Stream: wg-async-foundations

Topic: meeting 2019.12.17


tmandry (Dec 17 2019 at 18:00, on Zulip):

@WG-async-foundations meeting time!

tmandry (Dec 17 2019 at 18:02, on Zulip):

okay, let's start with issue triage

tmandry (Dec 17 2019 at 18:02, on Zulip):

Uncategorized issues

tmandry (Dec 17 2019 at 18:03, on Zulip):

Explain editions when trying to use async block in 2015 edition #67204

nikomatsakis (Dec 17 2019 at 18:04, on Zulip):

Hmm so this definitely seems confusing

tmandry (Dec 17 2019 at 18:04, on Zulip):

this error message seems pretty unfortunate

nikomatsakis (Dec 17 2019 at 18:05, on Zulip):

Yes.

nikomatsakis (Dec 17 2019 at 18:05, on Zulip):

It seems like @Esteban Küber and @centril are kind of debating how best to fix

nikomatsakis (Dec 17 2019 at 18:05, on Zulip):

I would put this as "on deck" but ideally @Esteban Küber could mentor somebody through it

nikomatsakis (Dec 17 2019 at 18:06, on Zulip):

I don't know how many "regular folks" will hit this

nikomatsakis (Dec 17 2019 at 18:06, on Zulip):

I know I have done, but mostly because I run rustc by hand pretty often

tmandry (Dec 17 2019 at 18:06, on Zulip):

yeah, sounds good

nikomatsakis (Dec 17 2019 at 18:06, on Zulip):

when testing out builds of the compiler

tmandry (Dec 17 2019 at 18:07, on Zulip):

ok, marked as OnDeck

tmandry (Dec 17 2019 at 18:07, on Zulip):

moving on

nikomatsakis (Dec 17 2019 at 18:07, on Zulip):

also add the Triaged label if you didn't

tmandry (Dec 17 2019 at 18:07, on Zulip):

ICE while compiling async/await code #67087

nikomatsakis (Dec 17 2019 at 18:08, on Zulip):

(I am reminded that I wanted to rework the queries, so that "focus" was just "those issues that are assigned")

Esteban Küber (Dec 17 2019 at 18:08, on Zulip):

Please chime on whether we want to make the more involved fix (including a parser change) or centrils idea to handle it later (which is slightly more verbose)

nikomatsakis (Dec 17 2019 at 18:08, on Zulip):

ok -- I was personally considering something even simpler, which would just be to look and say "ah an error at the async token, let's just tell them about async fn right there .."

nikomatsakis (Dec 17 2019 at 18:08, on Zulip):

but I guess the point would be to avoid a slew of other derived errors?

nikomatsakis (Dec 17 2019 at 18:10, on Zulip):

@tmandry seems like #67087 still doesn't have an issue to reproduce

tmandry (Dec 17 2019 at 18:10, on Zulip):

^^ it seems like @Esteban Küber's concern was that the parser also threw away the rest of the async block

nikomatsakis (Dec 17 2019 at 18:10, on Zulip):

I guess I'd either just leave it or mark it as triaged and suggest they remove the label later

tmandry (Dec 17 2019 at 18:11, on Zulip):

^^ it seems like Esteban Küber's concern was that the parser also threw away the rest of the async block

which I don't have a strong feeling about, personally

nikomatsakis (Dec 17 2019 at 18:12, on Zulip):

yeah I admit I didn't read too closely, I may not be understanding exactly what is happening

nikomatsakis (Dec 17 2019 at 18:12, on Zulip):

ok, I see

nikomatsakis (Dec 17 2019 at 18:12, on Zulip):

I was a bit confused

tmandry (Dec 17 2019 at 18:14, on Zulip):

I agree that esteban's approach will produce better diagnostics, and have no opinion on the complexity issue

tmandry (Dec 17 2019 at 18:15, on Zulip):

okay, it looks like you left some thoughts there

nikomatsakis (Dec 17 2019 at 18:15, on Zulip):

yeah

tmandry (Dec 17 2019 at 18:15, on Zulip):

ICE while compiling async/await code #67087

marked as triaged and left a note saying we'll revisit if there's a reproducer

tmandry (Dec 17 2019 at 18:16, on Zulip):

that's all of the untriaged issues for today

tmandry (Dec 17 2019 at 18:17, on Zulip):

Focus issues

tmandry (Dec 17 2019 at 18:17, on Zulip):

async fn presence affects an unrelated error message #66312

tmandry (Dec 17 2019 at 18:17, on Zulip):

@csmoe I saw that you left a backtrace in chat

tmandry (Dec 17 2019 at 18:18, on Zulip):

I guess it's not entirely clear what's happening from that

csmoe (Dec 17 2019 at 18:18, on Zulip):

csmoe I saw that you left a backtrace in chat

yes, got the debug log and backtraces, but don't know where to focus

nikomatsakis (Dec 17 2019 at 18:18, on Zulip):

if you want, I can try to take a look

nikomatsakis (Dec 17 2019 at 18:18, on Zulip):

it seems like you've been spinning on that for a while :(

csmoe (Dec 17 2019 at 18:19, on Zulip):

if you want, I can try to take a look

yes, help wanted :heart:

nikomatsakis (Dec 17 2019 at 18:20, on Zulip):

ok, maybe assign me for the moment then

tmandry (Dec 17 2019 at 18:20, on Zulip):

okay, anything else to discuss on this for now?

