C2370 error compiling codegen as static_class_data is forward-declared as extern const in headers, but defines as extern constexpr in cpp files about react-native-winrt HOT 6 CLOSED

I didnt notice this on the index.md, but I would think this should be added to WinRTTurboModule.props or targets to reduce a setup step for consumers

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The same inconsistency applies to static_enum_data and others too.

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MSVC is non-conforming by default. You have to compile with /Zc:externConstexpr.

More info here. The TL;DR is that constexpr is only useful/applies to definitions. The problem is that MSVC infers constexpr as internal linkage, even though that conflicts with the standard.

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this should be added to WinRTTurboModule.props or targets

Seems reasonable

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Actually, /Zc:externConstexpr isn't quite enough it seems. It resolves the constexpr const problem, but <ConformanceMode>true</ConformanceMode> is needed to workaround another issues when building vector_concat where the use of IVector and IVectorView are resolved against the namespaces of those names in base.h despite the local using namespace winrt::Windows::Foundation::Collections

Edit: Now that I have it building, I see the binary size drop from 3774 KiB -> 1729 KiB for the same config - great work on the optimizations!

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Oh, interesting. I hadn't realized that we took a dependency on proper two phase name lookup, but it's been a while since I last tried without it. Should be simple enough to add to the props file as well.

And awesome to hear about the size reduction!

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