{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"if"}]}
                if let Ok(mut an) = trait_def.ancestors(tcx, def_id)
                let trait_def = tcx.trait_def(trait_ref.def_id);
                    && let Some(specialization_graph::Node::Impl(parent)) = an.nth(1)