Generator message is unhelpful when syntax invalid (.Net 6, preview 2)

[Webreaper]

I've got some code like this:

    <a href="/image/@prevImage.ImageId" />

Which works fine. If I change it to a NavLink like this:

    <NavLink href="/image/@prevImage.ImageId" />

I get a cogent error message in .Net 5.0:

RAZORGENERATE : error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'href', text: ....

This is expected, as you don't support mixed attributes with C# and markup yet.

However, in .Net 6 preview 2, if I make the same change, I get:

CSC : warning CS8785: Generator 'RazorSourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'AggregateException' with message 'One or more errors occurred. (Specified argument was out of the range of valid values.
Done building target "CoreCompile" in project "Damselfly.Web.csproj".

...

/Users/markotway/LocalCloud/Development/Damselfly/Damselfly.Web/Pages/_Host.cshtml(24,43,24,46): error CS0246: The type or namespace name 'App' could not be found (are you missing a using directive or an assembly reference?)

(the second 'type or namespace could not be found' error is a knock-on error from the auto-generator failing earlier, but is completely confusing).

I think this may be a regression from this issue: dotnet/roslyn#46084 (fixed here: dotnet/roslyn#46804) or may be the new .Net 6 Blazor autogenerators not having exception errors generated correctly. Either way, it's unhelpful and makes it hard to understand which code change caused the breakage.

Target framework: .Net 6.0-preview-2 (x64 using Rosetta 2, not the Arm64 version)
Operating system: osx-arm64 11.3 beta running on a MacBook Pro M1
IDE: Visual Studio for Mac v8.9 (build 409)

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[mkArtakMSFT]

Thanks for contacting us. This may have been already fixed in 6.0-preview3. Do you mind trying it out and getting back to us if that is still broken? Thanks!

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