Do not return empty nodes in the refactoring helpers service.

[CyrusNajmabadi]

Fixes #58811

[Youssef1313]

I think the fix could be in line 137 (AbstractAddParameterCheckCodeRefactoringProvider.cs
), which might be missing getInnermostNodeForTie: true

                var firstParameterNode = (TParameterSyntax)root.FindNode(parameterSpan);

The challenge is to find a test case. Is there any scenario where the syntax tree can contain a ParameterList with missing parenthesis? this is a case where the ParameterSyntax and ParameterListSyntax might have the same span, so the cast will fail.

[sharwell]

which might be missing getInnermostNodeForTie: true

This could cause a problem for simple lambdas, where the parameter span is the same as the identifier span.

[CyrusNajmabadi]

I think the fix could be in line 137 (AbstractAddParameterCheckCodeRefactoringProvider.cs
), which might be missing getInnermostNodeForTie: true

Yes, i thought that was likely teh case too. However, i still can't figure out a repro for this. As such, i didn't want to make a change that doesn't certainly fix things. This change at least lets us know what is going on so we can narrow this down :)

[CyrusNajmabadi]

This could cause a problem for simple lambdas, where the parameter span is the same as the identifier span.

Technically that would be ok as this is FindNode and the 'identifier' is a token. That said, i still can't figure out how FindNode, when given the span of a parameter, is getting the ParameterList back instead. Taht's the weird thing here.

[CyrusNajmabadi]

/azp run

[Youssef1313]

I think the fix could be in line 137 (AbstractAddParameterCheckCodeRefactoringProvider.cs
), which might be missing getInnermostNodeForTie: true

Yes, i thought that was likely teh case too. However, i still can't figure out a repro for this. As such, i didn't want to make a change that doesn't certainly fix things. This change at least lets us know what is going on so we can narrow this down :)

Going to see if #58845 can hint to a repro

[CyrusNajmabadi]

actually i have a theory. let me try out parameters that are missing. that might cause some issues here.

[azure-pipelines]

Azure Pipelines successfully started running 4 pipeline(s).

[CyrusNajmabadi]

actually i have a theory. let me try out parameters that are missing. that might cause some issues here.

Yes. This is the case that hits this.