I remember it but the language changed so often that I didn't recall this right away. At least it's tried and scrapped and not based on some opinion.

I mean, like in Haskell the hard earned wisdom is that laziness should probably have been opt-in like OCaml making you write the rec keyword for recursive functions. I hope that one day we will get TCO in Rust as it's natural to implement many things recursively.

> in Haskell the hard earned wisdom is that laziness should probably have been opt-in like OCaml

is it? I am no haskeller, but I think I have seen some presentations or read papers in which lazyness by default was mentioned as something that haskell got right.

Do you have some links to read up on what you say?