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]

3 files changed, 3 insertions, 3 deletions

diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index a08b33b342b..eb6cb441606 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -435,7 +435,7 @@ impl ToSocketAddrs for str {
                 match $e {
                     Some(r) => r,
                     None => return Err(io::Error::new(io::ErrorKind::InvalidInput,
-                                                      $msg, None)),
+                                                      $msg)),
                 }
             )
         }
diff --git a/src/libstd/net/mod.rs b/src/libstd/net/mod.rs
index ee57300765e..a152b98822a 100644
--- a/src/libstd/net/mod.rs
+++ b/src/libstd/net/mod.rs
@@ -72,7 +72,7 @@ fn each_addr<A: ToSocketAddrs, F, T>(addr: A, mut f: F) -> io::Result<T>
     }
     Err(last_err.unwrap_or_else(|| {
         Error::new(ErrorKind::InvalidInput,
-                   "could not resolve to any addresses", None)
+                   "could not resolve to any addresses")
     }))
 }
 
diff --git a/src/libstd/net/udp.rs b/src/libstd/net/udp.rs
index 81151114962..511c2e3f8b2 100644
--- a/src/libstd/net/udp.rs
+++ b/src/libstd/net/udp.rs
@@ -76,7 +76,7 @@ impl UdpSocket {
         match try!(addr.to_socket_addrs()).next() {
             Some(addr) => self.0.send_to(buf, &addr),
             None => Err(Error::new(ErrorKind::InvalidInput,
-                                   "no addresses to send data to", None)),
+                                   "no addresses to send data to")),
         }
     }