> Yes, but IMO that makes the code a bit more abstract:
> You've left behind an explicit "is this collection non-empty" and you're instead relying on a property of a non-empty collection.
More abstract for who? I think virtually all Rust programmers would easily understand the `if let` snippet, virtually all PHP programmers would understand the PHP snippet, and virtually all programmers of any language would understand that a non-empty array has a first element. I'm not at all convinced that most programmers would correctly guess that a function called `reset` is used to access the first element in an array though.
A collection is non-empty if and only if it has a first element. Therefore checking for non-emptiness is the same as checking for the existence of a first element.
Edit: Added a `let` I had forgotten.