diff --git a/mk/tests.mk b/mk/tests.mk
index 052d0c18ed4e26e4545bdc1a5d2f22c3c9d06bd8..73aec5de8da321983812a1662fbfa2e0a0bccaa9 100644
--- a/mk/tests.mk
+++ b/mk/tests.mk
@@ -25,7 +25,8 @@ $(eval $(call RUST_CRATE,collectionstest))
 TEST_TARGET_CRATES = $(filter-out core rustc_unicode alloc_system libc \
 		     		  alloc_jemalloc,$(TARGET_CRATES)) \
 			collectionstest coretest
-TEST_DOC_CRATES = $(DOC_CRATES)
+TEST_DOC_CRATES = $(DOC_CRATES) arena flate fmt_macros getopts graphviz \
+                log rand rbml serialize syntax term test
 TEST_HOST_CRATES = $(filter-out rustc_typeck rustc_borrowck rustc_resolve \
 		   		rustc_trans rustc_lint,\
                      $(HOST_CRATES))
diff --git a/src/doc/trpl/documentation.md b/src/doc/trpl/documentation.md
index dc91c90b0fd62263494906e61a40866d936ed260..80aed0d1ca7da63aa3924dba3ee1c9cc4c6c4494 100644
--- a/src/doc/trpl/documentation.md
+++ b/src/doc/trpl/documentation.md
@@ -620,6 +620,18 @@ You can control a few aspects of the HTML that `rustdoc` generates through the
 
 This sets a few different options, with a logo, favicon, and a root URL.
 
+### Configuring documentation tests
+
+You can also configure the way that `rustdoc` tests your documentation examples
+through the `#![doc(test(..))]` attribute.
+
+```rust
+#![doc(test(attr(allow(unused_variables), deny(warnings))))]
+```
+
+This allows unused variables within the examples, but will fail the test for any
+other lint warning thrown.
+
 ## Generation options
 
 `rustdoc` also contains a few other options on the command line, for further customization:
diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index 899e7de4ed59f9ac769e75bb69e7550a02e30f93..4113f67e617d17bc4dc1f76c3d6ab292a9e84234 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -70,7 +70,7 @@
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
-       test(no_crate_inject))]
+       test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 #![no_std]
 #![cfg_attr(not(stage0), needs_allocator)]
 
diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index 5bc1c44e1b1fb11281cb64f1ec38a710e57da10c..2234d3608f3f38b4c722dc02f565c87fc0879d38 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -28,7 +28,8 @@
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       test(no_crate_inject, attr(deny(warnings))))]
 
