Is it employing anonymous enums? They come up for helping errors in the Rust community from time to time. The main dropback I see on relying on them is that t

Is it employing anonymous enums? They come up for helping errors in the Rust community from time to time. The main dropback I see on relying on them is that they make it easy to accidentally expose your implementation details as part of your public API, making it a breaking change to upgrade or change a dependency.