This patch marks `PartialEq`, `Eq`, `PartialOrd`, and `Ord` as
`#[stable]`, as well as the majorify of manual implementaitons of these
traits. The traits match the [reform
RFC](https://github.com/rust-lang/rfcs/pull/439).
Along the way, two changes are made:
* The recently-added type parameters for `Ord` and `Eq` are
removed. These were mistakenly added while adding them to `PartialOrd`
and `PartialEq`, but they don't make sense given the laws that are
required for (and use cases for) `Ord` and `Eq`.
* More explicit laws are added for `PartialEq` and `PartialOrd`,
connecting them to their associated mathematical concepts.
In the future, many of the impls should be generalized; see
since generalizing later is not a breaking change.
[breaking-change]
This patch marks `clone` stable, as well as the `Clone` trait, but
leaves `clone_from` unstable. The latter will be decided by the beta.
The patch also marks most manual implementations of `Clone` as stable,
except where the APIs are otherwise deprecated or where there is
uncertainty about providing `Clone`.
This commit makes `Cow` more usable by allowing it to be applied to
unsized types (as was intended) and providing some basic `ToOwned`
implementations on slice types. It also corrects the documentation for
`Cow` to no longer mention `DerefMut`, and adds an example.
Closes#19123
This commit makes `Cow` more usable by allowing it to be applied to
unsized types (as was intended) and providing some basic `ToOwned`
implementations on slice types. It also corrects the documentation for
`Cow` to no longer mention `DerefMut`, and adds an example.
Following [the collections reform
RFC](https://github.com/rust-lang/rfcs/pull/235),
this commit adds a new `borrow` module to libcore.
The module contains traits for borrowing data (`BorrowFrom` and
`BorrowFromMut`),
generalized cloning (`ToOwned`), and a clone-on-write smartpointer (`Cow`).
