Auto merge of rust-lang#87689 - JohnTitor:rollup-ns38b56, r=JohnTitor

Rollup of 13 pull requests

Successful merges:

 - rust-lang#86183 (Change environment variable getters to error recoverably)
 - rust-lang#86439 (Remove `Ipv4Addr::is_ietf_protocol_assignment`)
 - rust-lang#86509 (Move `os_str_bytes` to `sys::unix`)
 - rust-lang#86593 (Partially stabilize `const_slice_first_last`)
 - rust-lang#86936 (Add documentation for `Ipv6MulticastScope`)
 - rust-lang#87282 (Ensure `./x.py dist` adheres to `build.tools`)
 - rust-lang#87468 (Update rustfmt)
 - rust-lang#87504 (Update mdbook.)
 - rust-lang#87608 (Remove unused field `Session.system_library_path`)
 - rust-lang#87629 (Consistent spelling of "adapter" in the standard library)
 - rust-lang#87633 (Update compiler_builtins to fix i128 shift/mul on thumbv6m)
 - rust-lang#87644 (Recommend `swap_remove` in `Vec::remove` docs)
 - rust-lang#87653 (mark a UB doctest as no_run)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Cargo.lock

@@ -646,9 +646,9 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.47"
+version = "0.1.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd4ed89e0a5c3e50b15c0045fbe1ff8567b703bc07544faf935ddff0aaa7b65f"
+checksum = "20b1438ef42c655665a8ab2c1c6d605a305f031d38d9be689ddfef41a20f3aa2"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",
@@ -1495,9 +1495,9 @@ dependencies = [
 
 [[package]]
 name = "handlebars"
-version = "3.4.0"
+version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5deefd4816fb852b1ff3cb48f6c41da67be2d0e1d20b26a7a3b076da11f064b1"
+checksum = "72a0ffab8c36d0436114310c7e10b59b3307e650ddfabf6d006028e29a70c6e6"
 dependencies = [
  "log",
  "pest",
@@ -2100,9 +2100,9 @@ dependencies = [
 
 [[package]]
 name = "mdbook"
-version = "0.4.7"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28f6a882f3880ec68e96f60d6b543c34941e2f307ad10e2992e4db9acfe96529"
+checksum = "4ee73932975c44c485e541416d7c30abb31a053af7e49682f6e856f1e4d6ab2a"
 dependencies = [
  "ammonia",
  "anyhow",

compiler/rustc_session/src/session.rs

@@ -198,10 +198,6 @@ pub struct Session {
     /// exist under `std`. For example, wrote `str::from_utf8` instead of `std::str::from_utf8`.
     pub confused_type_with_std_module: Lock<FxHashMap<Span, Span>>,
 
-    /// Path for libraries that will take preference over libraries shipped by Rust.
-    /// Used by windows-gnu targets to priortize system mingw-w64 libraries.
-    pub system_library_path: OneThread<RefCell<Option<Option<PathBuf>>>>,
-
     /// Tracks the current behavior of the CTFE engine when an error occurs.
     /// Options range from returning the error without a backtrace to returning an error
     /// and immediately printing the backtrace to stderr.
@@ -1375,7 +1371,6 @@ pub fn build_session(
         driver_lint_caps,
         trait_methods_not_found: Lock::new(Default::default()),
         confused_type_with_std_module: Lock::new(Default::default()),
-        system_library_path: OneThread::new(RefCell::new(Default::default())),
         ctfe_backtrace,
         miri_unleashed_features: Lock::new(Default::default()),
         asm_arch,

library/alloc/src/vec/mod.rs

@@ -1360,6 +1360,12 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Removes and returns the element at position `index` within the vector,
     /// shifting all elements after it to the left.
     ///
+    /// Note: Because this shifts over the remaining elements, it has a
+    /// worst-case performance of O(n). If you don't need the order of elements
+    /// to be preserved, use [`swap_remove`] instead.
+    ///
+    /// [`swap_remove`]: Vec::swap_remove
+    ///
     /// # Panics
     ///
     /// Panics if `index` is out of bounds.

library/core/src/alloc/mod.rs

@@ -338,9 +338,9 @@ pub unsafe trait Allocator {
         Ok(new_ptr)
     }
 
-    /// Creates a "by reference" adaptor for this instance of `Allocator`.
+    /// Creates a "by reference" adapter for this instance of `Allocator`.
     ///
-    /// The returned adaptor also implements `Allocator` and will simply borrow this.
+    /// The returned adapter also implements `Allocator` and will simply borrow this.
     #[inline(always)]
     fn by_ref(&self) -> &Self
     where

library/core/src/iter/traits/iterator.rs

@@ -694,7 +694,7 @@ pub trait Iterator {
     /// more idiomatic to use a `for` loop, but `for_each` may be more legible
     /// when processing items at the end of longer iterator chains. In some
     /// cases `for_each` may also be faster than a loop, because it will use
-    /// internal iteration on adaptors like `Chain`.
+    /// internal iteration on adapters like `Chain`.
     ///
     /// [`for`]: ../../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
     ///
@@ -1293,7 +1293,7 @@ pub trait Iterator {
         Take::new(self, n)
     }
 
