Auto merge of #72727 - JohnTitor:rollup-nni16m2, r=JohnTitor

Rollup of 11 pull requests

Successful merges:

 - #71633 (Impl Error for Infallible)
 - #71843 (Tweak and stabilize AtomicN::fetch_update)
 - #72288 (Stabilization of weak-into-raw)
 - #72324 (Stabilize AtomicN::fetch_min and AtomicN::fetch_max)
 - #72452 (Clarified the documentation for Formatter::precision)
 - #72495 (Improve E0601 explanation)
 - #72534 (Improve missing `@` in slice binding pattern diagnostics)
 - #72547 (Added a codegen test for a recent optimization for overflow-checks=on)
 - #72711 (remove redundant `mk_const`)
 - #72713 (Whitelist #[allow_internal_unstable])
 - #72720 (Clarify the documentation of `take`)

Failed merges:

r? @ghost

src/liballoc/rc.rs

@@ -580,8 +580,6 @@ impl<T: ?Sized> Rc<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::rc::Rc;
     ///
     /// let x = Rc::new("hello".to_owned());
@@ -590,7 +588,7 @@ impl<T: ?Sized> Rc<T> {
     /// assert_eq!(x_ptr, Rc::as_ptr(&y));
     /// assert_eq!(unsafe { &*x_ptr }, "hello");
     /// ```
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(this: &Self) -> *const T {
         let ptr: *mut RcBox<T> = NonNull::as_ptr(this.ptr);
         let fake_ptr = ptr as *mut T;
@@ -1681,8 +1679,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::rc::Rc;
     /// use std::ptr;
     ///
@@ -1700,7 +1696,7 @@ impl<T> Weak<T> {
     /// ```
     ///
     /// [`null`]: ../../std/ptr/fn.null.html
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(&self) -> *const T {
         let offset = data_offset_sized::<T>();
         let ptr = self.ptr.cast::<u8>().as_ptr().wrapping_offset(offset);
@@ -1718,8 +1714,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::rc::{Rc, Weak};
     ///
     /// let strong = Rc::new("hello".to_owned());
@@ -1735,7 +1729,7 @@ impl<T> Weak<T> {
     ///
     /// [`from_raw`]: struct.Weak.html#method.from_raw
     /// [`as_ptr`]: struct.Weak.html#method.as_ptr
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn into_raw(self) -> *const T {
         let result = self.as_ptr();
         mem::forget(self);
@@ -1762,8 +1756,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::rc::{Rc, Weak};
     ///
     /// let strong = Rc::new("hello".to_owned());
@@ -1788,7 +1780,7 @@ impl<T> Weak<T> {
     /// [`Weak`]: struct.Weak.html
     /// [`new`]: struct.Weak.html#method.new
     /// [`forget`]: ../../std/mem/fn.forget.html
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub unsafe fn from_raw(ptr: *const T) -> Self {
         if ptr.is_null() {
             Self::new()

src/liballoc/sync.rs

@@ -579,8 +579,6 @@ impl<T: ?Sized> Arc<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::sync::Arc;
     ///
     /// let x = Arc::new("hello".to_owned());
@@ -589,7 +587,7 @@ impl<T: ?Sized> Arc<T> {
     /// assert_eq!(x_ptr, Arc::as_ptr(&y));
     /// assert_eq!(unsafe { &*x_ptr }, "hello");
     /// ```
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(this: &Self) -> *const T {
         let ptr: *mut ArcInner<T> = NonNull::as_ptr(this.ptr);
         let fake_ptr = ptr as *mut T;
@@ -1449,8 +1447,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::sync::Arc;
     /// use std::ptr;
     ///
@@ -1468,7 +1464,7 @@ impl<T> Weak<T> {
     /// ```
     ///
     /// [`null`]: ../../std/ptr/fn.null.html
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn as_ptr(&self) -> *const T {
         let offset = data_offset_sized::<T>();
         let ptr = self.ptr.cast::<u8>().as_ptr().wrapping_offset(offset);
@@ -1486,8 +1482,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::sync::{Arc, Weak};
     ///
     /// let strong = Arc::new("hello".to_owned());
@@ -1503,7 +1497,7 @@ impl<T> Weak<T> {
     ///
     /// [`from_raw`]: struct.Weak.html#method.from_raw
     /// [`as_ptr`]: struct.Weak.html#method.as_ptr
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub fn into_raw(self) -> *const T {
         let result = self.as_ptr();
         mem::forget(self);
@@ -1531,8 +1525,6 @@ impl<T> Weak<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(weak_into_raw)]
-    ///
     /// use std::sync::{Arc, Weak};
     ///
     /// let strong = Arc::new("hello".to_owned());
@@ -1557,7 +1549,7 @@ impl<T> Weak<T> {
     /// [`Weak`]: struct.Weak.html
     /// [`Arc`]: struct.Arc.html
     /// [`forget`]: ../../std/mem/fn.forget.html
-    #[unstable(feature = "weak_into_raw", issue = "60728")]
+    #[stable(feature = "weak_into_raw", since = "1.45.0")]
     pub unsafe fn from_raw(ptr: *const T) -> Self {
         if ptr.is_null() {
             Self::new()

