Merge ref 'a1dbb443527b' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: a1dbb443527bd126452875eb5d5860c1d001d761
Filtered ref: c2339048a82c55166f9b9ee83fd618be252a6e23

This merge was created using https://github.com/rust-lang/josh-sync.

4 files changed, 13 insertions, 7 deletions

diff --git a/library/std/src/io/buffered/bufreader/buffer.rs b/library/std/src/io/buffered/bufreader/buffer.rs
index 574288e579e..9b600cd5575 100644
--- a/library/std/src/io/buffered/bufreader/buffer.rs
+++ b/library/std/src/io/buffered/bufreader/buffer.rs
@@ -122,7 +122,7 @@ impl Buffer {
 
     /// Remove bytes that have already been read from the buffer.
     pub fn backshift(&mut self) {
-        self.buf.copy_within(self.pos.., 0);
+        self.buf.copy_within(self.pos..self.filled, 0);
         self.filled -= self.pos;
         self.pos = 0;
     }
diff --git a/library/std/src/io/copy.rs b/library/std/src/io/copy.rs
index 15e962924ac..d060ad52897 100644
--- a/library/std/src/io/copy.rs
+++ b/library/std/src/io/copy.rs
@@ -63,10 +63,11 @@ where
     R: Read,
     W: Write,
 {
-    cfg_if::cfg_if! {
-        if #[cfg(any(target_os = "linux", target_os = "android"))] {
+    cfg_select! {
+        any(target_os = "linux", target_os = "android") => {
             crate::sys::kernel_copy::copy_spec(reader, writer)
-        } else {
+        }
+        _ => {
             generic_copy(reader, writer)
         }
     }
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 562fdbf4ff7..dcfa189823f 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -18,7 +18,7 @@ use crate::{error, fmt, result, sys};
 /// This type is broadly used across [`std::io`] for any operation which may
 /// produce an error.
 ///
-/// This typedef is generally used to avoid writing out [`io::Error`] directly and
+/// This type alias is generally used to avoid writing out [`io::Error`] directly and
 /// is otherwise a direct mapping to [`Result`].
 ///
 /// While usual Rust style is to import types directly, aliases of [`Result`]
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index d351ee5e739..ff0e29e04c2 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -2461,7 +2461,7 @@ pub trait BufRead: Read {
     /// delimiter or EOF is found.
     ///
     /// If successful, this function will return the total number of bytes read,
-    /// including the delimiter byte.
+    /// including the delimiter byte if found.
     ///
     /// This is useful for efficiently skipping data such as NUL-terminated strings
     /// in binary file formats without buffering.
@@ -2489,7 +2489,7 @@ pub trait BufRead: Read {
     /// ```
     /// use std::io::{self, BufRead};
     ///
-    /// let mut cursor = io::Cursor::new(b"Ferris\0Likes long walks on the beach\0Crustacean\0");
+    /// let mut cursor = io::Cursor::new(b"Ferris\0Likes long walks on the beach\0Crustacean\0!");
     ///
     /// // read name
     /// let mut name = Vec::new();
@@ -2509,6 +2509,11 @@ pub trait BufRead: Read {
     ///     .expect("reading from cursor won't fail");
     /// assert_eq!(num_bytes, 11);
     /// assert_eq!(animal, b"Crustacean\0");
+    ///
+    /// // reach EOF
+    /// let num_bytes = cursor.skip_until(b'\0')
+    ///     .expect("reading from cursor won't fail");
+    /// assert_eq!(num_bytes, 1);
     /// ```
     #[stable(feature = "bufread_skip_until", since = "1.83.0")]
     fn skip_until(&mut self, byte: u8) -> Result<usize> {