Auto merge of #93499 - matthiaskrgr:rollup-icdex11, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #93395 (Improve suggestion for escaping reserved keywords)
 - #93403 (review the total_cmp documentation)
 - #93461 (Accommodate yield points in the format_args expansion)
 - #93462 (Document `SystemTime` platform precision)
 - #93471 (unix: Use metadata for `DirEntry::file_type` fallback)
 - #93480 (Remove deprecated and unstable slice_partition_at_index functions)
 - #93485 (core: Remove some redundant {}s from the sorting code)
 - #93494 (kmc-solid: Inherit the calling task's base priority in `Thread::new`)

Failed merges:

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

compiler/rustc_builtin_macros/src/format.rs

@@ -4,6 +4,7 @@ use Position::*;
 use rustc_ast as ast;
 use rustc_ast::ptr::P;
 use rustc_ast::tokenstream::TokenStream;
+use rustc_ast::visit::{self, Visitor};
 use rustc_ast::{token, BlockCheckMode, UnsafeSource};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::{pluralize, Applicability, DiagnosticBuilder};
@@ -788,17 +789,31 @@ impl<'a, 'b> Context<'a, 'b> {
         // the order provided to fmt::Arguments. When arguments are repeated, we
         // want the expression evaluated only once.
         //
-        // Thus in the not nicely ordered case we emit the following instead:
+        // Further, if any arg _after the first one_ contains a yield point such
+        // as `await` or `yield`, the above short form is inconvenient for the
+        // caller because it would keep a temporary of type ArgumentV1 alive
+        // across the yield point. ArgumentV1 can't implement Send since it
+        // holds a type-erased arbitrary type.
+        //
+        // Thus in the not nicely ordered case, and in the yielding case, we
+        // emit the following instead:
         //
         //     match (&$arg0, &$arg1, …) {
         //         args => [ArgumentV1::new(args.$i, …), ArgumentV1::new(args.$j, …), …]
         //     }
         //
         // for the sequence of indices $i, $j, … governed by fmt_arg_index_and_ty.
+        // This more verbose representation ensures that all arguments are
+        // evaluated a single time each, in the order written by the programmer,
+        // and that the surrounding future/generator (if any) is Send whenever
+        // possible.
+        let no_need_for_match =
+            nicely_ordered && !original_args.iter().skip(1).any(|e| may_contain_yield_point(e));
+
         for (arg_index, arg_ty) in fmt_arg_index_and_ty {
             let e = &mut original_args[arg_index];
             let span = e.span;
-            let arg = if nicely_ordered {
+            let arg = if no_need_for_match {
                 let expansion_span = e.span.with_ctxt(self.macsp.ctxt());
                 // The indices are strictly ordered so e has not been taken yet.
                 self.ecx.expr_addr_of(expansion_span, P(e.take()))
@@ -814,10 +829,10 @@ impl<'a, 'b> Context<'a, 'b> {
         let args_array = self.ecx.expr_vec(self.macsp, fmt_args);
         let args_slice = self.ecx.expr_addr_of(
             self.macsp,
-            if nicely_ordered {
+            if no_need_for_match {
                 args_array
             } else {
-                // In the !nicely_ordered case, none of the exprs were moved
+                // In the !no_need_for_match case, none of the exprs were moved
                 // away in the previous loop.
                 //
                 // This uses the arg span for `&arg` so that borrowck errors
@@ -1226,3 +1241,35 @@ pub fn expand_preparsed_format_args(
 
     cx.into_expr()
 }
+
+fn may_contain_yield_point(e: &ast::Expr) -> bool {
+    struct MayContainYieldPoint(bool);
+
+    impl Visitor<'_> for MayContainYieldPoint {
+        fn visit_expr(&mut self, e: &ast::Expr) {
+            if let ast::ExprKind::Await(_) | ast::ExprKind::Yield(_) = e.kind {
+                self.0 = true;
+            } else {
+                visit::walk_expr(self, e);
+            }
+        }
+
+        fn visit_mac_call(&mut self, _: &ast::MacCall) {
+            self.0 = true;
+        }
+
+        fn visit_attribute(&mut self, _: &ast::Attribute) {
+            // Conservatively assume this may be a proc macro attribute in
+            // expression position.
+            self.0 = true;
+        }
+
+        fn visit_item(&mut self, _: &ast::Item) {
+            // Do not recurse into nested items.
+        }
+    }
+
+    let mut visitor = MayContainYieldPoint(false);
+    visitor.visit_expr(e);
+    visitor.0
+}

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -192,10 +192,10 @@ impl<'a> Parser<'a> {
                 if ident.is_raw_guess()
                     && self.look_ahead(1, |t| valid_follow.contains(&t.kind)) =>
             {
-                err.span_suggestion(
-                    ident.span,
-                    "you can escape reserved keywords to use them as identifiers",
-                    format!("r#{}", ident.name),
+                err.span_suggestion_verbose(
+                    ident.span.shrink_to_lo(),
+                    &format!("escape `{}` to use it as an identifier", ident.name),
+                    "r#".to_owned(),
                     Applicability::MaybeIncorrect,
                 );
             }

library/core/src/num/f32.rs

@@ -1008,29 +1008,37 @@ impl f32 {
         Self::from_bits(u32::from_ne_bytes(bytes))
     }
 
