Trait core::marker::Sync

1.0.0 · source ·
pub unsafe auto trait Sync { }
Expand description

可以在线程之间安全共享引用的类型。

当编译器确定适当时,会自动实现此 trait。

确切的定义是:当且仅当 &TSend 时,类型 T 才是 Sync。 换句话说,如果在线程之间传递 &T 引用时没有 未定义的行为 (包括数据竞争) 的可能性。

正如人们所料,像 u8f64 这样的原始类型都是 Sync,包含它们的简单聚合类型也是如此,比如元组、结构体和枚举。 基本 Sync 类型的更多示例包括不可变类型 (例如 &T) 以及具有简单继承的可变性的类型,例如 Box<T>Vec<T> 和大多数其他集合类型。

(泛型参数必须为 Sync,才能使其容器为 [Sync]。)

该定义的一个令人惊讶的结果是 &mut TSync (如果 TSync),即使看起来可能提供了不同步的可变的。 诀窍是,共享引用 (即 & &mut T) 后面的可变引用将变为只读,就好像它是 & &T 一样。 因此,没有数据竞争的风险。

SyncSend 与引用的关系的简短概述:

  • &TSend 当且仅当 TSync
  • &mut TSend 当且仅当 TSend
  • &T&mut TSync 当且仅当 TSync

不是 Sync 的类型是具有非线程安全形式的 “内部可变性” 的类型,例如 CellRefCell。 这些类型甚至允许通过不可变,共享引用来更改其内容。 例如,Cell<T> 上的 set 方法采用 &self,因此它仅需要共享的引用 &Cell<T>。 该方法不执行同步,因此 Cell 不能为 Sync

另一个非 Sync 类型的例子是引用计数指针 Rc。 给定任何引用 &Rc<T>,您可以克隆新的 Rc<T>,以非原子方式修改引用计数。

对于确实需要线程安全的内部可变性的情况,Rust 提供 原子数据类型 以及通过 sync::Mutexsync::RwLock 进行的显式锁定。 这些类型可确保任何可变的都不会引起数据竞争,因此类型为 Sync。 同样,sync::Arc 提供了 Rc 的线程安全模拟。

任何具有内部可变性的类型还必须在值周围使用 cell::UnsafeCell 包装器,该包装器可以通过共享引用进行转变。 不这样做是 未定义的行为。 例如,从 &T&mut Ttransmute 无效。

有关 Sync 的更多详细信息,请参见 the Nomicon

Implementors§

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impl Sync for AtomicBool

1.34.0 · source§

impl Sync for AtomicI8

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impl Sync for AtomicI16

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impl Sync for AtomicI32

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impl Sync for AtomicI64

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impl Sync for AtomicIsize

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impl Sync for AtomicU8

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impl Sync for AtomicU16

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impl Sync for AtomicU32

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impl Sync for AtomicU64

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impl Sync for AtomicUsize

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impl Sync for Waker

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impl<Dyn: ?Sized> Sync for DynMetadata<Dyn>

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impl<T> !Sync for OnceCell<T>

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impl<T> Sync for ChunksExactMut<'_, T>where T: Sync,

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impl<T> Sync for ChunksMut<'_, T>where T: Sync,

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impl<T> Sync for RChunksExactMut<'_, T>where T: Sync,

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impl<T> Sync for RChunksMut<'_, T>where T: Sync,

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impl<T> Sync for AtomicPtr<T>

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impl<T: Sync> Sync for core::slice::Iter<'_, T>

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impl<T: Sync> Sync for core::slice::IterMut<'_, T>

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impl<T: ?Sized + Sync> Sync for SyncUnsafeCell<T>

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impl<T: ?Sized> !Sync for *const T

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impl<T: ?Sized> !Sync for *mut T

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impl<T: ?Sized> !Sync for Cell<T>

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impl<T: ?Sized> !Sync for RefCell<T>

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impl<T: ?Sized> !Sync for UnsafeCell<T>

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impl<T: ?Sized> !Sync for NonNull<T>

NonNull 指针不是 Sync,因为它们引用的数据可能是别名。

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impl<T: ?Sized> Sync for Exclusive<T>

Auto implementors§

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impl !Sync for RawWaker

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impl Sync for AsciiChar

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impl Sync for core::cmp::Ordering

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impl Sync for Infallible

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impl Sync for c_void

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impl Sync for core::fmt::Alignment

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impl Sync for IpAddr

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impl Sync for Ipv6MulticastScope

