# Struct alloc::boxed::ThinBox

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    pub struct ThinBox<T: ?Sized> { /* private fields */ }

🔬This is a nightly-only experimental API. (`thin_box` #92791)
Expand description

ThinBox.

A thin pointer for heap allocation, regardless of T.

## Examples

    #![feature(thin_box)]
    use std::boxed::ThinBox;

    let five = ThinBox::new(5);
    let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);

    use std::mem::{size_of, size_of_val};
    let size_of_ptr = size_of::<*const ()>();
    assert_eq!(size_of_ptr, size_of_val(&five));
    assert_eq!(size_of_ptr, size_of_val(&thin_slice));

Run

## Implementations§

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### impl<T> ThinBox<T>

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#### pub fn new(value: T) -> Self

🔬This is a nightly-only experimental API. (`thin_box` #92791)

Moves a type to the heap with its `Metadata` stored in the heap allocation instead of on the stack.

##### Examples

    #![feature(thin_box)]
    use std::boxed::ThinBox;

    let five = ThinBox::new(5);

Run
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### impl<Dyn: ?Sized> ThinBox<Dyn>

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#### pub fn new_unsize<T>(value: T) -> Selfwhere T: Unsize<Dyn>,

🔬This is a nightly-only experimental API. (`thin_box` #92791)

Moves a type to the heap with its `Metadata` stored in the heap allocation instead of on the stack.

##### Examples

    #![feature(thin_box)]
    use std::boxed::ThinBox;

    let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);

Run

## Trait Implementations§

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### impl<T: ?Sized + Debug> Debug for ThinBox<T>

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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: ?Sized> Deref for ThinBox<T>

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#### type Target = T

The resulting type after dereferencing.
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#### fn deref(&self) -> &T

Dereferences the value.
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### impl<T: ?Sized> DerefMut for ThinBox<T>

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#### fn deref_mut(&mut self) -> &mut T

Mutably dereferences the value.
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### impl<T: ?Sized + Display> Display for ThinBox<T>

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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: ?Sized> Drop for ThinBox<T>

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#### fn drop(&mut self)

Executes the destructor for this type. Read more
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### impl<T: ?Sized + Error> Error for ThinBox<T>

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#### fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any. Read more
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#### fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
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#### fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
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#### fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (`error_generic_member_access` #99301)
Provides type based access to context intended for error reports. Read more
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### impl<T: ?Sized + Send> Send for ThinBox<T>

`ThinBox<T>` is `Send` if `T` is `Send` because the data is owned.

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### impl<T: ?Sized + Sync> Sync for ThinBox<T>

`ThinBox<T>` is `Sync` if `T` is `Sync` because the data is owned.

## Auto Trait Implementations§

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### impl<T: ?Sized> RefUnwindSafe for ThinBox<T>where T: RefUnwindSafe,

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### impl<T: ?Sized> Unpin for ThinBox<T>where T: Unpin,

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### impl<T: ?Sized> UnwindSafe for ThinBox<T>where T: UnwindSafe,

## Blanket Implementations§

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### impl<T> Any for Twhere 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 Twhere 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 Twhere 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 Twhere 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<E> Provider for Ewhere E: Error + ?Sized,

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#### fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (`provide_any` #96024)
Data providers should implement this method to provide all values they are able to provide by using `demand`. Read more
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### impl<T> ToString for Twhere T: Display + ?Sized,

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#### default fn to_string(&self) -> String

Converts the given value to a `String`. Read more
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### impl<T, U> TryFrom<U> for Twhere 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 Twhere 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.