Merge from rustc

Author: The Miri Cronjob Bot

Cargo.lock

@@ -10,7 +10,7 @@ edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "=0.1.145", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "=0.1.146", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = { version = "0.8.5", default-features = false, features = ["alloc"] }

alloc/Cargo.toml

@@ -10,7 +10,7 @@ use core::hint;
 #[cfg(not(test))]
 use core::ptr::{self, NonNull};
 
-extern "Rust" {
+unsafe extern "Rust" {
     // 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
@@ -355,7 +355,7 @@ unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
 // # Allocation error handler
 
 #[cfg(not(no_global_oom_handling))]
-extern "Rust" {
+unsafe extern "Rust" {
     // 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.
@@ -426,7 +426,7 @@ pub mod __alloc_error_handler {
     // `#[alloc_error_handler]`.
     #[rustc_std_internal_symbol]
     pub unsafe fn __rdl_oom(size: usize, _align: usize) -> ! {
-        extern "Rust" {
+        unsafe extern "Rust" {
             // This symbol is emitted by rustc next to __rust_alloc_error_handler.
             // Its value depends on the -Zoom={panic,abort} compiler option.
             static __rust_alloc_error_handler_should_panic: u8;

alloc/src/alloc.rs

@@ -74,7 +74,7 @@ impl<I: Iterator> MergeIterInner<I> {
                 b_next = self.b.next();
             }
         }
-        if let (Some(ref a1), Some(ref b1)) = (&a_next, &b_next) {
+        if let (Some(a1), Some(b1)) = (&a_next, &b_next) {
             match cmp(a1, b1) {
                 Ordering::Less => self.peeked = b_next.take().map(Peeked::B),
                 Ordering::Greater => self.peeked = a_next.take().map(Peeked::A),

alloc/src/collections/btree/merge_iter.rs

@@ -132,9 +132,11 @@ fn test_difference() {
     check_difference(&[1, 3, 5, 9, 11], &[3, 6, 9], &[1, 5, 11]);
     check_difference(&[1, 3, 5, 9, 11], &[0, 1], &[3, 5, 9, 11]);
     check_difference(&[1, 3, 5, 9, 11], &[11, 12], &[1, 3, 5, 9]);
-    check_difference(&[-5, 11, 22, 33, 40, 42], &[-12, -5, 14, 23, 34, 38, 39, 50], &[
-        11, 22, 33, 40, 42,
-    ]);
+    check_difference(
+        &[-5, 11, 22, 33, 40, 42],
+        &[-12, -5, 14, 23, 34, 38, 39, 50],
+        &[11, 22, 33, 40, 42],
+    );
 
     if cfg!(miri) {
         // Miri is too slow
@@ -250,9 +252,11 @@ fn test_union() {
     check_union(&[], &[], &[]);
     check_union(&[1, 2, 3], &[2], &[1, 2, 3]);
     check_union(&[2], &[1, 2, 3], &[1, 2, 3]);
-    check_union(&[1, 3, 5, 9, 11, 16, 19, 24], &[-2, 1, 5, 9, 13, 19], &[
-        -2, 1, 3, 5, 9, 11, 13, 16, 19, 24,
-    ]);
+    check_union(
+        &[1, 3, 5, 9, 11, 16, 19, 24],
+        &[-2, 1, 5, 9, 13, 19],
+        &[-2, 1, 3, 5, 9, 11, 13, 16, 19, 24],
+    );
 }
 
 #[test]

alloc/src/collections/btree/set/tests.rs

@@ -696,9 +696,10 @@ fn test_cursor_mut_insert() {
     cursor.splice_after(p);
     cursor.splice_before(q);
     check_links(&m);
-    assert_eq!(m.iter().cloned().collect::<Vec<_>>(), &[
-        200, 201, 202, 203, 1, 100, 101, 102, 103, 8, 2, 3, 4, 5, 6
-    ]);
+    assert_eq!(
+        m.iter().cloned().collect::<Vec<_>>(),
+        &[200, 201, 202, 203, 1, 100, 101, 102, 103, 8, 2, 3, 4, 5, 6]
+    );
     let mut cursor = m.cursor_front_mut();
     cursor.move_prev();
     let tmp = cursor.split_before();
@@ -915,9 +916,10 @@ fn extract_if_complex() {
         assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
 
         assert_eq!(list.len(), 14);
-        assert_eq!(list.into_iter().collect::<Vec<_>>(), vec![
-            1, 7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39
-        ]);
+        assert_eq!(
+            list.into_iter().collect::<Vec<_>>(),
+            vec![1, 7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]
+        );
     }
 
