struct Unused<T>(PhantomData<T>);Available on (crate features
formatting or parsing) and crate feature alloc only.Expand description
A value that may be used in the future, but currently is not.
This struct exists so that data can semantically be passed around without actually passing it around. This way the data still exists if it is needed in the future.
Tuple Fields§
§0: PhantomData<T>Auto Trait Implementations§
impl<T> Freeze for Unused<T>
impl<T> RefUnwindSafe for Unused<T>where
T: RefUnwindSafe,
impl<T> Send for Unused<T>where
T: Send,
impl<T> Sync for Unused<T>where
T: Sync,
impl<T> Unpin for Unused<T>where
T: Unpin,
impl<T> UnwindSafe for Unused<T>where
T: UnwindSafe,
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§impl<T> SizedTypeProperties for T
impl<T> SizedTypeProperties for T
Source§#[doc(hidden)] const IS_ZST: bool = _
#[doc(hidden)] const IS_ZST: bool = _
🔬This is a nightly-only experimental API. (
sized_type_properties)Source§#[doc(hidden)] const LAYOUT: Layout = _
#[doc(hidden)] const LAYOUT: Layout = _
🔬This is a nightly-only experimental API. (
sized_type_properties)Source§#[doc(hidden)] const MAX_SLICE_LEN: usize = _
#[doc(hidden)] const MAX_SLICE_LEN: usize = _
🔬This is a nightly-only experimental API. (
sized_type_properties)The largest safe length for a
[Self]. Read more