Auto merge of #106866 - matthiaskrgr:rollup-r063s44, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #105526 (libcore: make result of iter::from_generator Clone)
 - #106563 (Fix `unused_braces` on generic const expr macro call)
 - #106661 (Stop probing for statx unless necessary)
 - #106820 (Deprioritize fulfillment errors that come from expansions.)
 - #106828 (rustdoc: remove `docblock` class from notable trait popover)
 - #106849 (Allocate one less vec while parsing arrays)
 - #106855 (rustdoc: few small cleanups)
 - #106860 (Remove various double spaces in the libraries.)

Failed merges:

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

compiler/rustc_lint/src/unused.rs

@@ -1105,6 +1105,7 @@ impl UnusedDelimLint for UnusedBraces {
                                 || matches!(expr.kind, ast::ExprKind::Lit(_)))
                             && !cx.sess().source_map().is_multiline(value.span)
                             && value.attrs.is_empty()
+                            && !expr.span.from_expansion()
                             && !value.span.from_expansion()
                             && !inner.span.from_expansion()
                         {

compiler/rustc_parse/src/parser/expr.rs

@@ -1475,9 +1475,8 @@ impl<'a> Parser<'a> {
             } else if self.eat(&token::Comma) {
                 // Vector with two or more elements.
                 let sep = SeqSep::trailing_allowed(token::Comma);
-                let (remaining_exprs, _) = self.parse_seq_to_end(close, sep, |p| p.parse_expr())?;
+                let (mut exprs, _) = self.parse_seq_to_end(close, sep, |p| p.parse_expr())?;
-                let mut exprs = vec![first_expr];
+                exprs.insert(0, first_expr);
-                exprs.extend(remaining_exprs);
                 ExprKind::Array(exprs)
             } else {
                 // Vector with one element

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -454,9 +454,11 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
         }
 
-        for (error, suppressed) in iter::zip(errors, is_suppressed) {
+        for from_expansion in [false, true] {
-            if !suppressed {
+            for (error, suppressed) in iter::zip(errors, &is_suppressed) {
-                self.report_fulfillment_error(error, body_id);
+                if !suppressed && error.obligation.cause.span.from_expansion() == from_expansion {
+                    self.report_fulfillment_error(error, body_id);
+                }
             }
         }
 

library/alloc/src/alloc.rs

@@ -20,7 +20,7 @@ use core::marker::Destruct;
 mod tests;
 
 extern "Rust" {
-    // These are the magic symbols to call the global allocator.  rustc generates
+    // These are the magic symbols to call the global allocator. rustc generates
     // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
     // (the code expanding that attribute macro generates those functions), or to call
     // the default implementations in std (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
@@ -353,7 +353,7 @@ pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Dest
 
 #[cfg(not(no_global_oom_handling))]
 extern "Rust" {
-    // This is the magic symbol to call the global alloc error handler.  rustc generates
+    // This is the magic symbol to call the global alloc error handler. rustc generates
     // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
     // default implementations below (`__rdl_oom`) otherwise.
     fn __rust_alloc_error_handler(size: usize, align: usize) -> !;

library/alloc/src/rc.rs

@@ -2179,7 +2179,7 @@ pub struct Weak<T: ?Sized> {
     // This is a `NonNull` to allow optimizing the size of this type in enums,
     // but it is not necessarily a valid pointer.
     // `Weak::new` sets this to `usize::MAX` so that it doesn’t need
-    // to allocate space on the heap.  That's not a value a real pointer
+    // to allocate space on the heap. That's not a value a real pointer
     // will ever have because RcBox has alignment at least 2.
     // This is only possible when `T: Sized`; unsized `T` never dangle.
     ptr: NonNull<RcBox<T>>,

library/alloc/src/sync.rs

@@ -295,7 +295,7 @@ pub struct Weak<T: ?Sized> {
     // This is a `NonNull` to allow optimizing the size of this type in enums,
     // but it is not necessarily a valid pointer.
     // `Weak::new` sets this to `usize::MAX` so that it doesn’t need
-    // to allocate space on the heap.  That's not a value a real pointer
+    // to allocate space on the heap. That's not a value a real pointer
     // will ever have because RcBox has alignment at least 2.
     // This is only possible when `T: Sized`; unsized `T` never dangle.
     ptr: NonNull<ArcInner<T>>,
@@ -1656,7 +1656,7 @@ impl<T: ?Sized> Arc<T> {
         //
         // The acquire label here ensures a happens-before relationship with any
         // writes to `strong` (in particular in `Weak::upgrade`) prior to decrements
-        // of the `weak` count (via `Weak::drop`, which uses release).  If the upgraded
+        // of the `weak` count (via `Weak::drop`, which uses release). If the upgraded
         // weak ref was never dropped, the CAS here will fail so we do not care to synchronize.
         if self.inner().weak.compare_exchange(1, usize::MAX, Acquire, Relaxed).is_ok() {
             // This needs to be an `Acquire` to synchronize with the decrement of the `strong`
@@ -1712,7 +1712,7 @@ unsafe impl<#[may_dangle] T: ?Sized> Drop for Arc<T> {
         }
 
         // This fence is needed to prevent reordering of use of the data and
-        // deletion of the data.  Because it is marked `Release`, the decreasing
+        // deletion of the data. Because it is marked `Release`, the decreasing
         // of the reference count synchronizes with this `Acquire` fence. This
         // means that use of the data happens before decreasing the reference
         // count, which happens before this fence, which happens before the
@@ -2172,7 +2172,7 @@ impl<T: ?Sized> Clone for Weak<T> {
         } else {
             return Weak { ptr: self.ptr };
         };
-        // See comments in Arc::clone() for why this is relaxed.  This can use a
+        // See comments in Arc::clone() for why this is relaxed. This can use a
         // fetch_add (ignoring the lock) because the weak count is only locked
         // where are *no other* weak pointers in existence. (So we can't be
         // running this code in that case).

library/alloc/src/vec/into_iter.rs

@@ -40,7 +40,7 @@ pub struct IntoIter<
     // to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
     pub(super) alloc: ManuallyDrop<A>,
     pub(super) ptr: *const T,
-    pub(super) end: *const T, // If T is a ZST, this is actually ptr+len.  This encoding is picked so that
+    pub(super) end: *const T, // If T is a ZST, this is actually ptr+len. This encoding is picked so that
                               // ptr == end is a quick test for the Iterator being empty, that works
                               // for both ZST and non-ZST.
 }
@@ -146,9 +146,9 @@ impl<T, A: Allocator> IntoIter<T, A> {
         let mut this = ManuallyDrop::new(self);
 
         // SAFETY: This allocation originally came from a `Vec`, so it passes
-        // all those checks.  We have `this.buf` ≤ `this.ptr` ≤ `this.end`,
+        // all those checks. We have `this.buf` ≤ `this.ptr` ≤ `this.end`,
         // so the `sub_ptr`s below cannot wrap, and will produce a well-formed
-        // range.  `end` ≤ `buf + cap`, so the range will be in-bounds.
+        // range. `end` ≤ `buf + cap`, so the range will be in-bounds.
         // Taking `alloc` is ok because nothing else is going to look at it,
         // since our `Drop` impl isn't going to run so there's no more code.
         unsafe {

library/alloc/src/vec/is_zero.rs

@@ -57,7 +57,7 @@ unsafe impl<T: IsZero, const N: usize> IsZero for [T; N] {
     #[inline]
     fn is_zero(&self) -> bool {
         // Because this is generated as a runtime check, it's not obvious that
-        // it's worth doing if the array is really long.  The threshold here
+        // it's worth doing if the array is really long. The threshold here
         // is largely arbitrary, but was picked because as of 2022-07-01 LLVM
         // fails to const-fold the check in `vec![[1; 32]; n]`
         // See https://github.com/rust-lang/rust/pull/97581#issuecomment-1166628022

library/alloc/src/vec/mod.rs

@@ -2429,7 +2429,7 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
         self.reserve(range.len());
 
