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

6 files changed, 51 insertions, 68 deletions

diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 8c38bc009cc..c1244abbfcb 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -52,7 +52,8 @@ pub struct BufferedReader<R> {
     cap: uint,
 }
 
-impl<R> fmt::Show for BufferedReader<R> where R: fmt::Show {
+#[stable]
+impl<R> fmt::Debug for BufferedReader<R> where R: fmt::Debug {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "BufferedReader {{ reader: {:?}, buffer: {}/{} }}",
                self.inner, self.cap - self.pos, self.buf.len())
@@ -150,7 +151,8 @@ pub struct BufferedWriter<W> {
     pos: uint
 }
 
-impl<W> fmt::Show for BufferedWriter<W> where W: fmt::Show {
+#[stable]
+impl<W> fmt::Debug for BufferedWriter<W> where W: fmt::Debug {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "BufferedWriter {{ writer: {:?}, buffer: {}/{} }}",
                self.inner.as_ref().unwrap(), self.pos, self.buf.len())
@@ -249,7 +251,8 @@ pub struct LineBufferedWriter<W> {
     inner: BufferedWriter<W>,
 }
 
-impl<W> fmt::Show for LineBufferedWriter<W> where W: fmt::Show {
+#[stable]
+impl<W> fmt::Debug for LineBufferedWriter<W> where W: fmt::Debug {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "LineBufferedWriter {{ writer: {:?}, buffer: {}/{} }}",
                self.inner.inner, self.inner.pos, self.inner.buf.len())
@@ -339,7 +342,8 @@ pub struct BufferedStream<S> {
     inner: BufferedReader<InternalBufferedWriter<S>>
 }
 
-impl<S> fmt::Show for BufferedStream<S> where S: fmt::Show {
+#[stable]
+impl<S> fmt::Debug for BufferedStream<S> where S: fmt::Debug {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         let reader = &self.inner;
         let writer = &self.inner.inner.0;
diff --git a/src/libstd/io/fs.rs b/src/libstd/io/fs.rs
index 64406d88253..cc36c5640d0 100644
--- a/src/libstd/io/fs.rs
+++ b/src/libstd/io/fs.rs
@@ -156,7 +156,7 @@ impl File {
                 })
             }
         }).update_err("couldn't open path as file", |e| {
-            format!("{}; path={:?}; mode={}; access={}", e, path.display(),
+            format!("{}; path={}; mode={}; access={}", e, path.display(),
                 mode_string(mode), access_string(access))
         })
     }
@@ -211,7 +211,7 @@ impl File {
     pub fn fsync(&mut self) -> IoResult<()> {
         self.fd.fsync()
             .update_err("couldn't fsync file",
-                        |e| format!("{}; path={:?}", e, self.path.display()))
+                        |e| format!("{}; path={}", e, self.path.display()))
     }
 
     /// This function is similar to `fsync`, except that it may not synchronize
@@ -221,7 +221,7 @@ impl File {
     pub fn datasync(&mut self) -> IoResult<()> {
         self.fd.datasync()
             .update_err("couldn't datasync file",
-                        |e| format!("{}; path={:?}", e, self.path.display()))
+                        |e| format!("{}; path={}", e, self.path.display()))
     }
 
     /// Either truncates or extends the underlying file, updating the size of
@@ -235,7 +235,7 @@ impl File {
     pub fn truncate(&mut self, size: i64) -> IoResult<()> {
         self.fd.truncate(size)
             .update_err("couldn't truncate file", |e|
-                format!("{}; path={:?}; size={:?}", e, self.path.display(), size))
+                format!("{}; path={}; size={}", e, self.path.display(), size))
     }
 
     /// Returns true if the stream has reached the end of the file.
@@ -255,7 +255,7 @@ impl File {
     pub fn stat(&self) -> IoResult<FileStat> {
         self.fd.fstat()
             .update_err("couldn't fstat file", |e|
-                format!("{}; path={:?}", e, self.path.display()))
+                format!("{}; path={}", e, self.path.display()))
     }
 }
 
