class A { }

let obj = A()

let array: [AnyObject] = [obj]

func isType<T, U>(x: T, type: U.Type) -> Bool {
    if let x = x as? U {
        return true
    } else {
        return false
    }
}

// This works
if let array = array as? [A] {
    println(true)
}

// This works
println(isType(obj, A.self))

// This doesn't
println(isType(array, [A].self))