 #![feature(alloc)]
 #![feature(box_syntax)]
diff --git a/src/libcollections/binary_heap.rs b/src/libcollections/binary_heap.rs
index 30fc22e400a81a65273278b7d8e41e875739eda3..72547a9a5d2ee7703bd13839d63966971a292e05 100644
--- a/src/libcollections/binary_heap.rs
+++ b/src/libcollections/binary_heap.rs
@@ -233,6 +233,7 @@ pub fn with_capacity(capacity: usize) -> BinaryHeap<T> {
     ///
     /// ```
     /// #![feature(binary_heap_extras)]
+    /// # #![allow(deprecated)]
     ///
     /// use std::collections::BinaryHeap;
     /// let heap = BinaryHeap::from_vec(vec![9, 1, 2, 7, 3, 2]);
diff --git a/src/libcollections/borrow.rs b/src/libcollections/borrow.rs
index bd1864b28cdd3e24e22621733a2a5d3a2e909d0d..9b8f8c8f5bb8466a8b4bc4c999fb2384ff8d62ee 100644
--- a/src/libcollections/borrow.rs
+++ b/src/libcollections/borrow.rs
@@ -72,6 +72,7 @@ fn to_owned(&self) -> T { self.clone() }
 /// ```
 /// use std::borrow::Cow;
 ///
+/// # #[allow(dead_code)]
 /// fn abs_all(input: &mut Cow<[i32]>) {
 ///     for i in 0..input.len() {
 ///         let v = input[i];
diff --git a/src/libcollections/btree/set.rs b/src/libcollections/btree/set.rs
index 121668fbb9d9d8026853f495c66cd13360b75956..0c70a1544ef92f21ea1558519a48b46db5a5bbea 100644
--- a/src/libcollections/btree/set.rs
+++ b/src/libcollections/btree/set.rs
@@ -89,6 +89,7 @@ impl<T: Ord> BTreeSet<T> {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(unused_mut)]
     /// use std::collections::BTreeSet;
     ///
     /// let mut set: BTreeSet<i32> = BTreeSet::new();
diff --git a/src/libcollections/fmt.rs b/src/libcollections/fmt.rs
index a31ad6c1093628c1b42b21d13a8cdfdce57bbc81..990575ebbb3361c15ce45f8c1d312f8957e804ba 100644
--- a/src/libcollections/fmt.rs
+++ b/src/libcollections/fmt.rs
@@ -150,6 +150,7 @@
 //! implement a method of the signature:
 //!
 //! ```
+//! # #![allow(dead_code)]
 //! # use std::fmt;
 //! # struct Foo; // our custom type
 //! # impl fmt::Display for Foo {
@@ -174,7 +175,6 @@
 //! like:
 //!
 //! ```
-//! #![feature(fmt_flags)]
 //! use std::fmt;
 //!
 //! #[derive(Debug)]
@@ -288,6 +288,7 @@
 //! off, some example usage is:
 //!
 //! ```
+//! # #![allow(unused_must_use)]
 //! use std::fmt;
 //! use std::io::{self, Write};
 //!
diff --git a/src/libcollections/lib.rs b/src/libcollections/lib.rs
index 670c32776df7b8679693129dc90cc7735bb8ffed..54b98c6e17992f8490d49fc04a6505b44335332c 100644
--- a/src/libcollections/lib.rs
+++ b/src/libcollections/lib.rs
@@ -27,7 +27,7 @@
        html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
-       test(no_crate_inject))]
+       test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 
 #![allow(trivial_casts)]
 #![cfg_attr(test, allow(deprecated))] // rand
diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs
index e6391f5c988a4bc9649ceceae9fe84e9e902b53b..85aefbfffb1ad04dfd9c60d6539ce9b12a4e6337 100644
--- a/src/libcollections/slice.rs
+++ b/src/libcollections/slice.rs
@@ -852,6 +852,7 @@ pub trait SliceConcatExt<T: ?Sized> {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(deprecated)]
     /// assert_eq!(["hello", "world"].connect(" "), "hello world");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcollections/str.rs b/src/libcollections/str.rs
index 104fbe699e09e94599428df367e7513ed994b265..a5013f4e75b18d8f3b14fb71d7d60c2fab46191e 100644
--- a/src/libcollections/str.rs
+++ b/src/libcollections/str.rs
@@ -298,7 +298,7 @@ pub unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut s
     /// done by `.chars()` or `.char_indices()`.
     ///
     /// ```
-    /// #![feature(str_char, core)]
+    /// #![feature(str_char)]
     ///
     /// use std::str::CharRange;
     ///
@@ -358,7 +358,7 @@ pub fn char_range_at(&self, start: usize) -> CharRange {
     /// done by `.chars().rev()` or `.char_indices()`.
     ///
     /// ```
-    /// #![feature(str_char, core)]
+    /// #![feature(str_char)]
     ///
     /// use std::str::CharRange;
     ///
@@ -634,6 +634,7 @@ pub fn lines(&self) -> Lines {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(deprecated)]
     /// let four_lines = "foo\r\nbar\n\r\nbaz";
     /// let v: Vec<&str> = four_lines.lines_any().collect();
     ///
@@ -643,6 +644,7 @@ pub fn lines(&self) -> Lines {
     /// Leaving off the trailing character:
     ///
     /// ```
+    /// # #![allow(deprecated)]
     /// let four_lines = "foo\r\nbar\n\r\nbaz\n";
     /// let v: Vec<&str> = four_lines.lines_any().collect();
     ///
@@ -1179,8 +1181,6 @@ pub fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P>
     /// # Examples
     ///
     /// ```
-    /// #![feature(str_match_indices)]
-    ///
     /// let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect();
     /// assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]);
     ///
@@ -1216,8 +1216,6 @@ pub fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P
     /// # Examples
     ///
     /// ```
-    /// #![feature(str_match_indices)]
-    ///
     /// let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect();
     /// assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]);
     ///
diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
index 4255665681c8a1491823af3ebc69ff8550a1db7c..804e798c600a5808b742d341bcce9f49c5696412 100644
--- a/src/libcollections/string.rs
+++ b/src/libcollections/string.rs
@@ -55,6 +55,7 @@ impl String {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(unused_mut)]
     /// let mut s = String::new();
     /// ```
     #[inline]
@@ -73,6 +74,20 @@ pub fn new() -> String {
     ///
     /// ```
     /// let mut s = String::with_capacity(10);
+    ///
+    /// // The String contains no chars, even though it has capacity for more
+    /// assert_eq!(s.len(), 0);
+    ///
+    /// // These are all done without reallocating...
+    /// let cap = s.capacity();
+    /// for i in 0..10 {
+    ///     s.push('a');
+    /// }
+    ///
+    /// assert_eq!(s.capacity(), cap);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// s.push('a');
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs
index c4e4059429f38b0885c1786662c2d274ce9dd2cf..9153d624268ed6d36d2c48f4701d779538a271ec 100644
--- a/src/libcollections/vec.rs
+++ b/src/libcollections/vec.rs
@@ -242,6 +242,7 @@ impl<T> Vec<T> {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(unused_mut)]
     /// let mut vec: Vec<i32> = Vec::new();
     /// ```
     #[inline]
diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index 9fcc2b3412aad444823f39d30f0459d2d2f7930e..59b05c21d80050b6902f7cb2d768241683cc8122 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -76,6 +76,7 @@
 //! a trait method that was originally defined to take `&self`.
 //!
 //! ```
+//! # #![allow(dead_code)]
 //! use std::cell::RefCell;
 //!
 //! struct Graph {
@@ -125,6 +126,7 @@
 //! }
 //!
 //! struct RcBox<T> {
+//! # #[allow(dead_code)]
 //!     value: T,
 //!     refcount: Cell<usize>
 //! }
@@ -776,6 +778,7 @@ fn deref_mut(&mut self) -> &mut T {
 /// use std::cell::UnsafeCell;
 /// use std::marker::Sync;
 ///
+/// # #[allow(dead_code)]
 /// struct NotThreadSafe<T> {
 ///     value: UnsafeCell<T>,
 /// }
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
index 302c9d0c3697440ac17bd863244df27dd477972e..5458a7b9c38b01b24ba479a71c29f617e965c924 100644
--- a/src/libcore/cmp.rs
+++ b/src/libcore/cmp.rs
@@ -140,8 +140,6 @@ unsafe fn from_i8_unchecked(v: i8) -> Ordering {
     /// This method can be used to reverse a comparison:
     ///
     /// ```
-    /// use std::cmp::Ordering;
-    ///
     /// let mut data: &mut [_] = &mut [2, 10, 5, 8];
     ///
     /// // sort the array from largest to smallest.
@@ -263,8 +261,6 @@ pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
     /// # Examples
     ///
     /// ```
-    /// use std::cmp::Ordering;
-    ///
     /// let result = 1.0 < 2.0;
     /// assert_eq!(result, true);
     ///
diff --git a/src/libcore/default.rs b/src/libcore/default.rs
index cbad72eae3d7d378ff1bd32bd6efdab209d28098..12c4a5ca200ad3b1c7271cc6baff8878764800b0 100644
--- a/src/libcore/default.rs
+++ b/src/libcore/default.rs
@@ -15,6 +15,7 @@
 //! that define a set of options:
 //!
 //! ```
+//! # #[allow(dead_code)]
 //! struct SomeOptions {
 //!     foo: i32,
 //!     bar: f32,
@@ -24,6 +25,7 @@
 //! How can we define some default values? You can use `Default`:
 //!
 //! ```
+//! # #[allow(dead_code)]
 //! #[derive(Default)]
 //! struct SomeOptions {
 //!     foo: i32,
@@ -40,6 +42,7 @@
 //! If you have your own type, you need to implement `Default` yourself:
 //!
 //! ```
+//! # #![allow(dead_code)]
 //! enum Kind {
 //!     A,
 //!     B,
@@ -66,6 +69,7 @@
 //! If you want to override a particular option, but still retain the other defaults:
 //!
 //! ```
+//! # #[allow(dead_code)]
 //! # #[derive(Default)]
 //! # struct SomeOptions {
 //! #     foo: i32,
@@ -88,6 +92,7 @@
 /// # Examples
 ///
 /// ```
+/// # #[allow(dead_code)]
 /// #[derive(Default)]
 /// struct SomeOptions {
 ///     foo: i32,
@@ -114,6 +119,7 @@ pub trait Default: Sized {
     /// Making your own:
     ///
     /// ```
+    /// # #[allow(dead_code)]
     /// enum Kind {
     ///     A,
     ///     B,
diff --git a/src/libcore/hash/mod.rs b/src/libcore/hash/mod.rs
index 4e038f455e1bea1bc5b17d851fbfea1f7bfdaaa1..0899dc28848195b844aab0e736f7442bbd84324a 100644
--- a/src/libcore/hash/mod.rs
+++ b/src/libcore/hash/mod.rs
@@ -45,6 +45,7 @@
 //!
 //! struct Person {
 //!     id: u32,
+//! # #[allow(dead_code)]
 //!     name: String,
 //!     phone: u64,
 //! }
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index ea4792bb495f6564d67db74fa8d5638730f7d94b..a094bcd0192d24664ae01e7b40e7fef6afcc045d 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -334,6 +334,7 @@