         // SAFETY:
-        // - `slice::range` guarantees  that the given range is valid for indexing self
+        // - `slice::range` guarantees that the given range is valid for indexing self
         unsafe {
             self.spec_extend_from_within(range);
         }
@@ -2686,7 +2686,7 @@ impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
 
     // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
     // required for this method definition, is not available. Instead use the
-    // `slice::to_vec`  function which is only available with cfg(test)
+    // `slice::to_vec` function which is only available with cfg(test)
     // NB see the slice::hack module in slice.rs for more information
     #[cfg(test)]
     fn clone(&self) -> Self {

library/alloc/tests/vec.rs

@@ -1849,7 +1849,7 @@ fn test_stable_pointers() {
     }
 
     // Test that, if we reserved enough space, adding and removing elements does not
-    // invalidate references into the vector (such as `v0`).  This test also
+    // invalidate references into the vector (such as `v0`). This test also
     // runs in Miri, which would detect such problems.
     // Note that this test does *not* constitute a stable guarantee that all these functions do not
     // reallocate! Only what is explicitly documented at

library/core/src/array/iter.rs

@@ -109,8 +109,8 @@ impl<T, const N: usize> IntoIter<T, N> {
     /// use std::array::IntoIter;
     /// use std::mem::MaybeUninit;
     ///
-    /// # // Hi!  Thanks for reading the code.  This is restricted to `Copy` because
+    /// # // Hi!  Thanks for reading the code. This is restricted to `Copy` because
-    /// # // otherwise it could leak.  A fully-general version this would need a drop
+    /// # // otherwise it could leak. A fully-general version this would need a drop
     /// # // guard to handle panics from the iterator, but this works for an example.
     /// fn next_chunk<T: Copy, const N: usize>(
     ///     it: &mut impl Iterator<Item = T>,
@@ -211,7 +211,7 @@ impl<T, const N: usize> IntoIter<T, N> {
         let initialized = 0..0;
 
         // SAFETY: We're telling it that none of the elements are initialized,
-        // which is trivially true.  And ∀N: usize, 0 <= N.
+        // which is trivially true. And ∀N: usize, 0 <= N.
         unsafe { Self::new_unchecked(buffer, initialized) }
     }
 

library/core/src/iter/range.rs

@@ -756,7 +756,7 @@ impl<A: Step> Iterator for ops::Range<A> {
     where
         Self: TrustedRandomAccessNoCoerce,
     {
-        // SAFETY: The TrustedRandomAccess contract requires that callers only  pass an index
+        // SAFETY: The TrustedRandomAccess contract requires that callers only pass an index
         // that is in bounds.
         // Additionally Self: TrustedRandomAccess is only implemented for Copy types
         // which means even repeated reads of the same index would be safe.

library/core/src/iter/sources/from_generator.rs

@@ -1,3 +1,4 @@
+use crate::fmt;
 use crate::ops::{Generator, GeneratorState};
 use crate::pin::Pin;
 
@@ -23,14 +24,21 @@ use crate::pin::Pin;
 /// ```
 #[inline]
 #[unstable(feature = "iter_from_generator", issue = "43122", reason = "generators are unstable")]
-pub fn from_generator<G: Generator<Return = ()> + Unpin>(
+pub fn from_generator<G: Generator<Return = ()> + Unpin>(generator: G) -> FromGenerator<G> {
-    generator: G,
-) -> impl Iterator<Item = G::Yield> {
     FromGenerator(generator)
 }
 
-struct FromGenerator<G>(G);
+/// An iterator over the values yielded by an underlying generator.
+///
+/// This `struct` is created by the [`iter::from_generator()`] function. See its documentation for
+/// more.
+///
+/// [`iter::from_generator()`]: from_generator
+#[unstable(feature = "iter_from_generator", issue = "43122", reason = "generators are unstable")]
+#[derive(Clone)]
+pub struct FromGenerator<G>(G);
 
+#[unstable(feature = "iter_from_generator", issue = "43122", reason = "generators are unstable")]
 impl<G: Generator<Return = ()> + Unpin> Iterator for FromGenerator<G> {
     type Item = G::Yield;
 
@@ -41,3 +49,10 @@ impl<G: Generator<Return = ()> + Unpin> Iterator for FromGenerator<G> {
         }
     }
 }
+
+#[unstable(feature = "iter_from_generator", issue = "43122", reason = "generators are unstable")]
+impl<G> fmt::Debug for FromGenerator<G> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("FromGenerator").finish()
+    }
+}

library/core/src/num/dec2flt/fpu.rs

@@ -26,7 +26,7 @@ mod fpu_precision {
     /// Developer's Manual (Volume 1).
     ///
     /// The only field which is relevant for the following code is PC, Precision Control. This
-    /// field determines the precision of the operations performed by the  FPU. It can be set to:
+    /// field determines the precision of the operations performed by the FPU. It can be set to:
     ///  - 0b00, single precision i.e., 32-bits
     ///  - 0b10, double precision i.e., 64-bits
     ///  - 0b11, double extended precision i.e., 80-bits (default state)

library/core/src/num/int_macros.rs

@@ -1538,7 +1538,7 @@ macro_rules! int_impl {
         ///
         /// ```
         /// #![feature(bigint_helper_methods)]
-        /// // Only the  most significant word is signed.
+        /// // Only the most significant word is signed.
         /// //
         #[doc = concat!("//   10  MAX    (a = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
         #[doc = concat!("// + -5    9    (b = -5 × 2^", stringify!($BITS), " + 9)")]
@@ -1646,7 +1646,7 @@ macro_rules! int_impl {
         ///
         /// ```
         /// #![feature(bigint_helper_methods)]
-        /// // Only the  most significant word is signed.
+        /// // Only the most significant word is signed.
         /// //
         #[doc = concat!("//    6    8    (a = 6 × 2^", stringify!($BITS), " + 8)")]
         #[doc = concat!("// - -5    9    (b = -5 × 2^", stringify!($BITS), " + 9)")]

library/core/src/pin.rs

@@ -753,7 +753,7 @@ impl<P: DerefMut> Pin<P> {
 impl<'a, T: ?Sized> Pin<&'a T> {
     /// Constructs a new pin by mapping the interior value.
     ///
-    /// For example, if you  wanted to get a `Pin` of a field of something,
+    /// For example, if you wanted to get a `Pin` of a field of something,
     /// you could use this to get access to that field in one line of code.
     /// However, there are several gotchas with these "pinning projections";
     /// see the [`pin` module] documentation for further details on that topic.
@@ -856,7 +856,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
 
     /// Construct a new pin by mapping the interior value.
     ///
-    /// For example, if you  wanted to get a `Pin` of a field of something,
+    /// For example, if you wanted to get a `Pin` of a field of something,
     /// you could use this to get access to that field in one line of code.
     /// However, there are several gotchas with these "pinning projections";
     /// see the [`pin` module] documentation for further details on that topic.

