std: Rename Show/String to Debug/Display

This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md

* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
  RFC and audited implementations now have the `#[stable]` attribute
  * Integers and floats no longer print a suffix
  * Smart pointers no longer print details that they are a smart pointer
  * Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
  `Display` must be implemented. With the loss of `String`, this has moved into
  libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
  warned about due to warnings being emitted on stage1+

While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.

[breaking-change]
Closes #21436

10 files changed, 48 insertions, 47 deletions

diff --git a/src/libcollections/bit.rs b/src/libcollections/bit.rs
index efd056b0d66..605828567b3 100644
--- a/src/libcollections/bit.rs
+++ b/src/libcollections/bit.rs
@@ -972,7 +972,7 @@ impl Ord for Bitv {
 }
 
 #[stable]
-impl fmt::Show for Bitv {
+impl fmt::Debug for Bitv {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         for bit in self.iter() {
             try!(write!(fmt, "{}", if bit { 1u32 } else { 0u32 }));
@@ -1727,7 +1727,7 @@ impl BitvSet {
     }
 }
 
-impl fmt::Show for BitvSet {
+impl fmt::Debug for BitvSet {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(fmt, "BitvSet {{"));
         let mut first = true;
@@ -2622,7 +2622,7 @@ mod bitv_set_test {
         s.insert(10);
         s.insert(50);
         s.insert(2);
-        assert_eq!("BitvSet {1u, 2u, 10u, 50u}", format!("{:?}", s));
+        assert_eq!("BitvSet {1, 2, 10, 50}", format!("{:?}", s));
     }
 
     #[test]
diff --git a/src/libcollections/btree/map.rs b/src/libcollections/btree/map.rs
index c56592177b4..8c2f00a5695 100644
--- a/src/libcollections/btree/map.rs
+++ b/src/libcollections/btree/map.rs
@@ -22,7 +22,7 @@ use core::prelude::*;
 use core::borrow::BorrowFrom;
 use core::cmp::Ordering;
 use core::default::Default;
-use core::fmt::Show;
+use core::fmt::Debug;
 use core::hash::{Hash, Hasher};
 use core::iter::{Map, FromIterator};
 use core::ops::{Index, IndexMut};
@@ -871,7 +871,7 @@ impl<K: Ord, V: Ord> Ord for BTreeMap<K, V> {
 }
 
 #[stable]
-impl<K: Show, V: Show> Show for BTreeMap<K, V> {
+impl<K: Debug, V: Debug> Debug for BTreeMap<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "BTreeMap {{"));
 
diff --git a/src/libcollections/btree/set.rs b/src/libcollections/btree/set.rs
index 4d71f9dbea8..5966c11be1b 100644
--- a/src/libcollections/btree/set.rs
+++ b/src/libcollections/btree/set.rs
@@ -16,7 +16,7 @@ use core::prelude::*;
 use core::borrow::BorrowFrom;
 use core::cmp::Ordering::{self, Less, Greater, Equal};
 use core::default::Default;
-use core::fmt::Show;
+use core::fmt::Debug;
 use core::fmt;
 // NOTE(stage0) remove import after a snapshot
 #[cfg(stage0)]
@@ -592,7 +592,7 @@ impl<'a, 'b, T: Ord + Clone> BitOr<&'b BTreeSet<T>> for &'a BTreeSet<T> {
 }
 
 #[stable]
-impl<T: Show> Show for BTreeSet<T> {
+impl<T: Debug> Debug for BTreeSet<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "BTreeSet {{"));
 
@@ -892,7 +892,7 @@ mod test {
 
         let set_str = format!("{:?}", set);
 
-        assert_eq!(set_str, "BTreeSet {1i, 2i}");
+        assert_eq!(set_str, "BTreeSet {1, 2}");
         assert_eq!(format!("{:?}", empty), "BTreeSet {}");
     }
 }
diff --git a/src/libcollections/dlist.rs b/src/libcollections/dlist.rs
index cce8cf398e1..73fd806c907 100644
--- a/src/libcollections/dlist.rs
+++ b/src/libcollections/dlist.rs
@@ -874,7 +874,7 @@ impl<A: Clone> Clone for DList<A> {
 }
 
 #[stable]
-impl<A: fmt::Show> fmt::Show for DList<A> {
+impl<A: fmt::Debug> fmt::Debug for DList<A> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "DList ["));
 
@@ -1333,7 +1333,7 @@ mod tests {
     #[test]
     fn test_show() {
         let list: DList<int> = range(0i, 10).collect();
-        assert_eq!(format!("{:?}", list), "DList [0i, 1i, 2i, 3i, 4i, 5i, 6i, 7i, 8i, 9i]");
+        assert_eq!(format!("{:?}", list), "DList [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]");
 
         let list: DList<&str> = vec!["just", "one", "test", "more"].iter()
                                                                    .map(|&s| s)
diff --git a/src/libcollections/enum_set.rs b/src/libcollections/enum_set.rs
index 1b852d0ba68..a40a590c51a 100644
--- a/src/libcollections/enum_set.rs
+++ b/src/libcollections/enum_set.rs
@@ -31,7 +31,7 @@ pub struct EnumSet<E> {
 
 impl<E> Copy for EnumSet<E> {}
 
-impl<E:CLike+fmt::Show> fmt::Show for EnumSet<E> {
+impl<E:CLike + fmt::Debug> fmt::Debug for EnumSet<E> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(fmt, "EnumSet {{"));
         let mut first = true;
diff --git a/src/libcollections/ring_buf.rs b/src/libcollections/ring_buf.rs
index b9cb4be7c18..badd7a8d6cc 100644
--- a/src/libcollections/ring_buf.rs
+++ b/src/libcollections/ring_buf.rs
@@ -1611,7 +1611,7 @@ impl<A> Extend<A> for RingBuf<A> {
 }
 
 #[stable]
-impl<T: fmt::Show> fmt::Show for RingBuf<T> {
+impl<T: fmt::Debug> fmt::Debug for RingBuf<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "RingBuf ["));
 
@@ -1630,7 +1630,7 @@ mod tests {
     use self::Taggypar::*;
     use prelude::*;
     use core::iter;
-    use std::fmt::Show;
+    use std::fmt::Debug;
     use std::hash::{self, SipHasher};
     use test::Bencher;
     use test;
@@ -1678,7 +1678,7 @@ mod tests {
     }
 
     #[cfg(test)]
-    fn test_parameterized<T:Clone + PartialEq + Show>(a: T, b: T, c: T, d: T) {
+    fn test_parameterized<T:Clone + PartialEq + Debug>(a: T, b: T, c: T, d: T) {
         let mut deq = RingBuf::new();
         assert_eq!(deq.len(), 0);
         deq.push_front(a.clone());
@@ -2302,7 +2302,7 @@ mod tests {
     #[test]
     fn test_show() {
         let ringbuf: RingBuf<int> = range(0i, 10).collect();
-        assert_eq!(format!("{:?}", ringbuf), "RingBuf [0i, 1i, 2i, 3i, 4i, 5i, 6i, 7i, 8i, 9i]");
+        assert_eq!(format!("{:?}", ringbuf), "RingBuf [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]");
 
         let ringbuf: RingBuf<&str> = vec!["just", "one", "test", "more"].iter()
                                                                         .map(|&s| s)
diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs
index 988ec4c661f..82966727037 100644
--- a/src/libcollections/slice.rs
+++ b/src/libcollections/slice.rs
@@ -2476,19 +2476,19 @@ mod tests {
         }
         let empty: Vec<int> = vec![];
         test_show_vec!(empty, "[]");
-        test_show_vec!(vec![1i], "[1i]");
-        test_show_vec!(vec![1i, 2, 3], "[1i, 2i, 3i]");
+        test_show_vec!(vec![1i], "[1]");
+        test_show_vec!(vec![1i, 2, 3], "[1, 2, 3]");
         test_show_vec!(vec![vec![], vec![1u], vec![1u, 1u]],
-                       "[[], [1u], [1u, 1u]]");
+                       "[[], [1], [1, 1]]");
 
         let empty_mut: &mut [int] = &mut[];
         test_show_vec!(empty_mut, "[]");
         let v: &mut[int] = &mut[1];
-        test_show_vec!(v, "[1i]");
+        test_show_vec!(v, "[1]");
         let v: &mut[int] = &mut[1, 2, 3];
-        test_show_vec!(v, "[1i, 2i, 3i]");
+        test_show_vec!(v, "[1, 2, 3]");
         let v: &mut [&mut[uint]] = &mut[&mut[], &mut[1u], &mut[1u, 1u]];
-        test_show_vec!(v, "[[], [1u], [1u, 1u]]");
+        test_show_vec!(v, "[[], [1], [1, 1]]");
     }
 
     #[test]
diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
index 5d35d8a8679..e6f438ecded 100644
--- a/src/libcollections/string.rs
+++ b/src/libcollections/string.rs
@@ -18,6 +18,7 @@ use core::prelude::*;
 
 use core::borrow::{Cow, IntoCow};
 use core::default::Default;
+use core::error::Error;
 use core::fmt;
 use core::hash;
 use core::iter::FromIterator;
@@ -40,6 +41,7 @@ pub struct String {
 
 /// A possible error value from the `String::from_utf8` function.
 #[stable]
+#[derive(Show)]
 pub struct FromUtf8Error {
     bytes: Vec<u8>,
     error: Utf8Error,
@@ -48,6 +50,7 @@ pub struct FromUtf8Error {
 /// A possible error value from the `String::from_utf16` function.
 #[stable]
 #[allow(missing_copy_implementations)]
+#[derive(Show)]
 pub struct FromUtf16Error(());
 
 impl String {
@@ -680,30 +683,28 @@ impl FromUtf8Error {
     pub fn utf8_error(&self) -> Utf8Error { self.error }
 }
 
-impl fmt::Show for FromUtf8Error {
+#[stable]
+impl fmt::Display for FromUtf8Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(self, f)
+        fmt::Display::fmt(&self.error, f)
     }
 }
 
 #[stable]
-impl fmt::String for FromUtf8Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(&self.error, f)
-    }
+impl Error for FromUtf8Error {
+    fn description(&self) -> &str { "invalid utf-8" }
 }
 
-impl fmt::Show for FromUtf16Error {
+#[stable]
+impl fmt::Display for FromUtf16Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(self, f)
+        fmt::Display::fmt("invalid utf-16: lone surrogate found", f)
     }
 }
 
 #[stable]
-impl fmt::String for FromUtf16Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt("invalid utf-16: lone surrogate found", f)
-    }
+impl Error for FromUtf16Error {
+    fn description(&self) -> &str { "invalid utf-16" }
 }
 
 #[stable]
@@ -814,18 +815,18 @@ impl Default for String {
 }
 
 #[stable]
-impl fmt::String for String {
+impl fmt::Display for String {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(&**self, f)
+        fmt::Display::fmt(&**self, f)
     }
 }
 
-#[unstable = "waiting on fmt stabilization"]
-impl fmt::Show for String {
+#[stable]
+impl fmt::Debug for String {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Show::fmt(&**self, f)
+        fmt::Debug::fmt(&**self, f)
     }
 }
 
@@ -934,7 +935,7 @@ pub trait ToString {
     fn to_string(&self) -> String;
 }
 
-impl<T: fmt::String + ?Sized> ToString for T {
+impl<T: fmt::Display + ?Sized> ToString for T {
     #[inline]
     fn to_string(&self) -> String {
         use core::fmt::Writer;
@@ -1295,10 +1296,10 @@ mod tests {
     fn test_vectors() {
         let x: Vec<int> = vec![];
         assert_eq!(format!("{:?}", x), "[]");
-        assert_eq!(format!("{:?}", vec![1i]), "[1i]");
-        assert_eq!(format!("{:?}", vec![1i, 2, 3]), "[1i, 2i, 3i]");
+        assert_eq!(format!("{:?}", vec![1i]), "[1]");
+        assert_eq!(format!("{:?}", vec![1i, 2, 3]), "[1, 2, 3]");
         assert!(format!("{:?}", vec![vec![], vec![1i], vec![1i, 1]]) ==
-               "[[], [1i], [1i, 1i]]");
+               "[[], [1], [1, 1]]");
     }
 
     #[test]
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs
index 4ddab8c533a..0b20a3a5f75 100644
--- a/src/libcollections/vec.rs
+++ b/src/libcollections/vec.rs
@@ -1486,10 +1486,10 @@ impl<T> Default for Vec<T> {
     }
 }
 
-#[unstable = "waiting on Show stability"]
-impl<T: fmt::Show> fmt::Show for Vec<T> {
+#[stable]
+impl<T: fmt::Debug> fmt::Debug for Vec<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Show::fmt(self.as_slice(), f)
+        fmt::Debug::fmt(self.as_slice(), f)
     }
 }
 
diff --git a/src/libcollections/vec_map.rs b/src/libcollections/vec_map.rs
index 7ff2e953588..f178d5bc7e9 100644
--- a/src/libcollections/vec_map.rs
+++ b/src/libcollections/vec_map.rs
@@ -513,7 +513,7 @@ impl<V: Ord> Ord for VecMap<V> {
 }
 
 #[stable]
-impl<V: fmt::Show> fmt::Show for VecMap<V> {
+impl<V: fmt::Debug> fmt::Debug for VecMap<V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         try!(write!(f, "VecMap {{"));
 
@@ -990,7 +990,7 @@ mod test_map {
         map.insert(3, 4i);
 
         let map_str = format!("{:?}", map);
-        assert!(map_str == "VecMap {1: 2i, 3: 4i}" || map_str == "{3: 4i, 1: 2i}");
+        assert!(map_str == "VecMap {1: 2, 3: 4}" || map_str == "{3: 4, 1: 2}");
         assert_eq!(format!("{:?}", empty), "VecMap {}");
     }