Identity operators in Swift

Question

If a is identical to c, b is identical to c, why a is not identical to b?

var a = [1, 2, 3]
var b = a
var c = a[0...2]
a === c                    // true
b === c                    // true
a === b                    // false

If a, b, c are constants:

let a = [1, 2, 3]
let b = a
let c = a[0...2]
a === c                    // true
b === c                    // true
a === b                    // true

Answer 1

You can remove the import Cocoa or import UIKit if you are playing with PlayGround to make it correct. It seems there is some type map thing in the Cocoa framework to mess things up. It should be a bug, I think.