Merge 45797e422a into d207d894cc

Ch. 2: intentionally use `{}` at first

Cargo.toml

@@ -2,7 +2,7 @@
 name = "rust-book"
 version = "0.0.1"
 description = "The Rust Book"
-edition = "2018"
+edition = "2021"
 
 [[bin]]
 name = "concat_chapters"

listings/ch02-guessing-game-tutorial/listing-02-01/src/main.rs

@@ -25,7 +25,7 @@ fn main() {
     // ANCHOR_END: expect
 
     // ANCHOR: print_guess
-    println!("You guessed: {guess}");
+    println!("You guessed: {}", guess);
     // ANCHOR_END: print_guess
 }
 // ANCHOR: all

listings/ch04-understanding-ownership/listing-04-01/src/main.rs

@@ -6,4 +6,4 @@ fn main() {
         // do stuff with s
     }                      // this scope is now over, and s is no longer valid
     // ANCHOR_END: here
-}
+}

listings/ch04-understanding-ownership/listing-04-03/src/main.rs

@@ -14,10 +14,10 @@ fn main() {
   // special happens.
 
 fn takes_ownership(some_string: String) { // some_string comes into scope
-    println!("{}", some_string);
+    println!("{some_string}");
 } // Here, some_string goes out of scope and `drop` is called. The backing
   // memory is freed.
 
 fn makes_copy(some_integer: i32) { // some_integer comes into scope
-    println!("{}", some_integer);
+    println!("{some_integer}");
 } // Here, some_integer goes out of scope. Nothing special happens.

listings/ch04-understanding-ownership/listing-04-05/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
 
     let (s2, len) = calculate_length(s1);
 
-    println!("The length of '{}' is {}.", s2, len);
+    println!("The length of '{s2}' is {len}.");
 }
 
 fn calculate_length(s: String) -> (String, usize) {

listings/ch04-understanding-ownership/no-listing-01-can-mutate-string/src/main.rs

@@ -4,6 +4,6 @@ fn main() {
 
     s.push_str(", world!"); // push_str() appends a literal to a String
 
-    println!("{}", s); // This will print `hello, world!`
-                       // ANCHOR_END: here
+    println!("{s}"); // This will print `hello, world!`
+                     // ANCHOR_END: here
 }

listings/ch04-understanding-ownership/no-listing-04-cant-use-after-move/src/main.rs

@@ -3,6 +3,6 @@ fn main() {
     let s1 = String::from("hello");
     let s2 = s1;
 
-    println!("{}, world!", s1);
+    println!("{s1}, world!");
     // ANCHOR_END: here
 }

listings/ch04-understanding-ownership/no-listing-05-clone/src/main.rs

@@ -3,6 +3,6 @@ fn main() {
     let s1 = String::from("hello");
     let s2 = s1.clone();
 
-    println!("s1 = {}, s2 = {}", s1, s2);
+    println!("s1 = {s1}, s2 = {s2}");
     // ANCHOR_END: here
 }

listings/ch04-understanding-ownership/no-listing-06-copy/src/main.rs

@@ -3,6 +3,6 @@ fn main() {
     let x = 5;
     let y = x;
 
-    println!("x = {}, y = {}", x, y);
+    println!("x = {x}, y = {y}");
     // ANCHOR_END: here
 }

listings/ch04-understanding-ownership/no-listing-07-reference/src/main.rs

@@ -6,7 +6,7 @@ fn main() {
     let len = calculate_length(&s1);
     // ANCHOR_END: here
 
-    println!("The length of '{}' is {}.", s1, len);
+    println!("The length of '{s1}' is {len}.");
 }
 
 fn calculate_length(s: &String) -> usize {

listings/ch04-understanding-ownership/no-listing-08-reference-with-annotations/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
 
     let len = calculate_length(&s1);
 
-    println!("The length of '{}' is {}.", s1, len);
+    println!("The length of '{s1}' is {len}.");
 }
 
 // ANCHOR: here

listings/ch04-understanding-ownership/no-listing-13-reference-scope-ends/src/main.rs

@@ -4,10 +4,10 @@ fn main() {
 
     let r1 = &s; // no problem
     let r2 = &s; // no problem
-    println!("{} and {}", r1, r2);
+    println!("{r1} and {r2}");
     // variables r1 and r2 will not be used after this point
 
     let r3 = &mut s; // no problem
-    println!("{}", r3);
+    println!("{r3}");
     // ANCHOR_END: here
 }

listings/ch04-understanding-ownership/no-listing-19-slice-error/src/main.rs

@@ -18,6 +18,6 @@ fn main() {
 
     s.clear(); // error!
 
