CODEWITHSUNDEEP
swiftprotocolsswift2protocol-extension
bogen
bogen

Reputation: 10422

How to call static methods on a protocol if they are defined in a protocol extension?

protocol Car {
    static func foo() 
}

struct Truck : Car {

}

extension Car {
    static func foo() {
        print("bar")
    }
}

Car.foo() // Does not work  
// Error: Car does not have a member named foo

Truck.foo() // Works

Xcode autocompletes the Car.foo() correctly, so what i'm asking is if its a bug that it doesn't compile (says it does not have a member named foo()). Could you call static methods directly on the protocol if they are defined in a protocol extension?

Upvotes: 12

Views: 6445

Answers (2)

Jeffery Thomas
Jeffery Thomas

Reputation: 42588

No, the error message isn't good, but it's telling you the correct thing.

Think of it this way, you can't have

protocol Car {
    static func foo() {
        print("bar")
    }
}

This compiles with the error "Protocol methods may not have bodies".

Protocol extensions don't add abilities to protocols which don't exist.

Upvotes: 1

Tikhonov Aleksandr
Tikhonov Aleksandr

Reputation: 14319

Apple doc

Protocols do not actually implement any functionality themselves. Nonetheless, any protocol you create will become a fully-fledged type for use in your code.

Therefore, you cannot call static methods directly of protocol.

Upvotes: 9

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