I got an error when upgrading to Marten 9 with my snapshot that worked in 8. I did manage to reproduce the error in this repo: https://github.com/mastoj/MartenNineUpgrade

To reproduce the error all you need to run is make run.

Running the app gives you the following error:

Unhandled exception. JasperFx.Events.Projections.InvalidProjectionException: No source-generated dispatcher found for Marten.Events.Aggregation.SingleStreamProjection<MyType, System.Guid>. When using conventional Apply/Create/ShouldDelete methods, the projection class must be declared partial in an assembly that references the JasperFx.Events.SourceGenerator analyzer, or alternatively override Evolve / EvolveAsync / DetermineAction / DetermineActionAsync directly. See docs/codegen/aot.md for the AOT publishing guide.