diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index 74f685a6de20e..d7cfccae29cec 100644
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -73,9 +73,9 @@ impl<T: ?Sized> !Send for *mut T { }
 /// impl Foo for Impl { }
 /// impl Bar for Impl { }
 ///
-/// let x: &Foo = &Impl;    // OK
-/// // let y: &Bar = &Impl; // error: the trait `Bar` cannot
-///                         // be made into an object
+/// let x: &dyn Foo = &Impl;    // OK
+/// // let y: &dyn Bar = &Impl; // error: the trait `Bar` cannot
+///                             // be made into an object
 /// ```
 ///
 /// [trait object]: ../../book/ch17-02-trait-objects.html
diff --git a/src/libcore/mem/mod.rs b/src/libcore/mem/mod.rs
index 770d1ca8e7501..e110e93a95412 100644
--- a/src/libcore/mem/mod.rs
+++ b/src/libcore/mem/mod.rs
@@ -510,6 +510,8 @@ pub fn swap<T>(x: &mut T, y: &mut T) {
 /// A simple example:
 ///
 /// ```
+/// #![feature(mem_take)]
+///
 /// use std::mem;
 ///
 /// let mut v: Vec<i32> = vec![1, 2];
@@ -540,7 +542,8 @@ pub fn swap<T>(x: &mut T, y: &mut T) {
 /// `self`, allowing it to be returned:
 ///
 /// ```
-/// # #![allow(dead_code)]
+/// #![feature(mem_take)]
+///
 /// use std::mem;
 ///
 /// # struct Buffer<T> { buf: Vec<T> }
diff --git a/src/libcore/raw.rs b/src/libcore/raw.rs
index 155429b0e4f54..75c329a7d6c10 100644
--- a/src/libcore/raw.rs
+++ b/src/libcore/raw.rs
@@ -53,7 +53,7 @@
 /// let value: i32 = 123;
 ///
 /// // let the compiler make a trait object
-/// let object: &Foo = &value;
+/// let object: &dyn Foo = &value;
 ///
 /// // look at the raw representation
 /// let raw_object: raw::TraitObject = unsafe { mem::transmute(object) };
@@ -65,7 +65,7 @@
 ///
 /// // construct a new object, pointing to a different `i32`, being
 /// // careful to use the `i32` vtable from `object`
-/// let synthesized: &Foo = unsafe {
+/// let synthesized: &dyn Foo = unsafe {
 ///      mem::transmute(raw::TraitObject {
 ///          data: &other_value as *const _ as *mut (),
 ///          vtable: raw_object.vtable,