{"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
        let post = if all_stable || all_unstable {
        let all_unstable = constraints.iter().all(|&(_, _, stable)| !stable.is_empty());
            // Don't redundantly say "trait `X`, trait `Y`", instead "traits `X` and `Y`"