Add small refactorings

[tranzystorekk]

Summary:

• Remove some redundant .iter()/.into_iter() calls
• Reduce nesting in if-else blocks that can be easily short circuited
• Use deref coercion to avoid some .as_...() calls

[Enselic]

Thanks for taking the time to make a contribution!

May I ask if you could please split the change up into smaller commits? The smaller the better, essentially. If there turns out to be a regression, smaller commits will give higher resolution for both git bisect and git revert. They also make code review easier.

I'm also curious if you used clippy to find these, or if you manually found them, if you don't mind me asking?

[tranzystorekk]

Hi, thanks for having me! 😄

I'll split the change in a bit.

I'm also curious if you used clippy to find these, or if you manually found them, if you don't mind me asking?

I scanned the code for common idioms manually, e.g. .iter or .as_, I also manually looked through all the if keywords. Sure wish clippy was this smart 😅

[Enselic]

I think it looks nice in general! Thanks! Just had two comments on the last commit.

(Please keep doing force-push so I can keep the commits when merging)

[Enselic]

This looks good to me now. Thanks!

I'll give other maintainers a chance to take a look before I merge.

[Enselic]

Thanks for taking a look, Keith. Let's merge this now to not delay #951.