     /// use std::mem;
     /// use std::ptr;
     ///
+    /// # #[allow(dead_code)]
     /// fn swap<T>(x: &mut T, y: &mut T) {
     ///     unsafe {
     ///         // Give ourselves some scratch space to work with
@@ -372,6 +373,7 @@
     /// ```
     /// use std::ptr;
     ///
+    /// # #[allow(dead_code)]
     /// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
     ///     let mut dst = Vec::with_capacity(elts);
     ///     dst.set_len(elts);
diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index f8c6e3cfdd7dd73ae024ce2f0e64ee6740454ff8..8558927e4acae35e9eb2108f3a67eda51f21ce02 100644
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -241,6 +241,7 @@
 //! method calls a closure on each element it iterates over:
 //!
 //! ```
+//! # #![allow(unused_must_use)]
 //! let v = vec![1, 2, 3, 4, 5];
 //! v.iter().map(|x| println!("{}", x));
 //! ```
@@ -419,7 +420,7 @@ pub trait Iterator {
     ///
     /// ```
     /// // an infinite iterator has no upper bound
-    /// let iter = (0..);
+    /// let iter = 0..;
     ///
     /// assert_eq!((0, None), iter.size_hint());
     /// ```
@@ -709,6 +710,7 @@ fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where
     /// If you're doing some sort of side effect, prefer [`for`] to `map()`:
     ///
     /// ```
+    /// # #![allow(unused_must_use)]
     /// // don't do this:
     /// (0..5).map(|x| println!("{}", x));
     ///
@@ -2695,7 +2697,7 @@ fn next_back(&mut self) -> Option<I::Item> { (**self).next_back() }
 ///
 /// ```
 /// // a finite range knows exactly how many times it will iterate
-/// let five = (0..5);
+/// let five = 0..5;
 ///
 /// assert_eq!(5, five.len());
 /// ```
@@ -2761,7 +2763,7 @@ pub trait ExactSizeIterator: Iterator {
     ///
     /// ```
     /// // a finite range knows exactly how many times it will iterate
-    /// let five = (0..5);
+    /// let five = 0..5;
     ///
     /// assert_eq!(5, five.len());
     /// ```
diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 94408072932ea5d6a5ad1690602d1331b8eaaba9..df7b7c437c3cc44ca3e8fd56c008aa43bed5b94b 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -60,7 +60,7 @@
        html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
-#![doc(test(no_crate_inject))]
+#![doc(test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 
 #![no_core]
 #![allow(raw_pointer_derive)]
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index a4a2552025bf760f5da11875c9328bcc4ab29b0f..bc8656b32b8e4e336b29bc4b2d022689cebec347 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -247,6 +247,7 @@
 /// Match arms:
 ///
 /// ```
+/// # #[allow(dead_code)]
 /// fn foo(x: Option<i32>) {
 ///     match x {
 ///         Some(n) if n >= 0 => println!("Some(Non-negative)"),
@@ -260,6 +261,7 @@
 /// Iterators:
 ///
 /// ```
+/// # #[allow(dead_code)]
 /// fn divide_by_three(x: u32) -> u32 { // one of the poorest implementations of x/3
 ///     for i in 0.. {
 ///         if 3*i < i { panic!("u32 overflow"); }
diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index 2f2dcc41a1c5e97f4cff1931748033efd782a42a..6e6ae6185278711079a75a1d4b0a87e81cc3e933 100644
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -42,6 +42,7 @@ impl<T> !Send for *mut T { }
 /// `?Sized` can be used to remove this bound if it is not appropriate.
 ///
 /// ```
+/// # #![allow(dead_code)]
 /// struct Foo<T>(T);
 /// struct Bar<T: ?Sized>(T);
 ///
@@ -106,6 +107,7 @@ pub trait Unsize<T: ?Sized> {
 /// `struct` can be `Copy`:
 ///
 /// ```
+/// # #[allow(dead_code)]
 /// struct Point {
 ///    x: i32,
 ///    y: i32,
@@ -115,6 +117,7 @@ pub trait Unsize<T: ?Sized> {
 /// A `struct` can be `Copy`, and `i32` is `Copy`, so therefore, `Point` is eligible to be `Copy`.
 ///
 /// ```
+/// # #![allow(dead_code)]
 /// # struct Point;
 /// struct PointList {
 ///     points: Vec<Point>,
@@ -303,6 +306,7 @@ fn default() -> $t<T> {
 /// ```
 /// use std::marker::PhantomData;
 ///
+/// # #[allow(dead_code)]
 /// struct Slice<'a, T:'a> {
 ///     start: *const T,
 ///     end: *const T,
@@ -323,6 +327,7 @@ fn default() -> $t<T> {
 /// mismatches by enforcing types in the method implementations:
 ///
 /// ```
+/// # #![allow(dead_code)]
 /// # trait ResType { fn foo(&self); }
 /// # struct ParamType;
 /// # mod foreign_lib {
@@ -393,6 +398,8 @@ unsafe impl<'a, T: Send + ?Sized> Send for &'a mut T {}
 /// #![feature(reflect_marker)]
 /// use std::marker::Reflect;
 /// use std::any::Any;
+///
+/// # #[allow(dead_code)]
 /// fn foo<T:Reflect+'static>(x: &T) {
 ///     let any: &Any = x;
 ///     if any.is::<u32>() { println!("u32"); }
diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index a87d135e42592551f518118a93969ca1ad6e436a..2f01ea383400a1d83ff6b4beabf4cfaa34dad754 100644
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -92,6 +92,7 @@
 /// use std::mem;
 /// use std::ptr;
 ///
+/// # #[allow(dead_code)]
 /// fn swap<T>(x: &mut T, y: &mut T) {
 ///     unsafe {
 ///         // Give ourselves some scratch space to work with
@@ -151,6 +152,7 @@ pub fn size_of_val<T: ?Sized>(val: &T) -> usize {
 /// # Examples
 ///
 /// ```
+/// # #![allow(deprecated)]
 /// use std::mem;
 ///
 /// assert_eq!(4, mem::min_align_of::<i32>());
@@ -167,6 +169,7 @@ pub fn min_align_of<T>() -> usize {
 /// # Examples
 ///
 /// ```
+/// # #![allow(deprecated)]
 /// use std::mem;
 ///
 /// assert_eq!(4, mem::min_align_of_val(&5i32));
@@ -414,6 +417,7 @@ pub fn swap<T>(x: &mut T, y: &mut T) {
 /// `self`, allowing it to be returned:
 ///
 /// ```
+/// # #![allow(dead_code)]
 /// use std::mem;
 /// # struct Buffer<T> { buf: Vec<T> }
 /// impl<T> Buffer<T> {
diff --git a/src/libcore/ops.rs b/src/libcore/ops.rs
index 1bfdafa7133927211b6016f455d6a3d7d8896e34..7ad49eef8f711aa09ec78545863556c6f974dcf9 100644
--- a/src/libcore/ops.rs
+++ b/src/libcore/ops.rs
@@ -947,6 +947,7 @@ fn shr(self, other: $f) -> $t {
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo += Foo;
@@ -996,6 +997,7 @@ fn add_assign(&mut self, other: $t) { *self += other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo -= Foo;
@@ -1045,6 +1047,7 @@ fn sub_assign(&mut self, other: $t) { *self -= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo *= Foo;
@@ -1094,6 +1097,7 @@ fn mul_assign(&mut self, other: $t) { *self *= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo /= Foo;
@@ -1143,6 +1147,7 @@ fn div_assign(&mut self, other: $t) { *self /= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo %= Foo;
@@ -1192,6 +1197,7 @@ fn rem_assign(&mut self, other: $t) { *self %= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo &= Foo;
@@ -1241,6 +1247,7 @@ fn bitand_assign(&mut self, other: $t) { *self &= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo |= Foo;
@@ -1290,6 +1297,7 @@ fn bitor_assign(&mut self, other: $t) { *self |= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo ^= Foo;
@@ -1339,6 +1347,7 @@ fn bitxor_assign(&mut self, other: $t) { *self ^= other }
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo <<= Foo;
@@ -1407,6 +1416,7 @@ fn shl_assign(&mut self, other: $f) {
 ///     }
 /// }
 ///
+/// # #[allow(unused_assignments)]
 /// fn main() {
 ///     let mut foo = Foo;
 ///     foo >>= Foo;
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 26e00867d84d54b430277bb808abacb5b09b6edb..7a3b83f68d0d881535784fc02f5734b208ed441a 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -275,6 +275,7 @@ pub fn as_mut(&mut self) -> Option<&mut T> {
     ///
     /// ```
     /// #![feature(as_slice)]
+    /// # #![allow(deprecated)]
     ///
     /// let mut x = Some("Diamonds");
     /// {
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index 71219155cc39fffb14b24bdc3864b8bbeffb993e..6e1f120a1db4826affa0dabbf9ac023c1d2afe5f 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -16,6 +16,7 @@
 //! and containing an error value.
 //!
 //! ```
+//! # #[allow(dead_code)]
 //! enum Result<T, E> {
 //!    Ok(T),
 //!    Err(E)
@@ -104,6 +105,7 @@
 //! something like this:
 //!
 //! ```no_run
+//! # #![allow(unused_must_use)] // \o/
 //! use std::fs::File;
 //! use std::io::prelude::*;
 //!
@@ -143,6 +145,7 @@
 //! # use std::fs::File;
 //! # use std::io::prelude::*;
 //! # use std::io;
+//! # #[allow(dead_code)]
 //! fn write_message() -> io::Result<()> {
 //!     let mut file = try!(File::create("valuable_data.txt"));
 //!     try!(file.write_all(b"important message"));
@@ -160,6 +163,7 @@
 //! It replaces this:
 //!
 //! ```
+//! # #![allow(dead_code)]
 //! use std::fs::File;
 //! use std::io::prelude::*;
 //! use std::io;
@@ -189,6 +193,7 @@
 //! With this:
 //!
 //! ```
+//! # #![allow(dead_code)]
 //! use std::fs::File;
 //! use std::io::prelude::*;
 //! use std::io;
@@ -422,6 +427,7 @@ pub fn as_slice(&self) -> &[T] {
     ///
     /// ```
     /// #![feature(as_slice)]
+    /// # #![allow(deprecated)]
     ///
     /// let mut x: Result<&str, u32> = Ok("Gold");
     /// {
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 18334ba91c61d2bdb028bce15895526ab94c14a4..7954bc3a0bf53e50046a4ad63f68eee94a757585 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -142,8 +142,6 @@ impl Utf8Error {
     /// Basic usage:
     ///
     /// ```
-    /// #![feature(utf8_error)]
-    ///
     /// use std::str;
     ///
     /// // some invalid bytes, in a vector
diff --git a/src/libflate/lib.rs b/src/libflate/lib.rs
index 51f387523294f43832cd263e485e6ae017d26ec3..513379b6558441003ae778625bb9c126f7246ea3 100644
--- a/src/libflate/lib.rs
+++ b/src/libflate/lib.rs
@@ -23,7 +23,8 @@
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       test(attr(deny(warnings))))]
 
