Swift '(int, int) -> $T4' is not identical to 'Point' - xcode

Question

I'm fairly new to swift and get this error. All I want the declaration to do is assign the 4 values to create 2 Point objects for a Line object. So Line(10, 20, 20, 40) should create two points at (10,20) and (20,40). But I get the error '(Int, Int) -> $T4' is not identical to 'Point'
class Point {
var x: Int = 0
var y: Int = 0
init(){
x = 0
y = 0
}
init(x: Int, y: Int) {
self.x = x
self.y = y
}
}
class Line: Point {
var pointA: Point
var pointB: Point
init(p1x: Int, p1y: Int, p2x: Int, p2y: Int) {
self.pointA(p1x, p1y)
self.pointB(p2x, p2y)
}
}
var lineA = Line(p1x:10, p1y:20 , p2x:20 , p2y:40)

Answer 1

Your code in Line's init is meaningless. This is not valid Swift:
self.pointA(p1x, p1y)
self.pointB(p2x, p2y)
You can't just stick parentheses after the name of a variable like that! Plus you are not writing your init correctly. Here's a possible fix:
class Line: Point {
var pointA: Point
var pointB: Point
init(p1x: Int, p1y: Int, p2x: Int, p2y: Int) {
self.pointA = Point(x:p1x, y:p1y)
self.pointB = Point(x:p2x, y:p2y)
super.init()
}
}
But as Antonio has already said, it all depends on what you're trying to do. My code above will cause your code to compile correctly, but I have no idea whether it does what you want, because what you're trying to do is utterly impossible to guess.

Answer 2

In the initializer you are missing to create instances - you are just trying to reference 2 properties as if they were methods. The correct way is:
init(p1x: Int, p1y: Int, p2x: Int, p2y: Int) {
self.pointA = Point(x: p1x, y: p1y)
self.pointB = Point(x: p2x, y: p2y)
}
There is an architectural mistake though: Line inherits from Point, but I see no relationship between the 2 classes - you should at least call the superclass initializer, but what to pass?
I would instead define only 1 new property in Line, and reuse the property already available in Point:
class Line: Point {
var pointB: Point
init(p1x: Int, p1y: Int, p2x: Int, p2y: Int) {
self.pointB = Point(x: p2x, y:p2y)
super.init(x: p1x, y: p1y)
}
}
I don't know if that makes sense (depending on what you want to achieve) - if not, then I would just make Line not inherit from Point. If you need a common interface, but with different implementations, then you can use a protocol adopted by the 2 classes.