`!` in pattern position

[RalfJung]

Sorry for the brevity, my comment was probably not very comprehensible. I felt like this was all already written up somewhere so I didn't want to spend the time to write it up again, but then I should have searched for the previous write-up instead of just leaving away all details.^^

So, I found the previous thread on the topic:

Blog post: never patterns, exhaustive matching, and uninhabited types

I wrote a blog post: RFC 1216 introduced ! as the sort of “canonical” uninhabited type in Rust, but actually one can readily make an uninhabited type of your very own just by declared an enum with no variants (e.g., enum Void { }). Since such an enum can never be instantiated, the type cannot have any values. Done. However, ever since the introduction of !, we’ve wrestled with some of its implications, particularly around exhaustiveness checking – that is, the checks the compiler does to ensur…

This should help resolve some of the confusion I caused. If there are still questions after reading that, please let me know.