{"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"span_edges:"}]}
    span_edges: IndexVec<Node, Option<SpantreeEdge<Node>>>,
    /// spantree. Nodes that aren't supernodes cannot have a spantree edge.
    /// Shared path buffer recycled by all calls to `yank_to_spantree_root`.