swift method argument names are weird with blocks

gistfile1.swift

import Foundation

class Thing {
    func doStuff(stuff:String) {
    }
    
    func doStuffWithAThing(stuff:String, athing:String) {
    }
    
    func doStuffWithTwoThings(stuff:String, thingOne:String, thingTwo:String) {
    }
    
    func doStuffWithThreeThings(stuff:String, thingOne:String, thingTwo:String, thingThree:String) {
    }
    
    func getStuff(success:()->()) {
    }
    
    func getStuffOrFail(success:()->(), failure:()->()) {
    }
    
    func getStuffOfFailWithThing(thing:String, success:()->(), failure:()->()) {
    }
    
    func getStuffOfFailWithThingAndFinally(thing:String, success:()->(), failure:()->(), finally:()->()) {
    }
}


let t = Thing()

// unnamed first arguement is fine
t.doStuff("")
t.doStuffWithAThing("", athing: "")
t.doStuffWithTwoThings("", thingOne: "", thingTwo: "")
t.doStuffWithThreeThings("", thingOne: "", thingTwo: "", thingThree: "")


// but with blocks, the last argument looses its name, sometimes.

t.getStuff { () -> () in
    // first argument doesn't require name, fine
    assert(true, "")
}


t.getStuffOrFail({ () -> () in
    // first argument doesn't require name, fine
    assert(true, "")
    }, failure: { () -> () in
        // second arguement requires name, great!
        assert(true, "")
})


t.getStuffOfFailWithThing("athing", success: { () -> () in
    assert(true, "")
    // second arguement requires name, great!
}) { () -> () in
    // wot. where did the failure: go ?!
    assert(true, "")
}

t.getStuffOfFailWithThingAndFinally("athing", success: { () -> () in
    assert(true, "")
    // second arguement requires name, great!
    }, failure: { () -> () in
        assert(true, "")
        // third arguement now requires a name, okaaaaay
}) { () -> () in
    // uh huh. so if the last argument is a block, and you have more than two arguments, it looses its name.
    assert(true, "")
}