Private func in swift are hidden from the ObjC runtime

gistfile1.txt

import Foundation

class Testing : NSObject
{
    private func privateWork() {
    }
    
    internal func internalWork(){
    }
    
    func check(){
        self.respondsToSelector(Selector("privateWork"))    //false
        self.respondsToSelector(Selector("internalWork"))   //true
    }
}

let t = Testing()
t.check()

@oleganza: I think Swift reserves the right to inline the private func. Much like the old JVM, it reserves the right to do lots of optimizations by enforcing rules.

@objc private func privateWork() - Now you get true//true, because it had to make a dynamically dispatched version which performSelector can see... just something to keep in mind.