No longer working in Swift 1.2

gistfile1.swift

// In Swift 1.1, I can use "let sideshow : Sideshow!". In Swift 1.2 it has to be a var
// Is this due to the change:
// "In an initializer, constant properties can now only assign a value once." ?

class Main {
    var name : String
    let sideshow : ImplicitlyUnwrappedOptional<Sideshow>
    init (name : String, referenceName : String) {
        self.name = name
        self.sideshow = Sideshow(name: referenceName, ref: self)
    }
}
/* Errors:
main.swift:16:25: error: 'self' used before all stored properties are initialized
        self.sideshow = Sideshow(name: referenceName, ref: self)
                        ^
main.swift:13:9: note: 'self.sideshow' not initialized
    let sideshow : ImplicitlyUnwrappedOptional<Sideshow>
        ^
main.swift:16:60: error: variable 'self.sideshow' used before being initialized
        self.sideshow = Sideshow(name: referenceName, ref: self)
*/
class Sideshow {
    let reference : Main
    var name : String
    init (name: String, ref reference : Main) {
        self.name = name
        self.reference = reference
    }
}

As I understand the docs, it is a kind of chicken and egg problem*:
Sideshow relies on self, which isn't complete without sideshow, so one reference has to be a variable.
That is ugly, but it is much simpler for the compiler to enforce that only complete objects are passed around, instead of checking each use of half-backed objects for possible problems.
Just tried: It is really possible to do multiple assignments of a constant... that is a little bit odd, but as init is a special case, I could live with that.
I guess they sacrificed ease of use for consistency - didn't they introduce

let x: Int
if a {
    x = 1
} else {
    x = 2
}

in the same release?
Maybe the special handling of constants in init was changed because of that.

*Of course, the "chicken and egg"-problem was solved years ago:
Eggs are one of natures oldest inventions and predate chickens by millions of years; so it should be called the "chicken-and-chicken-egg"-problem actually...