-    println!("the first word is: {}", word);
+    println!("the first word is: {word}");
 }
 // ANCHOR_END: here

listings/ch05-using-structs-to-structure-related-data/listing-05-12/src/main.rs

@@ -10,5 +10,5 @@ fn main() {
         height: 50,
     };
 
-    println!("rect1 is {:?}", rect1);
+    println!("rect1 is {rect1:?}");
 }

listings/ch05-using-structs-to-structure-related-data/output-only-02-pretty-debug/src/main.rs

@@ -10,5 +10,5 @@ fn main() {
         height: 50,
     };
 
-    println!("rect1 is {:#?}", rect1);
+    println!("rect1 is {rect1:#?}");
 }

listings/ch06-enums-and-pattern-matching/listing-06-06/src/main.rs

@@ -2,7 +2,7 @@ fn main() {
     // ANCHOR: here
     let config_max = Some(3u8);
     match config_max {
-        Some(max) => println!("The maximum is configured to be {}", max),
+        Some(max) => println!("The maximum is configured to be {max}"),
         _ => (),
     }
     // ANCHOR_END: here

listings/ch06-enums-and-pattern-matching/no-listing-09-variable-in-pattern/src/main.rs

@@ -19,7 +19,7 @@ fn value_in_cents(coin: Coin) -> u8 {
         Coin::Nickel => 5,
         Coin::Dime => 10,
         Coin::Quarter(state) => {
-            println!("State quarter from {:?}!", state);
+            println!("State quarter from {state:?}!");
             25
         }
     }

listings/ch06-enums-and-pattern-matching/no-listing-12-if-let/src/main.rs

@@ -2,7 +2,7 @@ fn main() {
     // ANCHOR: here
     let config_max = Some(3u8);
     if let Some(max) = config_max {
-        println!("The maximum is configured to be {}", max);
+        println!("The maximum is configured to be {max}");
     }
     // ANCHOR_END: here
 }

listings/ch06-enums-and-pattern-matching/no-listing-13-count-and-announce-match/src/main.rs

@@ -17,7 +17,7 @@ fn main() {
     // ANCHOR: here
     let mut count = 0;
     match coin {
-        Coin::Quarter(state) => println!("State quarter from {:?}!", state),
+        Coin::Quarter(state) => println!("State quarter from {state:?}!"),
         _ => count += 1,
     }
     // ANCHOR_END: here

listings/ch06-enums-and-pattern-matching/no-listing-14-count-and-announce-if-let-else/src/main.rs

@@ -17,7 +17,7 @@ fn main() {
     // ANCHOR: here
     let mut count = 0;
     if let Coin::Quarter(state) = coin {
-        println!("State quarter from {:?}!", state);
+        println!("State quarter from {state:?}!");
     } else {
         count += 1;
     }

listings/ch07-managing-growing-projects/quick-reference-example/src/main.rs

@@ -4,5 +4,5 @@ pub mod garden;
 
 fn main() {
     let plant = Asparagus {};
-    println!("I'm growing {:?}!", plant);
+    println!("I'm growing {plant:?}!");
 }

listings/ch08-common-collections/listing-08-23/src/main.rs

@@ -7,6 +7,6 @@ fn main() {
     scores.insert(String::from("Blue"), 10);
     scores.insert(String::from("Blue"), 25);
 
-    println!("{:?}", scores);
+    println!("{scores:?}");
     // ANCHOR_END: here
 }

listings/ch08-common-collections/listing-08-24/src/main.rs

@@ -8,6 +8,6 @@ fn main() {
     scores.entry(String::from("Yellow")).or_insert(50);
     scores.entry(String::from("Blue")).or_insert(50);
 
-    println!("{:?}", scores);
+    println!("{scores:?}");
     // ANCHOR_END: here
 }

listings/ch08-common-collections/listing-08-25/src/main.rs

@@ -11,6 +11,6 @@ fn main() {
         *count += 1;
     }
 
-    println!("{:?}", map);
+    println!("{map:?}");
     // ANCHOR_END: here
 }

listings/ch09-error-handling/listing-09-04/src/main.rs

@@ -5,6 +5,6 @@ fn main() {
 
     let greeting_file = match greeting_file_result {
         Ok(file) => file,
-        Err(error) => panic!("Problem opening the file: {:?}", error),
+        Err(error) => panic!("Problem opening the file: {error:?}"),
     };
 }

listings/ch09-error-handling/listing-09-05/src/main.rs

@@ -9,10 +9,10 @@ fn main() {
         Err(error) => match error.kind() {
             ErrorKind::NotFound => match File::create("hello.txt") {
                 Ok(fc) => fc,
-                Err(e) => panic!("Problem creating the file: {:?}", e),
+                Err(e) => panic!("Problem creating the file: {e:?}"),
             },
             other_error => {
-                panic!("Problem opening the file: {:?}", other_error);
+                panic!("Problem opening the file: {other_error:?}");
             }
         },
     };

listings/ch10-generic-types-traits-and-lifetimes/listing-10-01/src/main.rs

@@ -10,7 +10,7 @@ fn main() {
         }
     }
 
-    println!("The largest number is {}", largest);
+    println!("The largest number is {largest}");
     // ANCHOR_END: here
     assert_eq!(*largest, 100);
     // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-02/src/main.rs

