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## Attribute

# Struct Attribute

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    pub struct Attribute {
        pub kind: AttrKind,
        pub id: AttrId,
        pub style: AttrStyle,
        pub span: Span,
    }

Expand description

A syntax-level representation of an attribute.

## Fields§

§`kind: AttrKind`§`id: AttrId`§`style: AttrStyle`

Denotes if the attribute decorates the following construct (outer) or the construct this attribute is contained within (inner).

§`span: Span`

## Implementations§

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### impl Attribute

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#### pub fn get_normal_item(&self) -> &AttrItem

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#### pub fn replace_args(&mut self, new_args: AttrItemKind)

Replaces the arguments of this attribute with new arguments `AttrItemKind`. This is useful for making this attribute into a trace attribute, and should otherwise be avoided.

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#### pub fn unwrap_normal_item(self) -> AttrItem

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### impl Attribute

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#### pub fn style(&self) -> AttrStyle

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#### pub fn may_have_doc_links(&self) -> bool

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#### pub fn meta(&self) -> Option<MetaItem>

Extracts the MetaItem from inside this Attribute.

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#### pub fn meta_kind(&self) -> Option<MetaItemKind>

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#### pub fn token_trees(&self) -> Vec<TokenTree>

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#### pub fn deprecation_note(&self) -> Option<Ident>

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### impl Attribute

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#### pub fn id(&self) -> AttrId

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#### pub fn name(&self) -> Option<Symbol>

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#### pub fn meta_item_list(&self) -> Option<ThinVec<MetaItemInner>>

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#### pub fn value_str(&self) -> Option<Symbol>

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#### pub fn value_span(&self) -> Option<Span>

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#### pub fn path_matches(&self, name: &[Symbol]) -> bool

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#### pub fn is_doc_comment(&self) -> bool

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#### pub fn has_name(&self, name: Symbol) -> bool

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#### pub fn has_any_name(&self, names: &[Symbol]) -> bool

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#### pub fn span(&self) -> Span

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#### pub fn is_word(&self) -> bool

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#### pub fn path(&self) -> SmallVec<[Symbol; 1]>

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#### pub fn doc_str(&self) -> Option<Symbol>

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#### pub fn is_proc_macro_attr(&self) -> bool

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#### pub fn doc_str_and_fragment_kind(&self) -> Option<(Symbol, DocFragmentKind)>

## Trait Implementations§

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### impl AttributeExt for Attribute

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#### fn is_doc_comment(&self) -> Option<Span>

Returns `true` if it is a sugared doc comment (`///` or `//!` for example). So `#[doc = "doc"]` (which is a doc comment) and `#[doc(...)]` (which is not a doc comment) will return `false`.

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#### fn name(&self) -> Option<Symbol>

For a single-segment attribute, returns its name; otherwise, returns `None`.

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#### fn meta_item_list(&self) -> Option<ThinVec<MetaItemInner>>

Returns a list of meta items if the attribute is delimited with parenthesis:

    #[attr(a, b = "c")] // Returns `Some()`.
    #[attr = ""] // Returns `None`.
    #[attr] // Returns `None`.

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#### fn value_str(&self) -> Option<Symbol>

Returns the string value in:

    #[attribute = "value"]
                  ^^^^^^^

It returns `None` in any other cases, including doc comments if they are not under the form `#[doc = "..."]`.

It also returns `None` for:

    #[attr("value")]

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#### fn doc_str_and_fragment_kind(&self) -> Option<(Symbol, DocFragmentKind)>

Returns the documentation and its kind if this is a doc comment or a sugared doc comment.

- `///doc` returns `Some(("doc", DocFragmentKind::Sugared(CommentKind::Line)))`.
- `/** doc */` returns `Some(("doc", DocFragmentKind::Sugared(CommentKind::Block)))`.
- `#[doc = "doc"]` returns `Some(("doc", DocFragmentKind::Raw))`.
- `#[doc(...)]` returns `None`.

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#### fn doc_str(&self) -> Option<Symbol>

Returns the documentation if this is a doc comment or a sugared doc comment.

- `///doc` returns `Some("doc")`.
- `#[doc = "doc"]` returns `Some("doc")`.
- `#[doc(...)]` returns `None`.

