{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"//"}]}
        // would result in `{ [5 x i8] zeroinitializer, [3 x i8] undef, ...repeat 1M times... }`.
        // For example, `[(u32, u8); 1024 * 1024]` contains uninit padding in each element, and
        let max = cx.sess().opts.unstable_opts.uninit_const_chunk_threshold;