Implement ordering chaining

[rednum]

As discussed in: rust-lang/rfcs#1677

I've already started working on this and will open a PR soon.

[apasel422]

Reopening because this is a tracking issue.

[sfackler]

@rfcbot fcp merge

[SimonSapin]

Looks like @rfcbot missed @sfackler’s message?

I also think this addition looks good, and would like it to be stabilized.

[aturon]

@rfcbot fcp merge

[rfcbot]

Team member @aturon has proposed to merge this. The next step is review by the rest of the tagged teams:

• @BurntSushi
• @Kimundi
• @alexcrichton
• @aturon
• @brson
• @sfackler

No concerns currently listed.

Once these reviewers reach consensus, this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[alexcrichton]

ping @BurntSushi (checkbox)

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