由于两个存储的属性在Swift中不以任何方式交互，因此如何保持内存安全？

import UIKit

var robGlobal = Player(name: "Rob", health: 10, energy: 10)
var matt = Player(name: "Matt", health: 5, energy: 10)


struct Player {
    var name: String
    var health: Int
    var energy: Int
    
    static let maxHealth = 10
    mutating func restoreHealth() {
        health = Player.maxHealth
    }
    
    func balance(_ x: inout Int, _ y: inout Int) {
        let sum = x + y
        x = sum / 2
        y = sum - x
    }
    
}

class ViewController: UIViewController {
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        
        //MARK1: -Conflicting Access to self in Methods
        
        robGlobal.shareHealth(with: &matt)
        
        robGlobal.shareHealth(with: &robGlobal) // NOT OK in compile time Error: //Overlapping accesses to 'robGlobal', but modification requires exclusive access; consider copying to a local variable
        
        var robNewLocal = Player(name: "Rob", health: 10, energy: 10)
        
        robNewLocal.shareHealth(with: &robNewLocal) // NOT OK in compile time
        
        
        //MARK2: -Conflicting Access to properties in Methods
        
        robGlobal.someFunction()  // OK
        
        robGlobal.anotherFunction() // NOT OK in Run Time Error: Thread 1: Simultaneous accesses to 0x108cc4050, but modification requires exclusive access
        
    }
}


extension Player {
    mutating func shareHealth(with teammate: inout Player) {
        balance(&teammate.health, &health)
        
    }
    func someFunction() {
        var robLocal = Player(name: "Rob", health: 10, energy: 10)
        balance(&robLocal.health, &robLocal.energy)  // OK
    }
    
    func anotherFunction() {
        balance(&robGlobal.health, &robGlobal.energy)  // NOT OK in Run Time
    }
}

我试图了解 Swift 中的内存安全，我在两种情况之间感到困惑。

正如我在方法部分标记的MARK1: -Conflicting Access to self是有道理的。两次写访问相互重叠。在运行之前编译器已经给了我错误：

'robGlobal' 的重叠访问，但修改需要独占访问；考虑复制到局部变量

问题一：好的，但是MARK2部分呢？Swift 编译器进行了一些优化来解决这里对 struct 的写访问？

苹果解释说明如下解决方案，但我不清楚。

编译器可以证明保留了内存安全，因为这两个存储的属性不会以任何方式交互。

问题二：通过使全局运行时问题解决。但我想知道如何？还有为什么它不适用于 MARK1 部分，为什么？

PS：苹果文档在这里