On: I claim Rich Hickey is wrong about non-null arguments to functions (2020)

[kaba0]

You can have both union types and sum types (imo ideally), or in this case can easily choose to represent the result of the expensive computation in a more reasonable/descriptive way.

[codebje → kaba0]

Perhaps the more reasonable/descriptive way to represent the potentially no-value result of the computation is with a sum type, not a union type?