@@ -283,7 +283,7 @@ impl File {
 pub fn unlink(path: &Path) -> IoResult<()> {
     fs_imp::unlink(path)
            .update_err("couldn't unlink path", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 /// Given a path, query the file system to get information about a file,
@@ -310,7 +310,7 @@ pub fn unlink(path: &Path) -> IoResult<()> {
 pub fn stat(path: &Path) -> IoResult<FileStat> {
     fs_imp::stat(path)
            .update_err("couldn't stat path", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 /// Perform the same operation as the `stat` function, except that this
@@ -324,7 +324,7 @@ pub fn stat(path: &Path) -> IoResult<FileStat> {
 pub fn lstat(path: &Path) -> IoResult<FileStat> {
     fs_imp::lstat(path)
            .update_err("couldn't lstat path", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 /// Rename a file or directory to a new name.
@@ -424,14 +424,14 @@ pub fn copy(from: &Path, to: &Path) -> IoResult<()> {
 pub fn chmod(path: &Path, mode: io::FilePermission) -> IoResult<()> {
     fs_imp::chmod(path, mode.bits() as uint)
            .update_err("couldn't chmod path", |e|
-               format!("{}; path={:?}; mode={:?}", e, path.display(), mode))
+               format!("{}; path={}; mode={:?}", e, path.display(), mode))
 }
 
 /// Change the user and group owners of a file at the specified path.
 pub fn chown(path: &Path, uid: int, gid: int) -> IoResult<()> {
     fs_imp::chown(path, uid, gid)
            .update_err("couldn't chown path", |e|
-               format!("{}; path={:?}; uid={}; gid={}", e, path.display(), uid, gid))
+               format!("{}; path={}; uid={}; gid={}", e, path.display(), uid, gid))
 }
 
 /// Creates a new hard link on the filesystem. The `dst` path will be a
@@ -460,7 +460,7 @@ pub fn symlink(src: &Path, dst: &Path) -> IoResult<()> {
 pub fn readlink(path: &Path) -> IoResult<Path> {
     fs_imp::readlink(path)
            .update_err("couldn't resolve symlink for path", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 /// Create a new, empty directory at the provided path
@@ -483,7 +483,7 @@ pub fn readlink(path: &Path) -> IoResult<Path> {
 pub fn mkdir(path: &Path, mode: FilePermission) -> IoResult<()> {
     fs_imp::mkdir(path, mode.bits() as uint)
            .update_err("couldn't create directory", |e|
-               format!("{}; path={:?}; mode={:?}", e, path.display(), mode))
+               format!("{}; path={}; mode={}", e, path.display(), mode))
 }
 
 /// Remove an existing, empty directory
@@ -505,7 +505,7 @@ pub fn mkdir(path: &Path, mode: FilePermission) -> IoResult<()> {
 pub fn rmdir(path: &Path) -> IoResult<()> {
     fs_imp::rmdir(path)
            .update_err("couldn't remove directory", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 /// Retrieve a vector containing all entries within a provided directory
@@ -545,7 +545,7 @@ pub fn rmdir(path: &Path) -> IoResult<()> {
 pub fn readdir(path: &Path) -> IoResult<Vec<Path>> {
     fs_imp::readdir(path)
            .update_err("couldn't read directory",
-                       |e| format!("{}; path={:?}", e, path.display()))
+                       |e| format!("{}; path={}", e, path.display()))
 }
 
 /// Returns an iterator that will recursively walk the directory structure
@@ -555,7 +555,7 @@ pub fn readdir(path: &Path) -> IoResult<Vec<Path>> {
 pub fn walk_dir(path: &Path) -> IoResult<Directories> {
     Ok(Directories {
         stack: try!(readdir(path).update_err("couldn't walk directory",
-                                             |e| format!("{}; path={:?}", e, path.display())))
+                                             |e| format!("{}; path={}", e, path.display())))
     })
 }
 
