How far to take iterators to avoid `for` loops

@ExpHP Well I went a couple commits back in my crate repo to try and recreate the error - to no avail. I originally boxed in response to a compiler error stating that a size couldn’t be known at compile time. It was pretty early on, so I figured it must have something to do with Vec<String>. There must have been something else going on that has now been corrected.

Thank you for the pointer clarification, I appreciate your time. I got it now.