IncrementalValueProvider in my source generator:
Everything work as expected as long as the attribute parameter (here typeof(Point3))) is accessible in the current package.
If the typeof attribute parameter lives in an external package the PopulateTyypeMapping method is never called by the IncrementalValueProvider`. I think I understand that the compiler is unable to resolve the class so it skip the attribute, but it's very puzzling that there is no error message or warning emitted at compile time.