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Summary:
I have a UIViewController subclass that I'm trying to override traitCollectionDidChange(previousTraitCollection:) on and I can't because the compiler tells me that UITraitCollection is only available in iOS 8.0 and above. It gives me a Fix-It which adds the @available attribute to the method but then the compiler gives me an error saying "Overriding 'traitCollectionDidChange' must be as available as declaration it overrides". I believe this is because the UITraitEnvironment protocol has no @available attribute on it in the headers.

Steps to Reproduce:
1. Create a new Swift ios project with a deployment target of 7.0
2. Try to override the traitCollectionDidChange() method of the ViewController:

    @available(iOS 8.0, *)
    override func traitCollectionDidChange(previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)
    }

Expected Results:
I expected to be able to compile and run the application and for the app to be able to respond to traitCollection changes.

Actual Results:
Compiler error: "Overriding 'traitCollectionDidChange' must be as available as declaration it overrides."

Version:
Xcode Version 7.0 beta 3 (7A152u)
OSX 10.10.3

Configuration:
An ios project (Swift 2.0) with a deployment target of 7.0 and base SDK of 9.0