Swift is highly inspired by Standard ML. If you look at https://en.wikipedia.org/wiki/Standard_ML, you can see the similarities:

    fun dist ((x0, y0), (x1, y1)) = let
      val dx = x1 - x0
      val dy = y1 - y0
      in
        Math.sqrt (dx * dx + dy * dy)
      end

Because of that, it also has its exponential time complexity (see for example http://spacemanaki.com/blog/2014/08/04/Just-LOOK-at-the-humo...)

What makes things especially bad for Swift seems to be that it has function overloading and uses lots of it in its standard library, as that increases the constants in the exponentiation (for example, with 6 choices to make and 10 vs 2 possible overloads per decision point you get 10^6 = a million versus 2^6 = 64 options to consider)