Rewrite resolve

[brson]

I've heard from multiple people that resolve needs a complete rewrite. Nominating.

cc #11870 #3352

[nikomatsakis]

cc me

[nikomatsakis]

Additional tasks: clarify our rules (I have a plan, will post RFC soon)

[pnkfelix]

Not 1.0; marking P-high.

[flaper87]

cc #5765

[emberian]

Again \o/

[gereeter]

I'm working on this - just by reading and working on the code myself I have a pretty good idea of some major restructurings that ought to be done, but I'd greatly appreciate information about what others think needs to be fixed.

[gereeter]

More specifically, I plan to separate the passes of resolve to break the implicit data dependencies, make Module into an actual tree without any reference counting, use &mut for mutation instead of RefCell, and put things like import resolutions into side tables that hold borrowed pointers into the module tree.

[alexcrichton]

triage: P-low

[steveklabnik]

Triage: what would make this ticket actionable? the last meaningful comment was 18 months ago.

[hanna-kruppe]

Since the last meaningful comment has been made in October 2014, resolve has been split out into its own crate and touched by almost one thousand commits, including 87 that include the word "refactor" in their one-line commit message. Whatever code this issue originally referred to, odds are it's completely unrecognizable/gone by now.

[eddyb]

@petrochenkov and @jseyfried (and other people I forget now, sorry!) have put a lot of work into it