Set AnyCPU for ProjectReference to source generators

[huoyaoyuan]

The source generators are built with AnyCPU. When opening CoreLib in Visual Studio, it tries to load source generators from platform dependent path since CoreLib is platform dependent, and the generators are not in the solution.

An alternative approach is to include them in corelib.sln.

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[ViktorHofer]

Before merging we should double check that this doesn't cause double writes or overbuilds. Also cc @ericstj

[am11]

Should we also set it for

runtime/src/libraries/System.Private.CoreLib/gen/System.Private.CoreLib.Generators.csproj

Line 5 in 18bc115

</PropertyGroup>

?

[AaronRobinsonMSFT]

/cc @jkoritzinsky

[huoyaoyuan]

Before merging we should double check that this doesn't cause double writes or overbuilds.

Any instruction to decide this? Inspecting a binlog from full build?

[ViktorHofer]

The only projects that need this are the ones that set a platform that isn't AnyCPU, right? If so then I think it would be better to tell those projects to not flow the platform to referenced projects.

AFAIK that's the property that handles this: https://github.com/dotnet/msbuild/blob/c028e44472dde6a62689a1378d3ee649f903275a/src/Tasks/AssignProjectConfiguration.cs#L120-L125

VS defaults this to true but we already set it to false in runtime:

runtime/Directory.Build.props

Line 14 in b112eac

<!-- Propagate the configuration and platform to project references. When building in VS, this defaults to true.

Any idea why the platform still gets propagated? And yes, the corelib solution files need to be closure complete (meaning that all project references need to be part of the solution file).

[huoyaoyuan]

Any idea why the platform still gets propagated?

This answered why it worked fine for me previously. The setting was lifted from libraries in #91873 and became applicable to corelib. It seems that the purpose was to unset Configuration. /cc @vitek-karas

And yes, the corelib solution files need to be closure complete (meaning that all project references need to be part of the solution file).

This may also solve the problem in VS. Not sure whether we still need the SetPlatform, but ensuring generators are always AnyCPU looks more correct.

[ViktorHofer]

Closing in favor of #104561. Thanks for your contribution anyway.