diff --git a/CMakeLists.txt b/CMakeLists.txt
index 177972a3..2ca33457 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -202,6 +202,7 @@ if (NOT MSVC)
   add_cxx_compiler_flag("-Wconversion")
   add_cxx_compiler_flag("-Wno-sign-conversion")
   add_cxx_compiler_flag("-Wc++14-compat-pedantic")
+  add_cxx_compiler_flag("-Wdeprecated")
   add_cxx_compiler_flag("-Qunused-arguments")
   add_cxx_compiler_flag("-Wodr")
   add_cxx_compiler_flag("-flto-odr-type-merging")
diff --git a/td/telegram/MessagesManager.h b/td/telegram/MessagesManager.h
index 6ebe0992..ddfceb87 100644
--- a/td/telegram/MessagesManager.h
+++ b/td/telegram/MessagesManager.h
@@ -72,6 +72,12 @@ class MultiSequenceDispatcher;
 // Do not forget to update MessagesManager::update_message_content when one of the inheritors of this class changes
 class MessageContent {
  public:
+  MessageContent() = default;
+  MessageContent(const MessageContent &) = default;
+  MessageContent &operator=(const MessageContent &) = default;
+  MessageContent(MessageContent &&) = default;
+  MessageContent &operator=(MessageContent &&) = default;
+
   virtual int32 get_id() const = 0;
   virtual ~MessageContent() = default;
 };
diff --git a/td/telegram/SecureStorage.cpp b/td/telegram/SecureStorage.cpp
index e20cbb16..0f9b4e16 100644
--- a/td/telegram/SecureStorage.cpp
+++ b/td/telegram/SecureStorage.cpp
@@ -324,9 +324,9 @@ Result<BufferSlice> Encryptor::pread(int64 offset, int64 size) {
 }
 
 Result<EncryptedValue> encrypt_value(const Secret &secret, Slice data) {
-  auto random_prefix_view = BufferSliceDataView(gen_random_prefix(data.size()));
-  auto data_view = BufferSliceDataView(BufferSlice(data));
-  auto full_view = ConcatDataView(random_prefix_view, data_view);
+  BufferSliceDataView random_prefix_view{gen_random_prefix(data.size())};
+  BufferSliceDataView data_view{BufferSlice(data)};
+  ConcatDataView full_view{random_prefix_view, data_view};
 
   TRY_RESULT(hash, calc_value_hash(full_view));
 
@@ -353,9 +353,9 @@ Result<ValueHash> encrypt_file(const Secret &secret, std::string src, std::strin
   TRY_RESULT(dest_file, FileFd::open(dest, FileFd::Flags::Truncate | FileFd::Flags::Write | FileFd::Create));
   auto src_file_size = src_file.get_size();
 
-  auto random_prefix_view = BufferSliceDataView(gen_random_prefix(src_file_size));
-  auto data_view = FileDataView(src_file, src_file_size);
-  auto full_view = ConcatDataView(random_prefix_view, data_view);
+  BufferSliceDataView random_prefix_view(gen_random_prefix(src_file_size));
+  FileDataView data_view(src_file, src_file_size);
+  ConcatDataView full_view(random_prefix_view, data_view);
 
   TRY_RESULT(hash, calc_value_hash(full_view));
 
@@ -371,7 +371,7 @@ Status decrypt_file(const Secret &secret, const ValueHash &hash, std::string src
   TRY_RESULT(dest_file, FileFd::open(dest, FileFd::Flags::Truncate | FileFd::Flags::Write | FileFd::Create));
   auto src_file_size = src_file.get_size();
 
-  auto src_file_view = FileDataView(src_file, src_file_size);
+  FileDataView src_file_view(src_file, src_file_size);
 
   auto aes_cbc_state = calc_aes_cbc_state_sha512(PSLICE() << secret.as_slice() << hash.as_slice());
   Decryptor decryptor(aes_cbc_state);
diff --git a/td/telegram/SecureStorage.h b/td/telegram/SecureStorage.h
index b6afa97a..46b30bc3 100644
--- a/td/telegram/SecureStorage.h
+++ b/td/telegram/SecureStorage.h
@@ -63,6 +63,12 @@ class ValueHash {
 
 class DataView {
  public:
+  DataView() = default;
+  DataView(const DataView &) = delete;
+  DataView &operator=(const DataView &) = delete;
+  DataView(DataView &&) = delete;
+  DataView &operator=(DataView &&) = delete;
+
   virtual int64 size() const = 0;
   virtual Result<BufferSlice> pread(int64 offset, int64 size) = 0;
   virtual ~DataView() = default;
diff --git a/td/telegram/net/DcId.h b/td/telegram/net/DcId.h
index 74346672..8ce115e1 100644
--- a/td/telegram/net/DcId.h
+++ b/td/telegram/net/DcId.h
@@ -16,7 +16,6 @@ namespace td {
 class DcId {
  public:
   DcId() = default;
-  DcId(const DcId &other) = default;
 
   static bool is_valid(int32 dc_id) {
     return 1 <= dc_id && dc_id <= 1000;
diff --git a/test/secure_storage.cpp b/test/secure_storage.cpp
index 5dcd6f43..1b1b122d 100644
--- a/test/secure_storage.cpp
+++ b/test/secure_storage.cpp
@@ -32,10 +32,10 @@ TEST(SecureStorage, simple) {
   auto value_secret = Secret::create_new();
 
   {
-    auto value_view = BufferSliceDataView(value.copy());
+    BufferSliceDataView value_view(value.copy());
     BufferSlice prefix = gen_random_prefix(value_view.size());
-    auto prefix_view = BufferSliceDataView(std::move(prefix));
-    auto full_value_view = ConcatDataView(prefix_view, value_view);
+    BufferSliceDataView prefix_view(std::move(prefix));
+    ConcatDataView full_value_view(prefix_view, value_view);
     auto hash = calc_value_hash(full_value_view).move_as_ok();
 
     Encryptor encryptor(calc_aes_cbc_state_sha512(PSLICE() << value_secret.as_slice() << hash.as_slice()),