Swift 2, Extensions and Call Answers

Question

I'm not sure, it seems to me that this is some kind of error or poor implementation with protocol extensions in Swift 2.0.

I have protocol A, protocol b extending protocol A, and implementing methods in extending protocol B.

I matched the class instance to match protocol B, however, when checking with the responsesToSelector method for protocolA / B methods, the results were false.

import Cocoa import XCPlayground protocol ProtocolA : NSObjectProtocol { func functionA() } protocol ProtocolB : ProtocolA { func functionB() } extension ProtocolB { func functionA() { print("Passed functionA") } func functionB() { print("Passed functionB") } } class TestClass : NSObject, ProtocolB { override init () { } } var instance:TestClass = TestClass() instance.functionA() // Calls code OK.. if instance.respondsToSelector("functionA") { print("Responds to functionA") // **False, never passing here** } if instance.respondsToSelector("functionB") { print("Responds to functionB") // **False, never passing here** } 

Should be listed as an error?

Answer 1

Interesting. Looks like me. It recognizes class functions, but not extensions. Regardless of instance type. Moreover, the extension code will not compile, since protocol methods are not optional. So does a bug / feature really look like? in response to the implementation of the selector.