Stream: t-compiler

Topic: weekly meeting 2019-11-28 #54818


pnkfelix (Nov 28 2019 at 12:43, on Zulip):

Hi @T-compiler/meeting ; the triage meeting will be starting in 2 hours 17 minutes

pnkfelix (Nov 28 2019 at 12:43, on Zulip):

I will be doing pre-triage in a parallel topic

pnkfelix (Nov 28 2019 at 12:44, on Zulip):

For this week's WG checkin, we have WG-Async/Await and WG-Diagnostics scheduled.

pnkfelix (Nov 28 2019 at 12:45, on Zulip):

last week I created a dedicated topic in async-await for gathering announcements. So far, nothing posted there.

pnkfelix (Nov 28 2019 at 12:45, on Zulip):

similar story for dedicated topic in wg-diagnostics

pnkfelix (Nov 28 2019 at 12:46, on Zulip):

(but, its a new system; probably too soon to declare failure.)

pnkfelix (Nov 28 2019 at 12:47, on Zulip):

in any case, since both of the leads for WG-async-await are USA-based, I expect they will not be around due to Thanksgiving holiday there.

pnkfelix (Nov 28 2019 at 12:47, on Zulip):

but for WG-diagnostics: Is either @oli or @Esteban Küber around to potentially provide an update at the time of the T-compiler meeting? (Or send me one ahead of time?)

oli (Nov 28 2019 at 12:52, on Zulip):

:wave: I'm here

pnkfelix (Nov 28 2019 at 13:36, on Zulip):

:construction_worker: volunteer requested: need someone to identify (via bisection) which PR fixed this: "rustc crash on 1.39.0 stable with combination of async and .." #66618

pnkfelix (Nov 28 2019 at 15:02, on Zulip):

okay I've got my draft for today's agenda prepared

pnkfelix (Nov 28 2019 at 15:02, on Zulip):

Hi @T-compiler/meeting! Add a :wave: emoji to show you're here :)

pnkfelix (Nov 28 2019 at 15:02, on Zulip):

We'll start off with five minutes for:

pnkfelix (Nov 28 2019 at 15:02, on Zulip):

Announcements

simulacrum (Nov 28 2019 at 15:03, on Zulip):

perf has been fully migrated to new backing hardware for the collector

pnkfelix (Nov 28 2019 at 15:03, on Zulip):
pnkfelix (Nov 28 2019 at 15:04, on Zulip):

perf has been fully migrated to new backing hardware for the collector

what does this mean for us in practice?

simulacrum (Nov 28 2019 at 15:04, on Zulip):

in theory, nothing

simulacrum (Nov 28 2019 at 15:04, on Zulip):

in practice, it means that the collector is theoretically more accessible to e.g. ssh access for particular contributors

simulacrum (Nov 28 2019 at 15:04, on Zulip):

(this is largely not useful -- try builds + rust-timer queue are good enough -- but if you need to check something, contact me, and I can try and hook you up)

simulacrum (Nov 28 2019 at 15:06, on Zulip):

the new hardware is also a tad larger (6C/12T vs. 4C/8T) which might make perf a bit faster

Pietro Albini (Nov 28 2019 at 15:06, on Zulip):

we have both windows and linux running on github actions!

Pietro Albini (Nov 28 2019 at 15:06, on Zulip):

https://github.com/rust-lang/rust-gha/commit/d9b6712b6d102181f7d8fa53b9db415757300e64/checks?check_suite_id=332181608

Pietro Albini (Nov 28 2019 at 15:07, on Zulip):

at the moment they take 1hr25min for a full build, but that's going to slow down as we re-enable llvm and debug assertions on the slower builders

Pietro Albini (Nov 28 2019 at 15:07, on Zulip):

(we disabled them on the slowest azure builders to avoid going over 4 hours)

pnkfelix (Nov 28 2019 at 15:08, on Zulip):

