{"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"//"}]}
    // entire lhs is those tts. Or, it can be a "bare sequence", not wrapped in parens.
    // lhs is going to be like TokenTree::Delimited(...), where the
    if let mbe::TokenTree::Delimited(.., delimited) = lhs {