swift Mirror not setting member values as expected

I was hoping to use swift Mirror to create an extension that can change the properties of a struct.

It seems however that mutating the child items of the mirror is creating new instances and mutating those instead of the members of the method.

Below is a playground that shows my problem.

Can I use Mirror to achieve the goal of setting member values of structs that implement the given protocol, or should I take a different approach (and if so what)?

import Cocoa

struct Point {
  var x: Int = 0
  var y: Int = 0
}

protocol Shape {
  var origin: Point { get }
}

extension Shape {
//: The hope is to have a generic function that will set the value of all parameters of type 'Point' but it is not working. The fact that I do not need "mutating" for this function is another clue that it will not mutate the members of the Shape.
  mutating func clearAllPoints() {
    let mirror = Mirror(reflecting: self)
    
    for child in mirror.children {
      // It seems the line below creates a new point instance and it is not the same member of self.
      if var point = child.value as? Point {
        point.x = 0
        point.y = 0
      }
    }
  }
  
  func printAllPoints() {
    let mirror = Mirror(reflecting: self)
    for child in mirror.children {
      if let point = child.value as? Point {
        print("\(child.label!) = (x: \(point.x), y: \(point.y)")
      }
    }
  }
}
  
struct Rectangle: Shape {
  var origin = Point()
  var corner = Point()

  init() {
    origin = Point(x: 10, y: 10)
    corner = Point(x: 20, y: 30)
  }
}

var rect = Rectangle()
//: rect has just been initialised, and the line below correctly prints all Points as initialised.
rect.printAllPoints()
//: Hope is that the line below will clear all Points but ...
rect.clearAllPoints()
//: ... it does not. The line below prints all Points with exactly the same values.
rect.printAllPoints()