Awesome

Pietro Albini (Nov 28 2019 at 15:08, on Zulip):

also, macos is still probably going to be on azure for a while (we need macos 10.13 to avoid dropping support to i686 apple, and gha only has 10.15)

Pietro Albini (Nov 28 2019 at 15:08, on Zulip):

so I guess y'all should expect ~2hrs for a bors auto build once we land that

Pietro Albini (Nov 28 2019 at 15:08, on Zulip):

(all from me)

pnkfelix (Nov 28 2019 at 15:08, on Zulip):

Lets get the rest of the meeting started. (If anyone has an additional announcement to add, privmsg me and I'll allocate time at the end for it.)

pnkfelix (Nov 28 2019 at 15:09, on Zulip):

so, as previously mentioned, here is our agenda for today

pnkfelix (Nov 28 2019 at 15:09, on Zulip):

beta-nominations first

pnkfelix (Nov 28 2019 at 15:09, on Zulip):

beta-nom 1/2: "Handle non_exhaustive in borrow checking" #66722

pnkfelix (Nov 28 2019 at 15:11, on Zulip):

I think if this is okay for nightly, then its okay for beta

pnkfelix (Nov 28 2019 at 15:11, on Zulip):

(I will admit that I want to read over it again myself. but for now I'll mark beta-accepted.)

pnkfelix (Nov 28 2019 at 15:12, on Zulip):

beta-nom 2/2: "Fix some issues with attributes on unnamed fields" #66669

pnkfelix (Nov 28 2019 at 15:13, on Zulip):

(this one seemed like a clear win to me in terms of being "clearly the right thing")

pnkfelix (Nov 28 2019 at 15:13, on Zulip):

at least in terms of the effects on the test suite

pnkfelix (Nov 28 2019 at 15:13, on Zulip):

the words "HACK" in the PR itself do give one pause...

pnkfelix (Nov 28 2019 at 15:15, on Zulip):

the other options are that we: 2. decline to beta accept, or 3. wait until next week to decide on this one.

pnkfelix (Nov 28 2019 at 15:17, on Zulip):

okay lets beta-accept this

Esteban Küber (Nov 28 2019 at 15:17, on Zulip):

We can accept the beta nom and defer on the stable too

pnkfelix (Nov 28 2019 at 15:17, on Zulip):

next up, stable nominations

pnkfelix (Nov 28 2019 at 15:17, on Zulip):

yeah the only stable nom is what we just discussed, "Fix some issues with attributes on unnamed fields" #66669

pnkfelix (Nov 28 2019 at 15:18, on Zulip):

lets defer to next week on the stable nom there.

pnkfelix (Nov 28 2019 at 15:18, on Zulip):

okay, next: There are two PR's marked S-waiting-on-team.

pnkfelix (Nov 28 2019 at 15:18, on Zulip):

One of them, "Turn HIR indexing into a query" #59064, is awaiting a steering meeting. We don't need to talk about that here.

pnkfelix (Nov 28 2019 at 15:19, on Zulip):

The other, "PowerPC C ZST ABI fixes" #64259, was meant to have follow-up discussion, which did happen in a parallel zulip chat

pnkfelix (Nov 28 2019 at 15:19, on Zulip):

but the discussion sort of died out about three weeks ago

pnkfelix (Nov 28 2019 at 15:21, on Zulip):

part of the problem here is that I don't know if anyone on the team is in a position to evaluate these changes.

pnkfelix (Nov 28 2019 at 15:21, on Zulip):

or at least is in a position to drive the conversation forward to consensus

pnkfelix (Nov 28 2019 at 15:22, on Zulip):

Okay well clearly no one present here is volunteering to take over

pnkfelix (Nov 28 2019 at 15:23, on Zulip):

lets move along. (Maybe if we are still in same position next week I will self-assign or something)

pnkfelix (Nov 28 2019 at 15:23, on Zulip):

We have 37 open P-high issues. 21 of those issues are unassigned

Esteban Küber (Nov 28 2019 at 15:24, on Zulip):

Can you think of anyone that _could_ take it up (without considering whether they have the bandwidth)?

pnkfelix (Nov 28 2019 at 15:24, on Zulip):

that was a general alert. Maybe I should just put that as part of my standard announcements at the beginning.

pnkfelix (Nov 28 2019 at 15:24, on Zulip):

Can you think of anyone that _could_ take it up (without considering whether they have the bandwidth)?

