Swift 元素作为任意对象vs元素vs任意对象？

阅读苹果的代码，我看到了以下内容（谈论钥匙链服务）：

任何对象的用途是什么？

我认为可以简化为

query[kSecAttrService as String] = service as AnyObject

有线索吗

以下是苹果公司样本的完整片段：

private static func keychainQuery(withService service: String, account: String? = nil, accessGroup: String? = nil) -> [String : AnyObject] {
    var query = [String : AnyObject]()
    query[kSecClass as String] = kSecClassGenericPassword
    query[kSecAttrService as String] = service as AnyObject?

    if let account = account {
        query[kSecAttrAccount as String] = account as AnyObject?
    }

    if let accessGroup = accessGroup {
        query[kSecAttrAccessGroup as String] = accessGroup as AnyObject?
    }

    return query
}

---

也许这段代码是来自Swift 2的代码，在Swift 3+中是

private static func keychainQuery(withService service: String, account: String? = nil, accessGroup: String? = nil) -> [String : Any] {
    var query = [String : Any]()
    query[kSecClass as String] = kSecClassGenericPassword
    query[kSecAttrService as String] = service

    if let account = account {
        query[kSecAttrAccount as String] = account
    }

    if let accessGroup = accessGroup {
        query[kSecAttrAccessGroup as String] = accessGroup
    }

    return query
}

---

也许这段代码是来自Swift 2的代码，在Swift 3+中是

private static func keychainQuery(withService service: String, account: String? = nil, accessGroup: String? = nil) -> [String : Any] {
    var query = [String : Any]()
    query[kSecClass as String] = kSecClassGenericPassword
    query[kSecAttrService as String] = service

    if let account = account {
        query[kSecAttrAccount as String] = account
    }

    if let accessGroup = accessGroup {
        query[kSecAttrAccessGroup as String] = accessGroup
    }

    return query
}

---

谁说苹果的样本必须包含完美无瑕的代码？谁说苹果的样本必须包含完美无瑕的代码？您已从

AnyObject

移动到

Any

。你能告诉我为什么吗？因为在Swift 3+中，未指定的值类型是

Any

，未指定的引用类型是

AnyObject

。查询字典仅包含值类型。您已从

AnyObject

移动到

Any

。你能告诉我为什么吗？因为在Swift 3+中，未指定的值类型是

Any

，未指定的引用类型是

AnyObject

。查询字典仅包含值类型。