{"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
        let norm_return_ty = ocx.normalize(&cause, param_env, return_ty);
        let ocx = traits::ObligationCtxt::new_with_diagnostics(&infcx);
        ocx.register_bound(cause, param_env, norm_return_ty, term_did);