Add [[fallthrough]];.

src/action/action_unload.cpp

@@ -409,7 +409,7 @@ void COrder_Unload::Execute(CUnit &unit) /* override */
 			}
 			this->Retries = 0;
 			this->State = MOVE_TO_DROPZONE_STATE;
-			// fall through and move immediately
+			[[fallthrough]]; // fallthrough and move immediately
 		case MOVE_TO_DROPZONE_STATE:
 			switch (DoActionMove(unit)) {
 				case PF_UNREACHABLE:
@@ -424,7 +424,7 @@ void COrder_Unload::Execute(CUnit &unit) /* override */
 					// still moving or waiting to move
 					return;
 			}
-			// fall through
+			[[fallthrough]];
 		case UNLOAD_STATE:
 			// Leave the transporter
 			// FIXME: show still animations ?

src/map/fow.cpp

@@ -360,7 +360,7 @@ void CFogOfWar::Update(bool doAtOnce /*= false*/)
 
                 case States::cGenerateFog:
                     GenerateFog();
-                    /// pass through
+					[[fallthrough]];
                 default:
                     this->State++;
                     break;

src/network/netconnect.cpp

@@ -1277,13 +1277,13 @@ int CServer::Parse_Hello(int h, const CInitMessage_Hello &msg, const CHost &host
 void CServer::Parse_Resync(const int h)
 {
 	switch (networkStates[h].State) {
-		case ccs_mapinfo:
-		// a delayed ack - fall through..
+		case ccs_mapinfo: // a delayed ack..
+			[[fallthrough]];
 		case ccs_async:
 			// client has recvd welcome and is waiting for info
 			networkStates[h].State = ccs_synced;
 			networkStates[h].MsgCnt = 0;
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_synced: {
 			// this code path happens until client falls back to ICMWaiting
 			// (indicating Resync has completed)
@@ -1314,11 +1314,11 @@ void CServer::Parse_Waiting(const int h)
 		case ccs_connecting:
 			networkStates[h].State = ccs_connected;
 			networkStates[h].MsgCnt = 0;
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_needmap: // client has finished receiving the map and wants the info again
 			networkStates[h].State = ccs_connected;
 			networkStates[h].MsgCnt = 0;
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_connected: {
 			// this code path happens until client acknowledges the map
 			Send_Map(Hosts[h]);
@@ -1338,7 +1338,7 @@ void CServer::Parse_Waiting(const int h)
 					networkStates[i].State = ccs_async;
 				}
 			}
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_synced:
 			// the wanted state - do nothing.. until start...
 			networkStates[h].MsgCnt = 0;
@@ -1377,7 +1377,7 @@ void CServer::Parse_Map(const int h)
 		case ccs_connected:
 			networkStates[h].State = ccs_mapinfo;
 			networkStates[h].MsgCnt = 0;
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_mapinfo: {
 			// this code path happens until client acknowledges the state info
 			// by falling back to ICMWaiting with prev. State synced
@@ -1403,7 +1403,7 @@ void CServer::Parse_MapFragment(const int h, uint32_t fragmentIdx)
 			networkStates[h].State = ccs_needmap;
 			networkStates[h].MsgCnt = 0;
 			Assert(fragmentIdx == 0); // client keep asking for this fragment initially
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_needmap: {
 			Send_MapFragment(Hosts[h], fragmentIdx);
 			networkStates[h].MsgCnt++;
@@ -1429,7 +1429,7 @@ void CServer::Parse_State(const int h, const CInitMessage_State &msg)
 	switch (networkStates[h].State) {
 		case ccs_mapinfo:
 		// User State Change right after connect - should not happen, but..
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_synced:
 			// Default case: Client is in sync with us, but notes a local change
 			// networkStates[h].State = ccs_async;
@@ -1445,7 +1445,7 @@ void CServer::Parse_State(const int h, const CInitMessage_State &msg)
 					networkStates[i].State = ccs_async;
 				}
 			}
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_async: {
 			// this code path happens until client acknowledges the state change reply
 			// by sending ICMResync
@@ -1475,7 +1475,7 @@ void CServer::Parse_GoodBye(const int h)
 			// We can enter here from _ANY_ state!
 			networkStates[h].MsgCnt = 0;
 			networkStates[h].State = ccs_detaching;
-		/* Fall through */
+			[[fallthrough]];
 		case ccs_detaching: {
 			// this code path happens until client acknoledges the GoodBye
 			// by sending ICMSeeYou;