Flag for SyntaxValueProvider.ForAttributeWithMetadataName to respect attribute inheritance

[zotanmew]

Assuming it's possible to check for inherited (e.g. [AttributeUsage(AttributeTargets.Class, Inherited = true)]) attributes in the ForAttributeWithMetadataName algorithm without breaking the incremental aspect, would it be possible to get a flag for the ForAttributeWithMetadataName method to enable this behavior (at least for the immediate parent)?

This would be very useful for scenarios where e.g. a class library ships an abstract class with a virtual method whose implementation needs to be generated based on the content of the respective inherited class.

If this is not possible, is there a way to group a IncrementalValueProvider's results without breaking the incremental aspect? The only way I've found to do this is by calling .Collect() and doing the grouping in the RegisterSourceOutput action, which is significantly less efficient.

[CyrusNajmabadi]

Assuming it's possible to check for inherited (e.g. [AttributeUsage(AttributeTargets.Class, Inherited = true)]) attributes in the ForAttributeWithMetadataName algorithm without breaking the incremental aspect

It is not possible to do this.

and doing the grouping in the RegisterSourceOutput action, which is significantly less efficient.

What is less efficient about this?

[zotanmew]

It is not possible to do this.
That's unfortunate, thank you regardless!

What is less efficient about this?
It causes all output files to be regenerated when any matching inputs are modified, instead of only regenerating the modified group.