src/libcore/fmt/mod.rs

@@ -1618,7 +1618,8 @@ impl<'a> Formatter<'a> {
         self.width
     }
 
-    /// Optionally specified precision for numeric types.
+    /// Optionally specified precision for numeric types. Alternatively, the
+    /// maximum width for string types.
     ///
     /// # Examples
     ///

src/libcore/iter/traits/iterator.rs

@@ -1180,6 +1180,17 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(2));
     /// assert_eq!(iter.next(), None);
     /// ```
+    ///
+    /// If less than `n` elements are available,
+    /// `take` will limit itself to the size of the underlying iterator:
+    ///
+    /// ```
+    /// let v = vec![1, 2];
+    /// let mut iter = v.into_iter().take(5);
+    /// assert_eq!(iter.next(), Some(1));
+    /// assert_eq!(iter.next(), Some(2));
+    /// assert_eq!(iter.next(), None);
+    /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn take(self, n: usize) -> Take<Self>

src/libcore/sync/atomic.rs

@@ -1807,13 +1807,12 @@ new value. Returns a `Result` of `Ok(previous_value)` if the function returned `
 
 Note: This may call the function multiple times if the value has been changed from other threads in
 the meantime, as long as the function returns `Some(_)`, but the function will have been applied
-but once to the stored value.
+only once to the stored value.
 
-`fetch_update` takes two [`Ordering`] arguments to describe the memory
-ordering of this operation. The first describes the required ordering for loads
-and failed updates while the second describes the required ordering when the
-operation finally succeeds. Beware that this is different from the two
-modes in [`compare_exchange`]!
+`fetch_update` takes two [`Ordering`] arguments to describe the memory ordering of this operation.
+The first describes the required ordering for when the operation finally succeeds while the second
+describes the required ordering for loads. These correspond to the success and failure orderings of
+[`compare_exchange`] respectively.
 