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impl Sync for SocketAddr

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impl Sync for FpCategory

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impl Sync for IntErrorKind

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impl Sync for Which

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impl Sync for SearchStep

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impl Sync for core::sync::atomic::Ordering

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impl Sync for bool

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impl Sync for char

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impl Sync for f32

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impl Sync for f64

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impl Sync for i8

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impl Sync for i16

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impl Sync for i32

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impl Sync for i64

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impl Sync for i128

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impl Sync for isize

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impl Sync for str

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impl Sync for u8

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impl Sync for u16

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impl Sync for u32

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impl Sync for u64

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impl Sync for u128

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impl Sync for ()

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impl Sync for usize

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impl Sync for AllocError

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impl Sync for Layout

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impl Sync for LayoutError

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impl Sync for TypeId

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impl Sync for float64x1_t

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impl Sync for float64x1x2_t

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impl Sync for float64x1x3_t

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impl Sync for float64x1x4_t

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impl Sync for float64x2_t

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impl Sync for float64x2x2_t

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impl Sync for float64x2x3_t

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impl Sync for float64x2x4_t

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impl Sync for int16x2_t

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impl Sync for uint16x2_t

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impl Sync for APSR

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impl Sync for SY

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impl Sync for float32x2_t

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impl Sync for float32x2x2_t

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impl Sync for float32x2x3_t

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impl Sync for float32x2x4_t

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impl Sync for float32x4_t

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impl Sync for float32x4x2_t

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impl Sync for float32x4x3_t

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impl Sync for float32x4x4_t

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impl Sync for int8x4_t

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impl Sync for int8x8_t

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impl Sync for int8x8x2_t

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impl Sync for int8x8x3_t

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impl Sync for int8x8x4_t

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impl Sync for int8x16_t

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impl Sync for int8x16x2_t

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impl Sync for int8x16x3_t

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impl Sync for int8x16x4_t

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impl Sync for int16x4_t

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impl Sync for int16x4x2_t

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impl Sync for int16x4x3_t

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impl Sync for int16x4x4_t

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impl Sync for int16x8_t

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impl Sync for int16x8x2_t

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impl Sync for int16x8x3_t

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impl Sync for int16x8x4_t

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impl Sync for int32x2_t

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impl Sync for int32x2x2_t

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impl Sync for int32x2x3_t

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impl Sync for int32x2x4_t

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impl Sync for int32x4_t

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impl Sync for int32x4x2_t

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impl Sync for int32x4x3_t

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impl Sync for int32x4x4_t

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impl Sync for int64x1_t

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impl Sync for int64x1x2_t

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impl Sync for int64x1x3_t

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impl Sync for int64x1x4_t

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impl Sync for int64x2_t

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impl Sync for int64x2x2_t

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impl Sync for int64x2x3_t

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impl Sync for int64x2x4_t

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impl Sync for poly8x8_t

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impl Sync for poly8x8x2_t

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impl Sync for poly8x8x3_t

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impl Sync for poly8x8x4_t

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impl Sync for poly8x16_t

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impl Sync for poly8x16x2_t

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impl Sync for poly8x16x3_t

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impl Sync for poly8x16x4_t

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impl Sync for poly16x4_t

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impl Sync for poly16x4x2_t

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impl Sync for poly16x4x3_t

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impl Sync for poly16x4x4_t

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impl Sync for poly16x8_t

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impl Sync for poly16x8x2_t

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impl Sync for poly16x8x3_t

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impl Sync for poly16x8x4_t

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impl Sync for poly64x1_t

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impl Sync for poly64x1x2_t

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impl Sync for poly64x1x3_t

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impl Sync for poly64x1x4_t

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impl Sync for poly64x2_t

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impl Sync for poly64x2x2_t

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impl Sync for poly64x2x3_t

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impl Sync for poly64x2x4_t

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impl Sync for uint8x4_t

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impl Sync for uint8x8_t

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impl Sync for uint8x8x2_t

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impl Sync for uint8x8x3_t

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impl Sync for uint8x8x4_t

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impl Sync for uint8x16_t

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impl Sync for uint8x16x2_t

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impl Sync for uint8x16x3_t

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impl Sync for uint8x16x4_t

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impl Sync for uint16x4_t

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impl Sync for uint16x4x2_t

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impl Sync for uint16x4x3_t

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impl Sync for uint16x4x4_t

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impl Sync for uint16x8_t

