6 files changed, 23 insertions, 24 deletions
diff --git a/library/std/src/io/buffered/bufreader.rs b/library/std/src/io/buffered/bufreader.rs
index e7eee443624..989cec976b7 100644
--- a/library/std/src/io/buffered/bufreader.rs
+++ b/library/std/src/io/buffered/bufreader.rs
@@ -41,7 +41,7 @@ use crate::mem::MaybeUninit;
 ///
 ///     let mut line = String::new();
 ///     let len = reader.read_line(&mut line)?;
-///     println!("First line is {} bytes long", len);
+///     println!("First line is {len} bytes long");
 ///     Ok(())
 /// }
 /// ```
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 17e2b97545a..4a50e647c64 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -457,7 +457,7 @@ impl From<ErrorKind> for Error {
     ///
     /// let not_found = ErrorKind::NotFound;
     /// let error = Error::from(not_found);
-    /// assert_eq!("entity not found", format!("{}", error));
+    /// assert_eq!("entity not found", format!("{error}"));
     /// ```
     #[inline]
     fn from(kind: ErrorKind) -> Error {
@@ -561,7 +561,7 @@ impl Error {
     /// use std::io::Error;
     ///
     /// let os_error = Error::last_os_error();
-    /// println!("last OS error: {:?}", os_error);
+    /// println!("last OS error: {os_error:?}");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
@@ -618,7 +618,7 @@ impl Error {
     ///
     /// fn print_os_error(err: &Error) {
     ///     if let Some(raw_os_err) = err.raw_os_error() {
-    ///         println!("raw OS error: {:?}", raw_os_err);
+    ///         println!("raw OS error: {raw_os_err:?}");
     ///     } else {
     ///         println!("Not an OS error");
     ///     }
@@ -657,7 +657,7 @@ impl Error {
     ///
     /// fn print_error(err: &Error) {
     ///     if let Some(inner_err) = err.get_ref() {
-    ///         println!("Inner error: {:?}", inner_err);
+    ///         println!("Inner error: {inner_err:?}");
     ///     } else {
     ///         println!("No inner error");
     ///     }
@@ -731,7 +731,7 @@ impl Error {
     ///
     /// fn print_error(err: &Error) {
     ///     if let Some(inner_err) = err.get_ref() {
-    ///         println!("Inner error: {}", inner_err);
+    ///         println!("Inner error: {inner_err}");
     ///     } else {
     ///         println!("No inner error");
     ///     }
@@ -770,7 +770,7 @@ impl Error {
     ///
     /// fn print_error(err: Error) {
     ///     if let Some(inner_err) = err.into_inner() {
-    ///         println!("Inner error: {}", inner_err);
+    ///         println!("Inner error: {inner_err}");
     ///     } else {
     ///         println!("No inner error");
     ///     }
@@ -852,7 +852,7 @@ impl fmt::Display for Error {
         match self.repr.data() {
             ErrorData::Os(code) => {
                 let detail = sys::os::error_string(code);
-                write!(fmt, "{} (os error {})", detail, code)
+                write!(fmt, "{detail} (os error {code})")
             }
             ErrorData::Custom(ref c) => c.error.fmt(fmt),
             ErrorData::Simple(kind) => write!(fmt, "{}", kind.as_str()),
diff --git a/library/std/src/io/error/repr_bitpacked.rs b/library/std/src/io/error/repr_bitpacked.rs
index 4301e941b3d..1a0538f861a 100644
--- a/library/std/src/io/error/repr_bitpacked.rs
+++ b/library/std/src/io/error/repr_bitpacked.rs
@@ -161,8 +161,7 @@ impl Repr {
         // only run in libstd's tests, unless the user uses -Zbuild-std)
         debug_assert!(
             matches!(res.data(), ErrorData::Os(c) if c == code),
-            "repr(os) encoding failed for {}",
-            code,
+            "repr(os) encoding failed for {code}"
         );
         res
     }
diff --git a/library/std/src/io/error/tests.rs b/library/std/src/io/error/tests.rs
index c2c51553b20..6fd15fa8048 100644
--- a/library/std/src/io/error/tests.rs
+++ b/library/std/src/io/error/tests.rs
@@ -33,7 +33,7 @@ fn test_debug_error() {
          }}",
         code, kind, msg
     );
-    assert_eq!(format!("{:?}", err), expected);
+    assert_eq!(format!("{err:?}"), expected);
 }
 
