为什么这段Swift代码编译和运行时没有错误?

struct AStruct {
    var aValue: Int
}
let aStruct = AStruct(aValue: 3)
let aClass = aStruct as AnyObject  //Why does this line compile?
let ident = ObjectIdentifier(aClass)  //`ObjectIdentifier()` requires a reference object, but this code works

AnyObject (对于类对象)并且它是有效的。

我预计这一行会出现编译错误。

在下一行中,我将传递结构,cast to AnyObject to ObjectIdentifier() ,这要求它的参数是类对象。该代码运行并返回一个结果。我预计,如果该行被传递一个错误,它将在运行时崩溃 Any .