,7 @@ static vector<Slice> match_bank_card_numbers(Slice str) {
     }
     if (card_number_end != end) {
       uint32 next;
-      next_utf8_unsafe(card_number_end, &next, "match_bank_card_numbers 2");
+      next_utf8_unsafe(card_number_end, &next);
       if (next == '-' || next == '_' || get_unicode_simple_category(next) == UnicodeSimpleCategory::Letter) {
         continue;
       }
@@ -657,7 +657,7 @@ static vector<Slice> match_tg_urls(Slice str) {
       auto path_end_ptr = ptr + 1;
       while (path_end_ptr != end) {
         uint32 code = 0;
-        auto next_ptr = next_utf8_unsafe(path_end_ptr, &code, "match_tg_urls");
+        auto next_ptr = next_utf8_unsafe(path_end_ptr, &code);
         if (!is_url_path_symbol(code)) {
           break;
         }
@@ -739,7 +739,7 @@ static vector<Slice> match_urls(Slice str) {
     while (domain_begin_ptr != begin) {
       domain_begin_ptr = prev_utf8_unsafe(domain_begin_ptr);
       uint32 code = 0;
-      auto next_ptr = next_utf8_unsafe(domain_begin_ptr, &code, "match_urls 0");
+      auto next_ptr = next_utf8_unsafe(domain_begin_ptr, &code);
       if (!is_domain_symbol(code)) {
         domain_begin_ptr = next_ptr;
         break;
@@ -752,7 +752,7 @@ static vector<Slice> match_urls(Slice str) {
       // try to find '@' to the right if there is no '@' to the left
       while (domain_end_ptr != end) {
         uint32 code = 0;
-        auto next_ptr = next_utf8_unsafe(domain_end_ptr, &code, "match_urls");
+        auto next_ptr = next_utf8_unsafe(domain_end_ptr, &code);
         if (code == '@') {
           last_at_ptr = domain_end_ptr;
         }
@@ -765,7 +765,7 @@ static vector<Slice> match_urls(Slice str) {
     }
     while (domain_end_ptr != end) {
       uint32 code = 0;
-      auto next_ptr = next_utf8_unsafe(domain_end_ptr, &code, "match_urls 2");
+      auto next_ptr = next_utf8_unsafe(domain_end_ptr, &code);
       if (!is_domain_symbol(code)) {
         break;
       }
@@ -776,7 +776,7 @@ static vector<Slice> match_urls(Slice str) {
       while (domain_begin_ptr != begin) {
         domain_begin_ptr = prev_utf8_unsafe(domain_begin_ptr);
         uint32 code = 0;
-        auto next_ptr = next_utf8_unsafe(domain_begin_ptr, &code, "match_urls 3");
+        auto next_ptr = next_utf8_unsafe(domain_begin_ptr, &code);
         if (!is_user_data_symbol(code)) {
           domain_begin_ptr = next_ptr;
           break;
@@ -808,7 +808,7 @@ static vector<Slice> match_urls(Slice str) {
       auto path_end_ptr = url_end_ptr + 1;
       while (path_end_ptr != end) {
         uint32 code = 0;
-        auto next_ptr = next_utf8_unsafe(path_end_ptr, &code, "match_urls 4");
+        auto next_ptr = next_utf8_unsafe(path_end_ptr, &code);
         if (!is_url_path_symbol(code)) {
           break;
         }
@@ -836,7 +836,7 @@ static vector<Slice> match_urls(Slice str) {
       while (user_data_begin_ptr != begin) {
         user_data_begin_ptr = prev_utf8_unsafe(user_data_begin_ptr);
         uint32 code = 0;
-        auto next_ptr = next_utf8_unsafe(user_data_begin_ptr, &code, "match_urls 5");
+        auto next_ptr = next_utf8_unsafe(user_data_begin_ptr, &code);
         if (!is_user_data_symbol(code)) {
           user_data_begin_ptr = next_ptr;
           break;
@@ -856,7 +856,7 @@ static vector<Slice> match_urls(Slice str) {
         while (protocol_begin_ptr != begin) {
           protocol_begin_ptr = prev_utf8_unsafe(protocol_begin_ptr);
           uint32 code = 0;
-          auto next_ptr = next_utf8_unsafe(protocol_begin_ptr, &code, "match_urls 6");
+          auto next_ptr = next_utf8_unsafe(protocol_begin_ptr, &code);
           if (!is_protocol_symbol(code)) {
             protocol_begin_ptr = next_ptr;
             break;
@@ -876,7 +876,7 @@ static vector<Slice> match_urls(Slice str) {
         auto prefix_end = prefix.uend();
         auto prefix_back = prev_utf8_unsafe(prefix_end);
         uint32 code = 0;
-        next_utf8_unsafe(prefix_back, &code, "match_urls 7");
+        next_utf8_unsafe(prefix_back, &code);
         if (is_word_character(code) || code == '/' || code == '#' || code == '@') {
           is_bad = true;
         }
@@ -1669,7 +1669,7 @@ static void fix_entity_offsets(Slice text, vector<MessageEntity> &entities) {
     while (ptr != end && cnt > 0) {
       unsigned char c = ptr[0];
       utf16_pos += 1 + (c >= 0xf0);
-      ptr = next_utf8_unsafe(ptr, &skipped_code, "fix_entity_offsets");
+      ptr = next_utf8_unsafe(ptr, &skipped_code);
 
