{"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"if"}]}
        if !self.typeck_results.borrow().is_method_call(expr) {
        debug!("convert_place_op_to_mutable({:?}, {:?}, {:?})", op, expr, base_expr);
            debug!("convert_place_op_to_mutable - builtin, nothing to do");