Can't add local state to introspection types

[dljcollette]

I'm trying to add local state to the typename __Type, which is part of GraphQL introspection. My local schema looks like this:

type __Type {
   isSelected: Boolean!
}

I've added the isSelected @client in my query and also return a default value from my resolver. However, I'm getting the following error when I make a query:

Missing field isSelected in {
  "__typename": "__Type",
  "kind": "OBJECT",
  ...
}

I'm aware that typenames starting with __ are reserved so my first guess is that I can't (and maybe even shouldn't want to) extend types with reserved typenames when using apollo-link-state, though the error message does not tell. Could somebody confirm this is actually the issue?