Update for Rust nightly 2018-04-19

6 files changed, 562 insertions, 496 deletions

diff --git a/ctr-std/src/io/buffered.rs b/ctr-std/src/io/buffered.rs
index 4e7db5f..d6eac74 100644
--- a/ctr-std/src/io/buffered.rs
+++ b/ctr-std/src/io/buffered.rs
@@ -25,26 +25,32 @@ use memchr;
 /// results in a system call. A `BufReader` performs large, infrequent reads on
 /// the underlying [`Read`] and maintains an in-memory buffer of the results.
 ///
+/// `BufReader` can improve the speed of programs that make *small* and
+/// *repeated* read calls to the same file or network socket.  It does not
+/// help when reading very large amounts at once, or reading just one or a few
+/// times.  It also provides no advantage when reading from a source that is
+/// already in memory, like a `Vec<u8>`.
+///
 /// [`Read`]: ../../std/io/trait.Read.html
 /// [`TcpStream::read`]: ../../std/net/struct.TcpStream.html#method.read
 /// [`TcpStream`]: ../../std/net/struct.TcpStream.html
 ///
 /// # Examples
 ///
-/// ```
+/// ```no_run
 /// use std::io::prelude::*;
 /// use std::io::BufReader;
 /// use std::fs::File;
 ///
-/// # fn foo() -> std::io::Result<()> {
-/// let f = File::open("log.txt")?;
-/// let mut reader = BufReader::new(f);
+/// fn main() -> std::io::Result<()> {
+///     let f = File::open("log.txt")?;
+///     let mut reader = BufReader::new(f);
 ///
-/// let mut line = String::new();
-/// let len = reader.read_line(&mut line)?;
-/// println!("First line is {} bytes long", len);
-/// # Ok(())
-/// # }
+///     let mut line = String::new();
+///     let len = reader.read_line(&mut line)?;
+///     println!("First line is {} bytes long", len);
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct BufReader<R> {
@@ -59,15 +65,15 @@ impl<R: Read> BufReader<R> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::BufReader;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f = File::open("log.txt")?;
-    /// let reader = BufReader::new(f);
-    /// # Ok(())
-    /// # }
+    /// fn main() -> std::io::Result<()> {
+    ///     let f = File::open("log.txt")?;
+    ///     let reader = BufReader::new(f);
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new(inner: R) -> BufReader<R> {
@@ -80,15 +86,15 @@ impl<R: Read> BufReader<R> {
     ///
     /// Creating a buffer with ten bytes of capacity:
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::BufReader;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f = File::open("log.txt")?;
-    /// let reader = BufReader::with_capacity(10, f);
-    /// # Ok(())
-    /// # }
+    /// fn main() -> std::io::Result<()> {
+    ///     let f = File::open("log.txt")?;
+    ///     let reader = BufReader::with_capacity(10, f);
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn with_capacity(cap: usize, inner: R) -> BufReader<R> {
@@ -111,17 +117,17 @@ impl<R: Read> BufReader<R> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::BufReader;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f1 = File::open("log.txt")?;
-    /// let reader = BufReader::new(f1);
+    /// fn main() -> std::io::Result<()> {
+    ///     let f1 = File::open("log.txt")?;
+    ///     let reader = BufReader::new(f1);
     ///
-    /// let f2 = reader.get_ref();
-    /// # Ok(())
-    /// # }
+    ///     let f2 = reader.get_ref();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get_ref(&self) -> &R { &self.inner }
@@ -132,17 +138,17 @@ impl<R: Read> BufReader<R> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::BufReader;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f1 = File::open("log.txt")?;
-    /// let mut reader = BufReader::new(f1);
+    /// fn main() -> std::io::Result<()> {
+    ///     let f1 = File::open("log.txt")?;
+    ///     let mut reader = BufReader::new(f1);
     ///
-    /// let f2 = reader.get_mut();
-    /// # Ok(())
-    /// # }
+    ///     let f2 = reader.get_mut();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get_mut(&mut self) -> &mut R { &mut self.inner }
@@ -150,26 +156,55 @@ impl<R: Read> BufReader<R> {
     /// Returns `true` if there are no bytes in the internal buffer.
     ///
     /// # Examples
-    /// ```
+    //
+    /// ```no_run
     /// # #![feature(bufreader_is_empty)]
     /// use std::io::BufReader;
     /// use std::io::BufRead;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f1 = File::open("log.txt")?;
-    /// let mut reader = BufReader::new(f1);
-    /// assert!(reader.is_empty());
+    /// fn main() -> std::io::Result<()> {
+    ///     let f1 = File::open("log.txt")?;
+    ///     let mut reader = BufReader::new(f1);
+    ///     assert!(reader.is_empty());
     ///
-    /// if reader.fill_buf()?.len() > 0 {
-    ///     assert!(!reader.is_empty());
+    ///     if reader.fill_buf()?.len() > 0 {
+    ///         assert!(!reader.is_empty());
+    ///     }
+    ///     Ok(())
     /// }
-    /// # Ok(())
-    /// # }
     /// ```
     #[unstable(feature = "bufreader_is_empty", issue = "45323", reason = "recently added")]
+    #[rustc_deprecated(since = "1.26.0", reason = "use .buffer().is_empty() instead")]
     pub fn is_empty(&self) -> bool {
-        self.pos == self.cap
+        self.buffer().is_empty()
+    }
+
+    /// Returns a reference to the internally buffered data.
+    ///
+    /// Unlike `fill_buf`, this will not attempt to fill the buffer if it is empty.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # #![feature(bufreader_buffer)]
+    /// use std::io::{BufReader, BufRead};
+    /// use std::fs::File;
+    ///
+    /// fn main() -> std::io::Result<()> {
+    ///     let f = File::open("log.txt")?;
+    ///     let mut reader = BufReader::new(f);
+    ///     assert!(reader.buffer().is_empty());
+    ///
+    ///     if reader.fill_buf()?.len() > 0 {
+    ///         assert!(!reader.buffer().is_empty());
+    ///     }
+    ///     Ok(())
+    /// }
+    /// ```
+    #[unstable(feature = "bufreader_buffer", issue = "45323")]
+    pub fn buffer(&self) -> &[u8] {
+        &self.buf[self.pos..self.cap]
     }
 
     /// Unwraps this `BufReader`, returning the underlying reader.
