{"ast_node_type":"function","tokens":[{"end":52,"kind":"keyword","start":0,"text":"fn"}]}
    fn res(&self, def_id: impl Into<DefId>) -> Res {
impl<'a, 'ra, 'tcx> BuildReducedGraphVisitor<'a, 'ra, 'tcx> {
        let def_id = def_id.into();