library/core/src/ptr/mod.rs

@@ -1701,7 +1701,7 @@ pub(crate) const unsafe fn align_offset<T: Sized>(p: *const T, a: usize) -> usiz
         // offset is not a multiple of `stride`, the input pointer was misaligned and no pointer
         // offset will be able to produce a `p` aligned to the specified `a`.
         //
-        // The naive `-p (mod a)` equation  inhibits LLVM's ability to select instructions
+        // The naive `-p (mod a)` equation inhibits LLVM's ability to select instructions
         // like `lea`. We compute `(round_up_to_next_alignment(p, a) - p)` instead. This
         // redistributes operations around the load-bearing, but pessimizing `and` instruction
         // sufficiently for LLVM to be able to utilize the various optimizations it knows about.

library/core/src/slice/iter.rs

@@ -65,7 +65,7 @@ fn size_from_ptr<T>(_: *const T) -> usize {
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub struct Iter<'a, T: 'a> {
     ptr: NonNull<T>,
-    end: *const T, // If T is a ZST, this is actually ptr+len.  This encoding is picked so that
+    end: *const T, // If T is a ZST, this is actually ptr+len. This encoding is picked so that
     // ptr == end is a quick test for the Iterator being empty, that works
     // for both ZST and non-ZST.
     _marker: PhantomData<&'a T>,
@@ -186,7 +186,7 @@ impl<T> AsRef<[T]> for Iter<'_, T> {
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub struct IterMut<'a, T: 'a> {
     ptr: NonNull<T>,
-    end: *mut T, // If T is a ZST, this is actually ptr+len.  This encoding is picked so that
+    end: *mut T, // If T is a ZST, this is actually ptr+len. This encoding is picked so that
     // ptr == end is a quick test for the Iterator being empty, that works
     // for both ZST and non-ZST.
     _marker: PhantomData<&'a mut T>,

library/core/src/slice/iter/macros.rs

@@ -23,7 +23,7 @@ macro_rules! len {
             $self.end.addr().wrapping_sub(start.as_ptr().addr())
         } else {
             // We know that `start <= end`, so can do better than `offset_from`,
-            // which needs to deal in signed.  By setting appropriate flags here
+            // which needs to deal in signed. By setting appropriate flags here
             // we can tell LLVM this, which helps it remove bounds checks.
             // SAFETY: By the type invariant, `start <= end`
             let diff = unsafe { unchecked_sub($self.end.addr(), start.as_ptr().addr()) };

library/core/src/slice/mod.rs

@@ -703,7 +703,7 @@ impl<T> [T] {
 
             // Because this function is first compiled in isolation,
             // this check tells LLVM that the indexing below is
-            // in-bounds.  Then after inlining -- once the actual
+            // in-bounds. Then after inlining -- once the actual
             // lengths of the slices are known -- it's removed.
             let (a, b) = (&mut a[..n], &mut b[..n]);
 
@@ -1248,7 +1248,7 @@ impl<T> [T] {
         ArrayChunksMut::new(self)
     }
 
-    /// Returns an iterator over overlapping windows of `N` elements of  a slice,
+    /// Returns an iterator over overlapping windows of `N` elements of a slice,
     /// starting at the beginning of the slice.
     ///
     /// This is the const generic equivalent of [`windows`].
@@ -2476,7 +2476,7 @@ impl<T> [T] {
             let mid = left + size / 2;
 
             // SAFETY: the while condition means `size` is strictly positive, so
-            // `size/2 < size`.  Thus `left + size/2 < left + size`, which
+            // `size/2 < size`. Thus `left + size/2 < left + size`, which
             // coupled with the `left + size <= self.len()` invariant means
             // we have `left + size/2 < self.len()`, and this is in-bounds.
             let cmp = f(unsafe { self.get_unchecked(mid) });

library/core/src/slice/sort.rs

@@ -18,9 +18,9 @@ struct CopyOnDrop<T> {
 
 impl<T> Drop for CopyOnDrop<T> {
     fn drop(&mut self) {
-        // SAFETY:  This is a helper class.
+        // SAFETY: This is a helper class.
-        //          Please refer to its usage for correctness.
+        //         Please refer to its usage for correctness.
-        //          Namely, one must be sure that `src` and `dst` does not overlap as required by `ptr::copy_nonoverlapping`.
+        //         Namely, one must be sure that `src` and `dst` does not overlap as required by `ptr::copy_nonoverlapping`.
         unsafe {
             ptr::copy_nonoverlapping(self.src, self.dest, 1);
         }

library/core/tests/slice.rs

@@ -1488,7 +1488,7 @@ mod slice_index {
                 // optional:
                 //
                 // one or more similar inputs for which data[input] succeeds,
-                // and the corresponding output as an array.  This helps validate
+                // and the corresponding output as an array. This helps validate
                 // "critical points" where an input range straddles the boundary
                 // between valid and invalid.
                 // (such as the input `len..len`, which is just barely valid)

library/std/src/fs.rs

@@ -1512,7 +1512,7 @@ impl FileType {
     }
 
     /// Tests whether this file type represents a regular file.
-    /// The result is  mutually exclusive to the results of
+    /// The result is mutually exclusive to the results of
     /// [`is_dir`] and [`is_symlink`]; only zero or one of these
     /// tests may pass.
     ///

library/std/src/io/buffered/tests.rs

@@ -288,8 +288,8 @@ fn test_buffered_reader_seek_underflow_discard_buffer_between_seeks() {
     let mut reader = BufReader::with_capacity(5, ErrAfterFirstSeekReader { first_seek: true });
     assert_eq!(reader.fill_buf().ok(), Some(&[0, 0, 0, 0, 0][..]));
 
-    // The following seek will require two underlying seeks.  The first will
+    // The following seek will require two underlying seeks. The first will
-    // succeed but the second will fail.  This should still invalidate the
+    // succeed but the second will fail. This should still invalidate the
     // buffer.
     assert!(reader.seek(SeekFrom::Current(i64::MIN)).is_err());
     assert_eq!(reader.buffer().len(), 0);

library/std/src/os/fd/owned.rs

@@ -100,7 +100,7 @@ impl BorrowedFd<'_> {
 
         // For ESP-IDF, F_DUPFD is used instead, because the CLOEXEC semantics
         // will never be supported, as this is a bare metal framework with
-        // no capabilities for multi-process execution.  While F_DUPFD is also
+        // no capabilities for multi-process execution. While F_DUPFD is also
         // not supported yet, it might be (currently it returns ENOSYS).
         #[cfg(target_os = "espidf")]
         let cmd = libc::F_DUPFD;

library/std/src/panicking.rs

@@ -306,11 +306,11 @@ pub mod panic_count {
     // and after increase and decrease, but not necessarily during their execution.
     //
     // Additionally, the top bit of GLOBAL_PANIC_COUNT (GLOBAL_ALWAYS_ABORT_FLAG)
-    // records whether panic::always_abort() has been called.  This can only be
+    // records whether panic::always_abort() has been called. This can only be
     // set, never cleared.
     // panic::always_abort() is usually called to prevent memory allocations done by
     // the panic handling in the child created by `libc::fork`.
-    // Memory allocations performed in  a child created with `libc::fork` are undefined
+    // Memory allocations performed in a child created with `libc::fork` are undefined
     // behavior in most operating systems.
     // Accessing LOCAL_PANIC_COUNT in a child created by `libc::fork` would lead to a memory
     // allocation. Only GLOBAL_PANIC_COUNT can be accessed in this situation. This is

library/std/src/path.rs

@@ -607,7 +607,7 @@ pub struct Components<'a> {
 
     // true if path *physically* has a root separator; for most Windows
     // prefixes, it may have a "logical" root separator for the purposes of
-    // normalization, e.g.,  \\server\share == \\server\share\.
+    // normalization, e.g., \\server\share == \\server\share\.
     has_physical_root: bool,
 
