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Enforce non-lifetime-binders in supertrait preds are not object safe #108842

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We can't construct vtables for these supertraits.

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rustbot commented Mar 7, 2023

r? @TaKO8Ki

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@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 7, 2023
fn super_predicates_have_non_lifetime_binders(
tcx: TyCtxt<'_>,
trait_def_id: DefId,
) -> SmallVec<[Span; 1]> {
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Perf: I guess we could bail early here if !tcx.features().non_lifetime_binders...

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Seems reasonable to me.

@compiler-errors compiler-errors added the F-non_lifetime_binders `#![feature(non_lifetime_binders)]` label Mar 10, 2023
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r? compiler

@rustbot rustbot assigned b-naber and unassigned TaKO8Ki Mar 20, 2023
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r=me with or without the nit.

@@ -921,6 +924,9 @@ impl ObjectSafetyViolation {
.into()
}
}
ObjectSafetyViolation::SupertraitNonLifetimeBinder(_) => {
format!("predicate cannot reference non-lifetime `for<...>` bound variables").into()
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Should me maybe use a more user-friendly error message here? Can we expect users to know what predicates are?

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i would hope if they're using non-lifetime binders, but I guess i can de-types-ify the message by saying "where clause" 😸

fn super_predicates_have_non_lifetime_binders(
tcx: TyCtxt<'_>,
trait_def_id: DefId,
) -> SmallVec<[Span; 1]> {
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Seems reasonable to me.

@compiler-errors compiler-errors force-pushed the non_lifetime_binders-object-safe branch from 7d28725 to 720cc40 Compare March 20, 2023 22:39
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b-naber commented Mar 20, 2023

Thanks.

@bors r+ rollup

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bors commented Mar 20, 2023

📌 Commit 720cc40 has been approved by b-naber

It is now in the queue for this repository.

@bors 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 Mar 20, 2023
Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Mar 21, 2023
…rs-object-safe, r=b-naber

Enforce non-lifetime-binders in supertrait preds are not object safe

We can't construct vtables for these supertraits.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Mar 21, 2023
…rs-object-safe, r=b-naber

Enforce non-lifetime-binders in supertrait preds are not object safe

We can't construct vtables for these supertraits.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Mar 21, 2023
…rs-object-safe, r=b-naber

Enforce non-lifetime-binders in supertrait preds are not object safe

We can't construct vtables for these supertraits.
Noratrieb added a commit to Noratrieb/rust that referenced this pull request Mar 21, 2023
…rs-object-safe, r=b-naber

Enforce non-lifetime-binders in supertrait preds are not object safe

We can't construct vtables for these supertraits.
bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 21, 2023
Rollup of 10 pull requests

Successful merges:

 - rust-lang#106434 (Document `Iterator::sum/product` for Option/Result)
 - rust-lang#108326 (Implement read_buf for a few more types)
 - rust-lang#108842 (Enforce non-lifetime-binders in supertrait preds are not object safe)
 - rust-lang#108896 (new solver: make all goal evaluation able to be automatically rerun )
 - rust-lang#109124 (Add `dist.compression-profile` option to control compression speed)
 - rust-lang#109240 (Walk un-shifted nested `impl Trait` in trait when setting up default trait method assumptions)
 - rust-lang#109385 (fix typo)
 - rust-lang#109386 (add myself to mailmap)
 - rust-lang#109390 (Custom MIR: Support aggregate expressions)
 - rust-lang#109408 (not *all* retags might be explicit in Runtime MIR)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 0ef4da1 into rust-lang:master Mar 21, 2023
@rustbot rustbot added this to the 1.70.0 milestone Mar 21, 2023
@compiler-errors compiler-errors deleted the non_lifetime_binders-object-safe branch August 11, 2023 20:11
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5 participants