       pos = static_cast<int32>(ptr - begin);
       if (entity_begin == pos) {
diff --git a/td/telegram/MessagesDb.cpp b/td/telegram/MessagesDb.cpp
index 87a819201..e079426b3 100644
--- a/td/telegram/MessagesDb.cpp
+++ b/td/telegram/MessagesDb.cpp
@@ -736,7 +736,7 @@ class MessagesDbImpl final : public MessagesDbSyncInterface {
     for (auto ptr = query.ubegin(), end = query.uend(); ptr < end;) {
       uint32 code;
       auto code_ptr = ptr;
-      ptr = next_utf8_unsafe(ptr, &code, "prepare_query");
+      ptr = next_utf8_unsafe(ptr, &code);
       if (is_word_character(code)) {
         if (!in_word) {
           in_word = true;
diff --git a/td/telegram/StickersManager.cpp b/td/telegram/StickersManager.cpp
index be6267ca1..6ea30f7f9 100644
--- a/td/telegram/StickersManager.cpp
+++ b/td/telegram/StickersManager.cpp
@@ -8460,7 +8460,7 @@ vector<string> StickersManager::get_emoji_language_codes(const vector<string> &i
   }
   if (!text.empty()) {
     uint32 code = 0;
-    next_utf8_unsafe(text.ubegin(), &code, "get_emoji_language_codes");
+    next_utf8_unsafe(text.ubegin(), &code);
     if ((0x410 <= code && code <= 0x44F) || code == 0x401 || code == 0x451) {
       // the first letter is cyrillic
       if (!td::contains(language_codes, "ru") && !td::contains(language_codes, "uk") &&
diff --git a/tdutils/td/utils/Hints.cpp b/tdutils/td/utils/Hints.cpp
index dfe584fc5..762281315 100644
--- a/tdutils/td/utils/Hints.cpp
+++ b/tdutils/td/utils/Hints.cpp
@@ -34,7 +34,7 @@ vector<string> Hints::fix_words(vector<string> words) {
   return words;
 }
 