@@ -9,7 +9,7 @@ fn main() {
         }
     }
 
-    println!("The largest number is {}", largest);
+    println!("The largest number is {largest}");
 
     let number_list = vec![102, 34, 6000, 89, 54, 2, 43, 8];
 
@@ -21,5 +21,5 @@ fn main() {
         }
     }
 
-    println!("The largest number is {}", largest);
+    println!("The largest number is {largest}");
 }

listings/ch10-generic-types-traits-and-lifetimes/listing-10-03/src/main.rs

@@ -15,7 +15,7 @@ fn main() {
     let number_list = vec![34, 50, 25, 100, 65];
 
     let result = largest(&number_list);
-    println!("The largest number is {}", result);
+    println!("The largest number is {result}");
     // ANCHOR_END: here
     assert_eq!(*result, 100);
     // ANCHOR: here
@@ -23,7 +23,7 @@ fn main() {
     let number_list = vec![102, 34, 6000, 89, 54, 2, 43, 8];
 
     let result = largest(&number_list);
-    println!("The largest number is {}", result);
+    println!("The largest number is {result}");
     // ANCHOR_END: here
     assert_eq!(*result, 6000);
     // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-04/src/main.rs

@@ -27,7 +27,7 @@ fn main() {
     let number_list = vec![34, 50, 25, 100, 65];
 
     let result = largest_i32(&number_list);
-    println!("The largest number is {}", result);
+    println!("The largest number is {result}");
     // ANCHOR_END: here
     assert_eq!(*result, 100);
     // ANCHOR: here
@@ -35,7 +35,7 @@ fn main() {
     let char_list = vec!['y', 'm', 'a', 'q'];
 
     let result = largest_char(&char_list);
-    println!("The largest char is {}", result);
+    println!("The largest char is {result}");
     // ANCHOR_END: here
     assert_eq!(*result, 'y');
     // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-05/src/main.rs

@@ -14,10 +14,10 @@ fn main() {
     let number_list = vec![34, 50, 25, 100, 65];
 
     let result = largest(&number_list);
-    println!("The largest number is {}", result);
+    println!("The largest number is {result}");
 
     let char_list = vec!['y', 'm', 'a', 'q'];
 
     let result = largest(&char_list);
-    println!("The largest char is {}", result);
+    println!("The largest char is {result}");
 }

listings/ch10-generic-types-traits-and-lifetimes/listing-10-16/src/main.rs

@@ -6,5 +6,5 @@ fn main() {
         r = &x;
     }
 
-    println!("r: {}", r);
+    println!("r: {r}");
 }

listings/ch10-generic-types-traits-and-lifetimes/listing-10-17/src/main.rs

@@ -6,5 +6,5 @@ fn main() {
         r = &x;           //  |       |
     }                     // -+       |
                           //          |
-    println!("r: {}", r); //          |
+    println!("r: {r}");   //          |
 }                         // ---------+

listings/ch10-generic-types-traits-and-lifetimes/listing-10-18/src/main.rs

@@ -3,6 +3,6 @@ fn main() {
                           //           |
     let r = &x;           // --+-- 'a  |
                           //   |       |
-    println!("r: {}", r); //   |       |
+    println!("r: {r}");   //   |       |
                           // --+       |
 }                         // ----------+

listings/ch10-generic-types-traits-and-lifetimes/listing-10-19/src/main.rs

@@ -3,5 +3,5 @@ fn main() {
     let string2 = "xyz";
 
     let result = longest(string1.as_str(), string2);
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }

listings/ch10-generic-types-traits-and-lifetimes/listing-10-20/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
     let string2 = "xyz";
 
     let result = longest(string1.as_str(), string2);
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 
 // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-21/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
     let string2 = "xyz";
 
     let result = longest(string1.as_str(), string2);
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 
 // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-22/src/main.rs

