Codechange: Replace old non-standard attributes with C++17/20 standard attributes.

src/network/core/network_game_info.cpp

@@ -274,17 +274,17 @@ void DeserializeNetworkGameInfo(Packet *p, NetworkGameInfo *info, const GameInfo
 	switch (game_info_version) {
 		case 7:
 			info->ticks_playing = p->Recv_uint64();
-			FALLTHROUGH;
+			[[fallthrough]];
 
 		case 6:
 			newgrf_serialisation = (NewGRFSerializationType)p->Recv_uint8();
 			if (newgrf_serialisation >= NST_END) return;
-			FALLTHROUGH;
+			[[fallthrough]];
 
 		case 5: {
 			info->gamescript_version = (int)p->Recv_uint32();
 			info->gamescript_name = p->Recv_string(NETWORK_NAME_LENGTH);
-			FALLTHROUGH;
+			[[fallthrough]];
 		}
 
 		case 4: {
@@ -326,19 +326,19 @@ void DeserializeNetworkGameInfo(Packet *p, NetworkGameInfo *info, const GameInfo
 				*dst = c;
 				dst = &c->next;
 			}
-			FALLTHROUGH;
+			[[fallthrough]];
 		}
 
 		case 3:
 			info->calendar_date = Clamp(p->Recv_uint32(), 0, CalendarTime::MAX_DATE.base());
 			info->calendar_start = Clamp(p->Recv_uint32(), 0, CalendarTime::MAX_DATE.base());
-			FALLTHROUGH;
+			[[fallthrough]];
 
 		case 2:
 			info->companies_max  = p->Recv_uint8 ();
 			info->companies_on   = p->Recv_uint8 ();
 			p->Recv_uint8(); // Used to contain max-spectators.
-			FALLTHROUGH;
+			[[fallthrough]];
 
 		case 1:
 			info->server_name = p->Recv_string(NETWORK_NAME_LENGTH);

src/network/network_chat_gui.cpp

@@ -454,7 +454,7 @@ struct NetworkChatWindow : public Window {
 		switch (widget) {
 			case WID_NC_SENDBUTTON: /* Send */
 				SendChat(this->message_editbox.text.buf, this->dtype, this->dest);
-				FALLTHROUGH;
+				[[fallthrough]];
 
 			case WID_NC_CLOSE: /* Cancel */
 				this->Close();

src/network/network_content_gui.cpp

@@ -894,7 +894,7 @@ public:
 						return ES_HANDLED;
 					}
 					/* space is pressed and filter is focused. */
-					FALLTHROUGH;
+					[[fallthrough]];
 
 				default:
 					return ES_NOT_HANDLED;

src/network/network_gui.cpp

@@ -2134,7 +2134,7 @@ struct NetworkJoinStatusWindow : Window {
 							progress = 15; // We don't have the final size yet; the server is still compressing!
 							break;
 						}
-						FALLTHROUGH;
+						[[fallthrough]];
 
 					default: // Waiting is 15%, so the resting receivement of map is maximum 70%
 						progress = 15 + _network_join_bytes * (100 - 15) / _network_join_bytes_total;
@@ -2307,7 +2307,7 @@ struct NetworkCompanyPasswordWindow : public Window {
 		switch (widget) {
 			case WID_NCP_OK:
 				this->OnOk();
-				FALLTHROUGH;
+				[[fallthrough]];
 
 			case WID_NCP_CANCEL:
 				this->Close();

src/network/network_server.cpp

@@ -1362,7 +1362,7 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 		}
 		default:
 			Debug(net, 1, "Received unknown chat destination type {}; doing broadcast instead", desttype);
-			FALLTHROUGH;
+			[[fallthrough]];
 
 		case DESTTYPE_BROADCAST:
 			for (NetworkClientSocket *cs : NetworkClientSocket::Iterate()) {