Merge pull request #20128 from lnicola/sync-from-rust

Sync from downstream

4 files changed, 110 insertions, 5 deletions

diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index aa9e5fce1d4..d50ce02bda7 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -1517,9 +1517,7 @@ impl<T: Ord, const N: usize> From<[T; N]> for BTreeSet<T> {
 
         // use stable sort to preserve the insertion order.
         arr.sort();
-        let iter = IntoIterator::into_iter(arr).map(|k| (k, SetValZST::default()));
-        let map = BTreeMap::bulk_build_from_sorted_iter(iter, Global);
-        BTreeSet { map }
+        BTreeSet::from_sorted_iter(IntoIterator::into_iter(arr), Global)
     }
 }
 
diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs
index 48849bf7536..93bdad75380 100644
--- a/library/alloc/src/ffi/c_str.rs
+++ b/library/alloc/src/ffi/c_str.rs
@@ -1099,6 +1099,46 @@ impl From<&CStr> for CString {
     }
 }
 
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<CStr> for CString {
+    #[inline]
+    fn eq(&self, other: &CStr) -> bool {
+        **self == *other
+    }
+
+    #[inline]
+    fn ne(&self, other: &CStr) -> bool {
+        **self != *other
+    }
+}
+
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<&CStr> for CString {
+    #[inline]
+    fn eq(&self, other: &&CStr) -> bool {
+        **self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &&CStr) -> bool {
+        **self != **other
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<Cow<'_, CStr>> for CString {
+    #[inline]
+    fn eq(&self, other: &Cow<'_, CStr>) -> bool {
+        **self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &Cow<'_, CStr>) -> bool {
+        **self != **other
+    }
+}
+
 #[stable(feature = "cstring_asref", since = "1.7.0")]
 impl ops::Index<ops::RangeFull> for CString {
     type Output = CStr;
@@ -1181,6 +1221,75 @@ impl CStr {
     }
 }
 
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<CString> for CStr {
+    #[inline]
+    fn eq(&self, other: &CString) -> bool {
+        *self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &CString) -> bool {
+        *self != **other
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<Cow<'_, Self>> for CStr {
+    #[inline]
+    fn eq(&self, other: &Cow<'_, Self>) -> bool {
+        *self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &Cow<'_, Self>) -> bool {
+        *self != **other
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<CStr> for Cow<'_, CStr> {
+    #[inline]
+    fn eq(&self, other: &CStr) -> bool {
+        **self == *other
+    }
+
+    #[inline]
+    fn ne(&self, other: &CStr) -> bool {
+        **self != *other
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<&CStr> for Cow<'_, CStr> {
+    #[inline]
+    fn eq(&self, other: &&CStr) -> bool {
+        **self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &&CStr) -> bool {
+        **self != **other
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "c_string_eq_c_str", since = "CURRENT_RUSTC_VERSION")]
+impl PartialEq<CString> for Cow<'_, CStr> {
+    #[inline]
+    fn eq(&self, other: &CString) -> bool {
+        **self == **other
+    }
+
+    #[inline]
+    fn ne(&self, other: &CString) -> bool {
+        **self != **other
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl core::error::Error for NulError {
     #[allow(deprecated)]
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 4b8ea708e7e..010d17f7476 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -3004,7 +3004,6 @@ pub struct Weak<
     // `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
     // will ever have because RcInner has alignment at least 2.
-    // This is only possible when `T: Sized`; unsized `T` never dangle.
     ptr: NonNull<RcInner<T>>,
     alloc: A,
 }
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 17090925cfa..1e3c03977bd 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -342,7 +342,6 @@ pub struct Weak<
     // `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
     // will ever have because RcInner has alignment at least 2.
-    // This is only possible when `T: Sized`; unsized `T` never dangle.
     ptr: NonNull<ArcInner<T>>,
     alloc: A,
 }