diff --git a/book/3_generators_pin.html b/book/3_generators_pin.html
index bfc0ef4..353df8f 100644
--- a/book/3_generators_pin.html
+++ b/book/3_generators_pin.html
@@ -656,7 +656,7 @@ the syntax used in generators:</p>
     };
 </code></pre>
 <p>Compare that with a similar example using async blocks:</p>
-<pre><code>let mut fut = async || {
+<pre><code class="language-rust ignore">let mut fut = async || {
         let to_borrow = String::from(&quot;Hello&quot;);
         let borrowed = &amp;to_borrow;
         SomeResource::some_task().await;
diff --git a/book/print.html b/book/print.html
index bff45d5..e15a5ca 100644
--- a/book/print.html
+++ b/book/print.html
@@ -1553,7 +1553,7 @@ the syntax used in generators:</p>
     };
 </code></pre>
 <p>Compare that with a similar example using async blocks:</p>
-<pre><code>let mut fut = async || {
+<pre><code class="language-rust ignore">let mut fut = async || {
         let to_borrow = String::from(&quot;Hello&quot;);
         let borrowed = &amp;to_borrow;
         SomeResource::some_task().await;
diff --git a/src/3_generators_pin.md b/src/3_generators_pin.md
index b3d1ee3..9dda67e 100644
--- a/src/3_generators_pin.md
+++ b/src/3_generators_pin.md
@@ -562,7 +562,7 @@ let mut gen = move || {
 
 Compare that with a similar example using async blocks:
 
-```
+```rust, ignore
 let mut fut = async || {
         let to_borrow = String::from("Hello");
         let borrowed = &to_borrow;