Apple is handling a lot of accessibility features automatically for us when we use UIKit components like UITableView's and UICollectionView's.
Though I've noticed it doesn't work out of the box when you try a design like the App Store app, with a UICollectionView embedded in a UITableView.

When using VoiceOver, you will not be able to go through all items of your UICollectionView. Here's a video presenting the problem 👇

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VoiceOver stops at cells #2

To fix this issue, there's one weird trick. Simply subclass UICollectionView:

class AccessibleCollectionView: UICollectionView {
	override func accessibilityElementCount() -> Int {
		guard let dataSource = dataSource else {
			return 0
		}

		return dataSource.collectionView(self, numberOfItemsInSection: 0)
	}
}

or for supporting UICollectionView's with several sections:

class AccessibleCollectionView: UICollectionView {
	override func accessibilityElementCount() -> Int {
		guard let dataSource = dataSource else {
			return 0
		}

		let numberOfSections = dataSource.numberOfSections?(in: self) ?? 1
		var count = 0

		for section in 0..<numberOfSections {
			count += dataSource.collectionView(self, numberOfItemsInSection: section)
		}

		return count
	}
}

And... tadaaaa 🎉

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VoiceOver navigates til the end