(svn r21476) -Fix [FS#4299]: DC_FORCE_CLEAR_TILE should only add extra cost for clearing water for stuff which results in water after clearing.

src/landscape.cpp

@@ -609,7 +609,8 @@ CommandCost CmdLandscapeClear(TileIndex tile, DoCommandFlag flags, uint32 p1, ui
 {
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 	bool do_clear = false;
-	if ((flags & DC_FORCE_CLEAR_TILE) && HasTileWaterClass(tile) && IsTileOnWater(tile)) {
+	/* Test for stuff which results in water when cleared. Then add the cost to also clear the water. */
+	if ((flags & DC_FORCE_CLEAR_TILE) && HasTileWaterClass(tile) && IsTileOnWater(tile) && !IsWaterTile(tile) && !IsCoastTile(tile)) {
 		if ((flags & DC_AUTO) && GetWaterClass(tile) == WATER_CLASS_CANAL) return_cmd_error(STR_ERROR_MUST_DEMOLISH_CANAL_FIRST);
 		do_clear = true;
 		cost.AddCost(GetWaterClass(tile) == WATER_CLASS_CANAL ? _price[PR_CLEAR_CANAL] : _price[PR_CLEAR_WATER]);