@ -146,7 +146,7 @@ TileIndex TileAdd(TileIndex tile, TileIndexDiff offset)
assert(x < MapSizeX());
assert(y < MapSizeY());
assert(TileXY(x, y) == TILE_MASK(tile + add));
assert(TileXY(x, y) == TILE_MASK(tile + offset));
return TileXY(x, y);
}