1.0.0[][src]Trait core::hash::Hash

pub trait Hash {
    fn hash<H: Hasher>(&self, state: &mut H);

    fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)
    where
        Self: Sized
, { ... } }

A hashable type.

Types implementing Hash are able to be hashed with an instance of Hasher.

Implementing Hash

You can derive Hash with #[derive(Hash)] if all fields implement Hash. The resulting hash will be the combination of the values from calling hash on each field.

#[derive(Hash)]
struct Rustacean {
    name: String,
    country: String,
}Run

If you need more control over how a value is hashed, you can of course implement the Hash trait yourself:

use std::hash::{Hash, Hasher};

struct Person {
    id: u32,
    name: String,
    phone: u64,
}

impl Hash for Person {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.id.hash(state);
        self.phone.hash(state);
    }
}Run

Hash and Eq

When implementing both Hash and Eq, it is important that the following property holds:

k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes must also be equal. HashMap and HashSet both rely on this behavior.

Thankfully, you won't need to worry about upholding this property when deriving both Eq and Hash with #[derive(PartialEq, Eq, Hash)].

Required Methods

Feeds this value into the given Hasher.

Examples

use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};

let mut hasher = DefaultHasher::new();
7920.hash(&mut hasher);
println!("Hash is {:x}!", hasher.finish());Run

Provided Methods

Feeds a slice of this type into the given Hasher.

Examples

use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};

let mut hasher = DefaultHasher::new();
let numbers = [6, 28, 496, 8128];
Hash::hash_slice(&numbers, &mut hasher);
println!("Hash is {:x}!", hasher.finish());Run

