diff --git a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
index 12eb36008b..cbab7e0a1c 100644
--- a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
+++ b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
@@ -1048,7 +1048,6 @@ void mtpTextSerializeType(MTPStringLogger &to, const mtpPrime *&from, const mtpP
 	types.reserve(20); vtypes.reserve(20); stages.reserve(20); flags.reserve(20);\n\
 	types.push_back(mtpTypeId(cons)); vtypes.push_back(mtpTypeId(vcons)); stages.push_back(0); flags.push_back(0);\n\
 \n\
-	const mtpPrime *start = from;\n\
 	mtpTypeId type = cons, vtype = vcons;\n\
 	int32 stage = 0, flag = 0;\n\
 \n\
@@ -1064,13 +1063,13 @@ void mtpTextSerializeType(MTPStringLogger &to, const mtpPrime *&from, const mtpP
 				throw Exception("unknown type on stage > 0");\n\
 			}\n\
 			types.back() = type = *from;\n\
-			start = ++from;\n\
+			++from;\n\
 		}\n\
 \n\
 		int32 lev = level + types.size() - 1;\n\
 		auto it = serializers.constFind(type);\n\
 		if (it != serializers.cend()) {\n\
-			(*it.value())(to, stage, lev, types, vtypes, stages, flags, start, end, flag);\n\
+			(*it.value())(to, stage, lev, types, vtypes, stages, flags, from, end, flag);\n\
 		} else {\n\
 			mtpTextSerializeCore(to, from, end, type, lev, vtype);\n\
 			types.pop_back(); vtypes.pop_back(); stages.pop_back(); flags.pop_back();\n\
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 55d76433d4..2c90a99402 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -1612,7 +1612,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 	case mtpc_gzip_packed: {
 		DEBUG_LOG(("Message Info: gzip container"));
 		mtpBuffer response = ungzip(++from, end);
-		if (!response.size()) {
+		if (response.empty()) {
 			return HandleResult::RestartConnection;
 		}
 		return handleOneReceived(response.data(), response.data() + response.size(), msgId, serverTime, serverSalt, badTime);
diff --git a/Telegram/SourceFiles/mtproto/core_types.cpp b/Telegram/SourceFiles/mtproto/core_types.cpp
index 8a27619508..84a57235da 100644
--- a/Telegram/SourceFiles/mtproto/core_types.cpp
+++ b/Telegram/SourceFiles/mtproto/core_types.cpp
@@ -302,11 +302,11 @@ void mtpTextSerializeCore(MTPStringLogger &to, const mtpPrime *&from, const mtpP
 		result.resize(0);
 
 		z_stream stream;
-		stream.zalloc = 0;
-		stream.zfree = 0;
-		stream.opaque = 0;
+		stream.zalloc = nullptr;
+		stream.zfree = nullptr;
+		stream.opaque = nullptr;
 		stream.avail_in = 0;
-		stream.next_in = 0;
+		stream.next_in = nullptr;
 		int res = inflateInit2(&stream, 16 + MAX_WBITS);
 		if (res != Z_OK) {
 			throw Exception(QString("ungzip init, code: %1").arg(res));
@@ -331,7 +331,7 @@ void mtpTextSerializeCore(MTPStringLogger &to, const mtpPrime *&from, const mtpP
 		result.resize(result.size() - (stream.avail_out >> 2));
 		inflateEnd(&stream);
 
-		if (!result.size()) {
+		if (result.empty()) {
 			throw Exception("ungzip void data");
 		}
 		const mtpPrime *newFrom = result.constData(), *newEnd = result.constData() + result.size();