{"ast_node_type":"variable","tokens":[{"end":42,"kind":"keyword","start":0,"text":"let"}]}
        let arg = self.eval_operand(arg)?;
    fn check_unary_op(&mut self, op: UnOp, arg: &Operand<'tcx>, location: Location) -> Option<()> {
        // The only operator that can overflow is `Neg`.