@@ -178,17 +213,17 @@ impl<R: Read> BufReader<R> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::BufReader;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let f1 = File::open("log.txt")?;
-    /// let reader = BufReader::new(f1);
+    /// fn main() -> std::io::Result<()> {
+    ///     let f1 = File::open("log.txt")?;
+    ///     let reader = BufReader::new(f1);
     ///
-    /// let f2 = reader.into_inner();
-    /// # Ok(())
-    /// # }
+    ///     let f2 = reader.into_inner();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn into_inner(self) -> R { self.inner }
@@ -293,7 +328,7 @@ impl<R: Seek> Seek for BufReader<R> {
     /// where `n` minus the internal buffer length overflows an `i64`, two
     /// seeks will be performed instead of one. If the second seek returns
     /// `Err`, the underlying reader will be left at the same position it would
-    /// have if you seeked to `SeekFrom::Current(0)`.
+    /// have if you called `seek` with `SeekFrom::Current(0)`.
     ///
     /// [`seek_relative`]: #method.seek_relative
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
@@ -330,6 +365,12 @@ impl<R: Seek> Seek for BufReader<R> {
 /// `BufWriter` keeps an in-memory buffer of data and writes it to an underlying
 /// writer in large, infrequent batches.
 ///
+/// `BufWriter` can improve the speed of programs that make *small* and
+/// *repeated* write calls to the same file or network socket.  It does not
+/// help when writing very large amounts at once, or writing just one or a few
+/// times.  It also provides no advantage when writing to a destination that is
+/// in memory, like a `Vec<u8>`.
+///
 /// When the `BufWriter` is dropped, the contents of its buffer will be written
 /// out. However, any errors that happen in the process of flushing the buffer
 /// when the writer is dropped will be ignored. Code that wishes to handle such
@@ -696,34 +737,34 @@ impl<W> fmt::Display for IntoInnerError<W> {
 /// We can use `LineWriter` to write one line at a time, significantly
 /// reducing the number of actual writes to the file.
 ///
-/// ```
+/// ```no_run
 /// use std::fs::File;
 /// use std::io::prelude::*;
 /// use std::io::LineWriter;
 ///
-/// # fn foo() -> std::io::Result<()> {
-/// let road_not_taken = b"I shall be telling this with a sigh
+/// fn main() -> std::io::Result<()> {
+///     let road_not_taken = b"I shall be telling this with a sigh
 /// Somewhere ages and ages hence:
 /// Two roads diverged in a wood, and I -
 /// I took the one less traveled by,
 /// And that has made all the difference.";
 ///
-/// let file = File::create("poem.txt")?;
-/// let mut file = LineWriter::new(file);
+///     let file = File::create("poem.txt")?;
+///     let mut file = LineWriter::new(file);
 ///
-/// for &byte in road_not_taken.iter() {
-///    file.write(&[byte]).unwrap();
-/// }
+///     for &byte in road_not_taken.iter() {
+///        file.write(&[byte]).unwrap();
+///     }
 ///
-/// // let's check we did the right thing.
-/// let mut file = File::open("poem.txt")?;
-/// let mut contents = String::new();
+///     // let's check we did the right thing.
+///     let mut file = File::open("poem.txt")?;
+///     let mut contents = String::new();
 ///
-/// file.read_to_string(&mut contents)?;
+///     file.read_to_string(&mut contents)?;
 ///
-/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);
-/// # Ok(())
-/// # }
+///     assert_eq!(contents.as_bytes(), &road_not_taken[..]);
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct LineWriter<W: Write> {
@@ -736,15 +777,15 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::fs::File;
     /// use std::io::LineWriter;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let file = File::create("poem.txt")?;
-    /// let file = LineWriter::new(file);
-    /// # Ok(())
-    /// # }
+    /// fn main() -> std::io::Result<()> {
+    ///     let file = File::create("poem.txt")?;
+    ///     let file = LineWriter::new(file);
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn new(inner: W) -> LineWriter<W> {
@@ -757,15 +798,15 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::fs::File;
     /// use std::io::LineWriter;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let file = File::create("poem.txt")?;
-    /// let file = LineWriter::with_capacity(100, file);
-    /// # Ok(())
-    /// # }
+    /// fn main() -> std::io::Result<()> {
+    ///     let file = File::create("poem.txt")?;
+    ///     let file = LineWriter::with_capacity(100, file);
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn with_capacity(cap: usize, inner: W) -> LineWriter<W> {
@@ -779,17 +820,17 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::fs::File;
     /// use std::io::LineWriter;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let file = File::create("poem.txt")?;
-    /// let file = LineWriter::new(file);
+    /// fn main() -> std::io::Result<()> {
+    ///     let file = File::create("poem.txt")?;
+    ///     let file = LineWriter::new(file);
     ///
-    /// let reference = file.get_ref();
-    /// # Ok(())
-    /// # }
+    ///     let reference = file.get_ref();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get_ref(&self) -> &W { self.inner.get_ref() }
@@ -801,18 +842,18 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::fs::File;
     /// use std::io::LineWriter;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let file = File::create("poem.txt")?;
-    /// let mut file = LineWriter::new(file);
+    /// fn main() -> std::io::Result<()> {
+    ///     let file = File::create("poem.txt")?;
+    ///     let mut file = LineWriter::new(file);
     ///
-    /// // we can use reference just like file
-    /// let reference = file.get_mut();
-    /// # Ok(())
-    /// # }
+    ///     // we can use reference just like file
+    ///     let reference = file.get_mut();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn get_mut(&mut self) -> &mut W { self.inner.get_mut() }
@@ -827,18 +868,18 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::fs::File;
     /// use std::io::LineWriter;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let file = File::create("poem.txt")?;
