{"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
        let pat_column = PatternColumn::new(arms);
    if tycx.refutable && report.non_exhaustiveness_witnesses.is_empty() {
        lint_nonexhaustive_missing_variants(tycx, arms, &pat_column, scrut_ty)?;