{"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"//"}]}
        // variables. (Note that this set consists of "root variables".)
        // N0, which we call N. These are the *non-diverging* type
        let mut roots_reachable_from_non_diverging = DepthFirstSearch::new(&coercion_graph);