{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"///"}]}
    /// 2) Appropriate environment variable (erroring if this is set but not a usable executable)
    ///    It seems that this is a reasonable place to try for cargo, rustc, and rustup
    ///    example: for cargo, this checks $CARGO environment variable; for rustc, $RUSTC; etc