{"ast_node_type":"other","tokens":[{"end":44,"kind":"keyword","start":0,"text":"expr_def_id.to_def_id(),"}]}
                    expr_def_id.to_def_id(),
                let coroutine_output_ty = tcx.liberate_late_bound_regions(
                    closure_args.coroutine_closure_sig().map_bound(|sig| {