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compiler-errors opened this issue Nov 19, 2022 · 1 comment · Fixed by #113108
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Rust does not normalize opaque types with escaping bound vars #104601

compiler-errors opened this issue Nov 19, 2022 · 1 comment · Fixed by #113108
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A-impl-trait Area: `impl Trait`. Universally / existentially quantified anonymous types with static dispatch. F-type_alias_impl_trait `#[feature(type_alias_impl_trait)]` T-types Relevant to the types team, which will review and decide on the PR/issue.

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@compiler-errors
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compiler-errors commented Nov 19, 2022 •
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Opening this issue to record the fact that we don't normalize opaques with escaping bound vars in Reveal::All mode after #103509.

I am not aware of any impacts of this on regular rustc compilation sessions, at least not without using TAIT in some strange ways. However, this causes rust-lang/miri#2433 to reoccur, and makes me sad theoretically, since we should be revealing all opaques during monomorphization, for example.

Fixing this is not hard (43119d6, #100980), but doing it without incurring major performance penalties (#103423) is difficult.
@compiler-errors compiler-errors added A-impl-trait Area: `impl Trait`. Universally / existentially quantified anonymous types with static dispatch. T-types Relevant to the types team, which will review and decide on the PR/issue. labels Nov 19, 2022
@compiler-errors compiler-errors changed the title Normalizating Opaques with escaping bound vars Rust does not normalize opaque types with escaping bound vars Nov 19, 2022
@RalfJung RalfJung added the F-type_alias_impl_trait `#[feature(type_alias_impl_trait)]` label Nov 19, 2022
@RalfJung RalfJung mentioned this issue Nov 19, 2022
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@RalfJung
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FWIW the Miri ICE also needs type_alias_impl_trait.

@compiler-errors compiler-errors mentioned this issue Dec 20, 2022
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@compiler-errors compiler-errors mentioned this issue Jun 27, 2023
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@bors bors closed this as completed in a20a04e Jun 29, 2023
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A-impl-trait Area: `impl Trait`. Universally / existentially quantified anonymous types with static dispatch. F-type_alias_impl_trait `#[feature(type_alias_impl_trait)]` T-types Relevant to the types team, which will review and decide on the PR/issue.
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Normalize opaques with late-bound vars again compiler-errors/rust
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@RalfJung @compiler-errors