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🔬 move to universe-based lifetimes #48536

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nikomatsakis opened this issue Feb 25, 2018 · 1 comment
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🔬 move to universe-based lifetimes #48536

nikomatsakis opened this issue Feb 25, 2018 · 1 comment
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@nikomatsakis
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A-lifetimes Area: Lifetimes / regions C-enhancement Category: An issue proposing an enhancement or a PR with one. C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-traits Working group: Traits, https://internals.rust-lang.org/t/announcing-traits-working-group/6804

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@nikomatsakis
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rustc currently uses a "leak-check"-based system for handling higher-ranked bounds. This design has a few flaws (e.g. #33684), and doesn't scale well to quantification over types and other things. @sgrif has been exploring moving to an alternate system, which I am dubbing the "universe" system. This is the system used by chalk.

The currently implementation is in these two PRs:

#47861
#48407

This issue exists to track the move for now.
@nikomatsakis nikomatsakis added the WG-traits Working group: Traits, https://internals.rust-lang.org/t/announcing-traits-working-group/6804 label Feb 25, 2018
@nikomatsakis nikomatsakis changed the title move to universe-based lifetimes 🔬 move to universe-based lifetimes Feb 25, 2018
@nikomatsakis nikomatsakis mentioned this issue Feb 25, 2018
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@jkordish jkordish added C-enhancement Category: An issue proposing an enhancement or a PR with one. A-lifetimes Area: Lifetimes / regions T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. labels May 6, 2018
nikomatsakis added a commit to nikomatsakis/rust that referenced this issue Jun 25, 2018
@nikomatsakis
introduce canonicalize_hr_query_hack
dd8e744 
As the comment explains, this is needed to prevent subtype from going
awry in higher-ranked cases, due to rust-lang#33684. The proper fix here is
introducing universes (rust-lang#48536).
nikomatsakis added a commit to nikomatsakis/rust that referenced this issue Jun 26, 2018
@nikomatsakis
introduce canonicalize_hr_query_hack
1acffad 
As the comment explains, this is needed to prevent subtype from going
awry in higher-ranked cases, due to rust-lang#33684. The proper fix here is
introducing universes (rust-lang#48536).
@nikomatsakis nikomatsakis self-assigned this Oct 9, 2018
@nikomatsakis
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Implemented in #55517

@mark-i-m mark-i-m mentioned this issue Apr 1, 2019
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@bugadani bugadani mentioned this issue Oct 12, 2020
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@nikomatsakis nikomatsakis

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A-lifetimes Area: Lifetimes / regions C-enhancement Category: An issue proposing an enhancement or a PR with one. C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-traits Working group: Traits, https://internals.rust-lang.org/t/announcing-traits-working-group/6804
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