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impl Sync for uint16x8x2_t

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impl Sync for uint16x8x3_t

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impl Sync for uint16x8x4_t

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impl Sync for uint32x2_t

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impl Sync for uint32x2x2_t

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impl Sync for uint32x2x3_t

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impl Sync for uint32x2x4_t

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impl Sync for uint32x4_t

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impl Sync for uint32x4x2_t

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impl Sync for uint32x4x3_t

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impl Sync for uint32x4x4_t

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impl Sync for uint64x1_t

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impl Sync for uint64x1x2_t

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impl Sync for uint64x1x3_t

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impl Sync for uint64x1x4_t

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impl Sync for uint64x2_t

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impl Sync for uint64x2x2_t

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impl Sync for uint64x2x3_t

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impl Sync for uint64x2x4_t

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impl Sync for vector_bool_char

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impl Sync for vector_bool_int

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impl Sync for vector_bool_long

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impl Sync for vector_bool_short

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impl Sync for vector_double

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impl Sync for vector_float

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impl Sync for vector_signed_char

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impl Sync for vector_signed_int

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impl Sync for vector_signed_long

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impl Sync for vector_signed_short

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impl Sync for vector_unsigned_char

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impl Sync for vector_unsigned_int

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impl Sync for vector_unsigned_long

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impl Sync for vector_unsigned_short

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impl Sync for v128

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impl Sync for CpuidResult

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impl Sync for __m128

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impl Sync for __m128bh

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impl Sync for __m128d

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impl Sync for __m128i

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impl Sync for __m256

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impl Sync for __m256bh

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impl Sync for __m256d

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impl Sync for __m256i

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impl Sync for __m512

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impl Sync for __m512bh

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impl Sync for __m512d

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impl Sync for __m512i

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impl Sync for TryFromSliceError

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impl Sync for core::ascii::EscapeDefault

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impl Sync for BorrowError

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impl Sync for BorrowMutError

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impl Sync for CharTryFromError

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impl Sync for DecodeUtf16Error

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impl Sync for core::char::EscapeDebug

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impl Sync for core::char::EscapeDefault

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impl Sync for core::char::EscapeUnicode

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impl Sync for ParseCharError

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impl Sync for ToLowercase

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impl Sync for ToUppercase

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impl Sync for TryFromCharError

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impl Sync for CStr

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impl Sync for FromBytesUntilNulError

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impl Sync for FromBytesWithNulError

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impl Sync for Error

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impl Sync for SipHasher

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impl Sync for BasicBlock

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impl Sync for Assume

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impl Sync for AddrParseError

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impl Sync for Ipv4Addr

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impl Sync for Ipv6Addr

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impl Sync for SocketAddrV4

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impl Sync for SocketAddrV6

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impl Sync for NonZeroI8

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impl Sync for NonZeroI16

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impl Sync for NonZeroI32

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impl Sync for NonZeroI64

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impl Sync for NonZeroI128

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impl Sync for NonZeroIsize

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impl Sync for NonZeroU8

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impl Sync for NonZeroU16

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impl Sync for NonZeroU32

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impl Sync for NonZeroU64

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impl Sync for NonZeroU128

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impl Sync for NonZeroUsize

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impl Sync for ParseFloatError

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impl Sync for ParseIntError

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impl Sync for TryFromIntError

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impl Sync for RangeFull

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impl Sync for core::ptr::Alignment

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impl Sync for TimSortRun

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impl Sync for ParseBoolError

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impl Sync for Utf8Error

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impl Sync for RawWakerVTable

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impl Sync for Duration

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impl Sync for TryFromFloatSecsError

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impl Sync for PhantomPinned

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impl<'a> !Sync for Demand<'a>

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impl<'a> !Sync for Source<'a>

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impl<'a> !Sync for Arguments<'a>

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impl<'a> !Sync for Formatter<'a>

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impl<'a> !Sync for PanicInfo<'a>

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impl<'a> !Sync for Context<'a>

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impl<'a> Sync for Location<'a>

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impl<'a> Sync for EscapeAscii<'a>

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impl<'a> Sync for CharSearcher<'a>

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impl<'a> Sync for Bytes<'a>

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impl<'a> Sync for CharIndices<'a>

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impl<'a> Sync for Chars<'a>

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impl<'a> Sync for EncodeUtf16<'a>

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impl<'a> Sync for core::str::EscapeDebug<'a>

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impl<'a> Sync for core::str::EscapeDefault<'a>

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impl<'a> Sync for core::str::EscapeUnicode<'a>

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impl<'a> Sync for Lines<'a>

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impl<'a> Sync for LinesAny<'a>

