Swift 1.2 redeclares Objective-C method

I just updated from swift 1.1 to swift 1.2 and get compiler Error:

Method 'setVacation' redeclares Objective-C method 'setVacation:'

Here some code:

var vacation : Vacation?  
func setVacation(_vacation : Vacation)
{...}

But I need call setVacation

Is any suggestions how fix this?

This is cause by the change stated in Xcode 6.3beta release notes:

Swift now detects discrepancies between overloading and overriding in the Swift type system and the effective behavior seen via the Objective-C runtime. (18391046, 18383574) For example, the following conflict between the Objective-C setter for “property” in a class and the method “setProperty” in its extension is now diagnosed:

 class A : NSObject {
     var property: String = "Hello" // note: Objective-C method 'setProperty:’
                                    // previously declared by setter for
                                    // 'property’ here
 }
 extension A {
     func setProperty(str: String) { } // error: method ‘setProperty’
                                       // redeclares Objective-C method
                                       //'setProperty:’
 }

To fix this you need to make all you method signatures unique (as Objective-C does not provide method overload)

Or don't inherit from NSObject if you need Swift only class.