Default empty struct leads to allowing all keys

[pefeigl]

Hello!

I'd like to deal with helm values.yaml files via cuelang. I've started writing simple cuefiles for tests, however I've run into the following:

#sourceRef: {
  kind: string & "HelmRepository"
  name: string
  namespace: string
}

#helmRelease {
  sourceRef: #sourceRef | *{}
}

This leads to correctly evaling into something I can use for helm values, however the *{} (according to the documentation) allows all possible labels in that struct. I want to explicitly specify only an empty struct, nothing else should be allowed. I tried { ... _|_ }, but that seems to be invalid syntax. I've also tried close({}), but that doesn't disallow other labels either.

I'd be happy about any help, thanks very much!