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impl<'a> Sync for SplitAsciiWhitespace<'a>

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impl<'a> Sync for SplitWhitespace<'a>

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impl<'a> Sync for Utf8Chunk<'a>

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impl<'a> Sync for Utf8Chunks<'a>

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impl<'a, 'b> !Sync for DebugList<'a, 'b>

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impl<'a, 'b> !Sync for DebugMap<'a, 'b>

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impl<'a, 'b> !Sync for DebugSet<'a, 'b>

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impl<'a, 'b> !Sync for DebugStruct<'a, 'b>

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impl<'a, 'b> !Sync for DebugTuple<'a, 'b>

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impl<'a, 'b> Sync for CharSliceSearcher<'a, 'b>

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impl<'a, 'b> Sync for StrSearcher<'a, 'b>

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impl<'a, 'b, const N: usize> Sync for CharArrayRefSearcher<'a, 'b, N>

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impl<'a, 'f> !Sync for VaList<'a, 'f>

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impl<'a, A> Sync for core::option::Iter<'a, A>where A: Sync,

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impl<'a, A> Sync for core::option::IterMut<'a, A>where A: Sync,

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impl<'a, F> Sync for CharPredicateSearcher<'a, F>where F: Sync,

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impl<'a, I> Sync for ByRefSized<'a, I>where I: Sync,

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impl<'a, P> Sync for MatchIndices<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for Matches<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for RMatchIndices<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for RMatches<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for core::str::RSplit<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for core::str::RSplitN<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for RSplitTerminator<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for core::str::Split<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for core::str::SplitInclusive<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for core::str::SplitN<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, P> Sync for SplitTerminator<'a, P>where <P as Pattern<'a>>::Searcher: Sync,

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impl<'a, T> Sync for core::result::Iter<'a, T>where T: Sync,

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impl<'a, T> Sync for core::result::IterMut<'a, T>where T: Sync,

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impl<'a, T> Sync for Chunks<'a, T>where T: Sync,

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impl<'a, T> Sync for ChunksExact<'a, T>where T: Sync,

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impl<'a, T> Sync for RChunks<'a, T>where T: Sync,

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impl<'a, T> Sync for RChunksExact<'a, T>where T: Sync,

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impl<'a, T> Sync for Windows<'a, T>where T: Sync,

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impl<'a, T, P> Sync for GroupBy<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for GroupByMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for core::slice::RSplit<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for RSplitMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for core::slice::RSplitN<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for RSplitNMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for core::slice::Split<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for core::slice::SplitInclusive<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for SplitInclusiveMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for SplitMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for core::slice::SplitN<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, P> Sync for SplitNMut<'a, T, P>where P: Sync, T: Sync,

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impl<'a, T, const N: usize> !Sync for ArrayWindows<'a, T, N>

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impl<'a, T, const N: usize> Sync for core::slice::ArrayChunks<'a, T, N>where T: Sync,

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impl<'a, T, const N: usize> Sync for ArrayChunksMut<'a, T, N>where T: Sync,

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impl<'a, const N: usize> Sync for CharArraySearcher<'a, N>

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impl<'b, T> !Sync for Ref<'b, T>

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impl<'b, T> !Sync for RefMut<'b, T>

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impl<'f> !Sync for VaListImpl<'f>

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impl<A> Sync for Repeat<A>where A: Sync,

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impl<A> Sync for core::option::IntoIter<A>where A: Sync,

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impl<A, B> Sync for Chain<A, B>where A: Sync, B: Sync,

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impl<A, B> Sync for Zip<A, B>where A: Sync, B: Sync,

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impl<B, C> Sync for ControlFlow<B, C>where B: Sync, C: Sync,

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impl<F> Sync for PollFn<F>where F: Sync,

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impl<F> Sync for FromFn<F>where F: Sync,

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impl<F> Sync for OnceWith<F>where F: Sync,

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impl<F> Sync for RepeatWith<F>where F: Sync,

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impl<H> Sync for BuildHasherDefault<H>

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impl<I> Sync for FromIter<I>where I: Sync,

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impl<I> Sync for DecodeUtf16<I>where I: Sync,

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impl<I> Sync for Cloned<I>where I: Sync,

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impl<I> Sync for Copied<I>where I: Sync,

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impl<I> Sync for Cycle<I>where I: Sync,

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impl<I> Sync for Enumerate<I>where I: Sync,

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impl<I> Sync for Flatten<I>where I: Sync, <<I as Iterator>::Item as IntoIterator>::IntoIter: Sync,

