Stream: t-compiler/wg-nll

Topic: weekly meeting August 14


pnkfelix (Aug 14 2018 at 19:28, on Zulip):

Hi @WG-compiler-nll ; the weekly meeting will be held here in this (corrected) topic, starting in 2 minutes

pnkfelix (Aug 14 2018 at 19:32, on Zulip):

my internet at my temporary location continues to be terrible

pnkfelix (Aug 14 2018 at 19:33, on Zulip):

in any case, members of @WG-compiler-nll who have status updates to report should post them to the triage Paper; I see there are already some updates posted there.

pnkfelix (Aug 14 2018 at 19:35, on Zulip):

i've been semi-following progress over the past week++; I got impression that our main focus (or at least the one that Niko wanted more attention paid to?) was correctness concerns

pnkfelix (Aug 14 2018 at 19:36, on Zulip):

((of course continued improvements to diagnostics are welcome))

pnkfelix (Aug 14 2018 at 19:37, on Zulip):

for some reason, my browser's rendering of the paper triage document is not including actual hyperlinks for the numbered issues

pnkfelix (Aug 14 2018 at 19:37, on Zulip):

or wait, maybe some are just missing the actual hyperlinks...

davidtwco (Aug 14 2018 at 19:38, on Zulip):

I can't see any without hyperlinks at a glance.

DPC (Aug 14 2018 at 19:38, on Zulip):

yeh all have hyperlinks

pnkfelix (Aug 14 2018 at 19:38, on Zulip):

well in any case my internet woes mean I won't be attempted to fine tune the content there

pnkfelix (Aug 14 2018 at 19:38, on Zulip):

I'll leave that job up to you all

pnkfelix (Aug 14 2018 at 19:39, on Zulip):

(the #53124 is missing the link for me)

davidtwco (Aug 14 2018 at 19:39, on Zulip):

(I think it is just your end)

pnkfelix (Aug 14 2018 at 19:39, on Zulip):

but I'm suspecting its some local rendering issue

pnkfelix (Aug 14 2018 at 19:40, on Zulip):

anyway maybe someone else can attempt to summarize our status with respect to correctness, here in channel?

Santiago Pastorino (Aug 14 2018 at 19:40, on Zulip):

I'm getting back to rustc work this week but also I'm in Portland for Rustconf :)

pnkfelix (Aug 14 2018 at 19:40, on Zulip):

Just so I can feel like I'm aware of what's going on?

Santiago Pastorino (Aug 14 2018 at 19:40, on Zulip):

that's why I didn't fill the doc

pnkfelix (Aug 14 2018 at 19:40, on Zulip):

(the biggest correctness issue I'm aware of is the issue to respect user-provided type annotations, something that Niko put up a PR for that corrects a lot of the problems there but not all of them...)

davidtwco (Aug 14 2018 at 19:42, on Zulip):

I've not been too on top of the NLL PRs this week, I think the only correctness stuff going on is the type annotations that Niko is doing.

pnkfelix (Aug 14 2018 at 19:42, on Zulip):

also, in case anyone is not aware of it, I initiated the request to "stabilize" the NLL feature about 11 days ago: #43234

pnkfelix (Aug 14 2018 at 19:43, on Zulip):

I was a little surprised by the protocol here

Matthew Jasper (Aug 14 2018 at 19:43, on Zulip):

There's also the "fake access" for match doing too much access.

pnkfelix (Aug 14 2018 at 19:44, on Zulip):

@Matthew Jasper Oh that rings a bell; is that a NLL-sound issue, or an NLL-complete issue?

Matthew Jasper (Aug 14 2018 at 19:44, on Zulip):

NLL complete

pnkfelix (Aug 14 2018 at 19:45, on Zulip):

okay.

Matthew Jasper (Aug 14 2018 at 19:45, on Zulip):

#53114

pnkfelix (Aug 14 2018 at 19:45, on Zulip):

yes okay I think I remember seeing an issue that Niko and RalfJung filed about the fake match accesses...

pnkfelix (Aug 14 2018 at 19:47, on Zulip):

hmm maybe I am misremembering and thinking of #53198

pnkfelix (Aug 14 2018 at 19:48, on Zulip):

okay well in any case https://github.com/rust-lang/rust/issues?utf8=%E2%9C%93&q=is%3Aopen+is%3Aissue+label%3ANLL-sound+ is looking pretty good to me

pnkfelix (Aug 14 2018 at 19:50, on Zulip):

(assuming we can fix #47184 in a reasonable amount of time; I imagine I can tackle some of it either next week once I'm home (still on PTO but will have better internet and fewer distractions when Logan is asleep)...)

davidtwco (Aug 14 2018 at 19:50, on Zulip):

Is #51269 just needing a test or is there work to be done there?

pnkfelix (Aug 14 2018 at 19:50, on Zulip):

and #53172 is looking pretty good too

davidtwco (Aug 14 2018 at 19:52, on Zulip):

Are the remaining crates there not done because of errors or because it just hasn't been done?

