c# – VS2017调试元组任务时出错

repro只是创建一个新的WPF应用程序,添加System.ValueTuple,将此代码添加到MainWindow.xaml.cs,然后使用“return”在两行设置断点.

using System.Threading.Tasks;
using System.Windows;

namespace WpfApp2
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private async void Button_Click(object sender,RoutedEventArgs e)
        {
            var task1 = TaskWithLocalDebugInfo();
            var task2 = TaskWithoutLocalDebugInfo();
        }

        private async Task<bool> TaskWithLocalDebugInfo()
        {
            var viewableInLocalWindowAndHover = true;
            return viewableInLocalWindowAndHover;
        }

        private async Task<(bool,bool)> TaskWithoutLocalDebugInfo()
        {
            var notViewableInLocalWindowAndHover = true;
            return (notViewableInLocalWindowAndHover,notViewableInLocalWindowAndHover);
        }
    }
}

编辑：如果我添加不可查看的局部变量来监视,我得到：错误CS8182：预定义类型’ValueTuple`2’必须是结构.