-    /// Returns an ordering between self and other values.
+    /// Return the ordering between `self` and `other`.
+    ///
     /// Unlike the standard partial comparison between floating point numbers,
     /// this comparison always produces an ordering in accordance to
-    /// the totalOrder predicate as defined in IEEE 754 (2008 revision)
-    /// floating point standard. The values are ordered in following order:
-    /// - Negative quiet NaN
-    /// - Negative signaling NaN
-    /// - Negative infinity
-    /// - Negative numbers
-    /// - Negative subnormal numbers
-    /// - Negative zero
-    /// - Positive zero
-    /// - Positive subnormal numbers
-    /// - Positive numbers
-    /// - Positive infinity
-    /// - Positive signaling NaN
-    /// - Positive quiet NaN
-    ///
-    /// Note that this function does not always agree with the [`PartialOrd`]
-    /// and [`PartialEq`] implementations of `f32`. In particular, they regard
-    /// negative and positive zero as equal, while `total_cmp` doesn't.
+    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
+    /// floating point standard. The values are ordered in the following sequence:
+    ///
+    /// - negative quiet NaN
+    /// - negative signaling NaN
+    /// - negative infinity
+    /// - negative numbers
+    /// - negative subnormal numbers
+    /// - negative zero
+    /// - positive zero
+    /// - positive subnormal numbers
+    /// - positive numbers
+    /// - positive infinity
+    /// - positive signaling NaN
+    /// - positive quiet NaN.
+    ///
+    /// The ordering established by this function does not always agree with the
+    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
+    /// they consider negative and positive zero equal, while `total_cmp`
+    /// doesn't.
+    ///
+    /// The interpretation of the signaling NaN bit follows the definition in
+    /// the IEEE 754 standard, which may not match the interpretation by some of
+    /// the older, non-conformant (e.g. MIPS) hardware implementations.
     ///
     /// # Example
+    ///
     /// ```
     /// #![feature(total_cmp)]
     /// struct GoodBoy {

library/core/src/num/f64.rs

@@ -1024,29 +1024,37 @@ impl f64 {
         Self::from_bits(u64::from_ne_bytes(bytes))
     }
 
-    /// Returns an ordering between self and other values.
+    /// Return the ordering between `self` and `other`.
+    ///
     /// Unlike the standard partial comparison between floating point numbers,
     /// this comparison always produces an ordering in accordance to
-    /// the totalOrder predicate as defined in IEEE 754 (2008 revision)
-    /// floating point standard. The values are ordered in following order:
-    /// - Negative quiet NaN
-    /// - Negative signaling NaN
-    /// - Negative infinity
-    /// - Negative numbers
-    /// - Negative subnormal numbers
-    /// - Negative zero
-    /// - Positive zero
-    /// - Positive subnormal numbers
-    /// - Positive numbers
-    /// - Positive infinity
-    /// - Positive signaling NaN
-    /// - Positive quiet NaN
-    ///
-    /// Note that this function does not always agree with the [`PartialOrd`]
-    /// and [`PartialEq`] implementations of `f64`. In particular, they regard
-    /// negative and positive zero as equal, while `total_cmp` doesn't.
+    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
+    /// floating point standard. The values are ordered in the following sequence:
+    ///
+    /// - negative quiet NaN
+    /// - negative signaling NaN
+    /// - negative infinity
+    /// - negative numbers
+    /// - negative subnormal numbers
+    /// - negative zero
+    /// - positive zero
+    /// - positive subnormal numbers
+    /// - positive numbers
+    /// - positive infinity
+    /// - positive signaling NaN
+    /// - positive quiet NaN.
+    ///
+    /// The ordering established by this function does not always agree with the
+    /// [`PartialOrd`] and [`PartialEq`] implementations of `f64`. For example,
+    /// they consider negative and positive zero equal, while `total_cmp`
+    /// doesn't.
+    ///
+    /// The interpretation of the signaling NaN bit follows the definition in
+    /// the IEEE 754 standard, which may not match the interpretation by some of
+    /// the older, non-conformant (e.g. MIPS) hardware implementations.
     ///
     /// # Example
+    ///
     /// ```
     /// #![feature(total_cmp)]
     /// struct GoodBoy {

library/core/src/slice/mod.rs

@@ -2558,50 +2558,6 @@ impl<T> [T] {
         sort::quicksort(self, |a, b| f(a).lt(&f(b)));
     }
 