     // The iterator is double-ended, and these two states keep track of what has

library/std/src/sys/itron/thread.rs

@@ -294,7 +294,7 @@ impl Drop for Thread {
                 // Terminate and delete the task
                 // Safety: `self.task` still represents a task we own (because
                 //         this method or `join_inner` is called only once for
-                //         each `Thread`). The task  indicated that it's safe to
+                //         each `Thread`). The task indicated that it's safe to
                 //         delete by entering the `FINISHED` state.
                 unsafe { terminate_and_delete_task(self.task) };
 

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

@@ -149,12 +149,13 @@ cfg_has_statx! {{
     ) -> Option<io::Result<FileAttr>> {
         use crate::sync::atomic::{AtomicU8, Ordering};
 
-        // Linux kernel prior to 4.11 or glibc prior to glibc 2.28 don't support `statx`
+        // Linux kernel prior to 4.11 or glibc prior to glibc 2.28 don't support `statx`.
-        // We store the availability in global to avoid unnecessary syscalls.
+        // We check for it on first failure and remember availability to avoid having to
-        // 0: Unknown
+        // do it again.
-        // 1: Not available
+        #[repr(u8)]
-        // 2: Available
+        enum STATX_STATE{ Unknown = 0, Present, Unavailable }
-        static STATX_STATE: AtomicU8 = AtomicU8::new(0);
+        static STATX_SAVED_STATE: AtomicU8 = AtomicU8::new(STATX_STATE::Unknown as u8);
+
         syscall! {
             fn statx(
                 fd: c_int,
@@ -165,31 +166,44 @@ cfg_has_statx! {{
             ) -> c_int
         }
 
-        match STATX_STATE.load(Ordering::Relaxed) {
+        if STATX_SAVED_STATE.load(Ordering::Relaxed) == STATX_STATE::Unavailable as u8 {
-            0 => {
+            return None;
-                // It is a trick to call `statx` with null pointers to check if the syscall
-                // is available. According to the manual, it is expected to fail with EFAULT.
-                // We do this mainly for performance, since it is nearly hundreds times
-                // faster than a normal successful call.
-                let err = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
-                    .err()
-                    .and_then(|e| e.raw_os_error());
-                // We don't check `err == Some(libc::ENOSYS)` because the syscall may be limited
-                // and returns `EPERM`. Listing all possible errors seems not a good idea.
-                // See: https://github.com/rust-lang/rust/issues/65662
-                if err != Some(libc::EFAULT) {
-                    STATX_STATE.store(1, Ordering::Relaxed);
-                    return None;
-                }
-                STATX_STATE.store(2, Ordering::Relaxed);
-            }
-            1 => return None,
-            _ => {}
         }
 
         let mut buf: libc::statx = mem::zeroed();
         if let Err(err) = cvt(statx(fd, path, flags, mask, &mut buf)) {
-            return Some(Err(err));
+            if STATX_SAVED_STATE.load(Ordering::Relaxed) == STATX_STATE::Present as u8 {
+                return Some(Err(err));
+            }
+
+            // Availability not checked yet.
+            //
+            // First try the cheap way.
+            if err.raw_os_error() == Some(libc::ENOSYS) {
+                STATX_SAVED_STATE.store(STATX_STATE::Unavailable as u8, Ordering::Relaxed);
+                return None;
+            }
+
+            // Error other than `ENOSYS` is not a good enough indicator -- it is
+            // known that `EPERM` can be returned as a result of using seccomp to
+            // block the syscall.
+            // Availability is checked by performing a call which expects `EFAULT`
+            // if the syscall is usable.
+            // See: https://github.com/rust-lang/rust/issues/65662
+            // FIXME this can probably just do the call if `EPERM` was received, but
+            // previous iteration of the code checked it for all errors and for now
+            // this is retained.
+            // FIXME what about transient conditions like `ENOMEM`?
+            let err2 = cvt(statx(0, ptr::null(), 0, libc::STATX_ALL, ptr::null_mut()))
+                .err()
+                .and_then(|e| e.raw_os_error());
+            if err2 == Some(libc::EFAULT) {
+                STATX_SAVED_STATE.store(STATX_STATE::Present as u8, Ordering::Relaxed);
+                return Some(Err(err));
+            } else {
+                STATX_SAVED_STATE.store(STATX_STATE::Unavailable as u8, Ordering::Relaxed);
+                return None;
+            }
         }
 
         // We cannot fill `stat64` exhaustively because of private padding fields.
@@ -600,13 +614,13 @@ impl Iterator for ReadDir {
             loop {
                 // As of POSIX.1-2017, readdir() is not required to be thread safe; only
                 // readdir_r() is. However, readdir_r() cannot correctly handle platforms
-                // with unlimited or variable NAME_MAX.  Many modern platforms guarantee
+                // with unlimited or variable NAME_MAX. Many modern platforms guarantee
                 // thread safety for readdir() as long an individual DIR* is not accessed
                 // concurrently, which is sufficient for Rust.
                 super::os::set_errno(0);
                 let entry_ptr = readdir64(self.inner.dirp.0);
                 if entry_ptr.is_null() {
-                    // We either encountered an error, or reached the end.  Either way,
+                    // We either encountered an error, or reached the end. Either way,
                     // the next call to next() should return None.
                     self.end_of_stream = true;
 

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

@@ -587,7 +587,7 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
                         // - copy_file_range file is immutable or syscall is blocked by seccomp¹ (EPERM)
                         // - copy_file_range cannot be used with pipes or device nodes (EINVAL)
                         // - the writer fd was opened with O_APPEND (EBADF²)
-                        // and no bytes were written successfully yet.  (All these errnos should
+                        // and no bytes were written successfully yet. (All these errnos should
                         // not be returned if something was already written, but they happen in
                         // the wild, see #91152.)
                         //

library/std/src/sys/unix/process/process_fuchsia.rs

@@ -262,7 +262,7 @@ impl ExitStatus {
     // available on Fuchsia.
     //
     // It does not appear that Fuchsia is Unix-like enough to implement ExitStatus (or indeed many
-    // other things from std::os::unix) properly.  This veneer is always going to be a bodge.  So
+    // other things from std::os::unix) properly. This veneer is always going to be a bodge. So
     // while I don't know if these implementations are actually correct, I think they will do for
     // now at least.
     pub fn core_dumped(&self) -> bool {
@@ -277,9 +277,9 @@ impl ExitStatus {
 
     pub fn into_raw(&self) -> c_int {
         // We don't know what someone who calls into_raw() will do with this value, but it should
-        // have the conventional Unix representation.  Despite the fact that this is not
+        // have the conventional Unix representation. Despite the fact that this is not
         // standardised in SuS or POSIX, all Unix systems encode the signal and exit status the
-        // same way.  (Ie the WIFEXITED, WEXITSTATUS etc. macros have identical behaviour on every
+        // same way. (Ie the WIFEXITED, WEXITSTATUS etc. macros have identical behaviour on every
         // Unix.)
         //
         // The caller of `std::os::unix::into_raw` is probably wanting a Unix exit status, and may
@@ -287,14 +287,14 @@ impl ExitStatus {
         // different Unix variant.
         //
         // The other view would be to say that the caller on Fuchsia ought to know that `into_raw`
-        // will give a raw Fuchsia status (whatever that is - I don't know, personally).  That is
+        // will give a raw Fuchsia status (whatever that is - I don't know, personally). That is
         // not possible here because we must return a c_int because that's what Unix (including
         // SuS and POSIX) say a wait status is, but Fuchsia apparently uses a u64, so it won't
         // necessarily fit.
         //
         // It seems to me that the right answer would be to provide std::os::fuchsia with its
         // own ExitStatusExt, rather that trying to provide a not very convincing imitation of
-        // Unix.  Ie, std::os::unix::process:ExitStatusExt ought not to exist on Fuchsia.  But
+        // Unix. Ie, std::os::unix::process:ExitStatusExt ought not to exist on Fuchsia. But
         // fixing this up that is beyond the scope of my efforts now.
         let exit_status_as_if_unix: u8 = self.0.try_into().expect("Fuchsia process return code bigger than 8 bits, but std::os::unix::ExitStatusExt::into_raw() was called to try to convert the value into a traditional Unix-style wait status, which cannot represent values greater than 255.");
         let wait_status_as_if_unix = (exit_status_as_if_unix as c_int) << 8;