-    /// An iterator adaptor similar to [`fold`] that holds internal state and
+    /// An iterator adapter similar to [`fold`] that holds internal state and
     /// produces a new iterator.
     ///
     /// [`fold`]: Iterator::fold
@@ -1604,7 +1604,7 @@ pub trait Iterator {
 
     /// Borrows an iterator, rather than consuming it.
     ///
-    /// This is useful to allow applying iterator adaptors while still
+    /// This is useful to allow applying iterator adapters while still
     /// retaining ownership of the original iterator.
     ///
     /// # Examples

library/core/src/ptr/non_null.rs

@@ -173,8 +173,14 @@ impl<T: ?Sized> NonNull<T> {
     ///
     /// let mut x = 0u32;
     /// let ptr = unsafe { NonNull::new_unchecked(&mut x as *mut _) };
+    /// ```
+    ///
+    /// *Incorrect* usage of this function:
+    ///
+    /// ```rust,no_run
+    /// use std::ptr::NonNull;
     ///
-    /// // NEVER DO THAT!!!
+    /// // NEVER DO THAT!!! This is undefined behavior. ⚠️
     /// let ptr = unsafe { NonNull::<u32>::new_unchecked(std::ptr::null_mut()) };
     /// ```
     #[stable(feature = "nonnull", since = "1.25.0")]

library/core/src/slice/mod.rs

@@ -139,7 +139,7 @@ impl<T> [T] {
     /// assert_eq!(None, w.first());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn first(&self) -> Option<&T> {
         if let [first, ..] = self { Some(first) } else { None }
@@ -177,7 +177,7 @@ impl<T> [T] {
     /// }
     /// ```
     #[stable(feature = "slice_splits", since = "1.5.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn split_first(&self) -> Option<(&T, &[T])> {
         if let [first, tail @ ..] = self { Some((first, tail)) } else { None }
@@ -217,7 +217,7 @@ impl<T> [T] {
     /// }
     /// ```
     #[stable(feature = "slice_splits", since = "1.5.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn split_last(&self) -> Option<(&T, &[T])> {
         if let [init @ .., last] = self { Some((last, init)) } else { None }
@@ -256,7 +256,7 @@ impl<T> [T] {
     /// assert_eq!(None, w.last());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_const_unstable(feature = "const_slice_first_last", issue = "83570")]
+    #[rustc_const_stable(feature = "const_slice_first_last_not_mut", since = "1.56.0")]
     #[inline]
     pub const fn last(&self) -> Option<&T> {
         if let [.., last] = self { Some(last) } else { None }

library/core/tests/iter/adapters/mod.rs

@@ -24,7 +24,7 @@ use core::cell::Cell;
 
 /// An iterator that panics whenever `next` or next_back` is called
 /// after `None` has already been returned. This does not violate
-/// `Iterator`'s contract. Used to test that iterator adaptors don't
+/// `Iterator`'s contract. Used to test that iterator adapters don't
 /// poll their inner iterators after exhausting them.
 pub struct NonFused<I> {
     iter: I,

library/std/src/env.rs

@@ -185,15 +185,9 @@ impl fmt::Debug for VarsOs {
 ///
 /// # Errors
 ///
-/// Errors if the environment variable is not present.
-/// Errors if the environment variable is not valid Unicode. If this is not desired, consider using
-/// [`var_os`].
-///
-/// # Panics
-///
-/// This function may panic if `key` is empty, contains an ASCII equals sign
-/// `'='` or the NUL character `'\0'`, or when the value contains the NUL
-/// character.
+/// Returns `[None]` if the environment variable isn't set.
+/// Returns `[None]` if the environment variable is not valid Unicode. If this is not
+/// desired, consider using [`var_os`].
 ///
 /// # Examples
 ///
@@ -219,18 +213,17 @@ fn _var(key: &OsStr) -> Result<String, VarError> {
 }
 
