diff --git a/src/libcore/iter/iterator.rs b/src/libcore/iter/iterator.rs
index 209a22d534a2..da9af214207b 100644
--- a/src/libcore/iter/iterator.rs
+++ b/src/libcore/iter/iterator.rs
@@ -24,7 +24,7 @@ fn _assert_is_object_safe(_: &Iterator<Item=()>) {}
 /// This is the main iterator trait. For more about the concept of iterators
 /// generally, please see the [module-level documentation]. In particular, you
 /// may want to know how to [implement `Iterator`][impl].
-/// 
+///
 /// Note: Methods on infinite iterators that generally require traversing every
 /// element to produce a result may not terminate, even on traits for which a
 /// result is determinable in finite time.
diff --git a/src/libcore/iter/mod.rs b/src/libcore/iter/mod.rs
index 3a5a72d1b87c..ae10ac385ab5 100644
--- a/src/libcore/iter/mod.rs
+++ b/src/libcore/iter/mod.rs
@@ -297,14 +297,14 @@
 //! ```
 //!
 //! This will print the numbers `0` through `4`, each on their own line.
-//! 
+//!
 //! Bear in mind that methods on infinite iterators, even those for which a
 //! result can be computed in finite time, may not terminate. Specifically,
 //! methods such as [`min`], which in the general case require traversing
 //! every element in the iterator, are likely never to terminate for any
 //! infinite iterators.
-//! 
-//! ```
+//!
+//! ```no_run
 //! let positives = 1..;
 //! let least = positives.min().unwrap(); // Oh no! An infinite loop!
 //! // `positives.min` causes an infinite loop, so we won't reach this point!