Visual Studio design time build failing to recognize essential types like Void, IDisposable, Enum in test code

[carlossanlop]

@ViktorHofer

It seems a recent change broke design time build for test code in Visual Studio. Not sure if widespread or not, but I can repro this in System.Formats.Tar:

• Sync your local clone to the latest bits in main.
• Clean with git clean -fdx.
• Build with build.cmd clr+libs -rc release.
• Open the solution with build.cmd -vs System.Formats.Tar.
• Open any test file.
• Notice the red squiggle error messages, they say we cannot find System.Void, System.IDisposable, System.Enum.

[ghost]

Tagging subscribers to this area: @dotnet/area-infrastructure-libraries
See info in area-owners.md if you want to be subscribed.

Issue Details

---

@ViktorHofer

It seems a recent change broke design time build for test code in Visual Studio. Not sure if widespread or not, but I can repro this in System.Formats.Tar:

• Sync your local clone to the latest bits in main
• Build with build.cmd clr+libs -rc release
• Open the solution with build.cmd -vs System.Formats.Tar
• Open any test file.
• Notice the red squiggle error messages, they say we cannot find System.Void, System.IDisposable, System.Enum.

Author:	carlossanlop
Assignees:	-
Labels:	area-Infrastructure-libraries
Milestone:	-

[ViktorHofer]

That's because you have a ProjectReference to the source project even though the source assembly is already referenced as part of the live built microsoft.netcore.app.ref targeting pack:

runtime/src/libraries/System.Formats.Tar/tests/System.Formats.Tar.Tests.csproj

Lines 69 to 71 in 5992145

	<ItemGroup>
	<ProjectReference Include="..\src\System.Formats.Tar.csproj" />
	</ItemGroup>

When you remove that ProjectReference, the design time build failures go away. You can see in the design time binlog that the reference assembly is chosen from the ProjectReference's output folder:

[carlossanlop]

Thanks, that fixed it.

[ViktorHofer]

cc @ericstj as you might be interested in this. Seems there is a conflict between P2Ps when the assembly is also exposed inbox (via the targeting pack).

[ericstj]

yeah, that's not handled well in the SDK: dotnet/sdk#2674

It might be nice if our infrastructure did some validation around what sort of reference to use where. Guide people down the path of doing the right thing.

[ViktorHofer]

It might be nice if our infrastructure did some validation around what sort of reference to use where. Guide people down the path of doing the right thing.

This already works for a normal build because of

runtime/eng/targetingpacks.targets

Line 131 in 3116f28

<_targetingPackReferenceExclusion Include="@(_ResolvedProjectReferencePaths->Metadata('Filename'))" />

It might make more sense to investigate why this doesn't work for a design time build.