-vector<string> Hints::get_words(Slice name, bool is_search) {
+vector<string> Hints::get_words(Slice name) {
   bool in_word = false;
   string word;
   vector<string> words;
@@ -42,7 +42,7 @@ vector<string> Hints::get_words(Slice name, bool is_search) {
   auto end = name.uend();
   while (pos != end) {
     uint32 code;
-    pos = next_utf8_unsafe(pos, &code, is_search ? "get_words_search" : "get_words_add");
+    pos = next_utf8_unsafe(pos, &code);
 
     code = prepare_search_character(code);
     if (code == 0) {
@@ -94,7 +94,7 @@ void Hints::add(KeyT key, Slice name) {
       return;
     }
     vector<string> old_transliterations;
-    for (auto &old_word : get_words(it->second, false)) {
+    for (auto &old_word : get_words(it->second)) {
       delete_word(old_word, key, word_to_keys_);
 
       for (auto &w : get_word_transliterations(old_word, false)) {
@@ -116,7 +116,7 @@ void Hints::add(KeyT key, Slice name) {
   }
 
   vector<string> transliterations;
-  for (auto &word : get_words(name, false)) {
+  for (auto &word : get_words(name)) {
     add_word(word, key, word_to_keys_);
 
     for (auto &w : get_word_transliterations(word, false)) {
@@ -166,7 +166,7 @@ std::pair<size_t, vector<Hints::KeyT>> Hints::search(Slice query, int32 limit, b
     return {key_to_name_.size(), std::move(results)};
   }
 
-  auto words = get_words(query, true);
+  auto words = get_words(query);
   if (return_all_for_empty_query && words.empty()) {
     results.reserve(key_to_name_.size());
     for (auto &it : key_to_name_) {
diff --git a/tdutils/td/utils/Hints.h b/tdutils/td/utils/Hints.h
index d9f4115c7..f59e45f50 100644
--- a/tdutils/td/utils/Hints.h
+++ b/tdutils/td/utils/Hints.h
@@ -52,7 +52,7 @@ class Hints {
 
   static vector<string> fix_words(vector<string> words);
 
-  static vector<string> get_words(Slice name, bool is_search);
+  static vector<string> get_words(Slice name);
 
   static void add_search_results(vector<KeyT> &results, const string &word,
                                  const std::map<string, vector<KeyT>> &word_to_keys);
diff --git a/tdutils/td/utils/filesystem.cpp b/tdutils/td/utils/filesystem.cpp
index ae7483cf4..edb5df867 100644
--- a/tdutils/td/utils/filesystem.cpp
+++ b/tdutils/td/utils/filesystem.cpp
@@ -133,7 +133,7 @@ static string clean_filename_part(Slice name, int max_length) {
   int size = 0;
   for (auto *it = name.ubegin(); it != name.uend() && size < max_length;) {
     uint32 code;
-    it = next_utf8_unsafe(it, &code, "clean_filename_part");
+    it = next_utf8_unsafe(it, &code);
     if (!is_ok(code)) {
       if (prepare_search_character(code) == 0) {
         continue;
diff --git a/tdutils/td/utils/port/IPAddress.cpp b/tdutils/td/utils/port/IPAddress.cpp
index 7e1e72532..32c26403d 100644
--- a/tdutils/td/utils/port/IPAddress.cpp
+++ b/tdutils/td/utils/port/IPAddress.cpp
@@ -53,7 +53,7 @@ static void punycode(string &result, Slice part) {
   auto end = part.uend();
   while (begin != end) {
     uint32 code;
-    begin = next_utf8_unsafe(begin, &code, "punycode");
+    begin = next_utf8_unsafe(begin, &code);
     if (code <= 127u) {
       result += to_lower(static_cast<char>(code));
       processed++;
diff --git a/tdutils/td/utils/translit.cpp b/tdutils/td/utils/translit.cpp
index 3b1fbfd62..65cfcf007 100644
--- a/tdutils/td/utils/translit.cpp
+++ b/tdutils/td/utils/translit.cpp
@@ -56,7 +56,7 @@ static void add_word_transliterations(vector<string> &result, Slice word, bool a
   auto end = word.uend();
   while (pos != end) {
     uint32 code;
-    pos = next_utf8_unsafe(pos, &code, "add_word_transliterations");
+    pos = next_utf8_unsafe(pos, &code);
     auto it = simple_rules.find(code);
     if (it != simple_rules.end()) {
       s += it->second;
@@ -89,7 +89,7 @@ static void add_word_transliterations(vector<string> &result, Slice word, bool a
     }
 