+    /// fn main() -> std::io::Result<()> {
+    ///     let file = File::create("poem.txt")?;
     ///
-    /// let writer: LineWriter<File> = LineWriter::new(file);
+    ///     let writer: LineWriter<File> = LineWriter::new(file);
     ///
-    /// let file: File = writer.into_inner()?;
-    /// # Ok(())
-    /// # }
+    ///     let file: File = writer.into_inner()?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>> {
diff --git a/ctr-std/src/io/cursor.rs b/ctr-std/src/io/cursor.rs
index 76bcb5f..2673f3c 100644
--- a/ctr-std/src/io/cursor.rs
+++ b/ctr-std/src/io/cursor.rs
@@ -10,7 +10,6 @@
 
 use io::prelude::*;
 
-use core::convert::TryInto;
 use cmp;
 use io::{self, Initializer, SeekFrom, Error, ErrorKind};
 
@@ -260,9 +259,26 @@ fn slice_write(pos_mut: &mut u64, slice: &mut [u8], buf: &[u8]) -> io::Result<us
     Ok(amt)
 }
 
+/// Compensate removal of some impls per
+/// https://github.com/rust-lang/rust/pull/49305#issuecomment-376293243
+#[cfg(any(target_pointer_width = "16",
+          target_pointer_width = "32"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+    if n <= (<usize>::max_value() as u64) {
+        Ok(n as usize)
+    } else {
+        Err(())
+    }
+}
+
+#[cfg(any(target_pointer_width = "64"))]
+fn try_into(n: u64) -> Result<usize, ()> {
+    Ok(n as usize)
+}
+
 // Resizing write implementation
 fn vec_write(pos_mut: &mut u64, vec: &mut Vec<u8>, buf: &[u8]) -> io::Result<usize> {
-    let pos: usize = (*pos_mut).try_into().map_err(|_| {
+    let pos: usize = try_into(*pos_mut).map_err(|_| {
         Error::new(ErrorKind::InvalidInput,
                     "cursor position exceeds maximum possible vector length")
     })?;
diff --git a/ctr-std/src/io/error.rs b/ctr-std/src/io/error.rs
index f0b41f3..bdd675e 100644
--- a/ctr-std/src/io/error.rs
+++ b/ctr-std/src/io/error.rs
@@ -292,8 +292,8 @@ impl Error {
     /// # if cfg!(target_os = "linux") {
     /// use std::io;
     ///
-    /// let error = io::Error::from_raw_os_error(98);
-    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// let error = io::Error::from_raw_os_error(22);
+    /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
     /// # }
     /// ```
     ///
@@ -303,8 +303,8 @@ impl Error {
     /// # if cfg!(windows) {
     /// use std::io;
     ///
-    /// let error = io::Error::from_raw_os_error(10048);
-    /// assert_eq!(error.kind(), io::ErrorKind::AddrInUse);
+    /// let error = io::Error::from_raw_os_error(10022);
+    /// assert_eq!(error.kind(), io::ErrorKind::InvalidInput);
     /// # }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/ctr-std/src/io/mod.rs b/ctr-std/src/io/mod.rs
index 33d11eb..b02e133 100644
--- a/ctr-std/src/io/mod.rs
+++ b/ctr-std/src/io/mod.rs
@@ -24,21 +24,21 @@
 //! example, [`Read`] adds a [`read`][`Read::read`] method, which we can use on
 //! [`File`]s:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //! use std::fs::File;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let mut f = File::open("foo.txt")?;
-//! let mut buffer = [0; 10];
+//! fn main() -> io::Result<()> {
+//!     let mut f = File::open("foo.txt")?;
+//!     let mut buffer = [0; 10];
 //!
-//! // read up to 10 bytes
-//! f.read(&mut buffer)?;
+//!     // read up to 10 bytes
+//!     f.read(&mut buffer)?;
 //!
-//! println!("The bytes: {:?}", buffer);
-//! # Ok(())
-//! # }
+//!     println!("The bytes: {:?}", buffer);
+//!     Ok(())
+//! }
 //! ```
 //!
 //! [`Read`] and [`Write`] are so important, implementors of the two traits have a
@@ -52,25 +52,25 @@
 //! how the reading happens. [`Seek`] lets you control where the next byte is
 //! coming from:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //! use std::io::SeekFrom;
 //! use std::fs::File;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let mut f = File::open("foo.txt")?;
-//! let mut buffer = [0; 10];
+//! fn main() -> io::Result<()> {
+//!     let mut f = File::open("foo.txt")?;
+//!     let mut buffer = [0; 10];
 //!
-//! // skip to the last 10 bytes of the file
-//! f.seek(SeekFrom::End(-10))?;
+//!     // skip to the last 10 bytes of the file
+//!     f.seek(SeekFrom::End(-10))?;
 //!
-//! // read up to 10 bytes
-//! f.read(&mut buffer)?;
+//!     // read up to 10 bytes
+//!     f.read(&mut buffer)?;
 //!
-//! println!("The bytes: {:?}", buffer);
-//! # Ok(())
-//! # }
+//!     println!("The bytes: {:?}", buffer);
+//!     Ok(())
+//! }
 //! ```
 //!
 //! [`BufRead`] uses an internal buffer to provide a number of other ways to read, but
@@ -87,70 +87,70 @@
 //! For example, [`BufReader`] works with the [`BufRead`] trait to add extra
 //! methods to any reader:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //! use std::io::BufReader;
 //! use std::fs::File;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let f = File::open("foo.txt")?;
-//! let mut reader = BufReader::new(f);
-//! let mut buffer = String::new();
+//! fn main() -> io::Result<()> {
+//!     let f = File::open("foo.txt")?;
+//!     let mut reader = BufReader::new(f);
+//!     let mut buffer = String::new();
 //!
-//! // read a line into buffer
-//! reader.read_line(&mut buffer)?;
+//!     // read a line into buffer
+//!     reader.read_line(&mut buffer)?;
 //!
-//! println!("{}", buffer);
-//! # Ok(())
-//! # }
+//!     println!("{}", buffer);
+//!     Ok(())
+//! }
 //! ```
 //!
 //! [`BufWriter`] doesn't add any new ways of writing; it just buffers every call
 //! to [`write`][`Write::write`]:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //! use std::io::BufWriter;
 //! use std::fs::File;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let f = File::create("foo.txt")?;
-//! {
-//!     let mut writer = BufWriter::new(f);
+//! fn main() -> io::Result<()> {
+//!     let f = File::create("foo.txt")?;
+//!     {
+//!         let mut writer = BufWriter::new(f);
 //!
-//!     // write a byte to the buffer
-//!     writer.write(&[42])?;
+//!         // write a byte to the buffer
+//!         writer.write(&[42])?;
 //!
-//! } // the buffer is flushed once writer goes out of scope
+//!     } // the buffer is flushed once writer goes out of scope
 //!
-//! # Ok(())
-//! # }
+//!     Ok(())
+//! }
 //! ```
 //!
