Question about the scope of recursive modules

Learning
1 
module rec Person: sig include module type of (struct 
  type t = {
    name: string;
    pet: Cat.t; 
  } 
end : sig end)
end = Person

and Cat:sig
  type t = {
    name: string;
    isLazy: bool;
  }  
end = Cat

It complains about unbound type Cat.t, if I comment that line, everything is fine, is this a bug or expected behavior?
The error is Error: Illegal recursive module reference

2

I am not completely sure how much this is the specified behavior for recursive modules, but currently the module expression in module type of cannot refer to the recursive modules being defined.

3

Thanks for having a look, shall I file an issue on github repo?

4

You can certainly open a feature wish issue but do you have a more precise use case in mind?

5

Thanks, reported here https://github.com/ocaml/ocaml/issues/9574