@@ -605,7 +605,7 @@ pub fn mkdir_recursive(path: &Path, mode: FilePermission) -> IoResult<()> {
 
         let result = mkdir(&curpath, mode)
             .update_err("couldn't recursively mkdir",
-                        |e| format!("{}; path={:?}", e, path.display()));
+                        |e| format!("{}; path={}", e, path.display()));
 
         match result {
             Err(mkdir_err) => {
@@ -632,7 +632,7 @@ pub fn rmdir_recursive(path: &Path) -> IoResult<()> {
     rm_stack.push(path.clone());
 
     fn rmdir_failed(err: &IoError, path: &Path) -> String {
-        format!("rmdir_recursive failed; path={:?}; cause={}",
+        format!("rmdir_recursive failed; path={}; cause={}",
                 path.display(), err)
     }
 
@@ -692,14 +692,14 @@ pub fn rmdir_recursive(path: &Path) -> IoResult<()> {
 pub fn change_file_times(path: &Path, atime: u64, mtime: u64) -> IoResult<()> {
     fs_imp::utime(path, atime, mtime)
            .update_err("couldn't change_file_times", |e|
-               format!("{}; path={:?}", e, path.display()))
+               format!("{}; path={}", e, path.display()))
 }
 
 impl Reader for File {
     fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
         fn update_err<T>(result: IoResult<T>, file: &File) -> IoResult<T> {
             result.update_err("couldn't read file",
-                              |e| format!("{}; path={:?}",
+                              |e| format!("{}; path={}",
                                           e, file.path.display()))
         }
 
@@ -722,7 +722,7 @@ impl Writer for File {
     fn write(&mut self, buf: &[u8]) -> IoResult<()> {
         self.fd.write(buf)
             .update_err("couldn't write to file",
-                        |e| format!("{}; path={:?}", e, self.path.display()))
+                        |e| format!("{}; path={}", e, self.path.display()))
     }
 }
 
@@ -730,7 +730,7 @@ impl Seek for File {
     fn tell(&self) -> IoResult<u64> {
         self.fd.tell()
             .update_err("couldn't retrieve file cursor (`tell`)",
-                        |e| format!("{}; path={:?}", e, self.path.display()))
+                        |e| format!("{}; path={}", e, self.path.display()))
     }
 
     fn seek(&mut self, pos: i64, style: SeekStyle) -> IoResult<()> {
@@ -743,7 +743,7 @@ impl Seek for File {
             Err(e) => Err(e),
         };
         err.update_err("couldn't seek in file",
-                       |e| format!("{}; path={:?}", e, self.path.display()))
+                       |e| format!("{}; path={}", e, self.path.display()))
     }
 }
 
@@ -906,7 +906,7 @@ mod test {
         if cfg!(unix) {
             error!(result, "no such file or directory");
         }
-        error!(result, format!("path={:?}; mode=open; access=read", filename.display()));
+        error!(result, format!("path={}; mode=open; access=read", filename.display()));
     }
 
     #[test]
@@ -920,7 +920,7 @@ mod test {
         if cfg!(unix) {
             error!(result, "no such file or directory");
         }
-        error!(result, format!("path={:?}", filename.display()));
+        error!(result, format!("path={}", filename.display()));
     }
 
     #[test]
@@ -1188,7 +1188,7 @@ mod test {
         error!(result, "couldn't recursively mkdir");
         error!(result, "couldn't create directory");
         error!(result, "mode=0700");
-        error!(result, format!("path={:?}", file.display()));
+        error!(result, format!("path={}", file.display()));
     }
 
     #[test]
diff --git a/src/libstd/io/mem.rs b/src/libstd/io/mem.rs
index ee05a9e5596..e281bd3d7e8 100644
--- a/src/libstd/io/mem.rs
+++ b/src/libstd/io/mem.rs
@@ -432,8 +432,8 @@ mod test {
             writer.write(&[]).unwrap();
             assert_eq!(writer.tell(), Ok(8));
 
-            assert_eq!(writer.write(&[8, 9]).unwrap_err().kind, io::ShortWrite(1));
-            assert_eq!(writer.write(&[10]).unwrap_err().kind, io::EndOfFile);
+            assert_eq!(writer.write(&[8, 9]).err().unwrap().kind, io::ShortWrite(1));
+            assert_eq!(writer.write(&[10]).err().unwrap().kind, io::EndOfFile);
         }
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
         assert_eq!(buf, b);
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index dc21416df7b..bc86511165e 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -228,13 +228,12 @@ pub use self::FileAccess::*;
 pub use self::IoErrorKind::*;
 
 use char::CharExt;
-use clone::Clone;
 use default::Default;
-use error::{FromError, Error};
+use error::Error;
 use fmt;
 use int;
 use iter::{Iterator, IteratorExt};
-use marker::{Sized, Send};
+use marker::Sized;
 use mem::transmute;
 use ops::FnOnce;
 use option::Option;
@@ -340,7 +339,8 @@ impl IoError {
     }
 }
 