Implementors

impl Hash for NonZeroU8
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impl Hash for NonZeroU16
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impl Hash for NonZeroU32
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impl Hash for NonZeroU64
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impl Hash for NonZeroU128
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impl Hash for NonZeroUsize
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impl<T: Hash> Hash for Wrapping<T>
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impl<T> Hash for Discriminant<T>
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impl<T: Hash + ?Sized> Hash for ManuallyDrop<T>
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impl<Ret> Hash for fn() -> Ret
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impl<Ret> Hash for extern "C" fn() -> Ret
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impl<Ret> Hash for unsafe fn() -> Ret
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impl<Ret> Hash for unsafe extern "C" fn() -> Ret
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impl<Ret, A> Hash for fn(_: A) -> Ret
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impl<Ret, A> Hash for extern "C" fn(_: A) -> Ret
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impl<Ret, A> Hash for extern "C" fn(_: A, ...) -> Ret
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impl<Ret, A> Hash for unsafe fn(_: A) -> Ret
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impl<Ret, A> Hash for unsafe extern "C" fn(_: A) -> Ret
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impl<Ret, A> Hash for unsafe extern "C" fn(_: A, ...) -> Ret
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impl<Ret, A, B> Hash for fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Hash for extern "C" fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Hash for extern "C" fn(_: A, _: B, ...) -> Ret
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impl<Ret, A, B> Hash for unsafe fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Hash for unsafe extern "C" fn(_: A, _: B) -> Ret
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impl<Ret, A, B> Hash for unsafe extern "C" fn(_: A, _: B, ...) -> Ret
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impl<Ret, A, B, C> Hash for fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Hash for extern "C" fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Hash for extern "C" fn(_: A, _: B, _: C, ...) -> Ret
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impl<Ret, A, B, C> Hash for unsafe fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Hash for unsafe extern "C" fn(_: A, _: B, _: C) -> Ret
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impl<Ret, A, B, C> Hash for unsafe extern "C" fn(_: A, _: B, _: C, ...) -> Ret
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impl<Ret, A, B, C, D> Hash for fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Hash for extern "C" fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Hash for extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret
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impl<Ret, A, B, C, D> Hash for unsafe fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D) -> Ret
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impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret
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impl<Ret, A, B, C, D, E> Hash for fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret
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impl<Ret, A, B, C, D, E> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret
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impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret
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impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret
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impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, ...) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret
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impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, ...) -> Ret
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impl<T: ?Sized> Hash for NonNull<T>
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impl<T: ?Sized> Hash for PhantomData<T>
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impl Hash for Pinned
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impl<Y: Hash, R: Hash> Hash for GeneratorState<Y, R>
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impl Hash for RangeFull
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impl<Idx: Hash> Hash for Range<Idx>
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impl<Idx: Hash> Hash for RangeFrom<Idx>
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impl<Idx: Hash> Hash for RangeTo<Idx>
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impl<Idx: Hash> Hash for RangeInclusive<Idx>
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impl<Idx: Hash> Hash for RangeToInclusive<Idx>
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impl<T: Hash> Hash for Bound<T>
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impl Hash for Ordering
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impl<T: Hash> Hash for Reverse<T>
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impl Hash for TypeId
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impl<T: Hash> Hash for [T; 0]
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impl<T: Hash> Hash for [T; 1]
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impl<T: Hash> Hash for [T; 2]
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impl<T: Hash> Hash for [T; 3]
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impl<T: Hash> Hash for [T; 4]
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impl<T: Hash> Hash for [T; 5]
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impl<T: Hash> Hash for [T; 6]
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impl<T: Hash> Hash for [T; 7]
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impl<T: Hash> Hash for [T; 8]
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impl<T: Hash> Hash for [T; 9]
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impl<T: Hash> Hash for [T; 10]
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impl<T: Hash> Hash for [T; 11]
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impl<T: Hash> Hash for [T; 12]
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impl<T: Hash> Hash for [T; 13]
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impl<T: Hash> Hash for [T; 14]
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impl<T: Hash> Hash for [T; 15]
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impl<T: Hash> Hash for [T; 16]
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impl<T: Hash> Hash for [T; 17]
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impl<T: Hash> Hash for [T; 18]
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impl<T: Hash> Hash for [T; 19]
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impl<T: Hash> Hash for [T; 20]
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impl<T: Hash> Hash for [T; 21]
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impl<T: Hash> Hash for [T; 22]
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impl<T: Hash> Hash for [T; 23]
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impl<T: Hash> Hash for [T; 24]
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impl<T: Hash> Hash for [T; 25]
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impl<T: Hash> Hash for [T; 26]
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impl<T: Hash> Hash for [T; 27]
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impl<T: Hash> Hash for [T; 28]
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impl<T: Hash> Hash for [T; 29]
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impl<T: Hash> Hash for [T; 30]
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impl<T: Hash> Hash for [T; 31]
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impl<T: Hash> Hash for [T; 32]
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impl<T: Hash> Hash for Option<T>
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impl Hash for NoneError
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impl<T: Hash, E: Hash> Hash for Result<T, E>
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impl Hash for u8
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impl Hash for u16
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impl Hash for u32
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impl Hash for u64
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impl Hash for usize
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impl Hash for i8
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impl Hash for i16
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impl Hash for i32
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impl Hash for i64
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impl Hash for isize
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impl Hash for u128
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impl Hash for i128
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impl Hash for bool
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impl Hash for char
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impl Hash for str
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impl Hash for !
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impl Hash for ()
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impl<A> Hash for (A,) where
    A: Hash + ?Sized
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impl<A: Hash, B> Hash for (A, B) where
    B: Hash + ?Sized
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impl<A: Hash, B: Hash, C> Hash for (A, B, C) where
    C: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D> Hash for (A, B, C, D) where
    D: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E> Hash for (A, B, C, D, E) where
    E: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F> Hash for (A, B, C, D, E, F) where
    F: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G> Hash for (A, B, C, D, E, F, G) where
    G: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H> Hash for (A, B, C, D, E, F, G, H) where
    H: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I> Hash for (A, B, C, D, E, F, G, H, I) where
    I: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J> Hash for (A, B, C, D, E, F, G, H, I, J) where
    J: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J: Hash, K> Hash for (A, B, C, D, E, F, G, H, I, J, K) where
    K: Hash + ?Sized
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impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J: Hash, K: Hash, L> Hash for (A, B, C, D, E, F, G, H, I, J, K, L) where
    L: Hash + ?Sized
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impl<T: Hash> Hash for [T]
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impl<'a, T: ?Sized + Hash> Hash for &'a T
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impl<'a, T: ?Sized + Hash> Hash for &'a mut T
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impl<T: ?Sized> Hash for *const T
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impl<T: ?Sized> Hash for *mut T
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impl Hash for Error
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impl Hash for Duration
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impl<T: Hash> Hash for Poll<T>
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