impl Clone for Cow
small doc fixes

We don't need this &mut, and vec could use []s
RFC 248? I think you meant RFC 438.

There ain’t an RFC 248, while 438 looks to be what is being referred to:
https://github.com/rust-lang/rfcs/blob/master/text/0438-precedence-of-plus.md
fix expand_quote_ty function as parse_ty was changed and needs no arguments now
Fix typo in reference.md
Allow trailing commas in array patterns and attributes
Simplify `RefCell` code a bit, make `deref` a no-op.
std: add tests for the Vec<u8> Writer impl
std: add Reader impl for &[u8]
Link regions in `ref` bindings from fn arguments.
better wording
replace 'but' with 'and'
Improve documentation of checked_* functions
Update comment to current file path for intrinsics
lldb: Fix pretty printer for nullable-opt enums with fat pointers.
gdb: Fix pretty printer for nullable-opt enums with fat pointers.
Utilize fewer reexports

In regards to:

https://github.com/rust-lang/rust/issues/19253#issuecomment-64836729

This commit:

* Changes the #deriving code so that it generates code that utilizes fewer
  reexports (in particur Option::* and Result::*), which is necessary to
  remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized
libcore: add `Rhs` input parameter to comparison traits
Test PartialEq multidispatch
Fixed out of date comment on `copy_memory`