library/std/src/sys/unix/process/process_unix.rs

@@ -666,11 +666,11 @@ impl ExitStatus {
     }
 
     pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
-        // This assumes that WIFEXITED(status) && WEXITSTATUS==0 corresponds to status==0.  This is
+        // This assumes that WIFEXITED(status) && WEXITSTATUS==0 corresponds to status==0. This is
         // true on all actual versions of Unix, is widely assumed, and is specified in SuS
-        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html .  If it is not
+        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html. If it is not
         // true for a platform pretending to be Unix, the tests (our doctests, and also
-        // procsss_unix/tests.rs) will spot it.  `ExitStatusError::code` assumes this too.
+        // procsss_unix/tests.rs) will spot it. `ExitStatusError::code` assumes this too.
         match NonZero_c_int::try_from(self.0) {
             /* was nonzero */ Ok(failure) => Err(ExitStatusError(failure)),
             /* was zero, couldn't convert */ Err(_) => Ok(()),

library/std/src/sys/unix/process/process_unix/tests.rs

@@ -19,17 +19,17 @@ fn exitstatus_display_tests() {
     t(0x00000, "exit status: 0");
     t(0x0ff00, "exit status: 255");
 
-    // On MacOS, 0x0137f is WIFCONTINUED, not WIFSTOPPED.  Probably *BSD is similar.
+    // On MacOS, 0x0137f is WIFCONTINUED, not WIFSTOPPED. Probably *BSD is similar.
     //   https://github.com/rust-lang/rust/pull/82749#issuecomment-790525956
     // The purpose of this test is to test our string formatting, not our understanding of the wait
-    // status magic numbers.  So restrict these to Linux.
+    // status magic numbers. So restrict these to Linux.
     if cfg!(target_os = "linux") {
         t(0x0137f, "stopped (not terminated) by signal: 19 (SIGSTOP)");
         t(0x0ffff, "continued (WIFCONTINUED)");
     }
 
     // Testing "unrecognised wait status" is hard because the wait.h macros typically
-    // assume that the value came from wait and isn't mad.  With the glibc I have here
+    // assume that the value came from wait and isn't mad. With the glibc I have here
     // this works:
     if cfg!(all(target_os = "linux", target_env = "gnu")) {
         t(0x000ff, "unrecognised wait status: 255 0xff");

library/std/src/sys/unix/process/process_vxworks.rs

@@ -195,11 +195,11 @@ impl ExitStatus {
     }
 
     pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
-        // This assumes that WIFEXITED(status) && WEXITSTATUS==0 corresponds to status==0.  This is
+        // This assumes that WIFEXITED(status) && WEXITSTATUS==0 corresponds to status==0. This is
         // true on all actual versions of Unix, is widely assumed, and is specified in SuS
-        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html .  If it is not
+        // https://pubs.opengroup.org/onlinepubs/9699919799/functions/wait.html. If it is not
         // true for a platform pretending to be Unix, the tests (our doctests, and also
-        // procsss_unix/tests.rs) will spot it.  `ExitStatusError::code` assumes this too.
+        // procsss_unix/tests.rs) will spot it. `ExitStatusError::code` assumes this too.
         match NonZero_c_int::try_from(self.0) {
             Ok(failure) => Err(ExitStatusError(failure)),
             Err(_) => Ok(()),

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

@@ -73,7 +73,7 @@ impl Thread {
                 n => {
                     assert_eq!(n, libc::EINVAL);
                     // EINVAL means |stack_size| is either too small or not a
-                    // multiple of the system page size.  Because it's definitely
+                    // multiple of the system page size. Because it's definitely
                     // >= PTHREAD_STACK_MIN, it must be an alignment issue.
                     // Round up to the nearest page and try again.
                     let page_size = os::page_size();
@@ -755,10 +755,10 @@ pub mod guard {
         if cfg!(all(target_os = "linux", not(target_env = "musl"))) {
             // Linux doesn't allocate the whole stack right away, and
             // the kernel has its own stack-guard mechanism to fault
-            // when growing too close to an existing mapping.  If we map
+            // when growing too close to an existing mapping. If we map
             // our own guard, then the kernel starts enforcing a rather
             // large gap above that, rendering much of the possible
-            // stack space useless.  See #43052.
+            // stack space useless. See #43052.
             //
             // Instead, we'll just note where we expect rlimit to start
             // faulting, so our handler can report "stack overflow", and
@@ -774,14 +774,14 @@ pub mod guard {
             None
         } else if cfg!(target_os = "freebsd") {
             // FreeBSD's stack autogrows, and optionally includes a guard page
-            // at the bottom.  If we try to remap the bottom of the stack
+            // at the bottom. If we try to remap the bottom of the stack
-            // ourselves, FreeBSD's guard page moves upwards.  So we'll just use
+            // ourselves, FreeBSD's guard page moves upwards. So we'll just use
             // the builtin guard page.
             let stackptr = get_stack_start_aligned()?;
             let guardaddr = stackptr.addr();
             // Technically the number of guard pages is tunable and controlled
             // by the security.bsd.stack_guard_page sysctl, but there are
-            // few reasons to change it from the default.  The default value has
+            // few reasons to change it from the default. The default value has
             // been 1 ever since FreeBSD 11.1 and 10.4.
             const GUARD_PAGES: usize = 1;
             let guard = guardaddr..guardaddr + GUARD_PAGES * page_size;
@@ -877,9 +877,9 @@ pub mod guard {
             } else if cfg!(all(target_os = "linux", any(target_env = "gnu", target_env = "uclibc")))
             {
                 // glibc used to include the guard area within the stack, as noted in the BUGS
-                // section of `man pthread_attr_getguardsize`.  This has been corrected starting
+                // section of `man pthread_attr_getguardsize`. This has been corrected starting
                 // with glibc 2.27, and in some distro backports, so the guard is now placed at the
-                // end (below) the stack.  There's no easy way for us to know which we have at
+                // end (below) the stack. There's no easy way for us to know which we have at
                 // runtime, so we'll just match any fault in the range right above or below the
                 // stack base to call that fault a stack overflow.
                 Some(stackaddr - guardsize..stackaddr + guardsize)

library/std/src/sys/windows/os.rs

@@ -157,7 +157,7 @@ impl<'a> Iterator for SplitPaths<'a> {
         // Double quotes are used as a way of introducing literal semicolons
         // (since c:\some;dir is a valid Windows path). Double quotes are not
         // themselves permitted in path names, so there is no way to escape a
-        // double quote.  Quoted regions can appear in arbitrary locations, so
+        // double quote. Quoted regions can appear in arbitrary locations, so
         //
         //   c:\foo;c:\som"e;di"r;c:\bar
         //

library/std/src/sys/windows/thread.rs

@@ -26,7 +26,7 @@ impl Thread {
 
         // FIXME On UNIX, we guard against stack sizes that are too small but
         // that's because pthreads enforces that stacks are at least
-        // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
+        // PTHREAD_STACK_MIN bytes big. Windows has no such lower limit, it's
         // just that below a certain threshold you can't do anything useful.
         // That threshold is application and architecture-specific, however.
         let ret = c::CreateThread(

library/test/src/lib.rs

@@ -116,7 +116,7 @@ pub fn test_main(args: &[String], tests: Vec<TestDescAndFn>, options: Option<Opt
     } else {
         if !opts.nocapture {
             // If we encounter a non-unwinding panic, flush any captured output from the current test,
-            // and stop  capturing output to ensure that the non-unwinding panic message is visible.
+            // and stop capturing output to ensure that the non-unwinding panic message is visible.
             // We also acquire the locks for both output streams to prevent output from other threads
             // from interleaving with the panic message or appearing after it.
             let builtin_panic_hook = panic::take_hook();

library/test/src/term/terminfo/searcher.rs

@@ -30,7 +30,7 @@ pub(crate) fn get_dbpath_for_term(term: &str) -> Option<PathBuf> {
         }
     } else {
         // Found nothing in TERMINFO_DIRS, use the default paths:
-        // According to  /etc/terminfo/README, after looking at
+        // According to /etc/terminfo/README, after looking at
         // ~/.terminfo, ncurses will search /etc/terminfo, then
         // /lib/terminfo, and eventually /usr/share/terminfo.
         // On Haiku the database can be found at /boot/system/data/terminfo

src/librustdoc/formats/cache.rs

@@ -242,7 +242,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
         }
 
         // Index this method for searching later on.
-        if let Some(ref s) = item.name.or_else(|| {
+        if let Some(s) = item.name.or_else(|| {
             if item.is_stripped() {
                 None
             } else if let clean::ImportItem(ref i) = *item.kind &&
@@ -317,14 +317,15 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                             short_markdown_summary(x.as_str(), &item.link_names(self.cache))
                         });
                         let ty = item.type_();
-                        let name = s.to_string();
+                        if ty != ItemType::StructField
-                        if ty != ItemType::StructField || u16::from_str_radix(&name, 10).is_err() {
+                            || u16::from_str_radix(s.as_str(), 10).is_err()
+                        {
                             // In case this is a field from a tuple struct, we don't add it into
                             // the search index because its name is something like "0", which is
                             // not useful for rustdoc search.
                             self.cache.search_index.push(IndexItem {
                                 ty,
-                                name,
+                                name: s,
                                 path: join_with_double_colon(path),
                                 desc,
                                 parent,

src/librustdoc/html/format.rs

@@ -569,7 +569,7 @@ fn generate_macro_def_id_path(
     root_path: Option<&str>,
 ) -> Result<(String, ItemType, Vec<Symbol>), HrefError> {
     let tcx = cx.shared.tcx;
-    let crate_name = tcx.crate_name(def_id.krate).to_string();
+    let crate_name = tcx.crate_name(def_id.krate);
     let cache = cx.cache();
 
     let fqp: Vec<Symbol> = tcx
@@ -584,7 +584,7 @@ fn generate_macro_def_id_path(
             }
         })
         .collect();
-    let mut relative = fqp.iter().map(|elem| elem.to_string());
+    let mut relative = fqp.iter().copied();
     let cstore = CStore::from_tcx(tcx);
     // We need this to prevent a `panic` when this function is used from intra doc links...
     if !cstore.has_crate_data(def_id.krate) {
@@ -602,9 +602,9 @@ fn generate_macro_def_id_path(
     };
 
     let mut path = if is_macro_2 {
-        once(crate_name.clone()).chain(relative).collect()
+        once(crate_name).chain(relative).collect()
     } else {
-        vec![crate_name.clone(), relative.next_back().unwrap()]
+        vec![crate_name, relative.next_back().unwrap()]
     };
     if path.len() < 2 {
         // The minimum we can have is the crate name followed by the macro name. If shorter, then
@@ -614,17 +614,22 @@ fn generate_macro_def_id_path(
     }
 
     if let Some(last) = path.last_mut() {
-        *last = format!("macro.{}.html", last);
+        *last = Symbol::intern(&format!("macro.{}.html", last.as_str()));
     }
 
     let url = match cache.extern_locations[&def_id.krate] {
         ExternalLocation::Remote(ref s) => {
             // `ExternalLocation::Remote` always end with a `/`.
-            format!("{}{}", s, path.join("/"))
+            format!("{}{}", s, path.iter().map(|p| p.as_str()).join("/"))
         }
         ExternalLocation::Local => {
             // `root_path` always end with a `/`.
-            format!("{}{}/{}", root_path.unwrap_or(""), crate_name, path.join("/"))
+            format!(
+                "{}{}/{}",
+                root_path.unwrap_or(""),
+                crate_name,
+                path.iter().map(|p| p.as_str()).join("/")
+            )
         }
         ExternalLocation::Unknown => {
             debug!("crate {} not in cache when linkifying macros", crate_name);
@@ -1050,7 +1055,7 @@ fn fmt_type<'cx>(
                 _ => String::new(),
             };
             let m = mutability.print_with_space();
-            let amp = if f.alternate() { "&".to_string() } else { "&amp;".to_string() };
+            let amp = if f.alternate() { "&" } else { "&amp;" };
             match **ty {
                 clean::DynTrait(ref bounds, ref trait_lt)
                     if bounds.len() > 1 || trait_lt.is_some() =>

src/librustdoc/html/markdown.rs

@@ -30,7 +30,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::HirId;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::edition::Edition;
-use rustc_span::Span;
+use rustc_span::{Span, Symbol};
 
 use once_cell::sync::Lazy;
 use std::borrow::Cow;
@@ -198,7 +198,7 @@ fn slugify(c: char) -> Option<char> {
 
 #[derive(Clone, Debug)]
 pub struct Playground {
-    pub crate_name: Option<String>,
+    pub crate_name: Option<Symbol>,
     pub url: String,
 }
 
@@ -290,7 +290,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 .map(|l| map_line(l).for_code())
                 .intersperse("\n".into())
                 .collect::<String>();
-            let krate = krate.as_ref().map(|s| &**s);
+            let krate = krate.as_ref().map(|s| s.as_str());
             let (test, _, _) =
                 doctest::make_test(&test, krate, false, &Default::default(), edition, None);
             let channel = if test.contains("#![feature(") { "&amp;version=nightly" } else { "" };

src/librustdoc/html/render/context.rs

@@ -464,8 +464,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         // If user passed in `--playground-url` arg, we fill in crate name here
         let mut playground = None;
         if let Some(url) = playground_url {
-            playground =
+            playground = Some(markdown::Playground { crate_name: Some(krate.name(tcx)), url });
-                Some(markdown::Playground { crate_name: Some(krate.name(tcx).to_string()), url });
         }
         let mut layout = layout::Layout {
             logo: String::new(),
@@ -491,7 +490,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
                 }
                 (sym::html_playground_url, Some(s)) => {
                     playground = Some(markdown::Playground {
-                        crate_name: Some(krate.name(tcx).to_string()),
+                        crate_name: Some(krate.name(tcx)),
                         url: s.to_string(),
                     });
                 }