 Using [`Acquire`] as success ordering makes the store part
 of this operation [`Relaxed`], and using [`Release`] makes the final successful load
@@ -1831,24 +1830,21 @@ and must be equivalent to or weaker than the success ordering.
 # Examples
 
 ```rust
-#![feature(no_more_cas)]
 ", $extra_feature, "use std::sync::atomic::{", stringify!($atomic_type), ", Ordering};
 
 let x = ", stringify!($atomic_type), "::new(7);
-assert_eq!(x.fetch_update(|_| None, Ordering::SeqCst, Ordering::SeqCst), Err(7));
-assert_eq!(x.fetch_update(|x| Some(x + 1), Ordering::SeqCst, Ordering::SeqCst), Ok(7));
-assert_eq!(x.fetch_update(|x| Some(x + 1), Ordering::SeqCst, Ordering::SeqCst), Ok(8));
+assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |_| None), Err(7));
+assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |x| Some(x + 1)), Ok(7));
+assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |x| Some(x + 1)), Ok(8));
 assert_eq!(x.load(Ordering::SeqCst), 9);
 ```"),
                 #[inline]
-                #[unstable(feature = "no_more_cas",
-                       reason = "no more CAS loops in user code",
-                       issue = "48655")]
+                #[stable(feature = "no_more_cas", since = "1.45.0")]
                 #[$cfg_cas]
                 pub fn fetch_update<F>(&self,
-                                       mut f: F,
+                                       set_order: Ordering,
                                        fetch_order: Ordering,
-                                       set_order: Ordering) -> Result<$int_type, $int_type>
+                                       mut f: F) -> Result<$int_type, $int_type>
                 where F: FnMut($int_type) -> Option<$int_type> {
                     let mut prev = self.load(fetch_order);
                     while let Some(next) = f(prev) {
@@ -1882,7 +1878,6 @@ using [`Release`] makes the load part [`Relaxed`].
 # Examples
 
 ```
-#![feature(atomic_min_max)]
 ", $extra_feature, "use std::sync::atomic::{", stringify!($atomic_type), ", Ordering};
 
 let foo = ", stringify!($atomic_type), "::new(23);
@@ -1893,7 +1888,6 @@ assert_eq!(foo.load(Ordering::SeqCst), 42);
 If you want to obtain the maximum value in one step, you can use the following:
 
 ```
-#![feature(atomic_min_max)]
 ", $extra_feature, "use std::sync::atomic::{", stringify!($atomic_type), ", Ordering};
 
 let foo = ", stringify!($atomic_type), "::new(23);
@@ -1902,9 +1896,7 @@ let max_foo = foo.fetch_max(bar, Ordering::SeqCst).max(bar);
 assert!(max_foo == 42);
 ```"),
                 #[inline]
-                #[unstable(feature = "atomic_min_max",
-                       reason = "easier and faster min/max than writing manual CAS loop",
-                       issue = "48655")]
+                #[stable(feature = "atomic_min_max", since = "1.45.0")]
                 #[$cfg_cas]
                 pub fn fetch_max(&self, val: $int_type, order: Ordering) -> $int_type {
                     // SAFETY: data races are prevented by atomic intrinsics.
@@ -1933,7 +1925,6 @@ using [`Release`] makes the load part [`Relaxed`].
 # Examples
 
 ```
-#![feature(atomic_min_max)]
 ", $extra_feature, "use std::sync::atomic::{", stringify!($atomic_type), ", Ordering};
 
 let foo = ", stringify!($atomic_type), "::new(23);
@@ -1946,7 +1937,6 @@ assert_eq!(foo.load(Ordering::Relaxed), 22);
 If you want to obtain the minimum value in one step, you can use the following:
 
 ```
-#![feature(atomic_min_max)]
 ", $extra_feature, "use std::sync::atomic::{", stringify!($atomic_type), ", Ordering};
 
 let foo = ", stringify!($atomic_type), "::new(23);
@@ -1955,9 +1945,7 @@ let min_foo = foo.fetch_min(bar, Ordering::SeqCst).min(bar);
 assert_eq!(min_foo, 12);
 ```"),
                 #[inline]
-                #[unstable(feature = "atomic_min_max",
-                       reason = "easier and faster min/max than writing manual CAS loop",
-                       issue = "48655")]
+                #[stable(feature = "atomic_min_max", since = "1.45.0")]
                 #[$cfg_cas]
                 pub fn fetch_min(&self, val: $int_type, order: Ordering) -> $int_type {
                     // SAFETY: data races are prevented by atomic intrinsics.

