diff --git a/td/telegram/PhotoSize.cpp b/td/telegram/PhotoSize.cpp
index 673821b5d..c705f7f8e 100644
--- a/td/telegram/PhotoSize.cpp
+++ b/td/telegram/PhotoSize.cpp
@@ -126,7 +126,7 @@ FileId register_photo_size(FileManager *file_manager, const PhotoSizeSource &sou
                            PhotoFormat format) {
   LOG(DEBUG) << "Receive " << format << " photo " << id << " of type " << source.get_file_type("register_photo_size")
              << " from " << dc_id;
-  auto suggested_name = PSTRING() << source.get_unique_name(id) << '.' << format;
+  auto suggested_name = PSTRING() << source.get_unique_name(id, "register_photo_size") << '.' << format;
   auto file_location_source = owner_dialog_id.get_type() == DialogType::SecretChat ? FileLocationSource::FromUser
                                                                                    : FileLocationSource::FromServer;
   return file_manager->register_remote(
diff --git a/td/telegram/PhotoSizeSource.cpp b/td/telegram/PhotoSizeSource.cpp
index 8bc8cd5f9..9218af27d 100644
--- a/td/telegram/PhotoSizeSource.cpp
+++ b/td/telegram/PhotoSizeSource.cpp
@@ -64,11 +64,11 @@ FileType PhotoSizeSource::get_file_type(const char *source) const {
   }
 }
 
-string PhotoSizeSource::get_unique() const {
+string PhotoSizeSource::get_unique(const char *source) const {
   auto ptr = StackAllocator::alloc(16);
   MutableSlice data = ptr.as_slice();
   TlStorerUnsafe storer(data.ubegin());
-  switch (get_type("get_unique")) {
+  switch (get_type(source)) {
     case Type::Legacy:
       UNREACHABLE();
       break;
@@ -128,8 +128,8 @@ string PhotoSizeSource::get_unique() const {
   return string(data.begin(), size);
 }
 
-string PhotoSizeSource::get_unique_name(int64 photo_id) const {
-  switch (get_type("get_unique_name")) {
+string PhotoSizeSource::get_unique_name(int64 photo_id, const char *source) const {
+  switch (get_type(source)) {
     case Type::Thumbnail:
       CHECK(0 <= thumbnail().thumbnail_type && thumbnail().thumbnail_type <= 127);
       return PSTRING() << photo_id << '_' << thumbnail().thumbnail_type;
diff --git a/td/telegram/PhotoSizeSource.h b/td/telegram/PhotoSizeSource.h
index 67be7d800..d3dd2d227 100644
--- a/td/telegram/PhotoSizeSource.h
+++ b/td/telegram/PhotoSizeSource.h
@@ -242,10 +242,10 @@ struct PhotoSizeSource {
   }
 
   // returns unique representation of the source
-  string get_unique() const;
+  string get_unique(const char *source) const;
 
   // can't be called for Legacy sources
-  string get_unique_name(int64 photo_id) const;
+  string get_unique_name(int64 photo_id, const char *source) const;
 
   template <class StorerT>
   void store(StorerT &storer) const;
diff --git a/td/telegram/files/FileLocation.h b/td/telegram/files/FileLocation.h
index 5d3d07a11..c307dc454 100644
--- a/td/telegram/files/FileLocation.h
+++ b/td/telegram/files/FileLocation.h
@@ -102,10 +102,12 @@ struct PhotoRemoteFileLocation {
     if (id_ != other.id_) {
       return id_ < other.id_;
     }
-    return source_.get_unique() < other.source_.get_unique();
+    return source_.get_unique("PhotoRemoteFileLocation::operator<") <
+           other.source_.get_unique("PhotoRemoteFileLocation::operator<");
   }
   bool operator==(const PhotoRemoteFileLocation &other) const {
-    return id_ == other.id_ && source_.get_unique() == other.source_.get_unique();
+    return id_ == other.id_ && source_.get_unique("PhotoRemoteFileLocation::operator==") ==
+                                   other.source_.get_unique("PhotoRemoteFileLocation::operator==");
   }
 };
 
diff --git a/td/telegram/files/FileLocation.hpp b/td/telegram/files/FileLocation.hpp
index 978a21a55..5c8cf53e8 100644
--- a/td/telegram/files/FileLocation.hpp
+++ b/td/telegram/files/FileLocation.hpp
@@ -105,7 +105,7 @@ void PhotoRemoteFileLocation::parse(ParserT &parser) {
 template <class StorerT>
 void PhotoRemoteFileLocation::AsKey::store(StorerT &storer) const {
   using td::store;
-  auto unique = key.source_.get_unique();
+  auto unique = key.source_.get_unique("PhotoRemoteFileLocation::AsKey::store");
   switch (key.source_.get_type("PhotoRemoteFileLocation::AsKey::store")) {
     case PhotoSizeSource::Type::Legacy:
     case PhotoSizeSource::Type::StickerSetThumbnail: