Auto merge of rust-lang#114719 - compiler-errors:rollup-bf1vr51, r=compiler-errors

Rollup of 5 pull requests

Successful merges:

 - rust-lang#114194 (Inline trivial (noop) flush calls)
 - rust-lang#114257 (Avoid using `ptr::Unique` in `LinkedList` code)
 - rust-lang#114359 ([library/std] Replace condv while loop with `cvar.wait_while`.)
 - rust-lang#114402 (Fix documentation of impl From<Vec<T>> for Rc<[T]>)
 - rust-lang#114715 (Revert clippy lint [`filter_map_bool_then`])

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

Author: bors

library/alloc/src/collections/linked_list.rs

@@ -18,7 +18,7 @@ use core::hash::{Hash, Hasher};
 use core::iter::FusedIterator;
 use core::marker::PhantomData;
 use core::mem;
-use core::ptr::{NonNull, Unique};
+use core::ptr::NonNull;
 
 use super::SpecExtend;
 use crate::alloc::{Allocator, Global};
@@ -168,15 +168,16 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// Adds the given node to the front of the list.
     ///
     /// # Safety
-    /// `node` must point to a valid node that was boxed using the list's allocator.
+    /// `node` must point to a valid node that was boxed and leaked using the list's allocator.
+    /// This method takes ownership of the node, so the pointer should not be used again.
     #[inline]
-    unsafe fn push_front_node(&mut self, node: Unique<Node<T>>) {
+    unsafe fn push_front_node(&mut self, node: NonNull<Node<T>>) {
         // This method takes care not to create mutable references to whole nodes,
         // to maintain validity of aliasing pointers into `element`.
         unsafe {
             (*node.as_ptr()).next = self.head;
             (*node.as_ptr()).prev = None;
-            let node = Some(NonNull::from(node));
+            let node = Some(node);
 
             match self.head {
                 None => self.tail = node,
@@ -212,15 +213,16 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// Adds the given node to the back of the list.
     ///
     /// # Safety
-    /// `node` must point to a valid node that was boxed using the list's allocator.
+    /// `node` must point to a valid node that was boxed and leaked using the list's allocator.
+    /// This method takes ownership of the node, so the pointer should not be used again.
     #[inline]
-    unsafe fn push_back_node(&mut self, node: Unique<Node<T>>) {
+    unsafe fn push_back_node(&mut self, node: NonNull<Node<T>>) {
         // This method takes care not to create mutable references to whole nodes,
         // to maintain validity of aliasing pointers into `element`.
         unsafe {
             (*node.as_ptr()).next = None;
             (*node.as_ptr()).prev = self.tail;
-            let node = Some(NonNull::from(node));
+            let node = Some(node);
 
             match self.tail {
                 None => self.head = node,
@@ -842,8 +844,8 @@ impl<T, A: Allocator> LinkedList<T, A> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn push_front(&mut self, elt: T) {
         let node = Box::new_in(Node::new(elt), &self.alloc);
-        let node_ptr = Unique::from(Box::leak(node));
-        // SAFETY: node_ptr is a unique pointer to a node we boxed with self.alloc
+        let node_ptr = NonNull::from(Box::leak(node));
+        // SAFETY: node_ptr is a unique pointer to a node we boxed with self.alloc and leaked
         unsafe {
             self.push_front_node(node_ptr);
         }
@@ -890,8 +892,8 @@ impl<T, A: Allocator> LinkedList<T, A> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn push_back(&mut self, elt: T) {
         let node = Box::new_in(Node::new(elt), &self.alloc);
-        let node_ptr = Unique::from(Box::leak(node));
-        // SAFETY: node_ptr is a unique pointer to a node we boxed with self.alloc
+        let node_ptr = NonNull::from(Box::leak(node));
+        // SAFETY: node_ptr is a unique pointer to a node we boxed with self.alloc and leaked
         unsafe {
             self.push_back_node(node_ptr);
         }

library/alloc/src/rc.rs

@@ -2491,9 +2491,9 @@ impl<T, A: Allocator> From<Vec<T, A>> for Rc<[T], A> {
     ///
     /// ```
     /// # use std::rc::Rc;
-    /// let original: Box<Vec<i32>> = Box::new(vec![1, 2, 3]);
-    /// let shared: Rc<Vec<i32>> = Rc::from(original);
-    /// assert_eq!(vec![1, 2, 3], *shared);
+    /// let unique: Vec<i32> = vec![1, 2, 3];
+    /// let shared: Rc<[i32]> = Rc::from(unique);
+    /// assert_eq!(&[1, 2, 3], &shared[..]);
     /// ```
     #[inline]
     fn from(v: Vec<T, A>) -> Rc<[T], A> {

library/std/src/fs.rs

@@ -791,6 +791,7 @@ impl Write for &File {
         self.inner.is_write_vectored()
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         self.inner.flush()
     }
@@ -836,6 +837,7 @@ impl Write for File {
     fn is_write_vectored(&self) -> bool {
         (&&*self).is_write_vectored()
     }
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         (&*self).flush()
     }
@@ -881,6 +883,7 @@ impl Write for Arc<File> {
     fn is_write_vectored(&self) -> bool {
         (&**self).is_write_vectored()
     }
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         (&**self).flush()
     }

library/std/src/io/readbuf.rs

@@ -310,6 +310,7 @@ impl<'a> Write for BorrowedCursor<'a> {
         Ok(buf.len())
     }
 
+    #[inline]
     fn flush(&mut self) -> Result<()> {
         Ok(())
     }

library/std/src/net/tcp.rs

@@ -647,6 +647,7 @@ impl Write for TcpStream {
         self.0.is_write_vectored()
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
@@ -685,6 +686,7 @@ impl Write for &TcpStream {
         self.0.is_write_vectored()
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }

library/std/src/os/unix/net/stream.rs

@@ -712,6 +712,7 @@ impl<'a> io::Write for &'a UnixStream {
         self.0.is_write_vectored()
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }

library/std/src/process.rs

@@ -280,6 +280,7 @@ impl Write for ChildStdin {
         io::Write::is_write_vectored(&&*self)
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         (&*self).flush()
     }
@@ -299,6 +300,7 @@ impl Write for &ChildStdin {
         self.inner.is_write_vectored()
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }

library/std/src/sync/barrier.rs

@@ -130,11 +130,8 @@ impl Barrier {
         let local_gen = lock.generation_id;
         lock.count += 1;
         if lock.count < self.num_threads {
-            // We need a while loop to guard against spurious wakeups.
-            // https://en.wikipedia.org/wiki/Spurious_wakeup
-            while local_gen == lock.generation_id {
-                lock = self.cvar.wait(lock).unwrap();
-            }
+            let _guard =
+                self.cvar.wait_while(lock, |state| local_gen == state.generation_id).unwrap();
             BarrierWaitResult(false)
         } else {
             lock.count = 0;

library/std/src/sys/hermit/fs.rs

@@ -335,6 +335,7 @@ impl File {
         false
     }
 
+    #[inline]
     pub fn flush(&self) -> io::Result<()> {
         Ok(())
     }

library/std/src/sys/unix/fs.rs

@@ -1204,6 +1204,7 @@ impl File {
         self.0.write_vectored_at(bufs, offset)
     }
 
+    #[inline]
     pub fn flush(&self) -> io::Result<()> {
         Ok(())
     }

library/std/src/sys/unix/stdio.rs

@@ -54,6 +54,7 @@ impl io::Write for Stdout {
         true
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
@@ -81,6 +82,7 @@ impl io::Write for Stderr {
         true
     }
 
