{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
                let def_id = tcx.require_lang_item(lang_item, span);
            &hir::TyKind::Path(hir::QPath::LangItem(lang_item, span)) => {
                let (args, _) = self.lower_generic_args_of_path(