src/librustdoc/html/render/mod.rs

@@ -100,7 +100,7 @@ pub(crate) fn ensure_trailing_slash(v: &str) -> impl fmt::Display + '_ {
 #[derive(Debug)]
 pub(crate) struct IndexItem {
     pub(crate) ty: ItemType,
-    pub(crate) name: String,
+    pub(crate) name: Symbol,
     pub(crate) path: String,
     pub(crate) desc: String,
     pub(crate) parent: Option<DefId>,
@@ -1343,7 +1343,7 @@ fn notable_traits_decl(ty: &clean::Type, cx: &Context<'_>) -> (String, String) {
                     write!(
                         &mut out,
                         "<h3>Notable traits for <code>{}</code></h3>\
-                     <pre class=\"content\"><code>",
+                     <pre><code>",
                         impl_.for_.print(cx)
                     );
                 }
@@ -2769,8 +2769,8 @@ fn collect_paths_for_type(first_ty: clean::Type, cache: &Cache) -> Vec<String> {
     let mut work = VecDeque::new();
 
     let mut process_path = |did: DefId| {
-        let get_extern = || cache.external_paths.get(&did).map(|s| s.0.clone());
+        let get_extern = || cache.external_paths.get(&did).map(|s| &s.0);
-        let fqp = cache.exact_paths.get(&did).cloned().or_else(get_extern);
+        let fqp = cache.exact_paths.get(&did).or_else(get_extern);
 
         if let Some(path) = fqp {
             out.push(join_with_double_colon(&path));

src/librustdoc/html/render/print_item.rs

@@ -1027,8 +1027,8 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
         .chain(std::iter::once("implementors"))
         .collect();
     if let Some(did) = it.item_id.as_def_id() &&
-        let get_extern = { || cache.external_paths.get(&did).map(|s| s.0.clone()) } &&
+        let get_extern = { || cache.external_paths.get(&did).map(|s| &s.0) } &&
-        let Some(fqp) = cache.exact_paths.get(&did).cloned().or_else(get_extern) {
+        let Some(fqp) = cache.exact_paths.get(&did).or_else(get_extern) {
         js_src_path.extend(fqp[..fqp.len() - 1].iter().copied());
         js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), fqp.last().unwrap()));
     } else {

src/librustdoc/html/render/search_index.rs

@@ -35,7 +35,7 @@ pub(crate) fn build_index<'tcx>(
                 .map_or_else(String::new, |s| short_markdown_summary(&s, &item.link_names(cache)));
             cache.search_index.push(IndexItem {
                 ty: item.type_(),
-                name: item.name.unwrap().to_string(),
+                name: item.name.unwrap(),
                 path: join_with_double_colon(&fqp[..fqp.len() - 1]),
                 desc,
                 parent: Some(parent),
@@ -58,8 +58,8 @@ pub(crate) fn build_index<'tcx>(
     // Sort search index items. This improves the compressibility of the search index.
     cache.search_index.sort_unstable_by(|k1, k2| {
         // `sort_unstable_by_key` produces lifetime errors
-        let k1 = (&k1.path, &k1.name, &k1.ty, &k1.parent);
+        let k1 = (&k1.path, k1.name.as_str(), &k1.ty, &k1.parent);
-        let k2 = (&k2.path, &k2.name, &k2.ty, &k2.parent);
+        let k2 = (&k2.path, k2.name.as_str(), &k2.ty, &k2.parent);
         std::cmp::Ord::cmp(&k1, &k2)
     });
 
@@ -240,7 +240,7 @@ pub(crate) fn build_index<'tcx>(
             )?;
             crate_data.serialize_field(
                 "n",
-                &self.items.iter().map(|item| &item.name).collect::<Vec<_>>(),
+                &self.items.iter().map(|item| item.name.as_str()).collect::<Vec<_>>(),
             )?;
             crate_data.serialize_field(
                 "q",
@@ -299,7 +299,7 @@ pub(crate) fn build_index<'tcx>(
             )?;
             crate_data.serialize_field(
                 "p",
-                &self.paths.iter().map(|(it, s)| (it, s.to_string())).collect::<Vec<_>>(),
+                &self.paths.iter().map(|(it, s)| (it, s.as_str())).collect::<Vec<_>>(),
             )?;
             if has_aliases {
                 crate_data.serialize_field("a", &self.aliases)?;

src/librustdoc/html/static/css/rustdoc.css

@@ -1214,11 +1214,11 @@ a.test-arrow:hover {
 	content: "\00a0";
 }
 
-.notable .docblock {
+.notable .content {
 	margin: 0.25em 0.5em;
 }
 
-.notable .docblock pre, .notable .docblock code {
+.notable .content pre, .notable .content code {
 	background: transparent;
 	margin: 0;
 	padding: 0;
@@ -1226,6 +1226,10 @@ a.test-arrow:hover {
 	white-space: pre-wrap;
 }
 
+.notable .content > h3:first-child {
+	margin: 0 0 5px 0;
+}
+
 .search-failed {
 	text-align: center;
 	margin-top: 20px;

src/librustdoc/html/static/js/main.js

@@ -847,7 +847,7 @@ function loadCss(cssUrl) {
         window.hideAllModals(false);
         const ty = e.getAttribute("data-ty");
         const wrapper = document.createElement("div");
-        wrapper.innerHTML = "<div class=\"docblock\">" + window.NOTABLE_TRAITS[ty] + "</div>";
+        wrapper.innerHTML = "<div class=\"content\">" + window.NOTABLE_TRAITS[ty] + "</div>";
         wrapper.className = "notable popover";
         const focusCatcher = document.createElement("div");
         focusCatcher.setAttribute("tabindex", "0");

src/tools/miri/tests/pass-dep/shims/libc-fs-with-isolation.rs

@@ -22,7 +22,8 @@ fn main() {
     }
 
     // test `stat`
-    assert_eq!(fs::metadata("foo.txt").unwrap_err().kind(), ErrorKind::PermissionDenied);
+    let err = fs::metadata("foo.txt").unwrap_err();
+    assert_eq!(err.kind(), ErrorKind::PermissionDenied);
     // check that it is the right kind of `PermissionDenied`
-    assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
+    assert_eq!(err.raw_os_error(), Some(libc::EACCES));
 }

tests/rustdoc/doc-notable_trait-slice.bare_fn_matches.html

@@ -1 +1 @@
-<script type="text/json" id="notable-traits-data">{"&amp;'static [SomeStruct]":"&lt;h3&gt;Notable traits for &lt;code&gt;&amp;amp;[&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait_slice::SomeStruct\"&gt;SomeStruct&lt;/a&gt;]&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait_slice::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &amp;amp;[&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait_slice::SomeStruct\"&gt;SomeStruct&lt;/a&gt;]&lt;/span&gt;"}</script>
+<script type="text/json" id="notable-traits-data">{"&amp;'static [SomeStruct]":"&lt;h3&gt;Notable traits for &lt;code&gt;&amp;amp;[&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait_slice::SomeStruct\"&gt;SomeStruct&lt;/a&gt;]&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait_slice::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &amp;amp;[&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait_slice::SomeStruct\"&gt;SomeStruct&lt;/a&gt;]&lt;/span&gt;"}</script>

tests/rustdoc/doc-notable_trait.bare-fn.html

@@ -1 +1 @@
-<script type="text/json" id="notable-traits-data">{"SomeStruct":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/span&gt;"}</script>
+<script type="text/json" id="notable-traits-data">{"SomeStruct":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/span&gt;"}</script>

