Question about typeof().Guid

[kant2002]

When implementing tests I have approximate code

[ComImport]
[ComVisible(true)]
[Guid("D6DD68D1-86FD-4332-8666-9ABEDEA2D24C")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IComInterface
{
    void DoWork();
}

////

internal static Guid IComInterface_GUID = typeof(IComInterface).GUID;

This throws

Unhandled Exception: System.TypeInitializationException: A type initializer threw an exception. To determine which type, inspect the InnerException's StackTrace property.
 ---> System.Reflection.MissingMetadataException: 'PInvokeTests.IComInterface' is missing metadata. For more information, please visit http://go.microsoft.com/fwlink/?LinkID=392859
   at System.Reflection.Runtime.TypeInfos.RuntimeBlockedTypeInfo.get_GUID() + 0x42

I was not expecting that this cause any issues. Especially that I have that pattern in other project. Do tests have more aggressive NativeAOT settings then defaults?

[jkotas]

Yes, the tests have more restrictive reflection settings than the default.

[kant2002]

I understand that in general sense it is not possible to have typeof(XXX).GUID properly working, but can compiler ensure that if typeof operates on the well-known type which explicitly has GuidAttribute set, then this expression would be precomputed?

[jkotas]

@MichalStrehovsky ?

[MichalStrehovsky]

at System.Reflection.Runtime.TypeInfos.RuntimeBlockedTypeInfo.get_GUID()

RuntimeBlockedTypeInfo means that reflection blocking is active. The pinvoke test opts into that for its main assembly:

runtimelab/src/tests/nativeaot/SmokeTests/PInvoke/PInvoke.cs

Lines 15 to 20 in b1b2410

	// Make sure the interop data are present even without reflection
	namespace System.Runtime.CompilerServices
	{
	[AttributeUsage(AttributeTargets.All)]
	internal class __BlockAllReflectionAttribute : Attribute { }
	}

If you need to do reflection-y things, you either need to add another assembly to the pinvoke test (the attribute is applicable per assembly), or just add a new test.

I understand that in general sense it is not possible to have typeof(XXX).GUID properly working

I think in the general sense this should just work. The problem is opting into reflection blocking. We do that as a size optimization for some of the System.Private assemblies only. ...and in this test.

[jkotas]

I think it would be nice to just avoid reflection-y things for the ComWrappers test.