Codechange: Define INVALID_TOWN as a TownID (#7044)

src/road_cmd.cpp

@@ -333,7 +333,7 @@ static CommandCost RemoveRoad(TileIndex tile, DoCommandFlag flags, RoadBits piec
 						if (rt == ROADTYPE_ROAD && IsRoadOwner(tile, ROADTYPE_ROAD, OWNER_TOWN)) {
 							/* Update nearest-town index */
 							const Town *town = CalcClosestTownFromTile(tile);
-							SetTownIndex(tile, town == NULL ? (TownID)INVALID_TOWN : town->index);
+							SetTownIndex(tile, town == NULL ? INVALID_TOWN : town->index);
 						}
 						SetRoadBits(tile, ROAD_NONE, rt);
 						SetRoadTypes(tile, rts);
@@ -494,7 +494,7 @@ CommandCost CmdBuildRoad(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 	if ((Company::IsValidID(company) && p2 != 0) || (company == OWNER_TOWN && !Town::IsValidID(p2)) || (company == OWNER_DEITY && p2 != 0)) return CMD_ERROR;
 	if (company != OWNER_TOWN) {
 		const Town *town = CalcClosestTownFromTile(tile);
-		p2 = (town != NULL) ? town->index : (TownID)INVALID_TOWN;
+		p2 = (town != NULL) ? town->index : INVALID_TOWN;
 
 		if (company == OWNER_DEITY) {
 			company = OWNER_TOWN;
@@ -1444,7 +1444,7 @@ void UpdateNearestTownForRoadTiles(bool invalidate)
 
 	for (TileIndex t = 0; t < MapSize(); t++) {
 		if (IsTileType(t, MP_ROAD) && !IsRoadDepot(t) && !HasTownOwnedRoad(t)) {
-			TownID tid = (TownID)INVALID_TOWN;
+			TownID tid = INVALID_TOWN;
 			if (!invalidate) {
 				const Town *town = CalcClosestTownFromTile(t);
 				if (town != NULL) tid = town->index;

src/town.h

@@ -31,7 +31,7 @@ typedef TileMatrix<CargoTypes, 4> AcceptanceMatrix;
 static const uint CUSTOM_TOWN_NUMBER_DIFFICULTY  = 4; ///< value for custom town number in difficulty settings
 static const uint CUSTOM_TOWN_MAX_NUMBER = 5000;  ///< this is the maximum number of towns a user can specify in customisation
 
-static const uint INVALID_TOWN = 0xFFFF;
+static const TownID INVALID_TOWN = 0xFFFF;
 
 static const uint TOWN_GROWTH_WINTER = 0xFFFFFFFE; ///< The town only needs this cargo in the winter (any amount)
 static const uint TOWN_GROWTH_DESERT = 0xFFFFFFFF; ///< The town needs the cargo for growth when on desert (any amount)

src/town_cmd.cpp

@@ -3335,7 +3335,7 @@ Town *ClosestTownFromTile(TileIndex tile, uint threshold)
 			if (!HasTownOwnedRoad(tile)) {
 				TownID tid = GetTownIndex(tile);
 
-				if (tid == (TownID)INVALID_TOWN) {
+				if (tid == INVALID_TOWN) {
 					/* in the case we are generating "many random towns", this value may be INVALID_TOWN */
 					if (_generating_world) return CalcClosestTownFromTile(tile, threshold);
 					assert(Town::GetNumItems() == 0);