{"ast_node_type":"other","tokens":[{"end":50,"kind":"keyword","start":0,"text":"span:"}]}
                span: tcx.def_span(impl_m.def_id),
            return Err(tcx.sess.dcx().emit_err(MethodShouldReturnFuture {
                method_name: tcx.item_ident(impl_m.def_id),