Matthew Jasper (Aug 14 2018 at 19:52, on Zulip):

Yes, #51269 needs a decision on whether the code should be allowed or not.

pnkfelix (Aug 14 2018 at 19:52, on Zulip):

I think ... #51269 does still need a decision

pnkfelix (Aug 14 2018 at 19:52, on Zulip):

niko's comment there does not strike me as a decision

Matthew Jasper (Aug 14 2018 at 19:52, on Zulip):

The remaining crates are external deps AFAIK

pnkfelix (Aug 14 2018 at 19:52, on Zulip):

but rather as the beginning to a conversation

pnkfelix (Aug 14 2018 at 19:52, on Zulip):

:)

davidtwco (Aug 14 2018 at 19:52, on Zulip):

The remaining crates are external deps AFAIK

Makes sense. Is that issue done in that case?

pnkfelix (Aug 14 2018 at 19:53, on Zulip):

so wait are we basicaly done with #53172?

pnkfelix (Aug 14 2018 at 19:53, on Zulip):

So far that sounds like two votes for "closing as task complete"

davidtwco (Aug 14 2018 at 19:53, on Zulip):

Well, I'm not sure, I assume @Matthew Jasper is correct.

davidtwco (Aug 14 2018 at 19:54, on Zulip):

@memoryruins was the one working on this so he might know.

pnkfelix (Aug 14 2018 at 19:56, on Zulip):

"external dep" may be a relative notion here...

pnkfelix (Aug 14 2018 at 19:56, on Zulip):

liblibc is, AFAICT, a git submodule that is hosted in rust-lang/ github

pnkfelix (Aug 14 2018 at 19:57, on Zulip):

and libbacktrace and libcompiler_builtins (and stdsimd) are in rust-lang-nursery/ github

pnkfelix (Aug 14 2018 at 19:57, on Zulip):

So its not as obvious what the policy should be for them, as it would be for say crates that were on crates.io

pnkfelix (Aug 14 2018 at 19:57, on Zulip):

having said that

pnkfelix (Aug 14 2018 at 19:57, on Zulip):

I also see no need to change them

pnkfelix (Aug 14 2018 at 19:58, on Zulip):

so lets just close the issue

davidtwco (Aug 14 2018 at 19:59, on Zulip):

I opened #53351 after doing the compile-fail migration.

davidtwco (Aug 14 2018 at 20:00, on Zulip):

Someone who's particularly good at working out whether something is working as intended might want to look at that.

pnkfelix (Aug 14 2018 at 20:01, on Zulip):

i can do that

pnkfelix (Aug 14 2018 at 20:01, on Zulip):

i both have a bit of time and usually am pretty decent at the detective work necessary here

davidtwco (Aug 14 2018 at 20:02, on Zulip):

:thumbs_up:

pnkfelix (Aug 14 2018 at 20:02, on Zulip):

by the way: @davidtwco I don't know if @nikomatsakis already told you this

pnkfelix (Aug 14 2018 at 20:02, on Zulip):

but my usual way to deal with a test that fails in one mode but not another, when this is intended, is to tag an empty fn main() on the test with #[rustc_error]

pnkfelix (Aug 14 2018 at 20:03, on Zulip):

if you want me to provide more info on this, I can do so in a dedicated topic after the meeting

pnkfelix (Aug 14 2018 at 20:04, on Zulip):

((there do remain cases where it still made the most sense to use // ignore-test-compare-nll, but even then I think a lot of those cases are ones where the test is using revisions to explicitly encode the flags for AST-borrowck vs NLL vs something else when relevant...))

pnkfelix (Aug 14 2018 at 20:04, on Zulip):

okay that's 30 minutes and I'm tired of babbling

pnkfelix (Aug 14 2018 at 20:05, on Zulip):

are there any burning questions anyone wants to ask?

davidtwco (Aug 14 2018 at 20:05, on Zulip):

Yeah, I'm aware of that - @nikomatsakis has pointed it out and you have in a previous PR of mine too. I don't think most of them are using revisions. Not sure why I decided to go with the ignore-test-compare-nll comment but I'll try get that right in future.

pnkfelix (Aug 14 2018 at 20:07, on Zulip):

well its not a matter of "right" or "wrong"

pnkfelix (Aug 14 2018 at 20:08, on Zulip):

more like "Felix's way puts more work onto the autotest system, so that must be the best option" ;)

pnkfelix (Aug 14 2018 at 20:10, on Zulip):

but seriously: my thinking here is, if you use // ignore-test-compare-nll, then (unless there is some other similar variant test that does cover nll), then that's a case where we don't have anything double-checking when the NLL behavior changes on that case

pnkfelix (Aug 14 2018 at 20:10, on Zulip):

there are cases where that makes sense, but its not an avenue that I'd take lightly.

pnkfelix (Aug 14 2018 at 20:11, on Zulip):

Having said that, I'm not sure how many people take that much care when they see changes to the .stderr output

pnkfelix (Aug 14 2018 at 20:11, on Zulip):

there may be some people out there who are blindly passing --bless and committing the results, for all I know...

pnkfelix (Aug 14 2018 at 20:12, on Zulip):

(and if that's the case, then all the caution that I speak of is ... well, its not that important then...)

pnkfelix (Aug 14 2018 at 20:12, on Zulip):

But I'm babbling again

pnkfelix (Aug 14 2018 at 20:12, on Zulip):

okay well if there isn't anything else, then I'm going to see about diving into this list on #53351

davidtwco (Aug 14 2018 at 20:16, on Zulip):

That all makes sense.

nikomatsakis (Aug 15 2018 at 16:16, on Zulip):

hey all — sorry I missed the meeting — @pnkfelix regarding my thoughts on the focus, I do think we want to get all the sound/complete stuff buttoned down, but it seems to me that we're doing pretty good on that front (though we have to finish up the type annotation work). I need to get back to the type annot prob -- though I doubt I will do anything this week owing to RustConf -- but I confess I've mostly been worrying about perf lately.

Last update: Nov 22 2019 at 00:25UTC