NSInternalInconsistencyException error from collectionView in swift

Question

Hi I have two different cell(it may be 6-7 in the future) I return them by some case in cellForItem method of collection view but I got this error(the cell returned from -collectionView:cellForItemAtIndexPath: does not have a reuseIdentifier - cells must be retrieved by calling)

Here is my codes.

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if let idx = viewModel?.component?.firstIndex(where: { $0.type == .summary }) {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: SummaryCollectionViewCell.identifier, for: indexPath) as? SummaryCollectionViewCell else { return UICollectionViewCell() }
        if let summaryData = viewModel?.component?[idx].dataModel as? SummaryData {
            let summaryViewModel = SummaryCollectionViewCellViewModel(summaryData: summaryData)
            cell.configure(with: summaryViewModel)
        }
    } else if let idx = viewModel?.component?.firstIndex(where: { $0.type == .merchant }) {
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: MerchantCollectionViewCell.identifier, for: indexPath) as? MerchantCollectionViewCell else { return UICollectionViewCell() }
        if let merchantData = viewModel?.component?[idx].dataModel as? MerchantData {
            let merchantViewModel = MerchantCollectionViewCellViewModel(merchantData: merchantData)
            cell.configure(with: merchantViewModel)
        }
    }
    
    return UICollectionViewCell()
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 2
}

Answer 1

It is legal to say

return UICollectionViewCell()

in order to quiet the compiler, but it is illegal to execute it. You are executing it, because neither wing of your condition is returning a cell .

You are saying let cell = in both wings, but then you just throw cell away! You never say return cell . You must dequeue a cell, configure it, and return it . Do not return some other cell; return the cell you dequeued and configured, namely cell .