 #![feature(libc)]
 #![feature(staged_api)]
diff --git a/src/libfmt_macros/lib.rs b/src/libfmt_macros/lib.rs
index ed767ab1e5cf97e3116deb0d01ad71b37cc04682..dc69f38e4e7d0870f1259e1bb943ab189343ec41 100644
--- a/src/libfmt_macros/lib.rs
+++ b/src/libfmt_macros/lib.rs
@@ -24,7 +24,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 
 #![feature(staged_api)]
 #![feature(unicode)]
diff --git a/src/libgetopts/lib.rs b/src/libgetopts/lib.rs
index ab34f2e48ca4abcd813fe5826399d9bf06890e56..f49451f827d62306b1e95a163ddbafef9d1745fa 100644
--- a/src/libgetopts/lib.rs
+++ b/src/libgetopts/lib.rs
@@ -30,9 +30,11 @@
 //! file name following `-o`, and accepts both `-h` and `--help` as optional flags.
 //!
 //! ```{.rust}
+//! #![feature(rustc_private)]
+//!
 //! extern crate getopts;
 //! use getopts::{optopt,optflag,getopts,OptGroup,usage};
-//! use std::os;
+//! use std::env;
 //!
 //! fn do_work(inp: &str, out: Option<String>) {
 //!     println!("{}", inp);
@@ -44,11 +46,11 @@
 //!
 //! fn print_usage(program: &str, opts: &[OptGroup]) {
 //!     let brief = format!("Usage: {} [options]", program);
-//!     print!("{}", usage(brief, opts));
+//!     print!("{}", usage(&brief, opts));
 //! }
 //!
 //! fn main() {
-//!     let args: Vec<String> = os::args();
+//!     let args: Vec<String> = env::args().collect();
 //!
 //!     let program = args[0].clone();
 //!
@@ -56,22 +58,22 @@
 //!         optopt("o", "", "set output file name", "NAME"),
 //!         optflag("h", "help", "print this help menu")
 //!     ];
-//!     let matches = match getopts(args[1..], opts) {
+//!     let matches = match getopts(&args[1..], opts) {
 //!         Ok(m) => { m }
 //!         Err(f) => { panic!(f.to_string()) }
 //!     };
 //!     if matches.opt_present("h") {
-//!         print_usage(program, opts);
+//!         print_usage(&program, opts);
 //!         return;
 //!     }
 //!     let output = matches.opt_str("o");
 //!     let input = if !matches.free.is_empty() {
 //!         matches.free[0].clone()
 //!     } else {
-//!         print_usage(program, opts);
+//!         print_usage(&program, opts);
 //!         return;
 //!     };
-//!     do_work(input, output);
+//!     do_work(&input, output);
 //! }
 //! ```
 