@@ -5,7 +5,7 @@ fn main() {
     {
         let string2 = String::from("xyz");
         let result = longest(string1.as_str(), string2.as_str());
-        println!("The longest string is {}", result);
+        println!("The longest string is {result}");
     }
 }
 // ANCHOR_END: here

listings/ch10-generic-types-traits-and-lifetimes/listing-10-23/output.txt

@@ -9,8 +9,8 @@ error[E0597]: `string2` does not live long enough
   |                                            ^^^^^^^ borrowed value does not live long enough
 7 |     }
   |     - `string2` dropped here while still borrowed
-8 |     println!("The longest string is {}", result);
-  |                                          ------ borrow later used here
+8 |     println!("The longest string is {result}");
+  |                                      ------ borrow later used here
 
 For more information about this error, try `rustc --explain E0597`.
 error: could not compile `chapter10` (bin "chapter10") due to 1 previous error

listings/ch10-generic-types-traits-and-lifetimes/listing-10-23/src/main.rs

@@ -6,7 +6,7 @@ fn main() {
         let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
     }
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 // ANCHOR_END: here
 

listings/ch10-generic-types-traits-and-lifetimes/no-listing-08-only-one-reference-with-lifetime/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
     let string2 = "efghijklmnopqrstuvwxyz";
 
     let result = longest(string1.as_str(), string2);
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 
 // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/no-listing-09-unrelated-lifetime/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
     let string2 = "xyz";
 
     let result = longest(string1.as_str(), string2);
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 
 // ANCHOR: here

listings/ch10-generic-types-traits-and-lifetimes/no-listing-10-lifetimes-on-methods/src/main.rs

@@ -13,7 +13,7 @@ impl<'a> ImportantExcerpt<'a> {
 // ANCHOR: 3rd
 impl<'a> ImportantExcerpt<'a> {
     fn announce_and_return_part(&self, announcement: &str) -> &str {
-        println!("Attention please: {}", announcement);
+        println!("Attention please: {announcement}");
         self.part
     }
 }

listings/ch10-generic-types-traits-and-lifetimes/no-listing-11-generics-traits-and-lifetimes/src/main.rs

@@ -7,7 +7,7 @@ fn main() {
         string2,
         "Today is someone's birthday!",
     );
-    println!("The longest string is {}", result);
+    println!("The longest string is {result}");
 }
 
 // ANCHOR: here
@@ -21,7 +21,7 @@ fn longest_with_an_announcement<'a, T>(
 where
     T: Display,
 {
-    println!("Announcement! {}", ann);
+    println!("Announcement! {ann}");
     if x.len() > y.len() {
         x
     } else {

listings/ch11-writing-automated-tests/listing-11-10/src/lib.rs

@@ -1,5 +1,5 @@
 fn prints_and_returns_10(a: i32) -> i32 {
-    println!("I got the value {}", a);
+    println!("I got the value {a}");
     10
 }
 

listings/ch11-writing-automated-tests/listing-11-13/tests/integration_test.rs

@@ -1,6 +1,6 @@
-use adder;
+use adder::add_two;
 
 #[test]
 fn it_adds_two() {
-    assert_eq!(4, adder::add_two(2));
+    assert_eq!(4, add_two(2));
 }

listings/ch11-writing-automated-tests/no-listing-05-greeter/src/lib.rs

@@ -1,5 +1,5 @@
 pub fn greeting(name: &str) -> String {
-    format!("Hello {}!", name)
+    format!("Hello {name}!")
 }
 
 #[cfg(test)]

listings/ch11-writing-automated-tests/output-only-01-show-output/src/lib.rs

@@ -1,5 +1,5 @@
 pub fn prints_and_returns_10(a: i32) -> i32 {
-    println!("I got the value {}", a);
+    println!("I got the value {a}");
     10
 }
 

listings/ch12-an-io-project/listing-12-02/src/main.rs

@@ -6,6 +6,6 @@ fn main() {
     let query = &args[1];
     let file_path = &args[2];
 
-    println!("Searching for {}", query);
-    println!("In file {}", file_path);
+    println!("Searching for {query}");
+    println!("In file {file_path}");
 }

listings/ch12-an-io-project/listing-12-03/src/main.rs

@@ -6,6 +6,6 @@ fn main() {
     let query = &args[1];
     let file_path = &args[2];
 
-    println!("Searching for {}", query);
-    println!("In file {}", file_path);
+    println!("Searching for {query}");
+    println!("In file {file_path}");
 }

listings/ch12-an-io-project/listing-12-04/src/main.rs

@@ -10,9 +10,9 @@ fn main() {
     let query = &args[1];
     let file_path = &args[2];
 
