derive more traits for core::ops::ControlFlow

[canndrew]

I wanted to put a ControlFlow in a hash set but couldn't because it lacks the necessary impls. Is there any reason not to implement these?

[rust-highfive]

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[rust-highfive]

r? @yaahc

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[canndrew]

r? rust-lang/libs-api @rustbot label +T-libs-api -T-libs

[scottmcm]

Ord/PartialOrd were intentionally left out as described in https://rust-lang.github.io/rfcs/3058-try-trait-v2.html#traits-for-controlflow

I'd be inclined to leave it like that, unless you can give a good reason why one variant is less than the other. (Personally I might make it PartialOrd + !Ord, where partial_cmp gives None for mixing the variants, because I think having the order of variants matter is a misfeature, but I understand that's an unpopular position so don't actually propose it here.)

Eq/Hash seem fine to add, though.

[Mark-Simulacrum]

Going to move this back to waiting-on-author, since the PartialOrd/Ord probably should be dropped. It would be good to add a comment to this type with the explanation @scottmcm provided, so we don't accidentally do this in the future once that context has been paged out.

[yaahc]

r? rust-lang/libs

I've been taking a break from the review rotation for a while and didn't realize this one was still assigned to me, sorry about that.