     {
@@ -932,9 +934,10 @@ fn extract_if_complex() {
         assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
 
         assert_eq!(list.len(), 13);
-        assert_eq!(list.into_iter().collect::<Vec<_>>(), vec![
-            7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39
-        ]);
+        assert_eq!(
+            list.into_iter().collect::<Vec<_>>(),
+            vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35, 37, 39]
+        );
     }
 
     {
@@ -949,9 +952,10 @@ fn extract_if_complex() {
         assert_eq!(removed, vec![2, 4, 6, 18, 20, 22, 24, 26, 34, 36]);
 
         assert_eq!(list.len(), 11);
-        assert_eq!(list.into_iter().collect::<Vec<_>>(), vec![
-            7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35
-        ]);
+        assert_eq!(
+            list.into_iter().collect::<Vec<_>>(),
+            vec![7, 9, 11, 13, 15, 17, 27, 29, 31, 33, 35]
+        );
     }
 
     {

alloc/src/collections/linked_list/tests.rs

@@ -562,9 +562,10 @@ fn make_contiguous_head_to_end() {
         tester.push_front(i as char);
     }
 
-    assert_eq!(tester, [
-        'P', 'O', 'N', 'M', 'L', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K'
-    ]);
+    assert_eq!(
+        tester,
+        ['P', 'O', 'N', 'M', 'L', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K']
+    );
 
     // ABCDEFGHIJKPONML
     let expected_start = 0;

alloc/src/collections/vec_deque/tests.rs

@@ -397,7 +397,7 @@ impl CString {
         // information about the size of the allocation is correct on Rust's
         // side.
         unsafe {
-            extern "C" {
+            unsafe extern "C" {
                 /// Provided by libc or compiler_builtins.
                 fn strlen(s: *const c_char) -> usize;
             }
@@ -965,8 +965,9 @@ impl Default for Rc<CStr> {
     /// This may or may not share an allocation with other Rcs on the same thread.
     #[inline]
     fn default() -> Self {
-        let c_str: &CStr = Default::default();
-        Rc::from(c_str)
+        let rc = Rc::<[u8]>::from(*b"\0");
+        // `[u8]` has the same layout as `CStr`, and it is `NUL` terminated.
+        unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
     }
 }
 

alloc/src/ffi/c_str.rs

@@ -156,7 +156,6 @@
 #![feature(unicode_internals)]
 #![feature(unsize)]
 #![feature(unwrap_infallible)]
-#![feature(vec_pop_if)]
 // tidy-alphabetical-end
 //
 // Language features:

alloc/src/lib.rs

@@ -1462,18 +1462,18 @@ impl<T: ?Sized, A: Allocator> Rc<T, A> {
     /// Provides a raw pointer to the data.
     ///
     /// The counts are not affected in any way and the `Rc` is not consumed. The pointer is valid
-    /// for as long there are strong counts in the `Rc`.
+    /// for as long as there are strong counts in the `Rc`.
     ///
     /// # Examples
     ///
     /// ```
     /// use std::rc::Rc;
     ///
-    /// let x = Rc::new("hello".to_owned());
+    /// let x = Rc::new(0);
     /// let y = Rc::clone(&x);
     /// let x_ptr = Rc::as_ptr(&x);
     /// assert_eq!(x_ptr, Rc::as_ptr(&y));
-    /// assert_eq!(unsafe { &*x_ptr }, "hello");
+    /// assert_eq!(unsafe { *x_ptr }, 0);
     /// ```
     #[stable(feature = "weak_into_raw", since = "1.45.0")]
     #[rustc_never_returns_null_ptr]
@@ -2350,11 +2350,10 @@ impl<T: Default> Default for Rc<T> {
     fn default() -> Rc<T> {
         unsafe {
             Self::from_inner(
-                Box::leak(Box::write(Box::new_uninit(), RcInner {
-                    strong: Cell::new(1),
-                    weak: Cell::new(1),
-                    value: T::default(),
-                }))
+                Box::leak(Box::write(
+                    Box::new_uninit(),
+                    RcInner { strong: Cell::new(1), weak: Cell::new(1), value: T::default() },
+                ))
                 .into(),
             )
         }
@@ -2369,7 +2368,9 @@ impl Default for Rc<str> {
     /// This may or may not share an allocation with other Rcs on the same thread.
     #[inline]
     fn default() -> Self {
-        Rc::from("")
+        let rc = Rc::<[u8]>::default();
+        // `[u8]` has the same layout as `str`.
+        unsafe { Rc::from_raw(Rc::into_raw(rc) as *const str) }
     }
 }