-    println!("Searching for {}", query);
+    println!("Searching for {query}");
     // ANCHOR: here
-    println!("In file {}", file_path);
+    println!("In file {file_path}");
 
     let contents = fs::read_to_string(file_path)
         .expect("Should have been able to read the file");

listings/ch12-an-io-project/listing-12-05/src/main.rs

@@ -10,8 +10,8 @@ fn main() {
     // --snip--
     // ANCHOR_END: here
 
-    println!("Searching for {}", query);
-    println!("In file {}", file_path);
+    println!("Searching for {query}");
+    println!("In file {file_path}");
 
     let contents = fs::read_to_string(file_path)
         .expect("Should have been able to read the file");

listings/ch13-functional-features/listing-13-04/src/main.rs

@@ -1,10 +1,10 @@
 fn main() {
     let list = vec![1, 2, 3];
-    println!("Before defining closure: {:?}", list);
+    println!("Before defining closure: {list:?}");
 
-    let only_borrows = || println!("From closure: {:?}", list);
+    let only_borrows = || println!("From closure: {list:?}");
 
-    println!("Before calling closure: {:?}", list);
+    println!("Before calling closure: {list:?}");
     only_borrows();
-    println!("After calling closure: {:?}", list);
+    println!("After calling closure: {list:?}");
 }

listings/ch13-functional-features/listing-13-05/src/main.rs

@@ -1,9 +1,9 @@
 fn main() {
     let mut list = vec![1, 2, 3];
-    println!("Before defining closure: {:?}", list);
+    println!("Before defining closure: {list:?}");
 
     let mut borrows_mutably = || list.push(7);
 
     borrows_mutably();
-    println!("After calling closure: {:?}", list);
+    println!("After calling closure: {list:?}");
 }

listings/ch13-functional-features/listing-13-06/src/main.rs

@@ -2,9 +2,9 @@ use std::thread;
 
 fn main() {
     let list = vec![1, 2, 3];
-    println!("Before defining closure: {:?}", list);
+    println!("Before defining closure: {list:?}");
 
-    thread::spawn(move || println!("From thread: {:?}", list))
+    thread::spawn(move || println!("From thread: {list:?}"))
         .join()
         .unwrap();
 }

listings/ch13-functional-features/listing-13-07/src/main.rs

@@ -12,5 +12,5 @@ fn main() {
     ];
 
     list.sort_by_key(|r| r.width);
-    println!("{:#?}", list);
+    println!("{list:#?}");
 }

listings/ch13-functional-features/listing-13-08/src/main.rs

@@ -18,5 +18,5 @@ fn main() {
         sort_operations.push(value);
         r.width
     });
-    println!("{:#?}", list);
+    println!("{list:#?}");
 }

listings/ch13-functional-features/listing-13-09/src/main.rs

@@ -16,5 +16,5 @@ fn main() {
         num_sort_operations += 1;
         r.width
     });
-    println!("{:#?}, sorted in {num_sort_operations} operations", list);
+    println!("{list:#?}, sorted in {num_sort_operations} operations");
 }

listings/ch13-functional-features/listing-13-11/src/main.rs

@@ -5,7 +5,7 @@ fn main() {
     let v1_iter = v1.iter();
 
     for val in v1_iter {
-        println!("Got: {}", val);
+        println!("Got: {val}");
     }
     // ANCHOR_END: here
 }

listings/ch15-smart-pointers/listing-15-01/src/main.rs

@@ -1,4 +1,4 @@
 fn main() {
     let b = Box::new(5);
-    println!("b = {}", b);
+    println!("b = {b}");
 }

listings/ch15-smart-pointers/listing-15-24/src/main.rs

@@ -18,7 +18,7 @@ fn main() {
 
     *value.borrow_mut() += 10;
 
-    println!("a after = {:?}", a);
-    println!("b after = {:?}", b);
-    println!("c after = {:?}", c);
+    println!("a after = {a:?}");
+    println!("b after = {b:?}");
+    println!("c after = {c:?}");
 }

listings/ch16-fearless-concurrency/listing-16-01/src/main.rs

@@ -4,13 +4,13 @@ use std::time::Duration;
 fn main() {
     thread::spawn(|| {
         for i in 1..10 {
-            println!("hi number {} from the spawned thread!", i);
+            println!("hi number {i} from the spawned thread!");
             thread::sleep(Duration::from_millis(1));
         }
     });
 
     for i in 1..5 {
-        println!("hi number {} from the main thread!", i);
+        println!("hi number {i} from the main thread!");
         thread::sleep(Duration::from_millis(1));
     }
 }

listings/ch16-fearless-concurrency/listing-16-02/src/main.rs

@@ -4,13 +4,13 @@ use std::time::Duration;
 fn main() {
     let handle = thread::spawn(|| {
         for i in 1..10 {
-            println!("hi number {} from the spawned thread!", i);
+            println!("hi number {i} from the spawned thread!");
             thread::sleep(Duration::from_millis(1));
         }
     });
 