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#### fn id(&self) -> AttrId

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#### fn value_span(&self) -> Option<Span>

Gets the span of the value literal, as string, when using `#[attr = value]`
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#### fn symbol_path(&self) -> Option<SmallVec<[Symbol; 1]>>

Returns None for doc comments
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#### fn path_span(&self) -> Option<Span>

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#### fn path_matches(&self, name: &[Symbol]) -> bool

Checks whether the path of this attribute matches the name. Read more
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#### fn span(&self) -> Span

get the span of the entire attribute
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#### fn is_word(&self) -> bool

Returns whether the attribute is a path, without any arguments.
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#### fn doc_resolution_scope(&self) -> Option<AttrStyle>

Returns outer or inner if this is a doc attribute or a sugared doc comment, otherwise None. Read more
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#### fn is_automatically_derived_attr(&self) -> bool

Returns true if this attribute is `#[automatically_deived]`.
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#### fn is_doc_hidden(&self) -> bool

Returns `true` if this attribute contains `doc(hidden)`.
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#### fn is_doc_keyword_or_attribute(&self) -> bool

Returns `true` is this attribute contains `doc(keyword)` or `doc(attribute)`.
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#### fn is_rustc_doc_primitive(&self) -> bool

Returns `true` if this is a `#[rustc_doc_primitive]` attribute.
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#### fn has_name(&self, name: Symbol) -> bool

Returns true if the attribute’s first and only path segment is equal to the passed-in symbol.
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#### fn has_any_name(&self, names: &[Symbol]) -> bool

Returns true if the attribute’s first and only path segment is any of the passed-in symbols.
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#### fn path(&self) -> SmallVec<[Symbol; 1]>

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#### fn is_proc_macro_attr(&self) -> bool

Returns whether this attribute is any of the proc macro attributes. i.e. `proc_macro`, `proc_macro_attribute` or `proc_macro_derive`.
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### impl Clone for Attribute

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#### fn clone(&self) -> Attribute

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for Attribute

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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<__D: SpanDecoder> Decodable<__D> for Attribute

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#### fn decode(__decoder: &mut __D) -> Self

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### impl<__E: SpanEncoder> Encodable<__E> for Attribute

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#### fn encode(&self, __encoder: &mut __E)

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### impl HasAttrs for Attribute

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#### const SUPPORTS_CUSTOM_INNER_ATTRS: bool = false

This is `true` if this `HasAttrs` might support ‘custom’ (proc-macro) inner attributes. Attributes like `#![cfg]` and `#![cfg_attr]` are not considered ‘custom’ attributes. Read more
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#### fn attrs(&self) -> &[Attribute]

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#### fn visit_attrs(&mut self, _f: impl FnOnce(&mut AttrVec))

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### impl HasTokens for Attribute

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#### fn tokens(&self) -> Option<&LazyAttrTokenStream>

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#### fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>>

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### impl<V: MutVisitor> MutVisitable<V> for Attribute

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#### type Extra = ()

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#### fn visit_mut(&mut self, visitor: &mut V, extra: Self::Extra) -> V::Result

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### impl<__V> MutWalkable<__V> for Attribute
where __V: MutVisitor,

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#### fn walk_mut(&mut self, __visitor: &mut __V)

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### impl<'a, V: Visitor<'a>> Visitable<'a, V> for Attribute

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#### type Extra = ()

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#### fn visit(&'a self, visitor: &mut V, extra: Self::Extra) -> V::Result

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### impl<'__ast, __V> Walkable<'__ast, __V> for Attribute
where __V: Visitor<'__ast>,

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#### fn walk_ref(&'__ast self, __visitor: &mut __V) -> __V::Result

## Auto Trait Implementations§

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### impl DynSend for Attribute

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### impl DynSync for Attribute

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### impl Freeze for Attribute

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### impl RefUnwindSafe for Attribute

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### impl Send for Attribute

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### impl Sync for Attribute

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### impl Unpin for Attribute

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### impl UnsafeUnpin for Attribute

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### impl UnwindSafe for Attribute

## Blanket Implementations§

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### impl<T> Aligned for T

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#### const ALIGN: Alignment

Alignment of `Self`.
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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> 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> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. 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> Instrument for T

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#### fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided `Span`, returning an `Instrumented` wrapper. Read more
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#### fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current `Span`, returning an `Instrumented` wrapper. Read more
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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> IntoEither for T

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#### fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left` is `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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#### fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left(&self)` returns `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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### impl<T> MutVisitorResult for T

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#### type Result = ()

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### impl<T> Pointable for T

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#### const ALIGN: usize

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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#### unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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#### unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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#### unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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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.
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### impl<T> WithSubscriber for T

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#### fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more
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#### fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default `Subscriber` to this type, returning a `WithDispatch` wrapper. Read more

## Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain `repr(...)` attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes