-   kind: record
    fields:
    -   name: x
        value: {kind: string}
        required: true
    -   name: y
        value: {kind: boolean}
        required: true
    id: [shape, X]
-   kind: record
    fields:
    -   name: x
        value: {kind: string}
        required: false
    -   name: y
        value: {kind: boolean}
        required: false
    id: [shape, Y]