{"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"if"}]}
                if allowed.iter().all(|f| name.as_str() != f) {
            if let Some(allowed) = sess.opts.unstable_opts.allow_features.as_ref() {
                    sess.dcx().emit_err(FeatureNotAllowed { span: mi.span(), name });