{"ast_node_type":"other","tokens":[{"end":92,"kind":"keyword","start":0,"text":"impl<'a,"}]}
impl<'a, 'tcx, D: ConstraintGraphDirection> graph::Successors for RegionGraph<'a, 'tcx, D> {
    fn successors(&self, node: Self::Node) -> impl Iterator<Item = Self::Node> {