     for i in 1..5 {
-        println!("hi number {} from the main thread!", i);
+        println!("hi number {i} from the main thread!");
         thread::sleep(Duration::from_millis(1));
     }
 

listings/ch16-fearless-concurrency/listing-16-03/output.txt

@@ -5,15 +5,15 @@ error[E0373]: closure may outlive the current function, but it borrows `v`, whic
   |
 6 |     let handle = thread::spawn(|| {
   |                                ^^ may outlive borrowed value `v`
-7 |         println!("Here's a vector: {:?}", v);
-  |                                           - `v` is borrowed here
+7 |         println!("Here's a vector: {v:?}");
+  |                                     - `v` is borrowed here
   |
 note: function requires argument type to outlive `'static`
  --> src/main.rs:6:18
   |
 6 |       let handle = thread::spawn(|| {
   |  __________________^
-7 | |         println!("Here's a vector: {:?}", v);
+7 | |         println!("Here's a vector: {v:?}");
 8 | |     });
   | |______^
 help: to force the closure to take ownership of `v` (and any other referenced variables), use the `move` keyword

listings/ch16-fearless-concurrency/listing-16-03/src/main.rs

@@ -4,7 +4,7 @@ fn main() {
     let v = vec![1, 2, 3];
 
     let handle = thread::spawn(|| {
-        println!("Here's a vector: {:?}", v);
+        println!("Here's a vector: {v:?}");
     });
 
     handle.join().unwrap();

listings/ch16-fearless-concurrency/listing-16-04/src/main.rs

@@ -4,7 +4,7 @@ fn main() {
     let v = vec![1, 2, 3];
 
     let handle = thread::spawn(|| {
-        println!("Here's a vector: {:?}", v);
+        println!("Here's a vector: {v:?}");
     });
 
     drop(v); // oh no!

listings/ch16-fearless-concurrency/listing-16-05/src/main.rs

@@ -4,7 +4,7 @@ fn main() {
     let v = vec![1, 2, 3];
 
     let handle = thread::spawn(move || {
-        println!("Here's a vector: {:?}", v);
+        println!("Here's a vector: {v:?}");
     });
 
     handle.join().unwrap();

listings/ch16-fearless-concurrency/listing-16-08/src/main.rs

@@ -10,5 +10,5 @@ fn main() {
     });
 
     let received = rx.recv().unwrap();
-    println!("Got: {}", received);
+    println!("Got: {received}");
 }

listings/ch16-fearless-concurrency/listing-16-09/output.txt

@@ -7,8 +7,8 @@ error[E0382]: borrow of moved value: `val`
    |             --- move occurs because `val` has type `String`, which does not implement the `Copy` trait
 9  |         tx.send(val).unwrap();
    |                 --- value moved here
-10 |         println!("val is {}", val);
-   |                               ^^^ value borrowed here after move
+10 |         println!("val is {val}");
+   |                           ^^^ value borrowed here after move
    |
    = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 help: consider cloning the value if the performance cost is acceptable

listings/ch16-fearless-concurrency/listing-16-09/src/main.rs

@@ -7,9 +7,9 @@ fn main() {
     thread::spawn(move || {
         let val = String::from("hi");
         tx.send(val).unwrap();
-        println!("val is {}", val);
+        println!("val is {val}");
     });
 
     let received = rx.recv().unwrap();
-    println!("Got: {}", received);
+    println!("Got: {received}");
 }

listings/ch16-fearless-concurrency/listing-16-10/src/main.rs

@@ -20,6 +20,6 @@ fn main() {
     });
 
     for received in rx {
-        println!("Got: {}", received);
+        println!("Got: {received}");
     }
 }

listings/ch16-fearless-concurrency/listing-16-11/src/main.rs

@@ -38,7 +38,7 @@ fn main() {
     });
 
     for received in rx {
-        println!("Got: {}", received);
+        println!("Got: {received}");
     }
 
     // --snip--

listings/ch16-fearless-concurrency/listing-16-12/src/main.rs

@@ -8,5 +8,5 @@ fn main() {
         *num = 6;
     }
 
-    println!("m = {:?}", m);
+    println!("m = {m:?}");
 }

listings/ch16-fearless-concurrency/no-listing-01-join-too-early/src/main.rs

@@ -4,7 +4,7 @@ use std::time::Duration;
 fn main() {
     let handle = thread::spawn(|| {
         for i in 1..10 {
-            println!("hi number {} from the spawned thread!", i);
+            println!("hi number {i} from the spawned thread!");
             thread::sleep(Duration::from_millis(1));
         }
     });
@@ -12,7 +12,7 @@ fn main() {
     handle.join().unwrap();
 
