rollup merge of #21457: alexcrichton/issue-21436

Conflicts:
	src/liballoc/boxed.rs
	src/librustc/middle/traits/error_reporting.rs
	src/libstd/sync/mpsc/mod.rs

3 files changed, 31 insertions, 21 deletions

diff --git a/src/liballoc/arc.rs b/src/liballoc/arc.rs
index c0cd034abfa..5f8cd6baf9a 100644
--- a/src/liballoc/arc.rs
+++ b/src/liballoc/arc.rs
@@ -72,7 +72,7 @@ use core::prelude::*;
 use core::atomic;
 use core::atomic::Ordering::{Relaxed, Release, Acquire, SeqCst};
 use core::borrow::BorrowFrom;
-use core::fmt::{self, Show};
+use core::fmt;
 use core::cmp::{Ordering};
 use core::default::Default;
 use core::mem::{min_align_of, size_of};
@@ -578,16 +578,17 @@ impl<T: Ord> Ord for Arc<T> {
 #[stable]
 impl<T: Eq> Eq for Arc<T> {}
 
-impl<T: fmt::Show> fmt::Show for Arc<T> {
+#[stable]
+impl<T: fmt::Display> fmt::Display for Arc<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Arc({:?})", (**self))
+        fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable]
-impl<T: fmt::String> fmt::String for Arc<T> {
+impl<T: fmt::Debug> fmt::Debug for Arc<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(&**self, f)
+        fmt::Debug::fmt(&**self, f)
     }
 }
 
@@ -806,7 +807,7 @@ mod tests {
     #[test]
     fn show_arc() {
         let a = Arc::new(5u32);
-        assert!(format!("{:?}", a) == "Arc(5u32)")
+        assert_eq!(format!("{:?}", a), "5");
     }
 
     // Make sure deriving works with Arc<T>
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index dd953cabe7e..5ec08a1f254 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -16,17 +16,18 @@ use core::any::Any;
 use core::clone::Clone;
 use core::cmp::{PartialEq, PartialOrd, Eq, Ord, Ordering};
 use core::default::Default;
+use core::error::{Error, FromError};
 use core::fmt;
 use core::hash::{self, Hash};
 use core::iter::Iterator;
 use core::marker::Sized;
 use core::mem;
+use core::ops::{Deref, DerefMut};
 use core::option::Option;
 use core::ptr::Unique;
 use core::raw::TraitObject;
-use core::result::Result;
 use core::result::Result::{Ok, Err};
-use core::ops::{Deref, DerefMut};
+use core::result::Result;
 
 /// A value that represents the global exchange heap. This is the default
 /// place that the `box` keyword allocates into when no place is supplied.
@@ -157,20 +158,22 @@ impl BoxAny for Box<Any> {
     }
 }
 
-impl<T: ?Sized + fmt::Show> fmt::Show for Box<T> {
+#[stable]
+impl<T: fmt::Display + ?Sized> fmt::Display for Box<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Box({:?})", &**self)
+        fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable]
-impl<T: ?Sized + fmt::String> fmt::String for Box<T> {
+impl<T: fmt::Debug + ?Sized> fmt::Debug for Box<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(&**self, f)
+        fmt::Debug::fmt(&**self, f)
     }
 }
 
-impl fmt::Show for Box<Any> {
+#[stable]
+impl fmt::Debug for Box<Any> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.pad("Box<Any>")
     }
@@ -201,3 +204,9 @@ impl<'a, T> Iterator for Box<Iterator<Item=T> + 'a> {
         (**self).size_hint()
     }
 }
+
+impl<'a, E: Error + 'a> FromError<E> for Box<Error + 'a> {
+    fn from_error(err: E) -> Box<Error + 'a> {
+        Box::new(err)
+    }
+}
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 59bdd1e968c..f5a5025c665 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -606,17 +606,17 @@ impl<S: hash::Hasher, T: Hash<S>> Hash<S> for Rc<T> {
     }
 }
 
-#[unstable = "Show is experimental."]
-impl<T: fmt::Show> fmt::Show for Rc<T> {
+#[stable]
+impl<T: fmt::Display> fmt::Display for Rc<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Rc({:?})", **self)
+        fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable]
-impl<T: fmt::String> fmt::String for Rc<T> {
+impl<T: fmt::Debug> fmt::Debug for Rc<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(&**self, f)
+        fmt::Debug::fmt(&**self, f)
     }
 }
 
@@ -737,8 +737,8 @@ impl<T> Clone for Weak<T> {
     }
 }
 
-#[unstable = "Show is experimental."]
-impl<T: fmt::Show> fmt::Show for Weak<T> {
+#[stable]
+impl<T: fmt::Debug> fmt::Debug for Weak<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "(Weak)")
     }
@@ -1013,7 +1013,7 @@ mod tests {
     #[test]
     fn test_show() {
         let foo = Rc::new(75u);
-        assert!(format!("{:?}", foo) == "Rc(75u)")
+        assert_eq!(format!("{:?}", foo), "75");
     }
 
 }