 //! ## Standard input and output
 //!
 //! A very common source of input is standard input:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let mut input = String::new();
+//! fn main() -> io::Result<()> {
+//!     let mut input = String::new();
 //!
-//! io::stdin().read_line(&mut input)?;
+//!     io::stdin().read_line(&mut input)?;
 //!
-//! println!("You typed: {}", input.trim());
-//! # Ok(())
-//! # }
+//!     println!("You typed: {}", input.trim());
+//!     Ok(())
+//! }
 //! ```
 //!
 //! Note that you cannot use the [`?` operator] in functions that do not return
 //! a [`Result<T, E>`][`Result`] (e.g. `main`). Instead, you can call [`.unwrap()`]
 //! or `match` on the return value to catch any possible errors:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //!
 //! let mut input = String::new();
@@ -160,14 +160,14 @@
 //!
 //! And a very common source of output is standard output:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //!
-//! # fn foo() -> io::Result<()> {
-//! io::stdout().write(&[42])?;
-//! # Ok(())
-//! # }
+//! fn main() -> io::Result<()> {
+//!     io::stdout().write(&[42])?;
+//!     Ok(())
+//! }
 //! ```
 //!
 //! Of course, using [`io::stdout`] directly is less common than something like
@@ -179,22 +179,21 @@
 //! ways of iterating over I/O. For example, [`Lines`] is used to split over
 //! lines:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //! use std::io::prelude::*;
 //! use std::io::BufReader;
 //! use std::fs::File;
 //!
-//! # fn foo() -> io::Result<()> {
-//! let f = File::open("foo.txt")?;
-//! let reader = BufReader::new(f);
+//! fn main() -> io::Result<()> {
+//!     let f = File::open("foo.txt")?;
+//!     let reader = BufReader::new(f);
 //!
-//! for line in reader.lines() {
-//!     println!("{}", line?);
+//!     for line in reader.lines() {
+//!         println!("{}", line?);
+//!     }
+//!     Ok(())
 //! }
-//!
-//! # Ok(())
-//! # }
 //! ```
 //!
 //! ## Functions
@@ -203,13 +202,13 @@
 //! features. For example, we can use three of these functions to copy everything
 //! from standard input to standard output:
 //!
-//! ```
+//! ```no_run
 //! use std::io;
 //!
-//! # fn foo() -> io::Result<()> {
-//! io::copy(&mut io::stdin(), &mut io::stdout())?;
-//! # Ok(())
-//! # }
+//! fn main() -> io::Result<()> {
+//!     io::copy(&mut io::stdin(), &mut io::stdout())?;
+//!     Ok(())
+//! }
 //! ```
 //!
 //! [functions-list]: #functions-1
@@ -416,47 +415,47 @@ fn read_to_end<R: Read + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> Result<usize>
 ///
 /// [`File`]s implement `Read`:
 ///
-/// ```
-/// # use std::io;
+/// ```no_run
+/// use std::io;
 /// use std::io::prelude::*;
 /// use std::fs::File;
 ///
-/// # fn foo() -> io::Result<()> {
-/// let mut f = File::open("foo.txt")?;
-/// let mut buffer = [0; 10];
+/// fn main() -> io::Result<()> {
+///     let mut f = File::open("foo.txt")?;
+///     let mut buffer = [0; 10];
 ///
-/// // read up to 10 bytes
-/// f.read(&mut buffer)?;
+///     // read up to 10 bytes
+///     f.read(&mut buffer)?;
 ///
-/// let mut buffer = vec![0; 10];
-/// // read the whole file
-/// f.read_to_end(&mut buffer)?;
+///     let mut buffer = vec![0; 10];
+///     // read the whole file
+///     f.read_to_end(&mut buffer)?;
 ///
-/// // read into a String, so that you don't need to do the conversion.
-/// let mut buffer = String::new();
-/// f.read_to_string(&mut buffer)?;
+///     // read into a String, so that you don't need to do the conversion.
+///     let mut buffer = String::new();
+///     f.read_to_string(&mut buffer)?;
 ///
-/// // and more! See the other methods for more details.
-/// # Ok(())
-/// # }
+///     // and more! See the other methods for more details.
+///     Ok(())
+/// }
 /// ```
 ///
 /// Read from [`&str`] because [`&[u8]`][slice] implements `Read`:
 ///
-/// ```
+/// ```no_run
 /// # use std::io;
 /// use std::io::prelude::*;
 ///
-/// # fn foo() -> io::Result<()> {
-/// let mut b = "This string will be read".as_bytes();
-/// let mut buffer = [0; 10];
+/// fn main() -> io::Result<()> {
+///     let mut b = "This string will be read".as_bytes();
+///     let mut buffer = [0; 10];
 ///
-/// // read up to 10 bytes
-/// b.read(&mut buffer)?;
+///     // read up to 10 bytes
+///     b.read(&mut buffer)?;
 ///
-/// // etc... it works exactly as a File does!
-/// # Ok(())
-/// # }
+///     // etc... it works exactly as a File does!
+///     Ok(())
+/// }
 /// ```
 ///
 /// [`read()`]: trait.Read.html#tymethod.read
@@ -509,19 +508,19 @@ pub trait Read {
     /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
     /// [`File`]: ../fs/struct.File.html
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = [0; 10];
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = [0; 10];
     ///
-    /// // read up to 10 bytes
-    /// f.read(&mut buffer[..])?;
-    /// # Ok(())
-    /// # }
+    ///     // read up to 10 bytes
+    ///     f.read(&mut buffer[..])?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn read(&mut self, buf: &mut [u8]) -> Result<usize>;
@@ -582,20 +581,25 @@ pub trait Read {
     /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
     /// [`File`]: ../fs/struct.File.html
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = Vec::new();
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = Vec::new();
     ///
-    /// // read the whole file
-    /// f.read_to_end(&mut buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     // read the whole file
+    ///     f.read_to_end(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
+    ///
+    /// (See also the [`std::fs::read`] convenience function for reading from a
+    /// file.)
+    ///
+    /// [`std::fs::read`]: ../fs/fn.read.html
     #[stable(feature = "rust1", since = "1.0.0")]
     fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize> {
         read_to_end(self, buf)
@@ -621,19 +625,24 @@ pub trait Read {
     ///
     /// [file]: ../fs/struct.File.html
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = String::new();
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = String::new();
     ///
-    /// f.read_to_string(&mut buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     f.read_to_string(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
+    ///
+    /// (See also the [`std::fs::read_to_string`] convenience function for
+    /// reading from a file.)
