NuGet: 2.0.200921.6 release that introduced "C++20 coroutine support", still specifies /await in Microsoft.Windows.CppWinRT.targets file

[AlexBAV]

Latest release that introduced "C++20 coroutine support" still forces old behavior by having /await option in Microsoft.Windows.CppWinRT.targets file in NuGet package.

[kennykerr]

Yes, I noticed this:

cppwinrt/nuget/Microsoft.Windows.CppWinRT.props

Line 32 in fa6bb7a

<LanguageStandard Condition="'%(ClCompile.LanguageStandard)' == ''">stdcpp17</LanguageStandard>

Which I assume is forcing something, but it would be up to @jlaanstra or @Scottj1s or someone with good msbuild skills to contribute a PR to fix that.

[jlaanstra]

I suppose we want to only set /await it when the language version is C++ 17?

[kennykerr]

The /await flag is not the issue. The msbuild files seem to force C++17. The project templates must default to C++17, but must not prevent it from being changed (to something newer). That seems to be the problem - a developer cannot change it for their project.

[jlaanstra]

@kennykerr The line you mentioned only sets the LanguageStandard if it's not already specified and does so in the props file so the value in the project file always will always override it.

[kennykerr]

That's good to know. I thought the /await flag would be ignored by C++20 but if that's the issue it seems harmless to remove it by default. Developers using C++17 can always add it if they need to. I did confirm that /await forces VC to use the C++17 version of coroutines even when compiling for C++20. As it stands, there doesn't appear to be a way to override this as the cppwinrt.targets file appears to force the inclusion of /await.

[jlaanstra]

I'll submit a PR to fix this.

[kennykerr]

Thanks for your patience. I've fixed the msbuild issue and published another version of the nuget package that includes the fix: 2.0.201006.7

[AlexBAV]

I can confirm the latest version of NuGet package works correctly in standard-compliant mode. Excellent work @kennykerr and team!

Thank you!

[Zingam]

@kennykerr
Can I assume this was not included in Windows 10 SDK 10.0.19041.0 and Visual Studio 16.8.3?
I started a new UWP CMake 3.18 generated project.