CA2252 warnings with .NET 7 RC1 SDK

Version Used: .NET 7 RC1 SDK

Steps to Reproduce:

1. Clone the .NET Community Toolkit at https://github.com/CommunityToolkit/dotnet/commit/338172af682a5910ca33962211be1751d0dd2008
2. Run dotnet build on the solution

Expected Behavior:

The solution should build fine like it did up until now.

Actual Behavior:

A whole bunch of CA2252 warnings from the CommunityToolkit.HighPerformance.UnitTests project. This is using a bunch of types from CommunityToolkit.HighPerformance that are marked as [RequiresPreviewFeatures], but the test project using it is using <EnablePreviewFeatures> in the .csproj, so I’m not really sure why with the .NET 7 SDK this is causing issues.

Failing CI run: https://dev.azure.com/dotnet/CommunityToolkit/_build/results?buildId=78431&view=results.

cc. @333fred

[jeffhandley]

Ah, you’re right @Youssef1313!

The key section is here: https://github.com/dotnet/designs/blob/main/accepted/2021/preview-features/preview-features.md#meaning-of-property-in-multi-targeted-projects

This design detail was intended to handle scenarios around preview features that ship as part of the .NET SDK. The reported issue here does not involve .NET SDK preview feature, but the logic gets applied nonetheless.

The workarounds are to either target net7.0 or use the .NET 6 SDK. We should consider updating that logic to avoid this pitfall, but I think that would be out of scope for .NET 7 at this point.

[Youssef1313]

I guess https://github.com/dotnet/designs/pull/232 explains it. It looks by-design?