I don't know. Its pretty niche, I think.

pnkfelix (Nov 28 2019 at 15:27, on Zulip):

Regarding that list of P-high issues: I did mention at the outset of the meeting that I'm seeking a :construction_worker: volunteer to track down where this bug was fixed: "rustc crash on 1.39.0 stable with combination of async and .. #66618

pnkfelix (Nov 28 2019 at 15:28, on Zulip):

Beyond that, a lot of the other issues might fall under a common umbrella topic (e.g. normalization issues, which I'm hoping to spend some time on soon).

pnkfelix (Nov 28 2019 at 15:28, on Zulip):

Lets move on to the concrete nominations.

pnkfelix (Nov 28 2019 at 15:29, on Zulip):

I tagged "COPYRIGHT file is wildly out of date" #63232 as T-compiler, because I wanted to use that issue to draw attention to a more general problem

pnkfelix (Nov 28 2019 at 15:31, on Zulip):

In last weeks' planning meeting, we opted not to schedule a Friday meeting dedicated to licensing (see also compiler-team#220 and @Florian Gilcher 's draft guidelines )

pnkfelix (Nov 28 2019 at 15:31, on Zulip):

but we probably do need to identify a group of people willing to do some work here, in the short term, to deal with the licensing mess we've made for ourselves

pnkfelix (Nov 28 2019 at 15:32, on Zulip):

there was also a parallel zulip topic where @Florian Gilcher and I were discussing this matter.

pnkfelix (Nov 28 2019 at 15:33, on Zulip):

given the nature of the problem, and the fact that I don't expect many people to volunteer to manually review our source tree to try to identify licensing problems

pnkfelix (Nov 28 2019 at 15:34, on Zulip):

I mostly wanted to use this spot in the meeting for two things:

pnkfelix (Nov 28 2019 at 15:34, on Zulip):
  1. if you are willing to help out here, privmsg me or @Florian Gilcher
pnkfelix (Nov 28 2019 at 15:35, on Zulip):
  1. Regardless of whether you want to participate in a review of the existing source tree, the project in general needs to be a bit better about trying to catch problem pro-actively.
pnkfelix (Nov 28 2019 at 15:35, on Zulip):

the current example that is running through my mind is someone who adapted code from gcc for some compiler-builtins support library.

pnkfelix (Nov 28 2019 at 15:36, on Zulip):

in case I'm not being clear: We are not supposed to accept code like that into this project. Our license is not compatible with accepting such code.

pnkfelix (Nov 28 2019 at 15:37, on Zulip):

(it doesn't matter if you provide attribution. It doesn't matter if it was a trivial algorithm that no one could have patented; copyright law doesn't work that way.)

pnkfelix (Nov 28 2019 at 15:38, on Zulip):

anyway, I or someone else will probably be talking more about this in the future, probably via multiple channels to try to catch everyone's eyeballs

pnkfelix (Nov 28 2019 at 15:39, on Zulip):

next nominated issue

pnkfelix (Nov 28 2019 at 15:39, on Zulip):

nom: "under latest MinGW, cannot link with C code using stdout" #47048

pnkfelix (Nov 28 2019 at 15:39, on Zulip):

we started talking about this last week and then got side-tracked.

pnkfelix (Nov 28 2019 at 15:40, on Zulip):

at this point, here is my question regarding this bug: What is the Tier 1 platform we supposedly support here?

pnkfelix (Nov 28 2019 at 15:41, on Zulip):

if our CI is fixed to a narrow (and old) set of versions of mingw, then we probably shouldn't be claiming Tier 1 support for anything except those versions, right?