     for i in 1..5 {
-        println!("hi number {} from the main thread!", i);
+        println!("hi number {i} from the main thread!");
         thread::sleep(Duration::from_millis(1));
     }
 }

listings/ch16-fearless-concurrency/output-only-01-move-drop/output.txt

@@ -8,8 +8,8 @@ error[E0382]: use of moved value: `v`
 5  |
 6  |     let handle = thread::spawn(move || {
    |                                ------- value moved into closure here
-7  |         println!("Here's a vector: {:?}", v);
-   |                                           - variable moved due to use in closure
+7  |         println!("Here's a vector: {v:?}");
+   |                                     - variable moved due to use in closure
 ...
 10 |     drop(v); // oh no!
    |          ^ value used here after move

listings/ch16-fearless-concurrency/output-only-01-move-drop/src/main.rs

@@ -4,7 +4,7 @@ fn main() {
     let v = vec![1, 2, 3];
 
     let handle = thread::spawn(move || {
-        println!("Here's a vector: {:?}", v);
+        println!("Here's a vector: {v:?}");
     });
 
     drop(v); // oh no!

listings/ch18-patterns-and-matching/listing-18-02/src/main.rs

@@ -7,7 +7,7 @@ fn main() {
     stack.push(3);
 
     while let Some(top) = stack.pop() {
-        println!("{}", top);
+        println!("{top}");
     }
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-03/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
     let v = vec!['a', 'b', 'c'];
 
     for (index, value) in v.iter().enumerate() {
-        println!("{} is at index {}", value, index);
+        println!("{value} is at index {index}");
     }
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-07/src/main.rs

@@ -1,5 +1,5 @@
 fn print_coordinates(&(x, y): &(i32, i32)) {
-    println!("Current location: ({}, {})", x, y);
+    println!("Current location: ({x}, {y})");
 }
 
 fn main() {

listings/ch18-patterns-and-matching/listing-18-09/src/main.rs

@@ -2,7 +2,7 @@ fn main() {
     let some_option_value: Option<i32> = None;
     // ANCHOR: here
     if let Some(x) = some_option_value {
-        println!("{}", x);
+        println!("{x}");
     }
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-10/src/main.rs

@@ -1,7 +1,7 @@
 fn main() {
     // ANCHOR: here
     if let x = 5 {
-        println!("{}", x);
+        println!("{x}");
     };
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-11/src/main.rs

@@ -6,9 +6,9 @@ fn main() {
     match x {
         Some(50) => println!("Got 50"),
         Some(y) => println!("Matched, y = {y}"),
-        _ => println!("Default case, x = {:?}", x),
+        _ => println!("Default case, x = {x:?}"),
     }
 
-    println!("at the end: x = {:?}, y = {y}", x);
+    println!("at the end: x = {x:?}, y = {y}");
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-15/src/main.rs

@@ -19,7 +19,7 @@ fn main() {
             println!("Text message: {text}");
         }
         Message::ChangeColor(r, g, b) => {
-            println!("Change the color to red {r}, green {g}, and blue {b}",)
+            println!("Change the color to red {r}, green {g}, and blue {b}")
         }
     }
 }

listings/ch18-patterns-and-matching/listing-18-17/src/main.rs

@@ -1,5 +1,5 @@
 fn foo(_: i32, y: i32) {
-    println!("This code only uses the y parameter: {}", y);
+    println!("This code only uses the y parameter: {y}");
 }
 
 fn main() {

listings/ch18-patterns-and-matching/listing-18-18/src/main.rs

@@ -12,6 +12,6 @@ fn main() {
         }
     }
 
-    println!("setting is {:?}", setting_value);
+    println!("setting is {setting_value:?}");
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-21/src/main.rs

@@ -6,6 +6,6 @@ fn main() {
         println!("found a string");
     }
 
-    println!("{:?}", s);
+    println!("{s:?}");
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-22/src/main.rs

@@ -6,6 +6,6 @@ fn main() {
         println!("found a string");
     }
 
-    println!("{:?}", s);
+    println!("{s:?}");
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-23/src/main.rs

