{"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"//"}]}
    // requires a lot more complexity in the span refiner, for little benefit.)
    // (Ideally we should try to preserve _all_ non-dominating BCBs, but that
    covspans.dedup_by(|b, a| a.span.source_equal(b.span));