[swift-users] Law of Exclusivity runtime false positive?

[David Hart]

Hello,

In Xcode 9 beta 4, Swift 4, I’m getting runtime errors popping up for Simultaneous accesses and I think they may be false negatives. Here’s a stripped down version of my code:

class MyButton: UIButton {
	fileprivate var imageRect: CGRect = .zero
	fileprivate var titleRect: CGRect = .zero

        func updateRects() {
            if imageBeforeTitle {
                layoutHorizontally(leftRect: &imageRect, rightRect: &titleRect)
            } else {
                layoutHorizontally(leftRect: &titleRect, rightRect: &imageRect)
            }
        }

        func layoutHorizontally(leftRect: inout CGRect, rightRect: inout CGRect) {
            leftRect.origin.x = padding
            rightRect.origin.x = leftRect.maxX + spacing
        }
}

While the layoutHorizontally method has two CGRect inout parameters, never in my code do I pass the same CGRect. Any ideas if this is a bug I should post on bugs.swift.org or if I’m missing something?

David.
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