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impl<I> Sync for Fuse<I>where I: Sync,

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impl<I> Sync for Intersperse<I>where I: Sync, <I as Iterator>::Item: Sync,

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impl<I> Sync for Peekable<I>where I: Sync, <I as Iterator>::Item: Sync,

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impl<I> Sync for Skip<I>where I: Sync,

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impl<I> Sync for StepBy<I>where I: Sync,

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impl<I> Sync for Take<I>where I: Sync,

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impl<I, F> Sync for FilterMap<I, F>where F: Sync, I: Sync,

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impl<I, F> Sync for Inspect<I, F>where F: Sync, I: Sync,

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impl<I, F> Sync for Map<I, F>where F: Sync, I: Sync,

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impl<I, G> Sync for IntersperseWith<I, G>where G: Sync, I: Sync, <I as Iterator>::Item: Sync,

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impl<I, P> Sync for Filter<I, P>where I: Sync, P: Sync,

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impl<I, P> Sync for MapWhile<I, P>where I: Sync, P: Sync,

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impl<I, P> Sync for SkipWhile<I, P>where I: Sync, P: Sync,

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impl<I, P> Sync for TakeWhile<I, P>where I: Sync, P: Sync,

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impl<I, St, F> Sync for Scan<I, St, F>where F: Sync, I: Sync, St: Sync,

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impl<I, U, F> Sync for FlatMap<I, U, F>where F: Sync, I: Sync, <U as IntoIterator>::IntoIter: Sync,

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impl<I, const N: usize> Sync for core::iter::ArrayChunks<I, N>where I: Sync, <I as Iterator>::Item: Sync,

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impl<Idx> Sync for Range<Idx>where Idx: Sync,

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impl<Idx> Sync for RangeFrom<Idx>where Idx: Sync,

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impl<Idx> Sync for RangeInclusive<Idx>where Idx: Sync,

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impl<Idx> Sync for RangeTo<Idx>where Idx: Sync,

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impl<Idx> Sync for RangeToInclusive<Idx>where Idx: Sync,

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impl<P> Sync for Pin<P>where P: Sync,

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impl<Ret, T> Sync for fn (T₁, T₂, …, Tₙ) -> Ret

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impl<T> Sync for Bound<T>where T: Sync,

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impl<T> Sync for Option<T>where T: Sync,

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impl<T> Sync for Poll<T>where T: Sync,

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impl<T> Sync for [T]where T: Sync,

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impl<T> Sync for (T₁, T₂, …, Tₙ)where T: Sync,

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impl<T> Sync for Reverse<T>where T: Sync,

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impl<T> Sync for Pending<T>

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impl<T> Sync for Ready<T>where T: Sync,

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impl<T> Sync for Empty<T>

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impl<T> Sync for Once<T>where T: Sync,

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impl<T> Sync for Rev<T>where T: Sync,

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impl<T> Sync for Discriminant<T>

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impl<T> Sync for Saturating<T>where T: Sync,

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impl<T> Sync for Wrapping<T>where T: Sync,

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impl<T> Sync for Yeet<T>where T: Sync,

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impl<T> Sync for AssertUnwindSafe<T>where T: Sync,

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impl<T> Sync for core::result::IntoIter<T>where T: Sync,

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impl<T> Sync for MaybeUninit<T>where T: Sync,

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impl<T, E> Sync for Result<T, E>where E: Sync, T: Sync,

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impl<T, F = fn() -> T> !Sync for LazyCell<T, F>

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impl<T, F> Sync for Successors<T, F>where F: Sync, T: Sync,

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impl<T, const LANES: usize> Sync for Mask<T, LANES>where T: Sync,

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impl<T, const N: usize> Sync for [T; N]where T: Sync,

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impl<T, const N: usize> Sync for core::array::IntoIter<T, N>where T: Sync,

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impl<T, const N: usize> Sync for Simd<T, N>where T: Sync,

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impl<T, const N: usize> Sync for [MaybeUninit<T>; N]where T: Sync,

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impl<T: ?Sized> Sync for ManuallyDrop<T>where T: Sync,

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impl<T: ?Sized> Sync for PhantomData<T>where T: Sync,

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impl<Y, R> Sync for GeneratorState<Y, R>where R: Sync, Y: Sync,

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impl<const LANES: usize> Sync for LaneCount<LANES>

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impl<const N: usize> Sync for GetManyMutError<N>

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impl<const N: usize> Sync for [u8; N]