Swift 可选链在闭包中不起作用

Swift 可选链是一种方便而强大的语言特性，它允许我们在使用可选值时避免繁琐的空值检查。然而，当我们尝试在闭包中使用可选链时，可能会遇到一些问题。本文将探讨为何在闭包中使用可选链不起作用，并提供案例代码进行说明。

swift
class Person {
    var name: String?
    var age: Int?
    
    func introduce() {
        if let name = name, let age = age {
            print("My name is \(name) and I am \(age) years old.")
        } else {
            print("I am a person without a name or age.")
        }
    }
}
var person: Person? = Person()
person?.name = "John"
person?.age = 30
person?.introduce()
// 使用可选链调用闭包
person?.introduce = {
    if let name = self.name, let age = self.age {
        print("My name is \(name) and I am \(age) years old.")
    } else {
        print("I am a person without a name or age.")
    }
}
person?.introduce?()

swift
person?.introduce = {
    [weak self] in
    if let name = self?.name, let age = self?.age {
        print("My name is \(name) and I am \(age) years old.")
    } else {
        print("I am a person without a name or age.")
    }
}
person?.introduce?()