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Remove special-casing around AliasKind::Opaque when structurally resolving in new solver #119817

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merged 1 commit into from
Jan 12, 2024

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This fixes a few inconsistencies around where we don't eagerly resolve opaques to their (locally-defined) hidden types in the new solver. It essentially allows this code to work:

fn main() {
    type Tait = impl Sized;
    struct S {
        i: i32,
    }
    let x: Tait = S { i: 0 };
    println!("{}", x.i);
}

Since Tait is defined in main, we are able to poke through the type of x with deref.

r? lcnr

@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. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Jan 10, 2024
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rustbot commented Jan 10, 2024

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

{
return Some(ty);
}
if let DefineOpaqueTypes::No = define_opaque_types
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@compiler-errors compiler-errors Jan 10, 2024

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This is copied from #118915, since otherwise Opaque alias-eq ?0 won't reveal the opaque in Reveal::All mode.

The important part is the && let Reveal::UserFacing = param_env.reveal() line, since in reveal-all mode, we don't care if opaques are local or not, we always want to reveal them.

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r=me on the impl, but I am blocking this on #118915

@@ -23,7 +23,7 @@ impl<'tcx> StructurallyNormalizeExt<'tcx> for At<'_, 'tcx> {

if self.infcx.next_trait_solver() {
// FIXME(-Znext-solver): Should we resolve opaques here?
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remove the fixme

@lcnr lcnr added S-blocked Status: Blocked on something else such as an RFC or other implementation work. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 10, 2024
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lcnr commented Jan 12, 2024

@bors r+ rollup (new solver)

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bors commented Jan 12, 2024

📌 Commit 68c2f11 has been approved by lcnr

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-blocked Status: Blocked on something else such as an RFC or other implementation work. labels Jan 12, 2024
bors added a commit to rust-lang-ci/rust that referenced this pull request Jan 12, 2024
…llaumeGomez

Rollup of 6 pull requests

Successful merges:

 - rust-lang#119817 (Remove special-casing around `AliasKind::Opaque` when structurally resolving in new solver)
 - rust-lang#119819 (Check rust lints when an unknown lint is detected)
 - rust-lang#119872 (Give me a way to emit all the delayed bugs as errors (add `-Zeagerly-emit-delayed-bugs`))
 - rust-lang#119877 (Add more information to `visit_projection_elem`)
 - rust-lang#119884 (Rename `--env` option flag to `--env-set`)
 - rust-lang#119885 (Revert rust-lang#113923)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 46c3c01 into rust-lang:master Jan 12, 2024
11 checks passed
@rustbot rustbot added this to the 1.77.0 milestone Jan 12, 2024
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Jan 12, 2024
Rollup merge of rust-lang#119817 - compiler-errors:normalize-opaques, r=lcnr

Remove special-casing around `AliasKind::Opaque` when structurally resolving in new solver

This fixes a few inconsistencies around where we don't eagerly resolve opaques to their (locally-defined) hidden types in the new solver. It essentially allows this code to work:
```rust
fn main() {
    type Tait = impl Sized;
    struct S {
        i: i32,
    }
    let x: Tait = S { i: 0 };
    println!("{}", x.i);
}
```

Since `Tait` is defined in `main`, we are able to poke through the type of `x` with deref.

r? lcnr
@compiler-errors compiler-errors deleted the normalize-opaques branch January 12, 2024 23:38
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4 participants