I expect a common complaint to be “why isn’t [].into_iter() working in my tests? —oh, it’s 2018 edition”, though this can be mitigated by a specialised error me

I expect a common complaint to be “why isn’t [].into_iter() working in my tests? —oh, it’s 2018 edition”, though this can be mitigated by a specialised error message which didn’t exist last week when I first learned about this matter.