tests/rustdoc/doc-notable_trait.some-struct-new.html

@@ -1 +1 @@
-<script type="text/json" id="notable-traits-data">{"SomeStruct":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/span&gt;","Wrapper&lt;Self&gt;":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl&amp;lt;T:&amp;nbsp;&lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt;&amp;gt; &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/span&gt;"}</script>
+<script type="text/json" id="notable-traits-data">{"SomeStruct":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.SomeStruct.html\" title=\"struct doc_notable_trait::SomeStruct\"&gt;SomeStruct&lt;/a&gt;&lt;/span&gt;","Wrapper&lt;Self&gt;":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl&amp;lt;T:&amp;nbsp;&lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt;&amp;gt; &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/span&gt;"}</script>

tests/rustdoc/doc-notable_trait.wrap-me.html

@@ -1 +1 @@
-<script type="text/json" id="notable-traits-data">{"Wrapper&lt;Self&gt;":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl&amp;lt;T:&amp;nbsp;&lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt;&amp;gt; &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/span&gt;"}</script>
+<script type="text/json" id="notable-traits-data">{"Wrapper&lt;Self&gt;":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl&amp;lt;T:&amp;nbsp;&lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt;&amp;gt; &lt;a class=\"trait\" href=\"trait.SomeTrait.html\" title=\"trait doc_notable_trait::SomeTrait\"&gt;SomeTrait&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Wrapper.html\" title=\"struct doc_notable_trait::Wrapper\"&gt;Wrapper&lt;/a&gt;&amp;lt;T&amp;gt;&lt;/span&gt;"}</script>

tests/rustdoc/spotlight-from-dependency.odd.html

@@ -1 +1 @@
-<script type="text/json" id="notable-traits-data">{"Odd":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Odd.html\" title=\"struct foo::Odd\"&gt;Odd&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre class=\"content\"&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"{{channel}}/core/iter/traits/iterator/trait.Iterator.html\" title=\"trait core::iter::traits::iterator::Iterator\"&gt;Iterator&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Odd.html\" title=\"struct foo::Odd\"&gt;Odd&lt;/a&gt;&lt;/span&gt;&lt;span class=\"where fmt-newline\"&gt;    type &lt;a href=\"{{channel}}/core/iter/traits/iterator/trait.Iterator.html#associatedtype.Item\" class=\"associatedtype\"&gt;Item&lt;/a&gt; = &lt;a class=\"primitive\" href=\"{{channel}}/std/primitive.usize.html\"&gt;usize&lt;/a&gt;;&lt;/span&gt;"}</script>
+<script type="text/json" id="notable-traits-data">{"Odd":"&lt;h3&gt;Notable traits for &lt;code&gt;&lt;a class=\"struct\" href=\"struct.Odd.html\" title=\"struct foo::Odd\"&gt;Odd&lt;/a&gt;&lt;/code&gt;&lt;/h3&gt;&lt;pre&gt;&lt;code&gt;&lt;span class=\"where fmt-newline\"&gt;impl &lt;a class=\"trait\" href=\"{{channel}}/core/iter/traits/iterator/trait.Iterator.html\" title=\"trait core::iter::traits::iterator::Iterator\"&gt;Iterator&lt;/a&gt; for &lt;a class=\"struct\" href=\"struct.Odd.html\" title=\"struct foo::Odd\"&gt;Odd&lt;/a&gt;&lt;/span&gt;&lt;span class=\"where fmt-newline\"&gt;    type &lt;a href=\"{{channel}}/core/iter/traits/iterator/trait.Iterator.html#associatedtype.Item\" class=\"associatedtype\"&gt;Item&lt;/a&gt; = &lt;a class=\"primitive\" href=\"{{channel}}/std/primitive.usize.html\"&gt;usize&lt;/a&gt;;&lt;/span&gt;"}</script>

tests/ui/const-generics/unused_braces.fixed

@@ -2,10 +2,17 @@
 // run-rustfix
 #![warn(unused_braces)]
 
+macro_rules! make_1 {
+    () => {
+        1
+    }
+}
+
 struct A<const N: usize>;
 
 fn main() {
     let _: A<7>; // ok
     let _: A<7>; //~ WARN unnecessary braces
     let _: A<{ 3 + 5 }>; // ok
+    let _: A<{make_1!()}>; // ok
 }

tests/ui/const-generics/unused_braces.rs

@@ -2,10 +2,17 @@
 // run-rustfix
 #![warn(unused_braces)]
 
+macro_rules! make_1 {
+    () => {
+        1
+    }
+}
+
 struct A<const N: usize>;
 
 fn main() {
     let _: A<7>; // ok
     let _: A<{ 7 }>; //~ WARN unnecessary braces
     let _: A<{ 3 + 5 }>; // ok
+    let _: A<{make_1!()}>; // ok
 }

tests/ui/const-generics/unused_braces.stderr

@@ -1,5 +1,5 @@
 warning: unnecessary braces around const expression
-  --> $DIR/unused_braces.rs:9:14
+  --> $DIR/unused_braces.rs:15:14
    |
 LL |     let _: A<{ 7 }>;
    |              ^^ ^^

tests/ui/inference/cannot-infer-partial-try-return.stderr

@@ -1,8 +1,6 @@
 error[E0282]: type annotations needed
   --> $DIR/cannot-infer-partial-try-return.rs:20:9
    |
-LL |         infallible()?;
-   |         ------------- type must be known at this point
 LL |         Ok(())
    |         ^^ cannot infer type of the type parameter `E` declared on the enum `Result`
    |

tests/ui/inference/question-mark-type-infer.stderr

@@ -1,8 +1,13 @@
 error[E0282]: type annotations needed
-  --> $DIR/question-mark-type-infer.rs:10:30
+  --> $DIR/question-mark-type-infer.rs:10:21
    |
 LL |     l.iter().map(f).collect()?
-   |                              ^ cannot infer type
+   |                     ^^^^^^^ cannot infer type of the type parameter `B` declared on the associated function `collect`
+   |
+help: consider specifying the generic argument
+   |
+LL |     l.iter().map(f).collect::<Vec<_>>()?
+   |                            ++++++++++
 
 error: aborting due to previous error
 

tests/ui/issues/issue-69455.stderr

@@ -1,14 +1,16 @@
-error[E0282]: type annotations needed
+error[E0284]: type annotations needed
-  --> $DIR/issue-69455.rs:29:20
+  --> $DIR/issue-69455.rs:29:41
    |
 LL |     println!("{}", 23u64.test(xs.iter().sum()));
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the associated function `new_display`
+   |                          ----           ^^^ cannot infer type of the type parameter `S` declared on the associated function `sum`
+   |                          |
+   |                          type must be known at this point
    |
-   = note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = note: cannot satisfy `<u64 as Test<_>>::Output == _`
 help: consider specifying the generic argument
    |
-LL |     println!("{}", 23u64.test(xs.iter().sum())::<T>);
+LL |     println!("{}", 23u64.test(xs.iter().sum::<S>()));
-   |                                               +++++
+   |                                            +++++
 
 error[E0283]: type annotations needed
   --> $DIR/issue-69455.rs:29:41
@@ -33,5 +35,5 @@ LL |     println!("{}", 23u64.test(xs.iter().sum::<S>()));
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0282, E0283.
+Some errors have detailed explanations: E0283, E0284.
-For more information about an error, try `rustc --explain E0282`.
+For more information about an error, try `rustc --explain E0283`.

tests/ui/type/type-check/cannot_infer_local_or_vec_in_tuples.stderr

@@ -2,7 +2,7 @@ error[E0282]: type annotations needed for `(Vec<T>,)`
   --> $DIR/cannot_infer_local_or_vec_in_tuples.rs:2:9
    |
 LL |     let (x, ) = (vec![], );
-   |         ^^^^^
+   |         ^^^^^   ---------- type must be known at this point
    |
 help: consider giving this pattern a type, where the type for type parameter `T` is specified
    |