Struct `PhantomCovariant`

struct PhantomCovariant<T>(_)
where
    T: ?Sized

Zero-sized type used to mark a type parameter as covariant.

Types used as part of the return value from a function are covariant. If the type is also passed as a parameter then it is [invariant][PhantomInvariant]. See the reference for more information.

Note: If T is otherwise contravariant or invariant, the resulting type is invariant.

Layout

For all T, the following are guaranteed:

size_of::<PhantomCovariant<T>>() == 0
align_of::<PhantomCovariant<T>>() == 1

Implementations

`impl<T> PhantomCovariant<T>`

const fn new() -> Self: Constructs a new instance of the variance marker.

`impl<T> Any for PhantomCovariant<T>`

fn type_id(self: &Self) -> TypeId

`impl<T> Borrow for PhantomCovariant<T>`

fn borrow(self: &Self) -> &T

`impl<T> BorrowMut for PhantomCovariant<T>`

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

`impl<T> Clone for PhantomCovariant<T>`

fn clone(self: &Self) -> Self

`impl<T> CloneToUninit for PhantomCovariant<T>`

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

`impl<T> Copy for PhantomCovariant<T>`

`impl<T> Debug for PhantomCovariant<T>`

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

`impl<T> Default for PhantomCovariant<T>`

fn default() -> Self

`impl<T> Eq for PhantomCovariant<T>`

`impl<T> Freeze for PhantomCovariant<T>`

`impl<T> From for PhantomCovariant<T>`

fn from(t: T) -> T: Returns the argument unchanged.

`impl<T> Hash for PhantomCovariant<T>`

fn hash<H: Hasher>(self: &Self, _: &mut H)

`impl<T> Ord for PhantomCovariant<T>`

fn cmp(self: &Self, _: &Self) -> Ordering

`impl<T> PartialEq for PhantomCovariant<T>`

fn eq(self: &Self, _: &Self) -> bool

`impl<T> PartialOrd for PhantomCovariant<T>`

fn partial_cmp(self: &Self, _: &Self) -> Option<Ordering>

`impl<T> RefUnwindSafe for PhantomCovariant<T>`

`impl<T> Send for PhantomCovariant<T>`

`impl<T> Sync for PhantomCovariant<T>`

`impl<T> Unpin for PhantomCovariant<T>`

`impl<T> UnsafeUnpin for PhantomCovariant<T>`

`impl<T> UnwindSafe for PhantomCovariant<T>`

`impl<T> Variance for PhantomCovariant<T>`

`impl<T, U> Into for PhantomCovariant<T>`

fn into(self: Self) -> U

Calls U::from(self).

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

`impl<T, U> TryFrom for PhantomCovariant<T>`

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

`impl<T, U> TryInto for PhantomCovariant<T>`

fn try_into(self: Self) -> Result<U, <U as TryFrom<T>>::Error>