Enumerations of product type instances or checks on instances

[javierarrieta]

Hi, we are implementing a configuration for the definition of our domain and we would like to define a set of instances for a given product type that define our ADT/enum, so I tried this but it is not working:

schema _InternalContextType:
  id: int
  name: str
  description?: str

A = _InternalContextType { id = 1 name = "A" }
B = _InternalContextType { id = 2 name = "B" }
C = _InternalContextType { id = 3 name = "C" }

type ContextType = A | B | C

So when using the ContextType we can only use already created instances. Unfortunately that is failing as A is not defined according to the compiler/checker.

What alternatives do we have to implement the safety guards we need to apply?

Thanks!