How to refer to a global type from within a class that has a nested type with the same name?

问题

I have a class declared at the global scope and another class with the same name that is nested within some class.

class Address {
    var someProperty: String?
}

class ThirdPartyAPI {
    class Address {
        var someOtherProperty: String?
        init(fromAddress address: Address) {
            self.someOtherProperty = address.someProperty
        }
    }
}

The question is: how can I refer to a global class instead of the inner one from its initialiser? In the example given I've got an error Value of type 'ThirdPartyAPI.Address' has no member 'someProperty', which means that compiler refers to the inner Address instead of a global one.

回答1:

Use typealias

class Address {
    var someProperty: String?
}

typealias GlobalAddress = Address

class ThirdPartyAPI {
    class Address {
        var someOtherProperty: String?
        init(fromAddress address: GlobalAddress) {
            self.someOtherProperty = address.someProperty
        }
    }
}

回答2:

You can refer to types uniquely by prepending the module name. So if

class Address {
    var someProperty: String?
}

is defined in "MySuperApp" then you can refer to it as MySuperApp.Address:

class ThirdPartyAPI {

    class Address {
        var someOtherProperty: String?
        init(fromAddress address: MySuperApp.Address) {
            self.someOtherProperty = address.someProperty
        }
    }
}

(But if you have a choice then try to avoid the ambiguity to make your code easier to understand.)

来源：https://stackoverflow.com/questions/34380112/how-to-refer-to-a-global-type-from-within-a-class-that-has-a-nested-type-with-th