{"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"///"}]}
    /// `d` is `FieldIdx(1)` in `VariantIdx(1)`, and
    /// `b` is `FieldIdx(1)` in `VariantIdx(0)`,
    /// `f` is `FieldIdx(1)` in `VariantIdx(0)`.