Stabilize std::borrow #22210
Stabilize std::borrow #22210
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| /// } | ||
| /// ``` | ||
| #[stable(feature = "rust1", since = "1.0.0")] | ||
| pub enum Cow<'a, B: ?Sized + 'a> where B: ToOwned, <B as ToOwned>::Owned: 'a { |
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Could you explain why Owned now has a : 'a bound? The old implementation didn't have that. But, perhaps something changed?
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Other than the |
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(Also it's nice that |
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Have we pinged the community on the lost flexibility from BorrowFrom? I am always surprised what they manage to do with stuff. |
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The extra bounds were added because of #22246, which currently means we know less about associated types than we do type parameters that are used directly. Unfortunately, the bounds I added here are overly constraining, so this change is effectively blocked on the issue above. Actually, thinking more clearly about it there's no real loss in flexibility, because the coherence rules already basically rule out associating a different owned type with |
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| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT | |||
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How come this moved to libcollections?
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Needs a rebase, sorry. |
`no_late_bound_regions().unwrap()`, which allows us to write code that doesn't necessarily *fail* when there are higher-ranked trait bounds.
parameter environments so that it can be used elsewhere.
that it produces "outlives" relations for associated types. Add several tests relating to rust-lang#22246.
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@bors: r=alexcrichton ab59ee1 |
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This commit stabilizes `std::borrow`, making the following modifications to catch up the API with language changes: * It renames `BorrowFrom` to `Borrow`, as was originally intended (but blocked for technical reasons), and reorders the parameters accordingly. * It moves the type parameter of `ToOwned` to an associated type. This is somewhat less flexible, in that each borrowed type must have a unique owned type, but leads to a significant simplification for `Cow`. Flexibility can be regained by using newtyped slices, which is advisable for other reasons anyway. * It removes the owned type parameter from `Cow`, making the type much less verbose. * Deprecates the `is_owned` and `is_borrowed` predicates in favor of direct matching. The above API changes are relatively minor; the basic functionality remains the same, and essentially the whole module is now marked `#[stable]`. [breaking-change]
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Conflicts: src/libcollections/btree/map.rs src/libcollections/str.rs src/libcollections/vec.rs src/libcore/borrow.rs src/libcore/hash/mod.rs src/libstd/collections/hash/map.rs src/libstd/collections/hash/set.rs
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Merged in #22541 |
This commit stabilizes
std::borrow, making the following modificationsto catch up the API with language changes:
BorrowFromtoBorrow, as was originally intended (butblocked for technical reasons), and reorders the parameters
accordingly.
ToOwnedto an associated type. Thisis somewhat less flexible, in that each borrowed type must have a
unique owned type, but leads to a significant simplification for
Cow. Flexibility can be regained by using newtyped slices, which isadvisable for other reasons anyway.
Cow, making the type muchless verbose.
The above API changes are relatively minor; the basic functionality
remains the same, and essentially the whole module is now marked
#[stable].[breaking-change]
r? @alexcrichton @gankro