tmandry (Dec 17 2019 at 18:20, on Zulip):

if not, moving on

tmandry (Dec 17 2019 at 18:20, on Zulip):

Async-related type error messages defy expectations (in span location) #65180

tmandry (Dec 17 2019 at 18:21, on Zulip):

@csmoe have you been able to make any progress on this? or been preoccupied with the last issue?

csmoe (Dec 17 2019 at 18:23, on Zulip):

Async-related type error messages defy expectations (in span location) #65180

:sad: Fix for this issue was already there, but failed to min a repro case

nikomatsakis (Dec 17 2019 at 18:23, on Zulip):

maybe we should just give up

nikomatsakis (Dec 17 2019 at 18:23, on Zulip):

if it works

tmandry (Dec 17 2019 at 18:23, on Zulip):

oh, just noticed your PR

nikomatsakis (Dec 17 2019 at 18:23, on Zulip):

it doesn't seem worth wasting too much time on minimal reproductions

csmoe (Dec 17 2019 at 18:24, on Zulip):

Async-related type error messages defy expectations (in span location) #65180

:sad: Fix for this issue was already there, but failed to min a repro case

mixed with associate types and proc-macro :exhausted:

tmandry (Dec 17 2019 at 18:24, on Zulip):

yeah, sounds.. difficult

csmoe (Dec 17 2019 at 18:24, on Zulip):

it doesn't seem worth wasting too much time on minimal reproductions

okay, I'll reopen it

tmandry (Dec 17 2019 at 18:25, on Zulip):

sounds good, moving on

tmandry (Dec 17 2019 at 18:25, on Zulip):

non-send futures error at point of use, but could cite point of definition in some cases #64130

tmandry (Dec 17 2019 at 18:26, on Zulip):

@davidtwco now that both your PRs are merged, should we close this issue or leave it open?

nikomatsakis (Dec 17 2019 at 18:26, on Zulip):

I think we can maybe close it in favor of new bug reports

nikomatsakis (Dec 17 2019 at 18:27, on Zulip):

(@Aaron Hill opened a PR for some improvements, for example)

tmandry (Dec 17 2019 at 18:28, on Zulip):

okay, closed!

tmandry (Dec 17 2019 at 18:28, on Zulip):

async/await: awaiting inside a match block captures borrow too eagerly #57017

tmandry (Dec 17 2019 at 18:29, on Zulip):

@Aaron Hill are you still working on this?

nikomatsakis (Dec 17 2019 at 18:29, on Zulip):

@Aaron Hill and I had a long conversation about that the other day

nikomatsakis (Dec 17 2019 at 18:29, on Zulip):

I think they're still working on it

nikomatsakis (Dec 17 2019 at 18:30, on Zulip):

But it wasn't clear what the best way to be would fix it

tmandry (Dec 17 2019 at 18:30, on Zulip):

okay. looks like the PR is active

nikomatsakis (Dec 17 2019 at 18:30, on Zulip):

I believe the conversation was in #wg-async-foundations > "recorded types from MIR" PR #65782

nikomatsakis (Dec 17 2019 at 18:30, on Zulip):

hard problem

tmandry (Dec 17 2019 at 18:30, on Zulip):

alright, I guess we can continue to follow up in that thread then

tmandry (Dec 17 2019 at 18:31, on Zulip):

we're 1 min past the end of the meeting, and haven't gotten to OnDeck issues yet

Aaron Hill (Dec 17 2019 at 18:31, on Zulip):

Yes, I'm still working in that PR

tmandry (Dec 17 2019 at 18:31, on Zulip):

sorry.. I'm a bit slow today. still learning the ropes

nikomatsakis (Dec 17 2019 at 18:31, on Zulip):

we're 1 min past the end of the meeting, and haven't gotten to OnDeck issues yet

I think the idea here would not be to go through the issues one by one necessarily

nikomatsakis (Dec 17 2019 at 18:32, on Zulip):

but more to see if anybody is looking for something to do

Aaron Hill (Dec 17 2019 at 18:32, on Zulip):

Though as @nikomatsakis pointed out, specialization really makes things complicated

tmandry (Dec 17 2019 at 18:32, on Zulip):

but more to see if anybody is looking for something to do

okay. on that note, is anyone looking for something to do? :)

nikomatsakis (Dec 17 2019 at 18:33, on Zulip):

Not me :)

davidtwco (Dec 17 2019 at 18:34, on Zulip):

davidtwco now that both your PRs are merged, should we close this issue or leave it open?

I think close.

tmandry (Dec 17 2019 at 18:34, on Zulip):

oh, for reference
OnDeck issues

tmandry (Dec 17 2019 at 18:35, on Zulip):

no one has spoken up, but feel free to ping if you are looking for something

tmandry (Dec 17 2019 at 18:35, on Zulip):

okay, since we're over time already, I think we should wrap up

tmandry (Dec 17 2019 at 18:35, on Zulip):

:wave:

tmandry (Dec 17 2019 at 18:36, on Zulip):

thanks all for coming

nikomatsakis (Dec 17 2019 at 18:37, on Zulip):

Thanks @tmandry !

Last update: Jan 21 2020 at 08:20UTC