src/librustc_error_codes/error_codes/E0601.md

@@ -1,5 +1,6 @@
-No `main` function was found in a binary crate. To fix this error, add a
-`main` function. For example:
+No `main` function was found in a binary crate.
+
+To fix this error, add a `main` function:
 
 ```
 fn main() {

src/librustc_feature/builtin_attrs.rs

@@ -366,7 +366,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // FIXME(#14407)
     ungated!(rustc_const_stable, Whitelisted, template!(List: r#"feature = "name""#)),
     gated!(
-        allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."),
+        allow_internal_unstable, Whitelisted, template!(Word, List: "feat1, feat2, ..."),
         "allow_internal_unstable side-steps feature gating and stability checks",
     ),
     gated!(

src/librustc_mir/transform/const_prop.rs

@@ -606,7 +606,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
         Operand::Constant(Box::new(Constant {
             span,
             user_ty: None,
-            literal: self.tcx.mk_const(*ty::Const::from_scalar(self.tcx, scalar, ty)),
+            literal: ty::Const::from_scalar(self.tcx, scalar, ty),
         }))
     }
 

src/librustc_parse/parser/mod.rs

@@ -672,6 +672,26 @@ impl<'a> Parser<'a> {
                                 }
                             }
 
+                            // If this was a missing `@` in a binding pattern
+                            // bail with a suggestion
+                            // https://github.com/rust-lang/rust/issues/72373
+                            if self.prev_token.is_ident() && &self.token.kind == &token::DotDot {
+                                let msg = format!(
+                                    "if you meant to bind the contents of \
+                                    the rest of the array pattern into `{}`, use `@`",
+                                    pprust::token_to_string(&self.prev_token)
+                                );
+                                expect_err
+                                    .span_suggestion_verbose(
+                                        self.prev_token.span.shrink_to_hi().until(self.token.span),
+                                        &msg,
+                                        " @ ".to_string(),
+                                        Applicability::MaybeIncorrect,
+                                    )
+                                    .emit();
+                                break;
+                            }
+
                             // Attempt to keep parsing if it was an omitted separator.
                             match f(self) {
                                 Ok(t) => {

src/libstd/error.rs

@@ -14,6 +14,7 @@
 // reconsider what crate these items belong in.
 
 use core::array;
+use core::convert::Infallible;
 
 use crate::alloc::{AllocErr, LayoutErr};
 use crate::any::TypeId;
@@ -474,7 +475,7 @@ impl Error for string::FromUtf16Error {
 }
 
 #[stable(feature = "str_parse_error2", since = "1.8.0")]
-impl Error for string::ParseError {
+impl Error for Infallible {
     fn description(&self) -> &str {
         match *self {}
     }

src/test/codegen/integer-overflow.rs

@@ -0,0 +1,26 @@
+// no-system-llvm
+// compile-flags: -O -C overflow-checks=on
+
+#![crate_type = "lib"]
+
+
+pub struct S1<'a> {
+    data: &'a [u8],
+    position: usize,
+}
+
+// CHECK-LABEL: @slice_no_index_order
+#[no_mangle]
+pub fn slice_no_index_order<'a>(s: &'a mut S1, n: usize) -> &'a [u8] {
+    // CHECK-NOT: slice_index_order_fail
+    let d = &s.data[s.position..s.position+n];
+    s.position += n;
+    return d;
+}
+
+// CHECK-LABEL: @test_check
+#[no_mangle]
+pub fn test_check<'a>(s: &'a mut S1, x: usize, y: usize) -> &'a [u8] {
+    // CHECK: slice_index_order_fail
+    &s.data[x..y]
+}

src/test/ui/issues/issue-72373.rs

@@ -0,0 +1,9 @@
+fn foo(c: &[u32], n: u32) -> u32 {
+    match *c {
+        [h, ..] if h > n => 0,
+        [h, ..] if h == n => 1,
+        [h, ref ts..] => foo(c, n - h) + foo(ts, n),
+        //~^ ERROR expected one of `,`, `@`, `]`, or `|`, found `..`
+        [] => 0,
+    }
+}

src/test/ui/issues/issue-72373.stderr

@@ -0,0 +1,13 @@
+error: expected one of `,`, `@`, `]`, or `|`, found `..`
+  --> $DIR/issue-72373.rs:5:19
+   |
+LL |         [h, ref ts..] => foo(c, n - h) + foo(ts, n),
+   |                   ^^ expected one of `,`, `@`, `]`, or `|`
+   |
+help: if you meant to bind the contents of the rest of the array pattern into `ts`, use `@`
+   |
+LL |         [h, ref ts @ ..] => foo(c, n - h) + foo(ts, n),
+   |                    ^
+
+error: aborting due to previous error
+