fixed compilation with clang

dbms/programs/server/MySQLHandler.cpp

@@ -41,7 +41,8 @@ void MySQLHandler::run()
 
         LOG_TRACE(log, "Sent handshake");
 
-        auto handshake_response = packet_sender.receivePacket<HandshakeResponse>();
+        HandshakeResponse handshake_response;
+        packet_sender.receivePacket(handshake_response);
 
         LOG_DEBUG(log, "Capabilities: " << handshake_response.capability_flags
                                         << "\nmax_packet_size: "
@@ -74,7 +75,9 @@ void MySQLHandler::run()
         {
 
             packet_sender.sendPacket(AuthSwitchRequest(Authentication::ClearText, ""), true);
-            password = packet_sender.receivePacket<NullTerminatedString>().value;
+            NullTerminatedString password_packet;
+            packet_sender.receivePacket(password_packet);
+            password = password_packet.value;
         }
         else
         {

dbms/src/Core/MySQLProtocol.h

@@ -186,13 +186,9 @@ public:
         return std::move(buf.str());
     }
 
-    template<typename T>
-    T receivePacket()
+    void receivePacket(ReadPacket & packet)
     {
-        static_assert(std::is_base_of<ReadPacket, T>());
-        T packet;
-        packet.readPayload(std::move(receivePacketPayload()));
-        return packet;
+        packet.readPayload(receivePacketPayload());
     }
 
     template<class T>
@@ -301,10 +297,6 @@ public:
     String database;
     String auth_plugin_name;
 
-    HandshakeResponse() = default;
-
-    HandshakeResponse(const HandshakeResponse &) = default;
-
     void readPayload(String s) override
     {
         std::istringstream ss(s);
@@ -372,10 +364,6 @@ class NullTerminatedString : public ReadPacket
 public:
     String value;
 
-    NullTerminatedString() = default;
-
-    NullTerminatedString(const NullTerminatedString &) = default;
-
     void readPayload(String s) override
     {
         if (s.length() == 0 || s.back() != 0)
@@ -550,10 +538,6 @@ class ComFieldList : public ReadPacket
 public:
     String table, field_wildcard;
 
-    ComFieldList() = default;
-
-    ComFieldList(const ComFieldList &) = default;
-
     void readPayload(String payload)
     {
         std::istringstream ss(payload);