Is there a way to have a permission based on the document in which it's defined? I want to model a permission that should only be granted to the specific user's profile. Example:

definition user {
    permission user_can_view_some_private_info = this // "this" could be replaced with "self" or something that points back to the user doc
}

I know I can set a

relation self: user

but it feels like there may be a built-in way to do this without needing to set that relationship?