Minor understanding check about optionals.

[chakrit]

#First: {
  name?: string
  age: int
}
#Second: {
  metadata?: {
    name?: #First.name
  }
}

last: #Second & {
  metadata: {
    name: "Test"
  }
}

playground: https://cuelang.org/play/?id=t-73DC9ZoVe#w=function&i=cue&f=export&o=cue

This took me a while to understand why line 7 above name?: #First.name is errorneous. The confusion came from the fact that I specified a concrete value in the last: evaluated value so I thought that everything should checks out and the value export should succeed but it seemed that:

• Optionals are evaluated earlier that the process of collapsing values to a final concrete exportable one.
• Because #First.name is optional, referencing it in #Second does not make sense because optional-ness is not a property that is passed along 1st-class like regular string or int type specifier are.

My flawed thinking was that I thought the optional-ness of a field would be passed along just like string or int would and gets merged (union?) to produce a valid final value. Something like optional & 1 == 1 but optional & _|_ == _|_ which actually doesn't seem useful once I think about it this way.

It seems like it's not exactly a part of the type system, but more of a constraint on the struct type in general.

Is this the correct way to think about it?