feat: Structure referencing itself

[gaetbout]

Feature Request

Describe the Feature Request

It should be possible for a structure to reference itself:

struct Node {
    value: felt,
    left: Option::<Box::<Node>>,
    right: Option::<Box::<Node>>,
}

If the feature request is approved, would you be willing to submit a PR?
(Help can be provided if you need assistance submitting a PR)

I'd have no idea how to implement that feature.

• Yes
• No