Stream: t-compiler/wg-nll

Topic: #58840 cannot convert `ReScope(Node(238))` to a region vid


lqd (May 10 2019 at 00:41, on Zulip):

I think we still have issues with closures somehow, maybe fallout from the Universes PR. In particular @Matthew Jasper I was hoping #60449 would have fixed #58840 as a duplicate of #57464 since its error seemed so similar to your minimization (playground still ICEing on stable but not nightly) but the non-minimized repro project still ICEs on the latest nightly unfortunately. I'll try and minimize it if no one gets to that first.

lqd (May 10 2019 at 17:52, on Zulip):

I've pushed a version which is a bit more reduced but still far from minimal

lqd (May 10 2019 at 17:53, on Zulip):

I feel this error is still another strand in the ball of "unexpected region in query response" errors

lqd (May 10 2019 at 17:54, on Zulip):

this specific piece of code started ICEing in January, nightly-2019-01-04, but back then it was the older ICE in canonicalizer.rs

lqd (May 10 2019 at 17:57, on Zulip):

(IIRC this is the first nightly with Universes)

lqd (May 10 2019 at 17:58, on Zulip):

I dout it'll be especially useful to bisect for the new location of the ICE for this code ?

lqd (May 10 2019 at 18:13, on Zulip):

(in case it is helpful, it's nightly-2019-02-26 and I think it's probably the delay_span_bug from #58649 moving the ICE from the canonicalizer to universal_regions)

lqd (May 10 2019 at 18:14, on Zulip):

funny that all these happened with juniper_hyper :)

lqd (May 10 2019 at 18:20, on Zulip):

I'll try and keep reducing the code more and more, with juniper + hyper + futures + tokio it's still a bit big cough cough

lqd (May 11 2019 at 19:25, on Zulip):

ah nice, jethrogb has reduced it already ! playground

Matthew Jasper (May 11 2019 at 19:47, on Zulip):

https://github.com/rust-lang/rust/blob/3103fb2f72ad0443a354d4b6f5966645b5f85885/src/librustc/infer/opaque_types/mod.rs#L298

Matthew Jasper (May 11 2019 at 19:48, on Zulip):

We're skipping the new check in this case.

lqd (May 11 2019 at 19:54, on Zulip):

is the "we can just skip ahead" comment now incorrect because of universes ?

Matthew Jasper (May 11 2019 at 19:57, on Zulip):

It's incorrect because the relation that it's talking about is just a normal outlives predicate, which is not the same as what we're now doing.

lqd (May 11 2019 at 19:59, on Zulip):

I see

lqd (May 11 2019 at 19:59, on Zulip):

good find :thumbs_up:

lqd (May 11 2019 at 20:00, on Zulip):

so #60449 _should_ have fixed it, as expected

lqd (May 13 2019 at 12:52, on Zulip):

@Matthew Jasper :tada: on fixing it :)

lqd (May 14 2019 at 10:14, on Zulip):

I manually checked on the bigger repro on the latest nightly and we have the expected error instead of an ICE :thumbs_up:

lqd (May 14 2019 at 10:18, on Zulip):

what will juniper experience next !

Last update: Nov 21 2019 at 13:10UTC