環境

iPhone 11 Pro Max
iOS13.0
Xcode11.1 GM

原因

タイトルそのまま

エラーログ

error.log

*** Terminating app due to uncaught exception 'SKUnsupportedClassException', reason: 'SKStoreProductViewController may not be subclassed.'

対応

継承したクラスの削除
呼び出し処理の追記

SampleViewController.swift

internal final class SampleViewController {
    internal func openStoreProduct() {
        let storeProductViewController = SKStoreProductViewController()
        storeProductViewController.delegate = self

        // StoreのIDを追記
        let parameters = [SKStoreProductParameterITunesItemIdentifier: 000000];
        storeProductViewController.loadProduct(withParameters: parameters) { [weak self] status, error -> Void in
            guard let self = self else { return }
            if status {
                self.present(storeProductViewController, animated: true) { [weak self] in
                    // 閉じた時の処理
                }
            } else {
                if let error = error {
                    print("Error: \(error.localizedDescription)")
                }
            }
        }
    }
}

extension SampleViewController: SKStoreProductViewControllerDelegate {
    internal func productViewControllerDidFinish(_ viewController: SKStoreProductViewController) {
        viewController.dismiss(animated: true, completion: nil)
    }
}