{"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
        let name = Symbol::intern(tcx.symbol_name(instance).name);
        let instance = Instance::new_raw(did, ty::List::identity_for_item(tcx, did));
        if let Some(&existing_id) = self.seen_decls.get(&name) {