+    #[inline]
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }

src/tools/clippy/CHANGELOG.md

@@ -4844,7 +4844,6 @@ Released 2018-09-13
 [`field_reassign_with_default`]: https://rust-lang.github.io/rust-clippy/master/index.html#field_reassign_with_default
 [`filetype_is_file`]: https://rust-lang.github.io/rust-clippy/master/index.html#filetype_is_file
 [`filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_map
-[`filter_map_bool_then`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_map_bool_then
 [`filter_map_identity`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_map_identity
 [`filter_map_next`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_map_next
 [`filter_next`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_next

src/tools/clippy/clippy_lints/src/declared_lints.rs

@@ -337,7 +337,6 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::methods::EXPECT_USED_INFO,
     crate::methods::EXTEND_WITH_DRAIN_INFO,
     crate::methods::FILETYPE_IS_FILE_INFO,
-    crate::methods::FILTER_MAP_BOOL_THEN_INFO,
     crate::methods::FILTER_MAP_IDENTITY_INFO,
     crate::methods::FILTER_MAP_NEXT_INFO,
     crate::methods::FILTER_NEXT_INFO,

src/tools/clippy/clippy_lints/src/methods/filter_map_bool_then.rs

@@ -21,7 +21,6 @@ mod expect_used;
 mod extend_with_drain;
 mod filetype_is_file;
 mod filter_map;
-mod filter_map_bool_then;
 mod filter_map_identity;
 mod filter_map_next;
 mod filter_next;
@@ -3477,37 +3476,6 @@ declare_clippy_lint! {
     "disallows `.skip(0)`"
 }
 
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for usage of `bool::then` in `Iterator::filter_map`.
-    ///
-    /// ### Why is this bad?
-    /// This can be written with `filter` then `map` instead, which would reduce nesting and
-    /// separates the filtering from the transformation phase. This comes with no cost to
-    /// performance and is just cleaner.
-    ///
-    /// ### Limitations
-    /// Does not lint `bool::then_some`, as it eagerly evaluates its arguments rather than lazily.
-    /// This can create differing behavior, so better safe than sorry.
-    ///
-    /// ### Example
-    /// ```rust
-    /// # fn really_expensive_fn(i: i32) -> i32 { i }
-    /// # let v = vec![];
-    /// _ = v.into_iter().filter_map(|i| (i % 2 == 0).then(|| really_expensive_fn(i)));
-    /// ```
-    /// Use instead:
-    /// ```rust
-    /// # fn really_expensive_fn(i: i32) -> i32 { i }
-    /// # let v = vec![];
-    /// _ = v.into_iter().filter(|i| i % 2 == 0).map(|i| really_expensive_fn(i));
-    /// ```
-    #[clippy::version = "1.72.0"]
-    pub FILTER_MAP_BOOL_THEN,
-    style,
-    "checks for usage of `bool::then` in `Iterator::filter_map`"
-}
-
 declare_clippy_lint! {
     /// ### What it does
     /// Looks for calls to `RwLock::write` where the lock is only used for reading.
@@ -3676,7 +3644,6 @@ impl_lint_pass!(Methods => [
     FORMAT_COLLECT,
     STRING_LIT_CHARS_ANY,
     ITER_SKIP_ZERO,
-    FILTER_MAP_BOOL_THEN,
     READONLY_WRITE_LOCK
 ]);
 
@@ -3955,7 +3922,6 @@ impl Methods {
                 },
                 ("filter_map", [arg]) => {
                     unnecessary_filter_map::check(cx, expr, arg, name);
-                    filter_map_bool_then::check(cx, expr, arg, call_span);
                     filter_map_identity::check(cx, expr, arg, span);
                 },
                 ("find_map", [arg]) => {

src/tools/clippy/clippy_lints/src/methods/mod.rs

@@ -163,5 +163,3 @@ pub const OPTION_EXPECT: [&str; 4] = ["core", "option", "Option", "expect"];
 pub const FORMATTER: [&str; 3] = ["core", "fmt", "Formatter"];
 pub const DEBUG_STRUCT: [&str; 4] = ["core", "fmt", "builders", "DebugStruct"];
 pub const ORD_CMP: [&str; 4] = ["core", "cmp", "Ord", "cmp"];
-#[expect(clippy::invalid_paths)] // not sure why it thinks this, it works so
-pub const BOOL_THEN: [&str; 4] = ["core", "bool", "<impl bool>", "then"];