你好，我不是Swift开发人员，我只是从GitHub克隆存储库，在我更新Xcode版本和Swift之前，它一直在工作。我在这里寻求帮助，这是代码，我收到的构建错误说
编译器无法在合理的时间内对此表达式进行类型检查;尝试将表达式分解为不同的子表达式
是位于几个地方，我我只是不知道如何解决它.我在网上看到的问题是太难表达的代码和许多操作在一次.代码需要简化，但idk如何做到这一点在swift.任何帮助将是受欢迎的存储库是死的，所有者没有在线一年.
返回表达式|representedElements + cells.flatMap { group -> [UICollectionViewLayoutAttributes] in出错！x编译器无法在合理的时间内对该表达式进行类型检查;尝试将表达式分解为不同的子表达式

return representedElements + cells.flatMap { group -> [UICollectionViewLayoutAttributes] in
            guard let section = group.first?.indexPath.section else {
                return group
            }
            let evaluatedSectionInset = evaluatedSectionInsetForSection(at: section)
            let evaluatedMinimumInteritemSpacing = evaluatedMinimumInteritemSpacingForSection(at: section)
            var origin = (collectionView.bounds.width + evaluatedSectionInset.left - evaluatedSectionInset.right - group.reduce(0, { $0 + $1.frame.size.width }) - CGFloat(group.count - 1) * evaluatedMinimumInteritemSpacing) / 2
            // we reposition each element of a group
            return group.map {
                $0.frame.origin.x = origin
                origin += $0.frame.size.width + evaluatedMinimumInteritemSpacing
                return $0
            }
        }
    } else {
        for layoutAttributes in layoutAttributesForElements {
            guard layoutAttributes.representedElementKind == nil else {
                representedElements.append(layoutAttributes)
                continue
            }
            // copying is required to avoid "UICollectionViewFlowLayout cache mismatched frame"
            let currentItemAttributes = layoutAttributes.copy() as! UICollectionViewLayoutAttributes
            // if the current frame, once stretched to the full column doesn't intersect the previous frame then they are on different columns
            if previousFrame != nil && !currentItemAttributes.frame.intersects(CGRect(x: previousFrame!.origin.x, y: -.greatestFiniteMagnitude, width: previousFrame!.size.width, height: .infinity)) {
                cells.append([])
            }
            cells[cells.endIndex - 1].append(currentItemAttributes)
            previousFrame = currentItemAttributes.frame
        }
        // we reposition all elements
        return representedElements + cells.flatMap { group -> [UICollectionViewLayoutAttributes] in
            guard let section = group.first?.indexPath.section else {
                return group
            }
            let evaluatedSectionInset = evaluatedSectionInsetForSection(at: section)
            let evaluatedMinimumInteritemSpacing = evaluatedMinimumInteritemSpacingForSection(at: section)
            var origin = (collectionView.bounds.height + evaluatedSectionInset.top - evaluatedSectionInset.bottom - group.reduce(0, { $0 + $1.frame.size.height }) - CGFloat(group.count - 1) * evaluatedMinimumInteritemSpacing) / 2
            // we reposition each element of a group
            return group.map {
                $0.frame.origin.y = origin
                origin += $0.frame.size.height + evaluatedMinimumInteritemSpacing
                return $0
            }
        }
    }