Hi Marc,
>> The second class defines a static property that looks like it is
>> 'overriding' the static property from
>> the protocol extension, but since the types don't match (String vs.
>> String?), it sort of 'overloads'
>> the property (similar to function overloading). Nevertheless, the class
>> still fulfills the requirements
>> of the Trackable protocol, by inheriting the static property from the
>> protocol extension.
>
> Isn’t this a compiler bug?
>
> I didn’t realise that overloading properties was a thing? I’m pretty sure it
> isn’t, in which case the compiler should choke because there are two
> properties of the same name but divergent types available on the type.
>
> This behaviour seems to create major hard-to-detect hazards when using
> protocol extensions, which seems against the spirit of Swift.
Yeah, I guess overloading might not be the right term. You're right, properties
can't be overloaded in general. For example:
struct S {
static var x: Int { return 2 }
static var x = "" // error: invalid redeclaration of 'x'
}
You can only 'overload' properties that are inherited from a protocol
extension.
protocol P {}
extension P {
static var x: Int { return 2 }
}
struct S: P {
static var x = ""
}
I am not exactly sure why this is allowed, but maybe someone from the Swift
team can help.
Best regards,
Toni_______________________________________________
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