{"ast_node_type":"variable","tokens":[{"end":83,"kind":"keyword","start":0,"text":"let"}]}
            let parent_def_id = tcx.hir_get_parent_item(impl_item.hir_id()).def_id;
        hir::ImplItemKind::Fn(..) => {
            let containing_item = tcx.hir_expect_item(parent_def_id);