Tuple lambda语法突然在C＃中不起作用

Question

我正在使用.NET Framework 4.7，我已经实现了几种这样的语法

Task<(bool isSuccess, string message)> DownloadFileResource()

并且已经可以通过var达到结果而工作了>

var downloadResult = await BlobUtils.DownloadFileResource()
但是今天当我打开Visual Studio时，我的所有var都转换为dynamic类型，这是IDE的建议，不再是(bool isSuccess, string message)，并且在运行它时抛出错误

 Microsoft.CSharp.RuntimeBinder.RuntimeBinderException:
 'System.ValueTuple<bool,string>' does not contain a definition for > 'isSuccess'
    at CallSite.Target(Closure , CallSite , Object )
    at System.Dynamic.UpdateDelegates.UpdateAndExecute1[T0,TRet](CallSite  site, T0 arg0)
    at DataUnitCrawler.MainFormV3.<DownloadFileResource>d__10.MoveNext() in D:\Gannha\GannhaDesktopApp\DataUnitCrawler\MainFormV3.cs:line 97
 --- End of stack trace from previous location where exception was thrown ---
 at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
 at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
 at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() 
 at DataUnitCrawler.MainFormV3.<<-ctor>b__9_1>d.MoveNext() in D:\Gannha\GannhaDesktopApp\DataUnitCrawler\MainFormV3.cs:line 86
 --- End of stack trace from previous location where exception was thrown ---
 at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.<ThrowAsync>b__6_0(Object state)


************** Loaded Assemblies ************** mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
---------------------------------------- DataUnitCrawler
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/DataUnitCrawler.exe
---------------------------------------- System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
---------------------------------------- System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4001.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
---------------------------------------- System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
---------------------------------------- System.Data
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/System.Data/v4.0_4.0.0.0__b77a5c561934e089/System.Data.dll
---------------------------------------- System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
---------------------------------------- System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
---------------------------------------- DataUtility
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/DataUtility.DLL
---------------------------------------- Microsoft.WindowsAzure.Storage
    Assembly Version: 9.3.2.0
    Win32 Version: 9.3.2.0
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/Microsoft.WindowsAzure.Storage.DLL
---------------------------------------- Microsoft.CSharp
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.CSharp/v4.0_4.0.0.0__b03f5f7f11d50a3a/Microsoft.CSharp.dll
---------------------------------------- System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
---------------------------------------- Newtonsoft.Json
    Assembly Version: 12.0.0.0
    Win32 Version: 12.0.1.22727
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/Newtonsoft.Json.DLL
---------------------------------------- System.Numerics
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Numerics/v4.0_4.0.0.0__b77a5c561934e089/System.Numerics.dll
---------------------------------------- System.Runtime.Serialization
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Serialization/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Serialization.dll
---------------------------------------- System.Dynamic
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Dynamic/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Dynamic.dll
---------------------------------------- Anonymously Hosted DynamicMethods Assembly
    Assembly Version: 0.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_32/mscorlib/v4.0_4.0.0.0__b77a5c561934e089/mscorlib.dll
---------------------------------------- NLog
    Assembly Version: 4.0.0.0
    Win32 Version: 4.5.11.8645
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/NLog.DLL
---------------------------------------- NLog.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.2.3.167
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/NLog.Windows.Forms.DLL
---------------------------------------- System.ServiceModel
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4121.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.ServiceModel/v4.0_4.0.0.0__b77a5c561934e089/System.ServiceModel.dll
---------------------------------------- Microsoft.Azure.Storage.Blob
    Assembly Version: 11.1.1.0
    Win32 Version: 11.1.1
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/Microsoft.Azure.Storage.Blob.DLL
---------------------------------------- Microsoft.Azure.Storage.Common
    Assembly Version: 11.1.1.0
    Win32 Version: 11.1.1.0
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/Microsoft.Azure.Storage.Common.DLL
---------------------------------------- System.Net.Http
    Assembly Version: 4.2.0.0
    Win32 Version: 4.6.26011.01
    CodeBase: file:///D:/Gannha/GannhaDesktopApp/DataUnitCrawler/bin/Debug/System.Net.Http.DLL
----------------------------------------

************** JIT Debugging ************** To enable just-in-time (JIT) debugging, the .config file for this application or computer
(machine.config) must have the jitDebugging value set in the
system.windows.forms section. The application must also be compiled
with debugging enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" /> </configuration>

When JIT debugging is enabled, any unhandled exception will be sent to
the JIT debugger registered on the computer rather than be handled by
this dialog box.
[当我放置断点时，它们显示item1，item2而不是isSuccess，message

我通过明确声明进行了测试，它是否有效？非常困惑

总之，问题是我已经使用ValueTuple函数类型语法的(bool isSuccess, string message)很长时间了，并且通常在var中得到值。 var知道期望的类型，直到今天它才带有dynamic类型，并且不包含所有isSuccess，message属性。

更短：我所期望的：（我在.Net Core 2.1中进行了测试）

IDE的作用：

如何解决？是个错误吗？

我正在使用.NET Framework 4.7，我已经实现了一些类似于Task DownloadFileResource（）的语法，并且已经可以通过使用...

Answer 1

Answer 2