3 files changed, 79 insertions, 0 deletions
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index b07da0dc268..143a85ae321 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -1444,6 +1444,16 @@ pub struct Chain<T, U> {
     done_first: bool,
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl<T: fmt::Debug, U: fmt::Debug> fmt::Debug for Chain<T, U> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Chain")
+            .field("t", &self.first)
+            .field("u", &self.second)
+            .finish()
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Read, U: Read> Read for Chain<T, U> {
     fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
@@ -1485,6 +1495,7 @@ impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
 ///
 /// [`take()`]: trait.Read.html#method.take
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Take<T> {
     inner: T,
     limit: u64,
@@ -1602,6 +1613,7 @@ fn read_one_byte(reader: &mut Read) -> Option<Result<u8>> {
 ///
 /// [`bytes()`]: trait.Read.html#method.bytes
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Bytes<R> {
     inner: R,
 }
@@ -1623,6 +1635,7 @@ impl<R: Read> Iterator for Bytes<R> {
 /// [chars]: trait.Read.html#method.chars
 #[unstable(feature = "io", reason = "awaiting stability of Read::chars",
            issue = "27802")]
+#[derive(Debug)]
 pub struct Chars<R> {
     inner: R,
 }
@@ -1712,6 +1725,7 @@ impl fmt::Display for CharsError {
 ///
 /// [split]: trait.BufRead.html#method.split
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Split<B> {
     buf: B,
     delim: u8,
@@ -1743,6 +1757,7 @@ impl<B: BufRead> Iterator for Split<B> {
 ///
 /// [lines]: trait.BufRead.html#method.lines
 #[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
 pub struct Lines<B> {
     buf: B,
 }
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 1a65bee13b8..9d1c8942f8c 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -282,6 +282,13 @@ impl Stdin {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Stdin {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stdin { .. }")
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Read for Stdin {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
@@ -314,6 +321,13 @@ impl<'a> BufRead for StdinLock<'a> {
     fn consume(&mut self, n: usize) { self.inner.consume(n) }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl<'a> fmt::Debug for StdinLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StdinLock { .. }")
+    }
+}
+
 /// A handle to the global standard output stream of the current process.
 ///
 /// Each handle shares a global buffer of data to be written to the standard
@@ -424,6 +438,13 @@ impl Stdout {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Stdout {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stdout { .. }")
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for Stdout {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
@@ -449,6 +470,13 @@ impl<'a> Write for StdoutLock<'a> {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl<'a> fmt::Debug for StdoutLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StdoutLock { .. }")
+    }
+}
+
 /// A handle to the standard error stream of a process.
 ///
 /// For more information, see the [`io::stderr`] method.
@@ -545,6 +573,13 @@ impl Stderr {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Stderr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Stderr { .. }")
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Write for Stderr {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
@@ -570,6 +605,13 @@ impl<'a> Write for StderrLock<'a> {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl<'a> fmt::Debug for StderrLock<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("StderrLock { .. }")
+    }
+}
+
 /// Resets the thread-local stderr handle to the specified writer
 ///
 /// This will replace the current thread's stderr handle, returning the old
diff --git a/src/libstd/io/util.rs b/src/libstd/io/util.rs
index 2c6880281b5..436511031ef 100644
--- a/src/libstd/io/util.rs
+++ b/src/libstd/io/util.rs
@@ -10,6 +10,7 @@
 
 #![allow(missing_copy_implementations)]
 
+use fmt;
 use io::{self, Read, Write, ErrorKind, BufRead};
 
 /// Copies the entire contents of a reader into a writer.
@@ -97,6 +98,13 @@ impl BufRead for Empty {
     fn consume(&mut self, _n: usize) {}
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Empty {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Empty { .. }")
+    }
+}
+
 /// A reader which yields one byte over and over and over and over and over and...
 ///
 /// This struct is generally created by calling [`repeat()`][repeat]. Please
@@ -133,6 +141,13 @@ impl Read for Repeat {
     }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Repeat {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Repeat { .. }")
+    }
+}
+
 /// A writer which will move data into the void.
 ///
 /// This struct is generally created by calling [`sink()`][sink]. Please
@@ -165,6 +180,13 @@ impl Write for Sink {
     fn flush(&mut self) -> io::Result<()> { Ok(()) }
 }
 
+#[stable(feature = "std_debug", since = "1.15.0")]
+impl fmt::Debug for Sink {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Sink { .. }")
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use io::prelude::*;