Rust

Trick question: what is the return type of a function with body

{
   return || true
}

Let’s try a more difficult one with closures. What’s wrong with this closure

let closure = |x: &str| x;

OSS + Rust. I have one goal in life: the ability to stop thinking at will

You would need to specify a lifetime since you’re returning a borrowed reference. I don’t remember right now if you can annotate lifetimes in closures 😅 but you could do:

let closure = |x: &str| x.to_owned();

tricks with polynomials. Computational monadologist. Prev: ML HealthCareInc 🦄 | R&D PeopleFund | AI & Stats lecturer

No not necessarily. The compiler is smart enough to figure out the lifetime of the returned type because there is only a single borrowed reference as a parameter