[regression] Consuming C# component in C++ app results in non-compiling cppwinrt header

There problem with the generated source file in cppwinrt.exe

cppwinrt -input "C:\Program Files (x86)\Microsoft SDKs\Windows Kits\10\ExtensionSDKs\CppUnitTestFramework.Universal\16.0\References\CommonConfiguration\neutral\ Microsoft.VisualStudio.TestPlatform.TestExecutor.WinRTCore.winmd" -reference local -output "Generated Files""

The generated source file contains and cannot be compiled:

For instance
template<> struct hash<winrt::Microsoft::VisualStudio::TestPlatform::TestExecutor::WinRTCore::UnitTestClient> : winrt::impl::hash_base {};

Previous versions of cppwinrt.exe do not and compile successfully.

generated source file
"template<> struct hash<winrt::Microsoft::VisualStudio::TestPlatform::TestExecutor::WinRTCore::<CLR>UnitTestClient> : winrt::impl::hash_base {}; "

[asklar]

Seeing this too on a sample project; this seems pretty bad... @dragonbold which version of VS are you using? wondering if this might be a regression in VS 16.9 authoring of C# components.

Simple repro project: https://github.com/asklar/CLRImplRepro/

I binary-searched through the cppwinrt nugets and found that 2/25 is the 1st nuget where this regressed:
2.0.210225.3

The symptoms are the same.

I'm using Visual Studio 16.9.1.
I checked it here.

CppWinRT.2.0.210211.2　OK
CppWinRT.2.0.210225.3　NG

[kennykerr]

@DefaultRyan this looks like its related to the winmd reader change. If you're including non-WinRT types in the cache, then you need to tell cppwinrt to exclude them.

[DefaultRyan]

@DefaultRyan this looks like its related to the winmd reader change. If you're including non-WinRT types in the cache, then you need to tell cppwinrt to exclude them.

Taking a look at the repro project to confirm.

[DefaultRyan]

Confirmed that's the cause of the regression. Filed an issue on winmd and currently working on it. microsoft/winmd#17