{"ast_node_type":"function","tokens":[{"end":71,"kind":"keyword","start":0,"text":"fn"}]}
    fn eval_target_usize(&self, cnst: &MirConst) -> Result<u64, Error>;
    /// Evaluate constant as a target usize.
    fn eval_target_usize_ty(&self, cnst: &TyConst) -> Result<u64, Error>;