port the "autoref-arg" code used in overloaded operators to use the ptr adjustment table

[nikomatsakis]

We have this nice table in the tcx called adjustments that's supposed to track when an expression is being auto-ref'd or auto-deref'd. It would make borrowck, trans, and other pieces of code that are concerned with this "just work". But it's not being used for overloaded operators right now.

[pcwalton]

This is more of cleanup than an enhancement. Punting to 0.6.

[graydon]

non-critical for 0.6, de-milestoning

[jld]

#5304 is the const part of this, I think. There might be other pieces that are already done; it looked as if expr translation was using adjustments when I was fixing consts, I think.

[nikomatsakis]

@jld expr translation does use adjustments in general, but not to handle the autoref of arguments associated with operators.

[graydon]

Confirmed 2013-05-29, this is still legit and is not a backwards compatibility risk, just eliminating redundancy inside the compiler.

[graydon]

Visiting again for triage. Still appears to be a living issue in the compiler.

[emberian]

Visiting for triage, FIXME still present.

[nikomatsakis]

I have a branch that implemented this. It turns out to be somewhat more difficult than I anticipated, because the current rules permit things that autoref cannot currently express, such as using both autoref from an adjustment AND the magical operator autoref. I'm not a fan of supporting this anyhow but I deferred this branch in favor of finishing up some more pressing matters.

@nikomatsakis Can this be closed?

[nikomatsakis]

Sadly no. However, the difficulties I mentioned in my previous comment probably no longer apply since method dispatch has been made more regular.

[nikomatsakis]

(Actually, I wonder if it can be closed.. I may have accidentally done this while doing the method dispatch operator overloading.)

[nikomatsakis]

Well, I don't think we can close it, because the autoref machinery is still there, but it might be that all the interesting work is done.

[nikomatsakis]

and what remains is to remove the outdated code

[steveklabnik]

Triage: this seems to be about deep compiler stuff that's probably gone by now. Is that true, @nikomatsakis ?

[nikomatsakis]

Sadly it is not gone by now. But it's also a long standing bug that is not that important, MIR makes it even less relevant.