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Struct rkyv::with::Niche

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pub struct Niche;
Expand description

A wrapper that niches some type combinations.

A common type combination is Option<Box<T>>. By using a null pointer, the archived version can save some space on-disk.

§Example

use core::mem::size_of;

use rkyv::{with::Niche, Archive, Archived};

#[derive(Archive)]
struct BasicExample {
    value: Option<Box<str>>,
}

#[derive(Archive)]
struct NichedExample {
    #[rkyv(with = Niche)]
    value: Option<Box<str>>,
}

assert!(
    size_of::<Archived<BasicExample>>()
        > size_of::<Archived<NichedExample>>()
);

Trait Implementations§

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impl<T> ArchiveWith<Option<Box<T>>> for Niche
where T: ArchiveUnsized + ?Sized, ArchivedMetadata<T>: Default,

Available on crate feature alloc only.
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type Archived = ArchivedOptionBox<<T as ArchiveUnsized>::Archived>

The archived type of Self with F.
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type Resolver = OptionBoxResolver

The resolver of a Self with F.
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fn resolve_with( field: &Option<Box<T>>, resolver: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<i128>>> for Niche

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type Archived = ArchivedOptionNonZeroI128

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroI128>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<i16>>> for Niche

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type Archived = ArchivedOptionNonZeroI16

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroI16>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<i32>>> for Niche

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type Archived = ArchivedOptionNonZeroI32

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroI32>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<i64>>> for Niche

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type Archived = ArchivedOptionNonZeroI64

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroI64>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<i8>>> for Niche

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type Archived = ArchivedOptionNonZeroI8

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroI8>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<isize>>> for Niche

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type Archived = ArchivedOptionNonZeroI32

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroIsize>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<u128>>> for Niche

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type Archived = ArchivedOptionNonZeroU128

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroU128>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<u16>>> for Niche

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type Archived = ArchivedOptionNonZeroU16

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroU16>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<u32>>> for Niche

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type Archived = ArchivedOptionNonZeroU32

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroU32>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<u64>>> for Niche

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type Archived = ArchivedOptionNonZeroU64

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroU64>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<u8>>> for Niche

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type Archived = ArchivedOptionNonZeroU8

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroU8>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl ArchiveWith<Option<NonZero<usize>>> for Niche

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type Archived = ArchivedOptionNonZeroU32

The archived type of Self with F.
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type Resolver = ()

The resolver of a Self with F.
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fn resolve_with( field: &Option<NonZeroUsize>, _: Self::Resolver, out: Place<Self::Archived>, )

Resolves the archived type using a reference to the field type F.
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impl Debug for Niche

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<T, D> DeserializeWith<ArchivedOptionBox<<T as ArchiveUnsized>::Archived>, Option<Box<T>>, D> for Niche
where T: ArchiveUnsized + LayoutRaw + Pointee + ?Sized, T::Archived: DeserializeUnsized<T, D>, D: Fallible + ?Sized, D::Error: Source,

Available on crate feature alloc only.
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fn deserialize_with( field: &ArchivedOptionBox<T::Archived>, deserializer: &mut D, ) -> Result<Option<Box<T>>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI128, Option<NonZero<i128>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroI128, _: &mut D, ) -> Result<Option<NonZeroI128>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI16, Option<NonZero<i16>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroI16, _: &mut D, ) -> Result<Option<NonZeroI16>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI32, Option<NonZero<i32>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroI32, _: &mut D, ) -> Result<Option<NonZeroI32>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI32, Option<NonZero<isize>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroIsize, _: &mut D, ) -> Result<Option<NonZeroIsize>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI64, Option<NonZero<i64>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroI64, _: &mut D, ) -> Result<Option<NonZeroI64>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroI8, Option<NonZero<i8>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroI8, _: &mut D, ) -> Result<Option<NonZeroI8>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU128, Option<NonZero<u128>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroU128, _: &mut D, ) -> Result<Option<NonZeroU128>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU16, Option<NonZero<u16>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroU16, _: &mut D, ) -> Result<Option<NonZeroU16>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU32, Option<NonZero<u32>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroU32, _: &mut D, ) -> Result<Option<NonZeroU32>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU32, Option<NonZero<usize>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroUsize, _: &mut D, ) -> Result<Option<NonZeroUsize>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU64, Option<NonZero<u64>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroU64, _: &mut D, ) -> Result<Option<NonZeroU64>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<D> DeserializeWith<ArchivedOptionNonZeroU8, Option<NonZero<u8>>, D> for Niche
where D: Fallible + ?Sized,

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fn deserialize_with( field: &ArchivedOptionNonZeroU8, _: &mut D, ) -> Result<Option<NonZeroU8>, D::Error>

Deserializes the field type F using the given deserializer.
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impl<T, S> SerializeWith<Option<Box<T>>, S> for Niche
where T: SerializeUnsized<S> + ?Sized, S: Fallible + Writer + ?Sized, ArchivedMetadata<T>: Default,

Available on crate feature alloc only.
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fn serialize_with( field: &Option<Box<T>>, serializer: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<i128>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroI128>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<i16>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroI16>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<i32>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroI32>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<i64>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroI64>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<i8>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroI8>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<isize>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroIsize>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<u128>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroU128>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<u16>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroU16>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<u32>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroU32>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<u64>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroU64>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<u8>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroU8>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.
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impl<S: Fallible + ?Sized> SerializeWith<Option<NonZero<usize>>, S> for Niche

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fn serialize_with( _: &Option<NonZeroUsize>, _: &mut S, ) -> Result<Self::Resolver, S::Error>

Serializes the field type F using the given serializer.

Auto Trait Implementations§

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impl Freeze for Niche

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impl RefUnwindSafe for Niche

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impl Send for Niche

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impl Sync for Niche

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impl Unpin for Niche

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impl UnwindSafe for Niche

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> ArchivePointee for T

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type ArchivedMetadata = ()

The archived version of the pointer metadata for this type.
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fn pointer_metadata( _: &<T as ArchivePointee>::ArchivedMetadata, ) -> <T as Pointee>::Metadata

Converts some archived metadata to the pointer metadata for itself.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> LayoutRaw for T

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fn layout_raw(_: <T as Pointee>::Metadata) -> Result<Layout, LayoutError>

Returns the layout of the type.
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impl<T> Pointee for T

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type Metadata = ()

The metadata type for pointers and references to this type.
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.