@@ -88,7 +90,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 
 #![deny(missing_docs)]
 #![feature(staged_api)]
diff --git a/src/libgraphviz/lib.rs b/src/libgraphviz/lib.rs
index b82b7d122b3ce8205c760602202243faed391eeb..1fb54ed9071ab6b6939d79381b93889945d5cd58 100644
--- a/src/libgraphviz/lib.rs
+++ b/src/libgraphviz/lib.rs
@@ -47,7 +47,7 @@
 //! which is cyclic.
 //!
 //! ```rust
-//! #![feature(rustc_private, core, into_cow)]
+//! #![feature(rustc_private, into_cow)]
 //!
 //! use std::borrow::IntoCow;
 //! use std::io::Write;
@@ -150,9 +150,8 @@
 //! entity `&sube`).
 //!
 //! ```rust
-//! #![feature(rustc_private, core, into_cow)]
+//! #![feature(rustc_private)]
 //!
-//! use std::borrow::IntoCow;
 //! use std::io::Write;
 //! use graphviz as dot;
 //!
@@ -174,10 +173,10 @@
 //!         dot::Id::new(format!("N{}", n)).unwrap()
 //!     }
 //!     fn node_label<'b>(&'b self, n: &Nd) -> dot::LabelText<'b> {
-//!         dot::LabelText::LabelStr(self.nodes[*n].as_slice().into_cow())
+//!         dot::LabelText::LabelStr(self.nodes[*n].into())
 //!     }
 //!     fn edge_label<'b>(&'b self, _: &Ed) -> dot::LabelText<'b> {
-//!         dot::LabelText::LabelStr("&sube;".into_cow())
+//!         dot::LabelText::LabelStr("&sube;".into())
 //!     }
 //! }
 //!
@@ -209,9 +208,8 @@
 //! Hasse-diagram for the subsets of the set `{x, y}`.
 //!
 //! ```rust
-//! #![feature(rustc_private, core, into_cow)]
+//! #![feature(rustc_private)]
 //!
-//! use std::borrow::IntoCow;
 //! use std::io::Write;
 //! use graphviz as dot;
 //!
@@ -234,10 +232,10 @@
 //!     }
 //!     fn node_label<'b>(&'b self, n: &Nd<'b>) -> dot::LabelText<'b> {
 //!         let &(i, _) = n;
-//!         dot::LabelText::LabelStr(self.nodes[i].into_cow())
+//!         dot::LabelText::LabelStr(self.nodes[i].into())
 //!     }
 //!     fn edge_label<'b>(&'b self, _: &Ed<'b>) -> dot::LabelText<'b> {
-//!         dot::LabelText::LabelStr("&sube;".into_cow())
+//!         dot::LabelText::LabelStr("&sube;".into())
 //!     }
 //! }
 //!
@@ -283,7 +281,8 @@
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       test(attr(allow(unused_variables), deny(warnings))))]
 
