Form associated custom elements: cross shadow root form participation

[christophe-g]

Consider this:

1. An element holding a textfield:

@customElement('my-wrapped-field')
export class MyWrappedField extends LitElement {
  @property() label!: string
  render() {
    return html`
        <md-filled-text-field .label=${this.label} required></md-filled-text-field>
        `;
    }
}

2. Placed within a form

<form>
     <md-filled-text-field label="I participate to the form" required></md-filled-text-field>
     <my-wrapped-field label="I will not"></my-wrapped-field>
     <div>
        <md-filled-button>Submit</md-filled-button>
     </div>
<form>

The md-filled-text-field within the my-wrapped-field does not participate in the form (its .form is null) as it is not in the same shadow root.

Is there / will there be a way to pass the form to the my-wrapped-field so that such nested form participation construct could work?