Within the next few patches we will be using this new API.
Indeed. Also added a comment to explain the reasoning.
I'm not sure I agree. On the basis that "Rust might optimize iterators better than for loops" I vote to keep it that way.
For now this is pretty specific, but it might need to be moved later when more code paths use it.
Can you move this condition into a .filter()?
If you think it' is clearer that's fine. But I'm curious where "Rust might optimize iterators better than for loops" comes from. I did a quick test and it looks like the for loop actually generates slightly better code https://rust.godbolt.org/z/vFAWyZ
I might be using godbolt wrong but it looks like you are using different versions of rustc. When using 1.40 for both sides, I don't see any clear win on either side... but I'm not fluent in assembly either. As I'm sure you'll agree, this function is unlikely to show up in future profiles anyway.