Stabilize std::borrow

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]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/test/run-make/save-analysis/foo.rs b/src/test/run-make/save-analysis/foo.rs
index d90219b4221..b393afeef39 100644
--- a/src/test/run-make/save-analysis/foo.rs
+++ b/src/test/run-make/save-analysis/foo.rs
@@ -34,7 +34,7 @@ use std::mem::size_of;
 static uni: &'static str = "Les Miséééééééérables";
 static yy: usize = 25us;
 
-static bob: Option<std::vec::CowVec<'static, isize>> = None;
+static bob: Option<std::borrow::Cow<'static, [isize]>> = None;
 
 // buglink test - see issue #1337.