-    /// Reorder the slice such that the element at `index` is at its final sorted position.
-    #[unstable(feature = "slice_partition_at_index", issue = "55300")]
-    #[rustc_deprecated(since = "1.49.0", reason = "use the select_nth_unstable() instead")]
-    #[inline]
-    pub fn partition_at_index(&mut self, index: usize) -> (&mut [T], &mut T, &mut [T])
-    where
-        T: Ord,
-    {
-        self.select_nth_unstable(index)
-    }
-
-    /// Reorder the slice with a comparator function such that the element at `index` is at its
-    /// final sorted position.
-    #[unstable(feature = "slice_partition_at_index", issue = "55300")]
-    #[rustc_deprecated(since = "1.49.0", reason = "use select_nth_unstable_by() instead")]
-    #[inline]
-    pub fn partition_at_index_by<F>(
-        &mut self,
-        index: usize,
-        compare: F,
-    ) -> (&mut [T], &mut T, &mut [T])
-    where
-        F: FnMut(&T, &T) -> Ordering,
-    {
-        self.select_nth_unstable_by(index, compare)
-    }
-
-    /// Reorder the slice with a key extraction function such that the element at `index` is at its
-    /// final sorted position.
-    #[unstable(feature = "slice_partition_at_index", issue = "55300")]
-    #[rustc_deprecated(since = "1.49.0", reason = "use the select_nth_unstable_by_key() instead")]
-    #[inline]
-    pub fn partition_at_index_by_key<K, F>(
-        &mut self,
-        index: usize,
-        f: F,
-    ) -> (&mut [T], &mut T, &mut [T])
-    where
-        F: FnMut(&T) -> K,
-        K: Ord,
-    {
-        self.select_nth_unstable_by_key(index, f)
-    }
-
     /// Reorder the slice such that the element at `index` is at its final sorted position.
     ///
     /// This reordering has the additional property that any value at position `i < index` will be

library/core/src/slice/sort.rs

@@ -773,7 +773,7 @@ where
                 let mid = partition_equal(v, pivot, is_less);
 
                 // Continue sorting elements greater than the pivot.
-                v = &mut { v }[mid..];
+                v = &mut v[mid..];
                 continue;
             }
         }
@@ -784,7 +784,7 @@ where
         was_partitioned = was_p;
 
         // Split the slice into `left`, `pivot`, and `right`.
-        let (left, right) = { v }.split_at_mut(mid);
+        let (left, right) = v.split_at_mut(mid);
         let (pivot, right) = right.split_at_mut(1);
         let pivot = &pivot[0];
 
@@ -860,7 +860,7 @@ fn partition_at_index_loop<'a, T, F>(
         let (mid, _) = partition(v, pivot, is_less);
 
         // Split the slice into `left`, `pivot`, and `right`.
-        let (left, right) = { v }.split_at_mut(mid);
+        let (left, right) = v.split_at_mut(mid);
         let (pivot, right) = right.split_at_mut(1);
         let pivot = &pivot[0];
 

library/core/tests/lib.rs

@@ -46,7 +46,6 @@
 #![feature(is_sorted)]
 #![feature(pattern)]
 #![feature(sort_internals)]
-#![feature(slice_partition_at_index)]
 #![feature(slice_take)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(maybe_uninit_array_assume_init)]

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

@@ -84,10 +84,6 @@ impl Thread {
     ///
     /// See `thread::Builder::spawn_unchecked` for safety requirements.
     pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
-        // Inherit the current task's priority
-        let current_task = task::try_current_task_id().map_err(|e| e.as_io_error())?;
-        let priority = task::try_task_priority(current_task).map_err(|e| e.as_io_error())?;
-
         let inner = Box::new(ThreadInner {
             start: UnsafeCell::new(ManuallyDrop::new(p)),
             lifecycle: AtomicUsize::new(LIFECYCLE_INIT),
@@ -175,7 +171,8 @@ impl Thread {
                 exinf: inner_ptr as abi::EXINF,
                 // The entry point
                 task: Some(trampoline),
-                itskpri: priority,
+                // Inherit the calling task's base priority
+                itskpri: abi::TPRI_SELF,
                 stksz: stack,
                 // Let the kernel allocate the stack,
                 stk: crate::ptr::null_mut(),

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

@@ -598,7 +598,7 @@ impl DirEntry {
         target_os = "vxworks"
     ))]
     pub fn file_type(&self) -> io::Result<FileType> {
-        lstat(&self.path()).map(|m| m.file_type())
+        self.metadata().map(|m| m.file_type())
     }
 
     #[cfg(not(any(
@@ -616,7 +616,7 @@ impl DirEntry {
             libc::DT_SOCK => Ok(FileType { mode: libc::S_IFSOCK }),
             libc::DT_DIR => Ok(FileType { mode: libc::S_IFDIR }),
             libc::DT_BLK => Ok(FileType { mode: libc::S_IFBLK }),
-            _ => lstat(&self.path()).map(|m| m.file_type()),
+            _ => self.metadata().map(|m| m.file_type()),
         }
     }
 

library/std/src/time.rs

@@ -176,7 +176,12 @@ pub struct Instant(time::Instant);
 /// }
 /// ```
 ///
-/// # Underlying System calls
+/// # Platform-specific behavior
+///
+/// The precision of `SystemTime` can depend on the underlying OS-specific time format.
+/// For example, on Windows the time is represented in 100 nanosecond intervals whereas Linux
+/// can represent nanosecond intervals.
+///
 /// Currently, the following system calls are being used to get the current time using `now()`:
 ///
 /// |  Platform |               System call                                            |