[foldr]

To my mind, the issue is that a substantial portion of lifetime constraints reflect implementation details and not actual domain-level constraints that the programmer specifically wished to enforce. The same thing can of course happen with static type constraints generally, but I think not usually to the same extent.

>Go doesn't have function level generics

Not sure what you mean by this. Go functions can take generic parameters that satisfy a given interface (at compile time). E.g.

    func firstName[T AsBytes](name T) T

(You'd have to define the AsBytes interface yourself.)

>in Java you cannot add a new interface implementation to a builtin type

Yes ok, fair point.

[pkolaczk]

         func firstName[T AsBytes](name T) T

Ok, I stand corrected. Can you define AsBytes for string then?

[foldr]

> Can you define AsBytes for string then?

Yes. However, because strings in Go are immutable and byte arrays are necessarily mutable, you can’t safely convert strings to byte arrays (or vice versa) without copying, so it would not necessarily be a particularly useful interface.

By the way, this was an interesting discussion. I do see your overall point more than I did at the beginning of it, although I don’t think we completely see eye to eye on the costs/benefits of lifetimes.