SimpleSum derivation

[NPCRUS]

there are situations, where enum want to be used not as an complex ADT:

enum Complex:
  case First(value: Int)
  case Second

but rather as a simple enum, where variants don't have any arguments:

enum Simple:
  case First, Second

It would be handy if one can derive type class for enum that is compile time ensured to be simple:

object Show extends SimpleSumDerivation[Show] {
    inline def split[DerivationType : SimpleSumReflection]: Show[DerivationType] = value =>
        ???
}

in this case SimpleSumDerivation doesn't need a join method, since we exclude Product and the compiler should not be able to find or construct given for Show[Complex]

What I want to achieve with this idea:

• don't force type class author to implement Product related logic, when they only want to derive type class for simple enum
• compile time restrict "end"(wistreria -> type class author -> end user writing business logic) users to do summon[Show[Complex]] when the type class implementation is not intended for complex enums

Is it even possible, I would imagine we will need to implement some sort of compile time constraint in a form of IsSimpleSum[T: SumReflection]?
What do you think about this idea?