 #![feature(into_cow)]
 #![feature(str_escape)]
diff --git a/src/liblog/lib.rs b/src/liblog/lib.rs
index 9cb835bd8525d583c99eab127bd178f5048ad2cb..1de7ebfffdea28af1ed89028823eadc9d2170a5b 100644
--- a/src/liblog/lib.rs
+++ b/src/liblog/lib.rs
@@ -13,6 +13,7 @@
 //! # Examples
 //!
 //! ```
+//! # #![feature(rustc_private)]
 //! #[macro_use] extern crate log;
 //!
 //! fn main() {
@@ -167,7 +168,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 #![deny(missing_docs)]
 
 #![feature(box_syntax)]
diff --git a/src/liblog/macros.rs b/src/liblog/macros.rs
index 46b51f50c85831d2136363ef28e2279252809b7c..803a2df9ccc8baff67d46d6a3b15db71c8d49602 100644
--- a/src/liblog/macros.rs
+++ b/src/liblog/macros.rs
@@ -19,6 +19,7 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
 /// fn main() {
@@ -67,6 +68,7 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
 /// fn main() {
@@ -92,6 +94,7 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
 /// fn main() {
@@ -116,6 +119,7 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
 /// fn main() {
@@ -142,6 +146,7 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
 /// fn main() {
@@ -165,9 +170,10 @@
 /// # Examples
 ///
 /// ```
+/// # #![feature(rustc_private)]
 /// #[macro_use] extern crate log;
 ///
-/// struct Point { x: int, y: int }
+/// struct Point { x: i32, y: i32 }
 /// fn some_expensive_computation() -> Point { Point { x: 1, y: 2 } }
 ///
 /// fn main() {
diff --git a/src/librand/lib.rs b/src/librand/lib.rs
index b5a1eb9520cec6eb1983925f9ac4c40b6b3674cb..cf2118b45a471220df369249b1d7b4299cecee27 100644
--- a/src/librand/lib.rs
+++ b/src/librand/lib.rs
@@ -23,7 +23,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 #![no_std]
 #![staged_api]
 #![unstable(feature = "rand",
diff --git a/src/librbml/lib.rs b/src/librbml/lib.rs
index 1c6cb06d54ae4218530c3b3e22df155c442c83a6..a1b15cd9e6f11ebd28cbb9b43c4d1c9d8a9db439 100644
--- a/src/librbml/lib.rs
+++ b/src/librbml/lib.rs
@@ -121,7 +121,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 
 #![feature(rustc_private)]
 #![feature(staged_api)]
diff --git a/src/librustc_unicode/lib.rs b/src/librustc_unicode/lib.rs
index 467c974690062e70ab934a4efd771a916f8f7653..79ce8aacae815a6515e98617fe3959ee5f8bc96c 100644
--- a/src/librustc_unicode/lib.rs
+++ b/src/librustc_unicode/lib.rs
@@ -31,7 +31,7 @@
        html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
-       test(no_crate_inject))]
+       test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 #![no_std]
 
