From what I understand, this will be possible in the future with implicit union ...

unsafecast on Dec 8, 2022 | parent | context | favorite | on: Codon: A high-performance Python-like compiler usi...

From what I understand, this will be possible in the future with implicit union types. Wouldn't work with _arbitrary_ types, but with a set of types that can be computed at compile time (my guess is that this is possible in most real-world cases).