{"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
                    let Some(sig) = tcx.hir_node_by_def_id(did).fn_sig() else {
                AttributeKind::TargetFeature(features, attr_span) => {
                        tcx.dcx().span_delayed_bug(*attr_span, "target_feature applied to non-fn");