Compiler crashing issues reported through internal telemetry

[mkArtakMSFT]

Internal Error - System.ArgumentException: startCommentStar at Microsoft.AspNetCore.Razor.Language.Syntax.InternalSyntax.SyntaxFactory.RazorCommentBlock(SyntaxToken startCommentTransition, SyntaxToken startCommentStar, SyntaxToken comment, SyntaxToken endCommentStar, SyntaxToken endCommentTransition) at --- This actually looks like a compiler error @Artak could you file a separate issue to track? You should be able to use PRISM to better understand users who ran into this (Btw old editor would have killed VS in this scenario, new editor the experience falls over instead 😃)

More context: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1435565

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 7 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[javiercn]

@mkArtakMSFT can we get more details on the call stack for this one?

[mkArtakMSFT]

Here is the full exception stack trace that I could find:

Internal Error - System.ArgumentException: startCommentStar at Microsoft.AspNetCore.Razor.Language.Syntax.InternalSyntax.SyntaxFactory.RazorCommentBlock(SyntaxToken startCommentTransition, SyntaxToken startCommentStar, SyntaxToken comment, SyntaxToken endCommentStar, SyntaxToken endCommentTransition) at Microsoft.AspNetCore.Razor.Language.Legacy.TokenizerBackedParser`1.ParseRazorComment() at Microsoft.AspNetCore.Razor.Language.Legacy.CSharpCodeParser.ParseEmbeddedTransition(SyntaxListBuilder`1& builder) at Microsoft.AspNetCore.Razor.Language.Legacy.CSharpCodeParser.Balance(SyntaxListBuilder`1 builder, BalancingModes mode, SyntaxKind left, SyntaxKind right, SourceLocation start) at Microsoft.AspNetCore.Razor.Language.Legacy.CSharpCodeParser.Balance(SyntaxListBuilder`1 builder, BalancingModes mode) at Microsoft.AspNetCore.Razor.Language.Legacy.CSharpCodeParser.TryParseCondition(SyntaxListBuilder`1& builder) at Microsoft.AspNetCore.Razor.Language.Legacy.CSharpCodeParser.ParseCondit...

And it looks like this is the source of the exception, which indicates either a malformed Razor file or the code doesn't account for a valid scenario.

[javiercn]

@mkArtakMSFT thanks for the additional details.

Unfortunately, malformed files are definitely an scenario we need to handle.

@mkArtakMSFT it seems that the issue comes from our C# parser, so I'm going to put a pin on this one as there might be other work that might fix this in the future.

[davidwengier]

Reported in VS Mac too, with stack trace: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1558770