Polymorphic types offer mutations under some circumstances?

Polymorphic types shouldn't offer mutations currently, since they don't work.

Extracted from #2077

I can't find a way to create a Profile when creating an Individual

In my system, a Profile is always one of a few given types. It is unexpected that a Profile should be created without an associated e.g. Individual. Preferably, I would like to remove createProfile from my mutations altogether and expose only e.g. createIndividual. However, this means createIndividual needs to be able to create the base Profile, which it seems is not possible?

Current

mutation {
  createIndividual(input: {individual: {
    # This is the only property available in `individual`.
    profileByRowId {
      # There are no properties available here for creating a profile
    }
  }}) {
    id
  }
}

Expected

mutation {
  createIndividual(input: {individual: {
    profile: {
      name: "Felix"
    }
  }}) {
    id
  }
}

graphile / crystal

Polymorphic types offer mutations under some circumstances? #2083