     uint32 code;
-    pos = next_utf8_unsafe(pos, &code, "add_word_transliterations 2");
+    pos = next_utf8_unsafe(pos, &code);
     auto it = simple_rules.find(code);
     if (it != simple_rules.end()) {
       s += it->second;
diff --git a/tdutils/td/utils/utf8.cpp b/tdutils/td/utils/utf8.cpp
index db93a858d..e4e62cf06 100644
--- a/tdutils/td/utils/utf8.cpp
+++ b/tdutils/td/utils/utf8.cpp
@@ -6,7 +6,6 @@
 //
 #include "td/utils/utf8.h"
 
-#include "td/utils/logging.h"
 #include "td/utils/misc.h"
 #include "td/utils/SliceBuilder.h"
 #include "td/utils/unicode.h"
@@ -81,7 +80,7 @@ void append_utf8_character(string &str, uint32 ch) {
   }
 }
 
-const unsigned char *next_utf8_unsafe(const unsigned char *ptr, uint32 *code, const char *source) {
+const unsigned char *next_utf8_unsafe(const unsigned char *ptr, uint32 *code) {
   uint32 a = ptr[0];
   if ((a & 0x80) == 0) {
     *code = a;
@@ -96,7 +95,7 @@ const unsigned char *next_utf8_unsafe(const unsigned char *ptr, uint32 *code, co
     *code = ((a & 0x07) << 18) | ((ptr[1] & 0x3f) << 12) | ((ptr[2] & 0x3f) << 6) | (ptr[3] & 0x3f);
     return ptr + 4;
   }
-  LOG(FATAL) << a << " " << source;
+  UNREACHABLE();
   *code = 0;
   return ptr;
 }
@@ -107,7 +106,7 @@ string utf8_to_lower(Slice str) {
   auto end = str.uend();
   while (pos != end) {
     uint32 code;
-    pos = next_utf8_unsafe(pos, &code, "utf8_to_lower");
+    pos = next_utf8_unsafe(pos, &code);
     append_utf8_character(result, unicode_to_lower(code));
   }
   return result;
diff --git a/tdutils/td/utils/utf8.h b/tdutils/td/utils/utf8.h
index e16eef4d1..236cc87c0 100644
--- a/tdutils/td/utils/utf8.h
+++ b/tdutils/td/utils/utf8.h
@@ -49,7 +49,7 @@ inline const unsigned char *prev_utf8_unsafe(const unsigned char *ptr) {
 }
 
 /// moves pointer one UTF-8 character forward and saves code of the skipped character in *code
-const unsigned char *next_utf8_unsafe(const unsigned char *ptr, uint32 *code, const char *source);
+const unsigned char *next_utf8_unsafe(const unsigned char *ptr, uint32 *code);
 
 /// truncates UTF-8 string to the given length in Unicode characters
 template <class T>
diff --git a/tdutils/test/bitmask.cpp b/tdutils/test/bitmask.cpp
index 63b4c27bd..e81c406bb 100644
--- a/tdutils/test/bitmask.cpp
+++ b/tdutils/test/bitmask.cpp
@@ -50,7 +50,7 @@ class RangeSet {
     RangeSet res;
     for (auto begin = data.ubegin(); begin != data.uend();) {
       uint32 size;
-      begin = next_utf8_unsafe(begin, &size, "RangeSet");
+      begin = next_utf8_unsafe(begin, &size);
 
       if (!is_empty && size != 0) {
         res.ranges_.push_back({curr * BIT_SIZE, (curr + size) * BIT_SIZE});