 #![feature(core_char_ext)]
diff --git a/src/librustc_unicode/u_str.rs b/src/librustc_unicode/u_str.rs
index 2347cdebf2292e60ed550ccc33614c5dced79fb8..57d96bf43719e7fe442e0a94ea6c0c30254e2ecb 100644
--- a/src/librustc_unicode/u_str.rs
+++ b/src/librustc_unicode/u_str.rs
@@ -190,6 +190,7 @@ fn size_hint(&self) -> (usize, Option<usize>) {
 ///
 /// ```
 /// #![feature(unicode, decode_utf16)]
+/// # #![allow(deprecated)]
 ///
 /// extern crate rustc_unicode;
 ///
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 452feed3cdb4effa751e10616edabbd5867e9e98..9e1e3c6a558055436dc2fa38cc25b8bc3c8cf84c 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -77,8 +77,9 @@
 //! serialization API, using the derived serialization code.
 //!
 //! ```rust
-//! extern crate serialize;
-//! use serialize::json;
+//! # #![feature(rustc_private)]
+//! extern crate serialize as rustc_serialize; // for the deriving below
+//! use rustc_serialize::json;
 //!
 //! // Automatically generate `Decodable` and `Encodable` trait implementations
 //! #[derive(RustcDecodable, RustcEncodable)]
@@ -111,6 +112,7 @@
 //! ### Simple example of `ToJson` usage
 //!
 //! ```rust
+//! # #![feature(rustc_private)]
 //! extern crate serialize;
 //! use serialize::json::{self, ToJson, Json};
 //!
@@ -150,6 +152,7 @@
 //! ### Verbose example of `ToJson` usage
 //!
 //! ```rust
+//! # #![feature(rustc_private)]
 //! extern crate serialize;
 //! use std::collections::BTreeMap;
 //! use serialize::json::{self, Json, ToJson};
@@ -185,7 +188,7 @@
 //!     let json_str: String = json_obj.to_string();
 //!
 //!     // Deserialize like before
-//!     let decoded: TestStruct = json::decode(json_str)).unwrap();
+//!     let decoded: TestStruct = json::decode(&json_str).unwrap();
 //! }
 //! ```
 
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index 5b7bec41723cde69df2dc823c2030899dae9ee8a..4a766f14531374865b8aa505f9b772ace3bebcec 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -26,7 +26,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(allow(unused_variables), deny(warnings))))]
 
