diff --git a/src/ch12-01-accepting-command-line-arguments.md b/src/ch12-01-accepting-command-line-arguments.md
index 29d117185..92c9f4cd6 100644
--- a/src/ch12-01-accepting-command-line-arguments.md
+++ b/src/ch12-01-accepting-command-line-arguments.md
@@ -102,7 +102,7 @@ throughout the rest of the program. We do that in Listing 12-2.
 
 <span class="filename">Filename: src/main.rs</span>
 
-```rust,noplayground
+```rust,should_panic,noplayground
 {{#rustdoc_include ../listings/ch12-an-io-project/listing-12-02/src/main.rs}}
 ```
 
diff --git a/src/ch12-02-reading-a-file.md b/src/ch12-02-reading-a-file.md
index 05e56c7db..7ba7d92bd 100644
--- a/src/ch12-02-reading-a-file.md
+++ b/src/ch12-02-reading-a-file.md
@@ -22,7 +22,7 @@ shown in Listing 12-4.
 
 <span class="filename">Filename: src/main.rs</span>
 
-```rust,noplayground
+```rust,should_panic,noplayground
 {{#rustdoc_include ../listings/ch12-an-io-project/listing-12-04/src/main.rs:here}}
 ```
 
diff --git a/src/ch12-03-improving-error-handling-and-modularity.md b/src/ch12-03-improving-error-handling-and-modularity.md
index a99e43abb..32f0e571e 100644
--- a/src/ch12-03-improving-error-handling-and-modularity.md
+++ b/src/ch12-03-improving-error-handling-and-modularity.md
@@ -119,7 +119,7 @@ Listing 12-6 shows the improvements to the `parse_config` function.
 
 <span class="filename">Filename: src/main.rs</span>
 
-```rust,noplayground
+```rust,should_panic,noplayground
 {{#rustdoc_include ../listings/ch12-an-io-project/listing-12-06/src/main.rs:here}}
 ```
 
@@ -187,7 +187,7 @@ shows the changes we need to make.
 
 <span class="filename">Filename: src/main.rs</span>
 
-```rust,noplayground
+```rust,should_panic,noplayground
 {{#rustdoc_include ../listings/ch12-an-io-project/listing-12-07/src/main.rs:here}}
 ```