+    ///
+    /// [`std::fs::read_to_string`]: ../fs/fn.read_to_string.html
     #[stable(feature = "rust1", since = "1.0.0")]
     fn read_to_string(&mut self, buf: &mut String) -> Result<usize> {
         // Note that we do *not* call `.read_to_end()` here. We are passing
@@ -683,19 +692,19 @@ pub trait Read {
     /// [`ErrorKind::Interrupted`]: ../../std/io/enum.ErrorKind.html#variant.Interrupted
     /// [`ErrorKind::UnexpectedEof`]: ../../std/io/enum.ErrorKind.html#variant.UnexpectedEof
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = [0; 10];
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = [0; 10];
     ///
-    /// // read exactly 10 bytes
-    /// f.read_exact(&mut buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     // read exactly 10 bytes
+    ///     f.read_exact(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "read_exact", since = "1.6.0")]
     fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
@@ -726,28 +735,28 @@ pub trait Read {
     ///
     /// [file]: ../fs/struct.File.html
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::Read;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = Vec::new();
-    /// let mut other_buffer = Vec::new();
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = Vec::new();
+    ///     let mut other_buffer = Vec::new();
     ///
-    /// {
-    ///     let reference = f.by_ref();
+    ///     {
+    ///         let reference = f.by_ref();
     ///
-    ///     // read at most 5 bytes
-    ///     reference.take(5).read_to_end(&mut buffer)?;
+    ///         // read at most 5 bytes
+    ///         reference.take(5).read_to_end(&mut buffer)?;
     ///
-    /// } // drop our &mut reference so we can use f again
+    ///     } // drop our &mut reference so we can use f again
     ///
-    /// // original file still usable, read the rest
-    /// f.read_to_end(&mut other_buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     // original file still usable, read the rest
+    ///     f.read_to_end(&mut other_buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
@@ -772,19 +781,19 @@ pub trait Read {
     /// [`Err`]: ../../std/result/enum.Result.html#variant.Err
     /// [`None`]: ../../std/option/enum.Option.html#variant.None
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
     ///
-    /// for byte in f.bytes() {
-    ///     println!("{}", byte.unwrap());
+    ///     for byte in f.bytes() {
+    ///         println!("{}", byte.unwrap());
+    ///     }
+    ///     Ok(())
     /// }
-    /// # Ok(())
-    /// # }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn bytes(self) -> Bytes<Self> where Self: Sized {
@@ -812,20 +821,20 @@ pub trait Read {
     /// [`char`]: ../../std/primitive.char.html
     /// [`None`]: ../../std/option/enum.Option.html#variant.None
     ///
-    /// ```
+    /// ```no_run
     /// #![feature(io)]
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
     ///
-    /// for c in f.chars() {
-    ///     println!("{}", c.unwrap());
+    ///     for c in f.chars() {
+    ///         println!("{}", c.unwrap());
+    ///     }
+    ///     Ok(())
     /// }
-    /// # Ok(())
-    /// # }
     /// ```
     #[unstable(feature = "io", reason = "the semantics of a partial read/write \
                                          of where errors happen is currently \
@@ -847,23 +856,23 @@ pub trait Read {
     ///
     /// [file]: ../fs/struct.File.html
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f1 = File::open("foo.txt")?;
-    /// let mut f2 = File::open("bar.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut f1 = File::open("foo.txt")?;
+    ///     let mut f2 = File::open("bar.txt")?;
     ///
-    /// let mut handle = f1.chain(f2);
-    /// let mut buffer = String::new();
+    ///     let mut handle = f1.chain(f2);
+    ///     let mut buffer = String::new();
     ///
-    /// // read the value into a String. We could use any Read method here,
-    /// // this is just one example.
-    /// handle.read_to_string(&mut buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     // read the value into a String. We could use any Read method here,
+    ///     // this is just one example.
+    ///     handle.read_to_string(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn chain<R: Read>(self, next: R) -> Chain<Self, R> where Self: Sized {
@@ -885,21 +894,21 @@ pub trait Read {
     /// [`Ok(0)`]: ../../std/result/enum.Result.html#variant.Ok
     /// [`read()`]: trait.Read.html#tymethod.read
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut f = File::open("foo.txt")?;
-    /// let mut buffer = [0; 5];
+    /// fn main() -> io::Result<()> {
+    ///     let mut f = File::open("foo.txt")?;
+    ///     let mut buffer = [0; 5];
     ///
-    /// // read at most five bytes
-    /// let mut handle = f.take(5);
+    ///     // read at most five bytes
+    ///     let mut handle = f.take(5);
     ///
-    /// handle.read(&mut buffer)?;
-    /// # Ok(())
-    /// # }
+    ///     handle.read(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn take(self, limit: u64) -> Take<Self> where Self: Sized {
@@ -974,16 +983,16 @@ impl Initializer {
 ///
 /// # Examples
 ///
-/// ```
+/// ```no_run
 /// use std::io::prelude::*;
 /// use std::fs::File;
 ///
-/// # fn foo() -> std::io::Result<()> {
-/// let mut buffer = File::create("foo.txt")?;
+/// fn main() -> std::io::Result<()> {
+///     let mut buffer = File::create("foo.txt")?;
 ///
-/// buffer.write(b"some bytes")?;
-/// # Ok(())
-/// # }
+///     buffer.write(b"some bytes")?;
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(spotlight)]
@@ -1022,17 +1031,17 @@ pub trait Write {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = File::create("foo.txt")?;
+    /// fn main() -> std::io::Result<()> {
+    ///     let mut buffer = File::create("foo.txt")?;
     ///
-    /// // Writes some prefix of the byte string, not necessarily all of it.
-    /// buffer.write(b"some bytes")?;
-    /// # Ok(())
-    /// # }
+    ///     // Writes some prefix of the byte string, not necessarily all of it.
