diff --git a/listings/ch09-error-handling/listing-09-13/src/main.rs b/listings/ch09-error-handling/listing-09-13/src/main.rs
index 9e07c1ee25..42b7d32ef6 100644
--- a/listings/ch09-error-handling/listing-09-13/src/main.rs
+++ b/listings/ch09-error-handling/listing-09-13/src/main.rs
@@ -10,7 +10,7 @@ pub struct Guess {
 impl Guess {
     pub fn new(value: i32) -> Guess {
         if value < 1 || value > 100 {
-            panic!("Guess value must be between 1 and 100, got {}.", value);
+            panic!("Guess value must be between 1 and 100, got {value}.");
         }
 
         Guess { value }
diff --git a/listings/ch11-writing-automated-tests/listing-11-08/src/lib.rs b/listings/ch11-writing-automated-tests/listing-11-08/src/lib.rs
index 9391be5b1f..54e447bb93 100644
--- a/listings/ch11-writing-automated-tests/listing-11-08/src/lib.rs
+++ b/listings/ch11-writing-automated-tests/listing-11-08/src/lib.rs
@@ -5,7 +5,7 @@ pub struct Guess {
 impl Guess {
     pub fn new(value: i32) -> Guess {
         if value < 1 || value > 100 {
-            panic!("Guess value must be between 1 and 100, got {}.", value);
+            panic!("Guess value must be between 1 and 100, got {value}.");
         }
 
         Guess { value }
diff --git a/listings/ch11-writing-automated-tests/listing-11-09/src/lib.rs b/listings/ch11-writing-automated-tests/listing-11-09/src/lib.rs
index cc1c5c35d0..1bb464137b 100644
--- a/listings/ch11-writing-automated-tests/listing-11-09/src/lib.rs
+++ b/listings/ch11-writing-automated-tests/listing-11-09/src/lib.rs
@@ -9,13 +9,11 @@ impl Guess {
     pub fn new(value: i32) -> Guess {
         if value < 1 {
             panic!(
-                "Guess value must be greater than or equal to 1, got {}.",
-                value
+                "Guess value must be greater than or equal to 1, got {value}."
             );
         } else if value > 100 {
             panic!(
-                "Guess value must be less than or equal to 100, got {}.",
-                value
+                "Guess value must be less than or equal to 100, got {value}."
             );
         }
 
diff --git a/listings/ch11-writing-automated-tests/no-listing-08-guess-with-bug/src/lib.rs b/listings/ch11-writing-automated-tests/no-listing-08-guess-with-bug/src/lib.rs
index 32540ba83c..0f962fcd79 100644
--- a/listings/ch11-writing-automated-tests/no-listing-08-guess-with-bug/src/lib.rs
+++ b/listings/ch11-writing-automated-tests/no-listing-08-guess-with-bug/src/lib.rs
@@ -7,7 +7,7 @@ pub struct Guess {
 impl Guess {
     pub fn new(value: i32) -> Guess {
         if value < 1 {
-            panic!("Guess value must be between 1 and 100, got {}.", value);
+            panic!("Guess value must be between 1 and 100, got {value}.");
         }
 
         Guess { value }
diff --git a/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/src/lib.rs b/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/src/lib.rs
index 7703dd75ae..fb5fc0e77b 100644
--- a/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/src/lib.rs
+++ b/listings/ch11-writing-automated-tests/no-listing-09-guess-with-panic-msg-bug/src/lib.rs
@@ -7,13 +7,11 @@ impl Guess {
         // ANCHOR: here
         if value < 1 {
             panic!(
-                "Guess value must be less than or equal to 100, got {}.",
-                value
+                "Guess value must be less than or equal to 100, got {value}."
             );
         } else if value > 100 {
             panic!(
-                "Guess value must be greater than or equal to 1, got {}.",
-                value
+                "Guess value must be greater than or equal to 1, got {value}."
             );
         }
         // ANCHOR_END: here