Same-named argument and tuple labels?

Using Swift
11

@Slava_Pestov, thanks for the clarification. Can you also say whether the same-named argument and tuple labels as exemplified in the OP is a bug or not?

That is, should the following program compile (as it currently does):

func f(x a: Int, x b: Int) -> (y: Int, y: Int) {
    return (a, b)
}
print(f(x: 1, x: 2)) // prints (y: 1, y: 2)

?
(Note that x and y are used twice, producing same named argument and tuple labels.)

(I did report the single element tuple expression bug (not related to this thread) as SR-8109.)