{"ast_node_type":"variable","tokens":[{"end":100,"kind":"keyword","start":0,"text":"let"}]}
    let rustc_commit = match rustc_version_info(env.get("RUSTC").map(|s| s.as_str()))?.commit_hash {
    run_command_with_output_and_env(&[&"git", &"fetch"], rust_dir, Some(env))?;
        Some(commit_hash) => commit_hash,