 #[test]
@@ -65,8 +65,8 @@ fn test_const() {
 
     assert_eq!(E.kind(), ErrorKind::NotFound);
     assert_eq!(E.to_string(), "hello");
-    assert!(format!("{:?}", E).contains("\"hello\""));
-    assert!(format!("{:?}", E).contains("NotFound"));
+    assert!(format!("{E:?}").contains("\"hello\""));
+    assert!(format!("{E:?}").contains("NotFound"));
 }
 
 #[test]
@@ -101,7 +101,7 @@ fn test_simple_message_packing() {
             let e = &$err;
             // Check that the public api is right.
             assert_eq!(e.kind(), $kind);
-            assert!(format!("{:?}", e).contains($msg));
+            assert!(format!("{e:?}").contains($msg));
             // and we got what we expected
             assert_matches!(
                 e.repr.data(),
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 3fa965d08e6..6005270a75f 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -91,7 +91,7 @@
 //!     // read a line into buffer
 //!     reader.read_line(&mut buffer)?;
 //!
-//!     println!("{}", buffer);
+//!     println!("{buffer}");
 //!     Ok(())
 //! }
 //! ```
@@ -1035,7 +1035,7 @@ pub trait Read {
 /// fn main() -> io::Result<()> {
 ///     let stdin = io::read_to_string(io::stdin())?;
 ///     println!("Stdin was:");
-///     println!("{}", stdin);
+///     println!("{stdin}");
 ///     Ok(())
 /// }
 /// ```
@@ -1761,7 +1761,7 @@ pub trait Seek {
     ///     .open("foo.txt").unwrap();
     ///
     /// let hello = "Hello!\n";
-    /// write!(f, "{}", hello).unwrap();
+    /// write!(f, "{hello}").unwrap();
     /// f.rewind().unwrap();
     ///
     /// let mut buf = String::new();
@@ -1804,7 +1804,7 @@ pub trait Seek {
     ///     let mut f = File::open("foo.txt")?;
     ///
     ///     let len = f.stream_len()?;
-    ///     println!("The file is currently {} bytes long", len);
+    ///     println!("The file is currently {len} bytes long");
     ///     Ok(())
     /// }
     /// ```
@@ -1988,7 +1988,7 @@ pub trait BufRead: Read {
     /// let buffer = stdin.fill_buf().unwrap();
     ///
     /// // work with buffer
-    /// println!("{:?}", buffer);
+    /// println!("{buffer:?}");
     ///
     /// // ensure the bytes we worked with aren't returned again later
     /// let length = buffer.len();
@@ -2042,7 +2042,7 @@ pub trait BufRead: Read {
     ///     let mut line = String::new();
     ///     stdin.read_line(&mut line).unwrap();
     ///     // work with line
-    ///     println!("{:?}", line);
+    ///     println!("{line:?}");
     /// }
     /// ```
     #[unstable(feature = "buf_read_has_data_left", reason = "recently added", issue = "86423")]
diff --git a/library/std/src/io/stdio.rs b/library/std/src/io/stdio.rs
index 5414ff648d4..50344e602a9 100644
--- a/library/std/src/io/stdio.rs
+++ b/library/std/src/io/stdio.rs
@@ -349,10 +349,10 @@ impl Stdin {
     /// let mut input = String::new();
     /// match io::stdin().read_line(&mut input) {
     ///     Ok(n) => {
-    ///         println!("{} bytes read", n);
-    ///         println!("{}", input);
+    ///         println!("{n} bytes read");
+    ///         println!("{input}");
     ///     }
-    ///     Err(error) => println!("error: {}", error),
+    ///     Err(error) => println!("error: {error}"),
     /// }
     /// ```
     ///
@@ -953,7 +953,7 @@ where
     }
 
     if let Err(e) = global_s().write_fmt(args) {
-        panic!("failed printing to {}: {}", label, e);
+        panic!("failed printing to {label}: {e}");
     }
 }