Release v19.88.0

Added

• Fluent FromEvery and FromAll mappings can set a constant with ToValue(...), matching Set(...).ToValue(...) for concepts, enums and null. (#4663)

Fixed

• Registering a reactor, reducer or self-reducing read model whose only handlers take [EventTypeGenerationFor] types now fails with ObserverHasOnlyGenerationHandlers, naming the artifact and the generation types. Such an observer previously registered without any event types and never became active. (#4922)
• A projection declaration that uses an $eventContext member or path that does not exist on the event context is now rejected when it is compiled. It was previously accepted and failed only when the projection was built. (#4702)