{"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
    let report = |dis: Discr<'tcx>, idx, err: &mut Diag<'_>| {
    // Here `idx` refers to the order of which the discriminant appears, and its index in `vs`
        let var = adt.variant(idx); // HIR for the duplicate discriminant