Placing an apple in snake game written in Scala - scala

Question

To place an apple in an empty place, I'm using the emptySpots() method to locate the points of the cells that are empty or free.
When I implement the code below, my game runs fine:
def emptySpots() : Point = {
val emptyPointsList = new ArrayBuffer[Point]()
var emptyLocation : Point = new Point(0,0)
emptyLocation = Point(random.randomInt(upTo = 25), random.randomInt(upTo = 25))
emptyLocation
}
However, when I try to implement the code below, it shows me errors:
def emptySpots() : Point = {
val emptyPointsList = new ArrayBuffer[Point]()
var emptyLocation : Point = new Point(0,0)
for(i <- 0 until gridDims.height) {
for(j <- 0 until gridDims.width) {
if(getCellType(Point(i, j)) == Empty()) {
emptyPointsList += Point(i, j)
}
}
}
if(!emptyPointsList.isEmpty) {
emptyLocation = emptyPointsList(random.randomInt(emptyPointsList.size))
}
emptyLocation
}
The errors are:
I would appreciate if anyone could point out what's wrong in my second implementation to show me such errors where my first implementation works fine.
P.S. The randomInt() is not wrong here because it's supported by the imported package and library