 #![feature(box_syntax)]
 #![feature(collections)]
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 8c9c883508703089eb2bf3c96beba6dc9113c15f..1f34af617d588e409501a8b85cb7012c00f82c4a 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -908,13 +908,15 @@ pub enum Expr_ {
 /// separately. `position` represents the index of the associated
 /// item qualified with this Self type.
 ///
-///     <Vec<T> as a::b::Trait>::AssociatedItem
-///      ^~~~~     ~~~~~~~~~~~~~~^
-///      ty        position = 3
+/// ```ignore
+/// <Vec<T> as a::b::Trait>::AssociatedItem
+///  ^~~~~     ~~~~~~~~~~~~~~^
+///  ty        position = 3
 ///
-///     <Vec<T>>::AssociatedItem
-///      ^~~~~    ^
-///      ty       position = 0
+/// <Vec<T>>::AssociatedItem
+///  ^~~~~    ^
+///  ty       position = 0
+/// ```
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct QSelf {
     pub ty: P<Ty>,
diff --git a/src/libsyntax/ext/deriving/generic/mod.rs b/src/libsyntax/ext/deriving/generic/mod.rs
index 5c6e2fce8adcea845f8ddb607608648c9b622476..5a0fc4fda0ccac065a80812dc6b820125e4abb3d 100644
--- a/src/libsyntax/ext/deriving/generic/mod.rs
+++ b/src/libsyntax/ext/deriving/generic/mod.rs
@@ -54,6 +54,7 @@
 //! following snippet
 //!
 //! ```rust
+//! # #![allow(dead_code)]
 //! struct A { x : i32 }
 //!
 //! struct B(i32);
@@ -88,7 +89,7 @@
 //!
 //! ```rust
 //! trait PartialEq {
-//!     fn eq(&self, other: &Self);
+//!     fn eq(&self, other: &Self) -> bool;
 //! }
 //! impl PartialEq for i32 {
 //!     fn eq(&self, other: &i32) -> bool {
@@ -905,7 +906,7 @@ fn create_method(&self,
         })
     }
 
-    /// ```
+    /// ```ignore
     /// #[derive(PartialEq)]
     /// struct A { x: i32, y: i32 }
     ///
@@ -1010,7 +1011,7 @@ fn expand_static_struct_method_body(&self,
                                       &StaticStruct(struct_def, summary))
     }
 
-    /// ```
+    /// ```ignore
     /// #[derive(PartialEq)]
     /// enum A {
     ///     A1,
@@ -1596,7 +1597,7 @@ pub fn cs_fold<F>(use_foldl: bool,
 /// Call the method that is being derived on all the fields, and then
 /// process the collected results. i.e.
 ///
-/// ```
+/// ```ignore
 /// f(cx, span, vec![self_1.method(__arg_1_1, __arg_2_1),
 ///                  self_2.method(__arg_1_2, __arg_2_2)])
 /// ```
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index c56342371c84ed9a72dc305763626be38e3baea1..af0e7ce5c8d368a2030de2ac301d52ed1ccb2064 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -77,9 +77,10 @@ struct Context<'a, 'b:'a> {
 /// expressions.
 ///
 /// If parsing succeeds, the return value is:
-///
-///     Some((fmtstr, unnamed arguments, ordering of named arguments,
-///           named arguments))
+/// ```ignore
+/// Some((fmtstr, unnamed arguments, ordering of named arguments,
+///       named arguments))
+/// ```
 fn parse_args(ecx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
               -> Option<(P<ast::Expr>, Vec<P<ast::Expr>>, Vec<String>,
                          HashMap<String, P<ast::Expr>>)> {
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 524ac655d884467ea775d4178ac182a4968397f6..0cd27d1b0ccc38f037cb956450484fee7101e6bc 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -23,7 +23,8 @@
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       test(attr(deny(warnings))))]
 
 #![feature(associated_consts)]
 #![feature(drain)]
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index fde1058a785c0466147941e0a91eaba39729a675..1e38eebec5d635f86e7cd3d35dae16f2765e2129 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -3965,7 +3965,7 @@ fn forbid_lifetime(&mut self) -> PResult<()> {
 
     /// Parses an optional `where` clause and places it in `generics`.
     ///
-    /// ```
+    /// ```ignore
     /// where T : Trait<U, V> + 'b, 'a : 'b
     /// ```
     pub fn parse_where_clause(&mut self) -> PResult<ast::WhereClause> {
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index 7c5a46465f513163e2954a2d75b6059835a61a14..cbbd5289a5a2d5415a846ebfa050725f96aeac85 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -11,8 +11,10 @@
 //! This pretty-printer is a direct reimplementation of Philip Karlton's
 //! Mesa pretty-printer, as described in appendix A of
 //!
-//!     STAN-CS-79-770: "Pretty Printing", by Derek C. Oppen.
-//!     Stanford Department of Computer Science, 1979.
+//! ````ignore
+//! STAN-CS-79-770: "Pretty Printing", by Derek C. Oppen.
+//! Stanford Department of Computer Science, 1979.
+//! ````
 //!
 //! The algorithm's aim is to break a stream into as few lines as possible
 //! while respecting the indentation-consistency requirements of the enclosing
diff --git a/src/libterm/lib.rs b/src/libterm/lib.rs
index ced3a7d47d7b674a84d38babf317d6ed74e09edd..99bbd951766c68183712ad0570bf4203096df441 100644
--- a/src/libterm/lib.rs
+++ b/src/libterm/lib.rs
@@ -53,7 +53,8 @@
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(deny(warnings))))]
 #![deny(missing_docs)]
 
 #![feature(box_syntax)]
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 69b1d37bfc4ee9613b0da3a49f4a0c878b2ad6f0..89442fe1096fe6228e974a2655fb997a20d58383 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -32,7 +32,8 @@
 #![crate_type = "dylib"]
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+       html_root_url = "https://doc.rust-lang.org/nightly/",
+       test(attr(deny(warnings))))]
 
 #![feature(asm)]
 #![feature(box_syntax)]