Remove incorrect `delay_span_bug`#81532

estebank · 2021-01-29T19:49:22Z

The following code is supposed to compile

use std::ops::BitOr;

pub trait IntWrapper {
    type InternalStorage;
}

impl<T> BitOr for dyn IntWrapper<InternalStorage = T>
where
    Self: Sized,
    T: BitOr + BitOr<Output = T>,
{
    type Output = Self;
    fn bitor(self, _other: Self) -> Self {
        todo!()
    }
}

Before this change it would ICE. In #70998 the removed logic was added
to provide better suggestions, and the delay_span_bug guard was added
to protect against a potential logic error when returning traits. As it
happens, there are cases, like the one above, where traits can indeed be
returned, so valid code was being rejected.

Fix (but not close) #80207.

rust-highfive · 2021-01-29T19:49:25Z

r? @Mark-Simulacrum

(rust-highfive has picked a reviewer for you, use r? to override)

nagisa · 2021-01-29T21:51:58Z

Can the repro be added as a test case?

Mark-Simulacrum · 2021-01-31T22:42:01Z

r? @nagisa (or feel free to reassign, but this looks potentially urgent and I don't have the right knowledge to approve quickly I think)

nagisa · 2021-01-31T22:45:19Z

Yeah this seems reasonable enough to me, but this does need a regression test.

nagisa · 2021-01-31T22:52:18Z

Also cc @varkor who r=d the original PR.

The following code is supposed to compile ```rust use std::ops::BitOr; pub trait IntWrapper { type InternalStorage; } impl<T> BitOr for dyn IntWrapper<InternalStorage = T> where Self: Sized, T: BitOr + BitOr<Output = T>, { type Output = Self; fn bitor(self, _other: Self) -> Self { todo!() } } ``` Before this change it would ICE. In rust-lang#70998 the removed logic was added to provide better suggestions, and the `delay_span_bug` guard was added to protect against a potential logic error when returning traits. As it happens, there are cases, like the one above, where traits can indeed be returned, so valid code was being rejected. Fix rust-lang#80207.

estebank · 2021-02-03T16:53:58Z

r? @pnkfelix (just for expedience)

pnkfelix · 2021-02-03T17:03:34Z

@bors r+ p=10

bors · 2021-02-03T17:03:35Z

📌 Commit ede0a71 has been approved by pnkfelix

Rollup of 5 pull requests Successful merges: - rust-lang#80394 (make const_err a future incompat lint) - rust-lang#81532 (Remove incorrect `delay_span_bug`) - rust-lang#81692 (Update clippy) - rust-lang#81715 (Reduce tab formatting assertions to debug only) - rust-lang#81716 (Fix non-existent-field ICE for generic fields.) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

bors · 2021-02-03T20:52:54Z

⌛ Testing commit ede0a71 with merge 120b2a7...

apiraino · 2021-02-04T16:08:27Z

Beta backport approved, stable backport declined as per team compiler meeting, also mentioned here.

Remove incorrect `delay_span_bug` The following code is supposed to compile ```rust use std::ops::BitOr; pub trait IntWrapper { type InternalStorage; } impl<T> BitOr for dyn IntWrapper<InternalStorage = T> where Self: Sized, T: BitOr + BitOr<Output = T>, { type Output = Self; fn bitor(self, _other: Self) -> Self { todo!() } } ``` Before this change it would ICE. In rust-lang#70998 the removed logic was added to provide better suggestions, and the `delay_span_bug` guard was added to protect against a potential logic error when returning traits. As it happens, there are cases, like the one above, where traits can indeed be returned, so valid code was being rejected. Fix (but not close) rust-lang#80207.

[beta] backports This backports: * CI: only copy python.exe to python3.exe if the latter does not exist rust-lang#81762 * Make hitting the recursion limit in projection non-fatal rust-lang#81055 * Remove incorrect `delay_span_bug` rust-lang#81532 * introduce future-compatibility warning for forbidden lint groups rust-lang#81556 * Update cargo rust-lang#81755 * rustdoc: Fix visibility of trait and impl items rust-lang#81288 * Work around missing -dev packages in solaris docker image. rust-lang#81229 * Update LayoutError/LayoutErr stability attributes rust-lang#81767 * Revert 78373 ("dont leak return value after panic in drop") rust-lang#81257 * Rename `panic_fmt` lint to `non_fmt_panic` rust-lang#81729

estebank added beta-nominated Nominated for backporting to the compiler in the beta channel. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. stable-nominated Nominated for backporting to the compiler in the stable channel. labels Jan 29, 2021

rust-highfive assigned Mark-Simulacrum Jan 29, 2021

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 29, 2021

rust-highfive assigned nagisa and unassigned Mark-Simulacrum Jan 31, 2021

estebank force-pushed the ice-ice-baby branch from dfc7bdc to ede0a71 Compare February 3, 2021 16:53

rust-highfive assigned pnkfelix and unassigned nagisa Feb 3, 2021

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 3, 2021

m-ou-se mentioned this pull request Feb 3, 2021

Rollup of 5 pull requests #81718

Merged

bors merged commit 6695944 into rust-lang:master Feb 3, 2021

rustbot added this to the 1.51.0 milestone Feb 3, 2021

apiraino added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Feb 4, 2021

ehuss mentioned this pull request Feb 5, 2021

[beta] backports #81774

Merged

ehuss removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Feb 5, 2021

apiraino removed the stable-nominated Nominated for backporting to the compiler in the stable channel. label Feb 10, 2021

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Remove incorrect `delay_span_bug`#81532