 /// Fetches the environment variable `key` from the current process, returning
-/// [`None`] if the variable isn't set.
-///
-/// # Panics
-///
-/// This function may panic if `key` is empty, contains an ASCII equals sign
-/// `'='` or the NUL character `'\0'`, or when the value contains the NUL
-/// character.
+/// [`None`] if the variable isn't set or there's another error.
 ///
 /// Note that the method will not check if the environment variable
 /// is valid Unicode. If you want to have an error on invalid UTF-8,
 /// use the [`var`] function instead.
 ///
+/// # Errors
+///
+/// Returns `[None]` if the variable isn't set.
+/// May return `[None]` if the variable value contains the NUL character.
+///
 /// # Examples
 ///
 /// ```
@@ -249,7 +242,6 @@ pub fn var_os<K: AsRef<OsStr>>(key: K) -> Option<OsString> {
 
 fn _var_os(key: &OsStr) -> Option<OsString> {
     os_imp::getenv(key)
-        .unwrap_or_else(|e| panic!("failed to get environment variable `{:?}`: {}", key, e))
 }
 
 /// The error type for operations interacting with environment variables.

library/std/src/io/mod.rs

@@ -810,9 +810,9 @@ pub trait Read {
         default_read_exact(self, buf)
     }
 
-    /// Creates a "by reference" adaptor for this instance of `Read`.
+    /// Creates a "by reference" adapter for this instance of `Read`.
     ///
-    /// The returned adaptor also implements `Read` and will simply borrow this
+    /// The returned adapter also implements `Read` and will simply borrow this
     /// current reader.
     ///
     /// # Examples
@@ -889,7 +889,7 @@ pub trait Read {
         Bytes { inner: self }
     }
 
-    /// Creates an adaptor which will chain this stream with another.
+    /// Creates an adapter which will chain this stream with another.
     ///
     /// The returned `Read` instance will first read all bytes from this object
     /// until EOF is encountered. Afterwards the output is equivalent to the
@@ -927,7 +927,7 @@ pub trait Read {
         Chain { first: self, second: next, done_first: false }
     }
 
-    /// Creates an adaptor which will read at most `limit` bytes from it.
+    /// Creates an adapter which will read at most `limit` bytes from it.
     ///
     /// This function returns a new instance of `Read` which will read at most
     /// `limit` bytes, after which it will always return EOF ([`Ok(0)`]). Any
@@ -1326,7 +1326,7 @@ impl Initializer {
 /// * The [`write`] method will attempt to write some data into the object,
 ///   returning how many bytes were successfully written.
 ///
-/// * The [`flush`] method is useful for adaptors and explicit buffers
+/// * The [`flush`] method is useful for adapters and explicit buffers
 ///   themselves for ensuring that all buffered data has been pushed out to the
 ///   'true sink'.
 ///
@@ -1646,12 +1646,12 @@ pub trait Write {
     fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> Result<()> {
         // Create a shim which translates a Write to a fmt::Write and saves
         // off I/O errors. instead of discarding them
-        struct Adaptor<'a, T: ?Sized + 'a> {
+        struct Adapter<'a, T: ?Sized + 'a> {
             inner: &'a mut T,
             error: Result<()>,
         }
 
-        impl<T: Write + ?Sized> fmt::Write for Adaptor<'_, T> {
+        impl<T: Write + ?Sized> fmt::Write for Adapter<'_, T> {
             fn write_str(&mut self, s: &str) -> fmt::Result {
                 match self.inner.write_all(s.as_bytes()) {
                     Ok(()) => Ok(()),
@@ -1663,7 +1663,7 @@ pub trait Write {
             }
         }
 
-        let mut output = Adaptor { inner: self, error: Ok(()) };
+        let mut output = Adapter { inner: self, error: Ok(()) };
         match fmt::write(&mut output, fmt) {
             Ok(()) => Ok(()),
             Err(..) => {
@@ -1677,9 +1677,9 @@ pub trait Write {
         }
     }
 
-    /// Creates a "by reference" adaptor for this instance of `Write`.
+    /// Creates a "by reference" adapter for this instance of `Write`.
     ///
-    /// The returned adaptor also implements `Write` and will simply borrow this
+    /// The returned adapter also implements `Write` and will simply borrow this
     /// current writer.
     ///
     /// # Examples
@@ -2263,7 +2263,7 @@ pub trait BufRead: Read {
     }
 }
 
-/// Adaptor to chain together two readers.
+/// Adapter to chain together two readers.
 ///
 /// This struct is generally created by calling [`chain`] on a reader.
 /// Please see the documentation of [`chain`] for more details.
@@ -2414,7 +2414,7 @@ impl<T, U> SizeHint for Chain<T, U> {
     }
 }
 
-/// Reader adaptor which limits the bytes read from an underlying reader.
+/// Reader adapter which limits the bytes read from an underlying reader.
 ///
 /// This struct is generally created by calling [`take`] on a reader.
 /// Please see the documentation of [`take`] for more details.