std: Stabilize last bits of io::Error

This commit stabilizes a few remaining bits of the `io::Error` type:

* The `Error::new` method is now stable. The last `detail` parameter was removed
  and the second `desc` parameter was generalized to `E: Into<Box<Error>>` to
  allow creating an I/O error from any form of error. Currently there is no form
  of downcasting, but this will be added in time.

* An implementation of `From<&str> for Box<Error>` was added to liballoc to
  allow construction of errors from raw strings.

* The `Error::raw_os_error` method was stabilized as-is.

* Trait impls for `Clone`, `Eq`, and `PartialEq` were removed from `Error` as it
  is not possible to use them with trait objects.

This is a breaking change due to the modification of the `new` method as well as
the removal of the trait implementations for the `Error` type.

[breaking-change]

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 8eea06bf6b0..9abc30b7da8 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -165,7 +165,7 @@ impl<W: Write> BufWriter<W> {
             match self.inner.as_mut().unwrap().write(&self.buf[written..]) {
                 Ok(0) => {
                     ret = Err(Error::new(ErrorKind::WriteZero,
-                                         "failed to write the buffered data", None));
+                                         "failed to write the buffered data"));
                     break;
                 }
                 Ok(n) => written += n,