xcode - Swift "guard let"解包失败

Question

无法使用 Swift 2.2、Xcode 版本 7.3 (7D175) 解开可选类型

“守卫让”失败

但是“guard var”有效

请帮忙!这是怎么回事？

编辑1

    let localPresenter = presenter
    let localDataSource = dataSource
    let configurator: ViewControllerConfigurator = { inputView in
        let a = inputView as? ChatTableViewController
        guard var chatListController = a else {
            throw ApplicationErrors.ModuleConfigureError.WrongViewInput
        }
        localPresenter.view = chatListController
        chatListController.presenter = localPresenter
        chatListController.tableView.dataSource = localDataSource
    }

编辑2此代码运行良好:

        let localPresenter = presenter
        let localDataSource = dataSource
        let configurator: ViewControllerConfigurator = { inputView in
            let a = inputView as? ChatTableViewController
            if let chatListController = a {
                localPresenter.view = chatListController
                chatListController.presenter = localPresenter
                chatListController.tableView.dataSource = localDataSource
            } else {
                throw ApplicationErrors.ModuleConfigureError.WrongViewInput
            }
        }

Answer 1

看起来这是 lldb 中的一个错误。如果我在带有“guard”的行上设置断点，则“guard”失败:

但是如果我将此断点移过保护 block ，则代码可以正常工作: