gistfile1.swift

protocol BaseCommandProtocol {
    func requestComplete()
}

extension BaseCommandProtocol {
    func requestComplete() {
        // For subclasser overrides
        print("You should override this")
    }
}

class BaseCommand: BaseCommandProtocol {
}

class GetAccountSettingsCommand: BaseCommand {
    func requestComplete() {
        print("This is not called")
    }
}

let x: BaseCommandProtocol = GetAccountSettingsCommand()

// How do I make this call the method on GetAccountSettingsCommand instead of the default implementation from the protocol extension?
x.requestComplete()