+    ///     buffer.write(b"some bytes")?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn write(&mut self, buf: &[u8]) -> Result<usize>;
@@ -1047,18 +1056,18 @@ pub trait Write {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::prelude::*;
     /// use std::io::BufWriter;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = BufWriter::new(File::create("foo.txt")?);
+    /// fn main() -> std::io::Result<()> {
+    ///     let mut buffer = BufWriter::new(File::create("foo.txt")?);
     ///
-    /// buffer.write(b"some bytes")?;
-    /// buffer.flush()?;
-    /// # Ok(())
-    /// # }
+    ///     buffer.write(b"some bytes")?;
+    ///     buffer.flush()?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn flush(&mut self) -> Result<()>;
@@ -1082,16 +1091,16 @@ pub trait Write {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = File::create("foo.txt")?;
+    /// fn main() -> std::io::Result<()> {
+    ///     let mut buffer = File::create("foo.txt")?;
     ///
-    /// buffer.write_all(b"some bytes")?;
-    /// # Ok(())
-    /// # }
+    ///     buffer.write_all(b"some bytes")?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
@@ -1131,19 +1140,19 @@ pub trait Write {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = File::create("foo.txt")?;
+    /// fn main() -> std::io::Result<()> {
+    ///     let mut buffer = File::create("foo.txt")?;
     ///
-    /// // this call
-    /// write!(buffer, "{:.*}", 2, 1.234567)?;
-    /// // turns into this:
-    /// buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?;
-    /// # Ok(())
-    /// # }
+    ///     // this call
+    ///     write!(buffer, "{:.*}", 2, 1.234567)?;
+    ///     // turns into this:
+    ///     buffer.write_fmt(format_args!("{:.*}", 2, 1.234567))?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn write_fmt(&mut self, fmt: fmt::Arguments) -> Result<()> {
@@ -1187,19 +1196,19 @@ pub trait Write {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::Write;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> std::io::Result<()> {
-    /// let mut buffer = File::create("foo.txt")?;
+    /// fn main() -> std::io::Result<()> {
+    ///     let mut buffer = File::create("foo.txt")?;
     ///
-    /// let reference = buffer.by_ref();
+    ///     let reference = buffer.by_ref();
     ///
-    /// // we can use reference just like our original buffer
-    /// reference.write_all(b"some bytes")?;
-    /// # Ok(())
-    /// # }
+    ///     // we can use reference just like our original buffer
+    ///     reference.write_all(b"some bytes")?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn by_ref(&mut self) -> &mut Self where Self: Sized { self }
@@ -1217,19 +1226,19 @@ pub trait Write {
 ///
 /// [file]: ../fs/struct.File.html
 ///
-/// ```
+/// ```no_run
 /// use std::io;
 /// use std::io::prelude::*;
 /// use std::fs::File;
 /// use std::io::SeekFrom;
 ///
-/// # fn foo() -> io::Result<()> {
-/// let mut f = File::open("foo.txt")?;
+/// fn main() -> io::Result<()> {
+///     let mut f = File::open("foo.txt")?;
 ///
-/// // move the cursor 42 bytes from the start of the file
-/// f.seek(SeekFrom::Start(42))?;
-/// # Ok(())
-/// # }
+///     // move the cursor 42 bytes from the start of the file
+///     f.seek(SeekFrom::Start(42))?;
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Seek {
@@ -1320,7 +1329,7 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
 ///
 /// A locked standard input implements `BufRead`:
 ///
-/// ```
+/// ```no_run
 /// use std::io;
 /// use std::io::prelude::*;
 ///
@@ -1342,21 +1351,21 @@ fn read_until<R: BufRead + ?Sized>(r: &mut R, delim: u8, buf: &mut Vec<u8>)
 /// [`lines`]: #method.lines
 /// [`Read`]: trait.Read.html
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, BufReader};
 /// use std::io::prelude::*;
 /// use std::fs::File;
 ///
-/// # fn foo() -> io::Result<()> {
-/// let f = File::open("foo.txt")?;
-/// let f = BufReader::new(f);
+/// fn main() -> io::Result<()> {
+///     let f = File::open("foo.txt")?;
+///     let f = BufReader::new(f);
 ///
-/// for line in f.lines() {
-///     println!("{}", line.unwrap());
-/// }
+///     for line in f.lines() {
+///         println!("{}", line.unwrap());
+///     }
 ///
-/// # Ok(())
-/// # }
+///     Ok(())
+/// }
 /// ```
 ///
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1383,7 +1392,7 @@ pub trait BufRead: Read {
     ///
     /// A locked standard input implements `BufRead`:
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     ///
@@ -1437,8 +1446,6 @@ pub trait BufRead: Read {
     ///
     /// If successful, this function will return the total number of bytes read.
     ///
-    /// An empty buffer returned indicates that the stream has reached EOF.
-    ///
     /// # Errors
     ///
     /// This function will ignore all instances of [`ErrorKind::Interrupted`] and
@@ -1508,6 +1515,8 @@ pub trait BufRead: Read {
     /// error is encountered then `buf` may contain some bytes already read in
     /// the event that all data read so far was valid UTF-8.