@@ -9,7 +9,7 @@ fn main() {
     let origin = Point { x: 0, y: 0, z: 0 };
 
     match origin {
-        Point { x, .. } => println!("x is {}", x),
+        Point { x, .. } => println!("x is {x}"),
     }
     // ANCHOR_END: here
 }

listings/ch18-patterns-and-matching/listing-18-25/src/main.rs

@@ -3,7 +3,7 @@ fn main() {
 
     match numbers {
         (.., second, ..) => {
-            println!("Some numbers: {}", second)
+            println!("Some numbers: {second}")
         },
     }
 }

listings/ch18-patterns-and-matching/listing-18-26/src/main.rs

@@ -3,8 +3,8 @@ fn main() {
     let num = Some(4);
 
     match num {
-        Some(x) if x % 2 == 0 => println!("The number {} is even", x),
-        Some(x) => println!("The number {} is odd", x),
+        Some(x) if x % 2 == 0 => println!("The number {x} is even"),
+        Some(x) => println!("The number {x} is odd"),
         None => (),
     }
     // ANCHOR_END: here

listings/ch18-patterns-and-matching/listing-18-27/src/main.rs

@@ -5,8 +5,8 @@ fn main() {
     match x {
         Some(50) => println!("Got 50"),
         Some(n) if n == y => println!("Matched, n = {n}"),
-        _ => println!("Default case, x = {:?}", x),
+        _ => println!("Default case, x = {x:?}"),
     }
 
-    println!("at the end: x = {:?}, y = {y}", x);
+    println!("at the end: x = {x:?}, y = {y}");
 }

listings/ch18-patterns-and-matching/listing-18-29/src/main.rs

@@ -9,11 +9,11 @@ fn main() {
     match msg {
         Message::Hello {
             id: id_variable @ 3..=7,
-        } => println!("Found an id in range: {}", id_variable),
+        } => println!("Found an id in range: {id_variable}"),
         Message::Hello { id: 10..=12 } => {
             println!("Found an id in another range")
         }
-        Message::Hello { id } => println!("Found some other id: {}", id),
+        Message::Hello { id } => println!("Found some other id: {id}"),
     }
     // ANCHOR_END: here
 }

listings/ch19-advanced-features/listing-19-09/src/main.rs

@@ -1,5 +1,5 @@
 static HELLO_WORLD: &str = "Hello, world!";
 
 fn main() {
-    println!("name is: {}", HELLO_WORLD);
+    println!("name is: {HELLO_WORLD}");
 }

listings/ch19-advanced-features/listing-19-10/src/main.rs

@@ -10,6 +10,6 @@ fn main() {
     add_to_count(3);
 
     unsafe {
-        println!("COUNTER: {}", COUNTER);
+        println!("COUNTER: {COUNTER}");
     }
 }

listings/ch19-advanced-features/listing-19-22/src/main.rs

@@ -7,7 +7,7 @@ trait OutlinePrint: fmt::Display {
         let len = output.len();
         println!("{}", "*".repeat(len + 4));
         println!("*{}*", " ".repeat(len + 2));
-        println!("* {} *", output);
+        println!("* {output} *");
         println!("*{}*", " ".repeat(len + 2));
         println!("{}", "*".repeat(len + 4));
     }

listings/ch19-advanced-features/listing-19-23/src/main.rs

@@ -10,5 +10,5 @@ impl fmt::Display for Wrapper {
 
 fn main() {
     let w = Wrapper(vec![String::from("hello"), String::from("world")]);
-    println!("w = {}", w);
+    println!("w = {w}");
 }

listings/ch19-advanced-features/listing-19-27/src/main.rs

@@ -9,5 +9,5 @@ fn do_twice(f: fn(i32) -> i32, arg: i32) -> i32 {
 fn main() {
     let answer = do_twice(add_one, 5);
 
-    println!("The answer is: {}", answer);
+    println!("The answer is: {answer}");
 }

listings/ch19-advanced-features/no-listing-02-impl-outlineprint-for-point/src/main.rs

@@ -6,7 +6,7 @@ trait OutlinePrint: fmt::Display {
         let len = output.len();
         println!("{}", "*".repeat(len + 4));
         println!("*{}*", " ".repeat(len + 2));
-        println!("* {} *", output);
+        println!("* {output} *");
         println!("*{}*", " ".repeat(len + 2));
         println!("{}", "*".repeat(len + 4));
     }

listings/ch19-advanced-features/no-listing-03-impl-display-for-point/src/main.rs

@@ -4,7 +4,7 @@ trait OutlinePrint: fmt::Display {
         let len = output.len();
         println!("{}", "*".repeat(len + 4));
         println!("*{}*", " ".repeat(len + 2));
-        println!("* {} *", output);
+        println!("* {output} *");
         println!("*{}*", " ".repeat(len + 2));
         println!("{}", "*".repeat(len + 4));
     }

listings/ch20-web-server/listing-20-02/src/main.rs

@@ -21,5 +21,5 @@ fn handle_connection(mut stream: TcpStream) {
         .take_while(|line| !line.is_empty())
         .collect();
 
-    println!("Request: {:#?}", http_request);
+    println!("Request: {http_request:#?}");
 }