由于AutoLayout，tableHeaderView中的UISearchController崩溃

Question

我正在学习UISearchController，很多例子表明你创建了一个UISearchController并将searchController.searchBar放在tableHeaderView中。所以我在我的代码中做了这个，它看起来没问题，直到我开始输入，然后转到详细视图，然后返回并且崩溃时出现以下错误：

*** Terminating app due to uncaught exception 'NSGenericException', reason: 'Unable to activate constraint with anchors <NSLayoutYAxisAnchor:0x61000007a780 "UIView:0x7f89e7f2df20.top"> and <NSLayoutYAxisAnchor:0x608000075dc0 "UINavigationBar:0x7f89e7c0cc10.bottom"> because they have no common ancestor.  Does the constraint or its anchors reference items in different view hierarchies?  That's illegal.'

我创建UISearchController的代码如下：

    let searchController = UISearchController(searchResultsController: nil)
    extendedLayoutIncludesOpaqueBars = true
    searchController.searchResultsUpdater = self
    searchController.dimsBackgroundDuringPresentation = false
    definesPresentationContext = true
    tableView.tableHeaderView = searchController.searchBar // remove and it works

如果我删除了最后一行tableView.tableHeaderView = searchController.searchBar，我不会遇到任何崩溃。有没有什么需要做才能让这个工作？我加了一个GIF动画来表明它失败了。