     ///
+    /// [`read_until`]: #method.read_until
+    ///
     /// # Examples
     ///
     /// [`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
@@ -1645,19 +1654,19 @@ impl<T, U> Chain<T, U> {
     ///
     /// # Examples
     ///
-    /// ```
-    /// # use std::io;
+    /// ```no_run
+    /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut foo_file = File::open("foo.txt")?;
-    /// let mut bar_file = File::open("bar.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut foo_file = File::open("foo.txt")?;
+    ///     let mut bar_file = File::open("bar.txt")?;
     ///
-    /// let chain = foo_file.chain(bar_file);
-    /// let (foo_file, bar_file) = chain.into_inner();
-    /// # Ok(())
-    /// # }
+    ///     let chain = foo_file.chain(bar_file);
+    ///     let (foo_file, bar_file) = chain.into_inner();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "more_io_inner_methods", since = "1.20.0")]
     pub fn into_inner(self) -> (T, U) {
@@ -1668,19 +1677,19 @@ impl<T, U> Chain<T, U> {
     ///
     /// # Examples
     ///
-    /// ```
-    /// # use std::io;
+    /// ```no_run
+    /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut foo_file = File::open("foo.txt")?;
-    /// let mut bar_file = File::open("bar.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut foo_file = File::open("foo.txt")?;
+    ///     let mut bar_file = File::open("bar.txt")?;
     ///
-    /// let chain = foo_file.chain(bar_file);
-    /// let (foo_file, bar_file) = chain.get_ref();
-    /// # Ok(())
-    /// # }
+    ///     let chain = foo_file.chain(bar_file);
+    ///     let (foo_file, bar_file) = chain.get_ref();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "more_io_inner_methods", since = "1.20.0")]
     pub fn get_ref(&self) -> (&T, &U) {
@@ -1695,19 +1704,19 @@ impl<T, U> Chain<T, U> {
     ///
     /// # Examples
     ///
-    /// ```
-    /// # use std::io;
+    /// ```no_run
+    /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut foo_file = File::open("foo.txt")?;
-    /// let mut bar_file = File::open("bar.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut foo_file = File::open("foo.txt")?;
+    ///     let mut bar_file = File::open("bar.txt")?;
     ///
-    /// let mut chain = foo_file.chain(bar_file);
-    /// let (foo_file, bar_file) = chain.get_mut();
-    /// # Ok(())
-    /// # }
+    ///     let mut chain = foo_file.chain(bar_file);
+    ///     let (foo_file, bar_file) = chain.get_mut();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "more_io_inner_methods", since = "1.20.0")]
     pub fn get_mut(&mut self) -> (&mut T, &mut U) {
@@ -1794,20 +1803,20 @@ impl<T> Take<T> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let f = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let f = File::open("foo.txt")?;
     ///
-    /// // read at most five bytes
-    /// let handle = f.take(5);
+    ///     // read at most five bytes
+    ///     let handle = f.take(5);
     ///
-    /// println!("limit: {}", handle.limit());
-    /// # Ok(())
-    /// # }
+    ///     println!("limit: {}", handle.limit());
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn limit(&self) -> u64 { self.limit }
@@ -1819,24 +1828,23 @@ impl<T> Take<T> {
     ///
     /// # Examples
     ///
-    /// ```
-    /// #![feature(take_set_limit)]
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let f = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let f = File::open("foo.txt")?;
     ///
-    /// // read at most five bytes
-    /// let mut handle = f.take(5);
-    /// handle.set_limit(10);
+    ///     // read at most five bytes
+    ///     let mut handle = f.take(5);
+    ///     handle.set_limit(10);
     ///
-    /// assert_eq!(handle.limit(), 10);
-    /// # Ok(())
-    /// # }
+    ///     assert_eq!(handle.limit(), 10);
+    ///     Ok(())
+    /// }
     /// ```
-    #[unstable(feature = "take_set_limit", issue = "42781")]
+    #[stable(feature = "take_set_limit", since = "1.27.0")]
     pub fn set_limit(&mut self, limit: u64) {
         self.limit = limit;
     }
@@ -1845,21 +1853,21 @@ impl<T> Take<T> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut file = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut file = File::open("foo.txt")?;
     ///
-    /// let mut buffer = [0; 5];
-    /// let mut handle = file.take(5);
-    /// handle.read(&mut buffer)?;
+    ///     let mut buffer = [0; 5];
+    ///     let mut handle = file.take(5);
+    ///     handle.read(&mut buffer)?;
     ///
-    /// let file = handle.into_inner();
-    /// # Ok(())
-    /// # }
+    ///     let file = handle.into_inner();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "io_take_into_inner", since = "1.15.0")]
     pub fn into_inner(self) -> T {
@@ -1870,21 +1878,21 @@ impl<T> Take<T> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut file = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut file = File::open("foo.txt")?;
     ///
-    /// let mut buffer = [0; 5];
-    /// let mut handle = file.take(5);
-    /// handle.read(&mut buffer)?;
+    ///     let mut buffer = [0; 5];
+    ///     let mut handle = file.take(5);
+    ///     handle.read(&mut buffer)?;
     ///
-    /// let file = handle.get_ref();
-    /// # Ok(())
-    /// # }
+    ///     let file = handle.get_ref();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "more_io_inner_methods", since = "1.20.0")]
     pub fn get_ref(&self) -> &T {
@@ -1899,21 +1907,21 @@ impl<T> Take<T> {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io;
     /// use std::io::prelude::*;
     /// use std::fs::File;
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let mut file = File::open("foo.txt")?;
+    /// fn main() -> io::Result<()> {
+    ///     let mut file = File::open("foo.txt")?;
     ///
-    /// let mut buffer = [0; 5];
-    /// let mut handle = file.take(5);
-    /// handle.read(&mut buffer)?;
+    ///     let mut buffer = [0; 5];
+    ///     let mut handle = file.take(5);
+    ///     handle.read(&mut buffer)?;
     ///
-    /// let file = handle.get_mut();
-    /// # Ok(())
-    /// # }
+    ///     let file = handle.get_mut();
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "more_io_inner_methods", since = "1.20.0")]
     pub fn get_mut(&mut self) -> &mut T {
diff --git a/ctr-std/src/io/stdio.rs b/ctr-std/src/io/stdio.rs
index 831688b..2472bed 100644
--- a/ctr-std/src/io/stdio.rs
+++ b/ctr-std/src/io/stdio.rs
@@ -17,7 +17,7 @@ use io::{self, Initializer, BufReader, LineWriter};
 use sync::{Arc, Mutex, MutexGuard};
 use sys::stdio;
 use sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
-use thread::{LocalKey, LocalKeyState};
+use thread::LocalKey;
 
 /// Stdout used by print! and println! macros
 thread_local! {
