Stabilize std::borrow #22210
Stabilize std::borrow #22210
Conversation
aturon
force-pushed
the
stab-final-borrow
branch
4 times, most recently
from
bf2b260 to
a5fd359
Compare
| /// } | ||
| /// ``` | ||
| #[stable(feature = "rust1", since = "1.0.0")] | ||
| pub enum Cow<'a, B: ?Sized + 'a> where B: ToOwned, <B as ToOwned>::Owned: 'a { |
There was a problem hiding this comment.
Could you explain why Owned now has a : 'a bound? The old implementation didn't have that. But, perhaps something changed?
|
Other than the |
|
(Also it's nice that |
|
Have we pinged the community on the lost flexibility from BorrowFrom? I am always surprised what they manage to do with stuff. |
|
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 |
| @@ -0,0 +1,310 @@ | |||
| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT | |||
There was a problem hiding this comment.
How come this moved to libcollections?
|
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.
aturon
force-pushed
the
stab-final-borrow
branch
from
a5fd359 to
96d2ba9
Compare
aturon
force-pushed
the
stab-final-borrow
branch
2 times, most recently
from
1a9467e to
a99e698
Compare
aturon
force-pushed
the
stab-final-borrow
branch
from
a99e698 to
ab59ee1
Compare
|
@bors: r=alexcrichton ab59ee1 |
aturon
force-pushed
the
stab-final-borrow
branch
from
ab59ee1 to
1d46e3b
Compare
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]
aturon
force-pushed
the
stab-final-borrow
branch
from
1d46e3b to
9b70775
Compare
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
|
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