Implement cmp and ops reform

[alexcrichton]

Tracking issue for rust-lang/rfcs#439

[Gankra]

What's the implementation plan?

[japaric]

I'll look into the comparison traits, which seems like one of the few things currently actionable. (Anything that needs associated types is blocked on #18594, #19129, etc)

[alexcrichton]

@gankro I think that @japaric is right in that the entire RFC isn't necessarily actionable right now, but I do think that we should try to implement as much as possible in the meantime. Just knowing the list of blockers would be helpful!

[aturon]

Nominating P-backcompat-lang 1.0 (though we may want to triage parts of this separately.)

[japaric]

I think that another actionable item is changing Add et al. from by-ref to by-value.

[aturon]

@japaric

I think that another actionable item is changing Add et al. from by-ref to by-value.

Agreed. That will likely need to be coordinated with language changes, since currently & is implicitly added to the arguments. @nikomatsakis was working recently in this area and could probably help guide the staging.

[nikomatsakis]

On Fri, Nov 21, 2014 at 08:53:05AM -0800, Aaron Turon wrote:

Agreed. That will likely need to be coordinated with language
changes, since currently & is implicitly added to the
arguments. @nikomatsakis was working recently in this area and could
probably help guide the staging.

Hmm. Yes, ping me, or I can try to get started on this. Sorry for the
delay, way behind on github mail.

[japaric]

I think that another actionable item is changing Add et al. from by-ref to by-value.

I'll look into this during this week. I'm now somewhat familiar with this part of the compiler, and this looks doable now. I'll ping @nikomatsakis on IRC if I find any issue that I can't sort out.