static CommandCost ClearTile_Water(TileIndex tile, DoCommandFlag flags)
{
	bool canal_on_river = HasTileCanalOnRiver(tile);
	switch (GetWaterTileType(tile)) {
		case WATER_TILE_CLEAR: {
			if (flags & DC_NO_WATER) return_cmd_error(STR_ERROR_CAN_T_BUILD_ON_WATER);

			Money base_cost = IsCanal(tile) ? _price[PR_CLEAR_CANAL] : _price[PR_CLEAR_WATER];
			if (IsRiver(tile) && _game_mode == GM_NORMAL && !_cheats.magic_bulldozer.value) base_cost = 0;

			/* Make sure freeform edges are allowed or it's not an edge tile. */
			if (!_settings_game.construction.freeform_edges && (!IsInsideMM(TileX(tile), 1, MapMaxX() - 1) ||
					!IsInsideMM(TileY(tile), 1, MapMaxY() - 1))) {
				return_cmd_error(STR_ERROR_TOO_CLOSE_TO_EDGE_OF_MAP);
			}

			/* Make sure no vehicle is on the tile */
			CommandCost ret = EnsureNoVehicleOnGround(tile);
			if (ret.Failed()) return ret;

			Owner owner = GetTileOwner(tile);
			if (owner != OWNER_WATER && owner != OWNER_NONE) {
				CommandCost ret = CheckTileOwnership(tile);
				if (ret.Failed()) { // Canals of OWNER_NONE or of same owner always succeed.
					/* Fail Oil Rig on random creation on canal owned by any company when the setting is on. */
					if (_settings_game.construction.build_on_competitor_canal && _current_company == OWNER_NONE) return ret;
					/* Fail Oil Rig on prospecting on canal of competitor when the setting is on. */
					if (_settings_game.construction.build_on_competitor_canal && _current_company == OWNER_TOWN && _local_company != owner) return ret;
					/* Fail for clearance check. */
					if (_settings_game.construction.build_on_competitor_canal && _current_company == _local_company && _local_company != owner) return ret;
					/* Fail for everything else when the setting is off. */
					if (!_settings_game.construction.build_on_competitor_canal) return ret;
				}
			}

			if (flags & DC_EXEC) {
				if (IsCanal(tile) && Company::IsValidID(owner)) {
					Company::Get(owner)->infrastructure.water--;
					DirtyCompanyInfrastructureWindows(owner);
				}
				bool restore_river = HasTileWaterClass(tile) && GetWaterClass(tile) == WATER_CLASS_RIVER;
				uint8 same_aspect = GetWaterTileRandomBits(tile);

				DoClearSquare(tile);
				if (canal_on_river)	{
					MakeRiver(tile, Random());
				}
				if (restore_river && (_game_mode == GM_NORMAL && !_cheats.magic_bulldozer.value)) {
					MakeRiver(tile, same_aspect);
				}
				MarkCanalsAndRiversAroundDirty(tile);
			}

			return CommandCost(EXPENSES_CONSTRUCTION, base_cost);
		}

		case WATER_TILE_COAST: {
			Slope slope = GetTileSlope(tile);

			/* Make sure no vehicle is on the tile */
			CommandCost ret = EnsureNoVehicleOnGround(tile);
			if (ret.Failed()) return ret;

			if (flags & DC_EXEC) {
				DoClearSquare(tile);
				MarkCanalsAndRiversAroundDirty(tile);
			}
			if (IsSlopeWithOneCornerRaised(slope)) {
				return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_CLEAR_WATER]);
			} else {
				return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_CLEAR_ROUGH]);
			}
		}

		case WATER_TILE_LOCK: {
			static const TileIndexDiffC _lock_tomiddle_offs[][DIAGDIR_END] = {
				/*   NE       SE        SW      NW       */
				{ { 0,  0}, {0,  0}, { 0, 0}, {0,  0} }, // LOCK_PART_MIDDLE
				{ {-1,  0}, {0,  1}, { 1, 0}, {0, -1} }, // LOCK_PART_LOWER
				{ { 1,  0}, {0, -1}, {-1, 0}, {0,  1} }, // LOCK_PART_UPPER
			};

			if (flags & DC_AUTO) return_cmd_error(STR_ERROR_BUILDING_MUST_BE_DEMOLISHED);
			if (_current_company == OWNER_WATER) return CMD_ERROR;
			/* move to the middle tile.. */
			return RemoveLock(tile + ToTileIndexDiff(_lock_tomiddle_offs[GetLockPart(tile)][GetLockDirection(tile)]), flags);
		}

		case WATER_TILE_DEPOT:
			if (flags & DC_AUTO) return_cmd_error(STR_ERROR_BUILDING_MUST_BE_DEMOLISHED);
			return RemoveShipDepot(tile, flags);

		default:
			NOT_REACHED();
	}
}