>small union which julia handles efficiently at runtime Oh! I didn't realize Julia already optimized small unions. https://julialang.org/blog/2018/08/union-sp

>small union which julia handles efficiently at runtime Oh! I didn't realize Julia already optimized small unions. https://julialang.org/blog/2018/08/union-splitting/ https://julialang.org/blog/2018/08/union-splitting/ https://docs.julialang.org/en/v1/devdocs/isbitsunionarrays/ https://docs.julialang.org/en/v1/devdocs/isbitsunionarrays/ I wasn't quite sure whether something like this was possible given the semantics of Julia. Personally, I'd still prefer something more explicit, so it would be more obvious when a union is being handled efficiently. But given that small unions are optimized, I can see why Julia would make the opposite decision. This makes me feel a lot better about writing Julia code with union types. Thanks