pnkfelix (Nov 28 2019 at 15:42, on Zulip):

(independently, it does sound like some people are discussing solutions on issue #53454 ...)

pnkfelix (Nov 28 2019 at 15:44, on Zulip):

And another question: Do we have any active MinGW (MSYS2?) users present who would be willing to try to help address this?

pnkfelix (Nov 28 2019 at 15:44, on Zulip):

hey @T-compiler/meeting , should I just switch to WG-checkins so that we can adjourn early?

pnkfelix (Nov 28 2019 at 15:45, on Zulip):

... okay then ... let's hear from @oli regarding WG-diagnostics

oli (Nov 28 2019 at 15:45, on Zulip):

wg-diagnostics is moving slow on implementing all the diagnostic rendering out of tree in https://github.com/rust-lang/annotate-snippets-rs/

oli (Nov 28 2019 at 15:45, on Zulip):

but there's new work happening since last week

pnkfelix (Nov 28 2019 at 15:47, on Zulip):

great, thanks @oli

lqd (Nov 28 2019 at 15:47, on Zulip):

(@pnkfelix I'll take the :construction_worker: #66618)

pnkfelix (Nov 28 2019 at 15:48, on Zulip):

there were a few other nominated issues on the agenda, but I figured I could demote them to mere announcements

pnkfelix (Nov 28 2019 at 15:48, on Zulip):
pnkfelix (Nov 28 2019 at 15:49, on Zulip):

unless someone convinces me that I need to use rfcbot merge or whatever to poll the whole T-compiler team

pnkfelix (Nov 28 2019 at 15:49, on Zulip):

(but I'm not inclined to do so; I'd rather r+ the PR, with rollup=never, and then let people find out if there are real performance regressions from it)

pnkfelix (Nov 28 2019 at 15:50, on Zulip):
centril (Nov 28 2019 at 15:50, on Zulip):

lang already discussed Box and perf numbers seem good, evenrollup=never is probably overkill

pnkfelix (Nov 28 2019 at 15:50, on Zulip):

namely, @Simon Sapin has put up PR #66841, which adds the intrinsics you'd need to recover the old "so awesomely fast and who cares about UB" behavior

pnkfelix (Nov 28 2019 at 15:52, on Zulip):

okay, that's all from me

pnkfelix (Nov 28 2019 at 15:52, on Zulip):

bye, thanks for joining @T-compiler/meeting !

centril (Nov 28 2019 at 15:53, on Zulip):

@pnkfelix what happened to never_type?

pnkfelix (Nov 28 2019 at 15:55, on Zulip):

pnkfelix what happened to never_type?

are you asking about an issue that should have been on the nominated list?

pnkfelix (Nov 28 2019 at 15:56, on Zulip):

I know that I curated the list that I put up for this week, rather than dynamically selecting from our usual overload of nominated issues. But I don't recall anything about never_type there, except for maybe the fallback issue which may be P-high, not nominated?

pnkfelix (Nov 28 2019 at 15:56, on Zulip):

oh and there's the bug about Infallible, maybe you mean that, @centril ?

centril (Nov 28 2019 at 15:56, on Zulip):

yea that one

centril (Nov 28 2019 at 15:57, on Zulip):

probably should circle back to T-lang?

pnkfelix (Nov 28 2019 at 15:57, on Zulip):

to be honest I wasn't certain from reading over the dialogue there whether that was a T-compiler matter to resolve

centril (Nov 28 2019 at 15:58, on Zulip):

I was joking on a rust-lang/reference issue that "I wonder how long it lasts" (the stabilization...) :D

pnkfelix (Nov 28 2019 at 15:58, on Zulip):

but at the same time I failed to tag it as T-lang

pnkfelix (Nov 28 2019 at 16:03, on Zulip):

okay now added comment to #66757 and tagged it as T-lang

Last update: Dec 12 2019 at 01:35UTC