impl Radix for RevOrd isn’t helpful since RevOrd isn’t Copy

[andersk]

All the RadixHeapMap operations require K: Radix + Ord + Copy. It seems the intended way to make a min-heap is via the RevOrd wrapper, for which a Radix implementation is defined. But RevOrd can’t actually be used since it doesn’t derive Copy.

Perhaps a Radix impl for std::cmp::Reverse should be added, since Reverse derives Copy at least in 1.26 beta (rust-lang/rust#47379).

[mpdn]

Yeah, now that std has a official reverse order wrapper, it would no doubt be best to use that. I have just pushed a bunch of changes to 0.3 to update it to more modern Rust, including Reverse support.