Struct PhantomContravariant
#[repr(transparent)]
pub struct PhantomContravariant<T>(pub(in ::marker::variance) PhantomData<fn(T)>)
where
T: ?Sized,;Zero-sized type used to mark a type parameter as contravariant.
Types passed as arguments to a function are contravariant. If the type is also part of the return value from a function then it is [invariant][PhantomInvariant]. See the reference for more information.
Note: If T is otherwise covariant or invariant, the resulting type is invariant.
Layout
For all T, the following are guaranteed:
size_of::<PhantomContravariant<T>>() == 0align_of::<PhantomContravariant<T>>() == 1
Fields
0: PhantomData<fn(T)>
Implementations
impl<T> PhantomContravariant<T>
where
T: ?Sized,
const fn new() -> SelfConstructs a new instance of the variance marker.
Trait Implementations
impl<T> Clone for PhantomContravariant<T>
where
T: ?Sized,
fn clone(&self) -> Self
impl<T> Copy for PhantomContravariant<T>
where
T: ?Sized,
impl<T> Debug for PhantomContravariant<T>
where
T: ?Sized,
fn fmt(&self, f: &mut Formatter<'_>) -> Result
impl<T> Default for PhantomContravariant<T>
where
T: ?Sized,
fn default() -> Self
impl<T> Eq for PhantomContravariant<T>
where
T: ?Sized,
impl<T> Hash for PhantomContravariant<T>
where
T: ?Sized,
fn hash<H: Hasher>(&self, &mut H)
impl<T> Ord for PhantomContravariant<T>
where
T: ?Sized,
fn cmp(&self, &Self) -> Ordering
impl<T> PartialEq for PhantomContravariant<T>
where
T: ?Sized,
fn eq(&self, &Self) -> bool
impl<T> PartialOrd for PhantomContravariant<T>
where
T: ?Sized,
fn partial_cmp(&self, &Self) -> Option<Ordering>
impl<T> PrivateItems for PhantomContravariant<T>
where
T: ?Sized,
const VALUE: Self = _;
impl<T> TrivialClone for PhantomContravariant<T>
where
T: ?Sized,
impl<T> Variance for PhantomContravariant<T>
where
T: ?Sized,
Auto Trait Implementations
impl<T> Freeze for PhantomContravariant<T>
where
PhantomData<fn(T)>: Freeze,
T: ?Sized,
impl<T> RefUnwindSafe for PhantomContravariant<T>
where
PhantomData<fn(T)>: RefUnwindSafe,
T: ?Sized,
impl<T> Send for PhantomContravariant<T>
where
PhantomData<fn(T)>: Send,
T: ?Sized,
impl<T> Sync for PhantomContravariant<T>
where
PhantomData<fn(T)>: Sync,
T: ?Sized,
impl<T> Unpin for PhantomContravariant<T>
where
PhantomData<fn(T)>: Unpin,
T: ?Sized,
impl<T> UnsafeUnpin for PhantomContravariant<T>
where
PhantomData<fn(T)>: UnsafeUnpin,
T: ?Sized,
impl<T> UnwindSafe for PhantomContravariant<T>
where
PhantomData<fn(T)>: UnwindSafe,
T: ?Sized,
Blanket Implementations
impl<T> Any for PhantomContravariant<T>
where
T: 'static + ?Sized,
fn type_id(&self) -> TypeId
impl<T> Borrow<T> for PhantomContravariant<T>
where
T: ?Sized,
fn borrow(&self) -> &T
impl<T> BorrowMut<T> for PhantomContravariant<T>
where
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
impl<T> CloneToUninit for PhantomContravariant<T>
where
T: Clone,
unsafe fn clone_to_uninit(&self, dest: *mut u8)
impl<T> From<T> for PhantomContravariant<T>
fn from(t: T) -> TReturns the argument unchanged.
impl<T> Printable for PhantomContravariant<T>
where
T: Copy + Debug,
impl<T> SizeHint for PhantomContravariant<T>
where
T: ?Sized,
fn lower_bound(&self) -> usizefn upper_bound(&self) -> Option<usize>
impl<T> SizedTypeProperties for PhantomContravariant<T>
impl<T, U> Into<U> for PhantomContravariant<T>
where
U: From<T>,
fn into(self) -> UCalls
U::from(self).That is, this conversion is whatever the implementation of
[From]<T> for Uchooses to do.
impl<T, U> TryFrom<U> for PhantomContravariant<T>
where
U: Into<T>,
type Error = Infallible;fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
impl<T, U> TryInto<U> for PhantomContravariant<T>
where
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error;fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>