[adenozine]

So, like Erlang?

What’s an example of a language that does this by default?

[qsort]

Idiomatic usages of ML-family languages (Haskell, OCaml) are very close to that.

[eru]

Common Lisp Object System might do something like that?

[packetlost]

Rust

[adenozine]

I'd rather gouge my eyes out than work with Rust code. Horrific.