@@ -171,29 +171,29 @@ pub struct StdinLock<'a> {
 ///
 /// Using implicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Read};
 ///
-/// # fn foo() -> io::Result<String> {
-/// let mut buffer = String::new();
-/// io::stdin().read_to_string(&mut buffer)?;
-/// # Ok(buffer)
-/// # }
+/// fn main() -> io::Result<()> {
+///     let mut buffer = String::new();
+///     io::stdin().read_to_string(&mut buffer)?;
+///     Ok(())
+/// }
 /// ```
 ///
 /// Using explicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Read};
 ///
-/// # fn foo() -> io::Result<String> {
-/// let mut buffer = String::new();
-/// let stdin = io::stdin();
-/// let mut handle = stdin.lock();
+/// fn main() -> io::Result<()> {
+///     let mut buffer = String::new();
+///     let stdin = io::stdin();
+///     let mut handle = stdin.lock();
 ///
-/// handle.read_to_string(&mut buffer)?;
-/// # Ok(buffer)
-/// # }
+///     handle.read_to_string(&mut buffer)?;
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stdin() -> Stdin {
@@ -225,17 +225,17 @@ impl Stdin {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::{self, Read};
     ///
-    /// # fn foo() -> io::Result<String> {
-    /// let mut buffer = String::new();
-    /// let stdin = io::stdin();
-    /// let mut handle = stdin.lock();
+    /// fn main() -> io::Result<()> {
+    ///     let mut buffer = String::new();
+    ///     let stdin = io::stdin();
+    ///     let mut handle = stdin.lock();
     ///
-    /// handle.read_to_string(&mut buffer)?;
-    /// # Ok(buffer)
-    /// # }
+    ///     handle.read_to_string(&mut buffer)?;
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn lock(&self) -> StdinLock {
@@ -369,29 +369,29 @@ pub struct StdoutLock<'a> {
 ///
 /// Using implicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Write};
 ///
-/// # fn foo() -> io::Result<()> {
-/// io::stdout().write(b"hello world")?;
+/// fn main() -> io::Result<()> {
+///     io::stdout().write(b"hello world")?;
 ///
-/// # Ok(())
-/// # }
+///     Ok(())
+/// }
 /// ```
 ///
 /// Using explicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Write};
 ///
-/// # fn foo() -> io::Result<()> {
-/// let stdout = io::stdout();
-/// let mut handle = stdout.lock();
+/// fn main() -> io::Result<()> {
+///     let stdout = io::stdout();
+///     let mut handle = stdout.lock();
 ///
-/// handle.write(b"hello world")?;
+///     handle.write(b"hello world")?;
 ///
-/// # Ok(())
-/// # }
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stdout() -> Stdout {
@@ -419,17 +419,17 @@ impl Stdout {
     ///
     /// # Examples
     ///
-    /// ```
+    /// ```no_run
     /// use std::io::{self, Write};
     ///
-    /// # fn foo() -> io::Result<()> {
-    /// let stdout = io::stdout();
-    /// let mut handle = stdout.lock();
+    /// fn main() -> io::Result<()> {
+    ///     let stdout = io::stdout();
+    ///     let mut handle = stdout.lock();
     ///
-    /// handle.write(b"hello world")?;
+    ///     handle.write(b"hello world")?;
     ///
-    /// # Ok(())
-    /// # }
+    ///     Ok(())
+    /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn lock(&self) -> StdoutLock {
@@ -505,29 +505,29 @@ pub struct StderrLock<'a> {
 ///
 /// Using implicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Write};
 ///
-/// # fn foo() -> io::Result<()> {
-/// io::stderr().write(b"hello world")?;
+/// fn main() -> io::Result<()> {
+///     io::stderr().write(b"hello world")?;
 ///
-/// # Ok(())
-/// # }
+///     Ok(())
+/// }
 /// ```
 ///
 /// Using explicit synchronization:
 ///
-/// ```
+/// ```no_run
 /// use std::io::{self, Write};
 ///
-/// # fn foo() -> io::Result<()> {
-/// let stderr = io::stderr();
-/// let mut handle = stderr.lock();
+/// fn main() -> io::Result<()> {
+///     let stderr = io::stderr();
+///     let mut handle = stderr.lock();
 ///
-/// handle.write(b"hello world")?;
+///     handle.write(b"hello world")?;
 ///
-/// # Ok(())
-/// # }
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn stderr() -> Stderr {
@@ -663,29 +663,31 @@ pub fn set_print(sink: Option<Box<Write + Send>>) -> Option<Box<Write + Send>> {
 ///
 /// This function is used to print error messages, so it takes extra
 /// care to avoid causing a panic when `local_stream` is unusable.
-/// For instance, if the TLS key for the local stream is uninitialized
-/// or already destroyed, or if the local stream is locked by another
+/// For instance, if the TLS key for the local stream is
+/// already destroyed, or if the local stream is locked by another
 /// thread, it will just fall back to the global stream.
 ///
 /// However, if the actual I/O causes an error, this function does panic.
-fn print_to<T>(args: fmt::Arguments,
-               local_s: &'static LocalKey<RefCell<Option<Box<Write+Send>>>>,
-               global_s: fn() -> T,
-               label: &str) where T: Write {
-    let result = match local_s.state() {
-        LocalKeyState::Uninitialized |
-        LocalKeyState::Destroyed => global_s().write_fmt(args),
-        LocalKeyState::Valid => {
-            local_s.with(|s| {
-                if let Ok(mut borrowed) = s.try_borrow_mut() {
-                    if let Some(w) = borrowed.as_mut() {
-                        return w.write_fmt(args);
-                    }
-                }
-                global_s().write_fmt(args)
-            })
+fn print_to<T>(
+    args: fmt::Arguments,
+    local_s: &'static LocalKey<RefCell<Option<Box<Write+Send>>>>,
+    global_s: fn() -> T,
+    label: &str,
+)
+where
+    T: Write,
+{
+    let result = local_s.try_with(|s| {
+        if let Ok(mut borrowed) = s.try_borrow_mut() {
+            if let Some(w) = borrowed.as_mut() {
+                return w.write_fmt(args);
+            }
         }
-    };
+        global_s().write_fmt(args)
+    }).unwrap_or_else(|_| {
+        global_s().write_fmt(args)
+    });
+
     if let Err(e) = result {
         panic!("failed printing to {}: {}", label, e);
     }
diff --git a/ctr-std/src/io/util.rs b/ctr-std/src/io/util.rs
index 45d281e..195310a 100644
--- a/ctr-std/src/io/util.rs
+++ b/ctr-std/src/io/util.rs
@@ -34,16 +34,15 @@ use mem;
 /// ```
 /// use std::io;
 ///
-/// # fn foo() -> io::Result<()> {
-/// let mut reader: &[u8] = b"hello";
-/// let mut writer: Vec<u8> = vec![];
+/// fn main() -> io::Result<()> {
+///     let mut reader: &[u8] = b"hello";
+///     let mut writer: Vec<u8> = vec![];
 ///
-/// io::copy(&mut reader, &mut writer)?;
+///     io::copy(&mut reader, &mut writer)?;
 ///
-/// assert_eq!(&b"hello"[..], &writer[..]);
-/// # Ok(())
-/// # }
-/// # foo().unwrap();
+///     assert_eq!(&b"hello"[..], &writer[..]);
+///     Ok(())
+/// }
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> io::Result<u64>