-impl fmt::String for IoError {
+#[stable]
+impl fmt::Display for IoError {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             IoError { kind: OtherIoError, desc: "unknown error", detail: Some(ref detail) } =>
@@ -354,19 +354,7 @@ impl fmt::String for IoError {
 }
 
 impl Error for IoError {
-    fn description(&self) -> &str {
-        self.desc
-    }
-
-    fn detail(&self) -> Option<String> {
-        self.detail.clone()
-    }
-}
-
-impl FromError<IoError> for Box<Error + Send> {
-    fn from_error(err: IoError) -> Box<Error + Send> {
-        box err
-    }
+    fn description(&self) -> &str { self.desc }
 }
 
 /// A list specifying general categories of I/O error.
@@ -1781,6 +1769,7 @@ pub struct UnstableFileStat {
 bitflags! {
     /// A set of permissions for a file or directory is represented by a set of
     /// flags which are or'd together.
+    #[derive(Show)]
     flags FilePermission: u32 {
         const USER_READ     = 0o400,
         const USER_WRITE    = 0o200,
@@ -1822,13 +1811,8 @@ impl Default for FilePermission {
     fn default() -> FilePermission { FilePermission::empty() }
 }
 
-impl fmt::Show for FilePermission {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(self, f)
-    }
-}
-
-impl fmt::String for FilePermission {
+#[stable]
+impl fmt::Display for FilePermission {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{:04o}", self.bits)
     }
diff --git a/src/libstd/io/net/ip.rs b/src/libstd/io/net/ip.rs
index adc122ff447..e8e065533e5 100644
--- a/src/libstd/io/net/ip.rs
+++ b/src/libstd/io/net/ip.rs
@@ -38,7 +38,8 @@ pub enum IpAddr {
     Ipv6Addr(u16, u16, u16, u16, u16, u16, u16, u16)
 }
 
-impl fmt::String for IpAddr {
+#[stable]
+impl fmt::Display for IpAddr {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             Ipv4Addr(a, b, c, d) =>
@@ -69,7 +70,8 @@ pub struct SocketAddr {
     pub port: Port,
 }
 
-impl fmt::String for SocketAddr {
+#[stable]
+impl fmt::Display for SocketAddr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.ip {
             Ipv4Addr(..) => write!(f, "{}:{}", self.ip, self.port),
diff --git a/src/libstd/io/process.rs b/src/libstd/io/process.rs
index 43ca7b13145..7b0a86777f6 100644
--- a/src/libstd/io/process.rs
+++ b/src/libstd/io/process.rs
@@ -397,7 +397,7 @@ impl Command {
     }
 }
 
-impl fmt::String for Command {
+impl fmt::Debug for Command {
     /// Format the program and arguments of a Command for display. Any
     /// non-utf8 data is lossily converted using the utf8 replacement
     /// character.
@@ -496,7 +496,7 @@ pub enum StdioContainer {
 
 /// Describes the result of a process after it has terminated.
 /// Note that Windows have no signals, so the result is usually ExitStatus.
-#[derive(PartialEq, Eq, Clone, Copy)]
+#[derive(PartialEq, Eq, Clone, Copy, Show)]
 pub enum ProcessExit {
     /// Normal termination with an exit status.
     ExitStatus(int),
@@ -505,15 +505,8 @@ pub enum ProcessExit {
     ExitSignal(int),
 }
 
-impl fmt::Show for ProcessExit {
-    /// Format a ProcessExit enum, to nicely present the information.
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::String::fmt(self, f)
-    }
-}
-
-
-impl fmt::String for ProcessExit {
+#[stable]
+impl fmt::Display for ProcessExit {
     /// Format a ProcessExit enum, to nicely present the information.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {