{"ast_node_type":"variable","tokens":[{"end":88,"kind":"keyword","start":0,"text":"let"}]}
    let opt_stage = if thin { llvm::OptStage::ThinLTO } else { llvm::OptStage::FatLTO };
    debug!("running the pass manager");
    let opt_level = config.opt_level.unwrap_or(config::OptLevel::No);