Trait const_default::ConstDefault [−][src]
Expand description
Implements a compilation time default value for the implemented type.
Note
Unlike the Default
trait implementation the DEFAULT
of implementations
of this trait can be used in constant evaluation contexts.
Example
const VEC: Vec<u8> = <Vec<u8> as ConstDefault>::DEFAULT;
The above code works while the below code does not:
ⓘ
const VEC: Vec<u8> = <Vec<u8> as Default>::default();
Associated Constants
Implementations on Foreign Types
impl<'a, T> ConstDefault for Cow<'a, T> where
T: ToOwned + ?Sized + 'a,
<T as ToOwned>::Owned: ConstDefault,
This is supported on crate features std
or alloc
only.
impl<'a, T> ConstDefault for Cow<'a, T> where
T: ToOwned + ?Sized + 'a,
<T as ToOwned>::Owned: ConstDefault,
This is supported on crate features
std
or alloc
only.impl<K: Ord, V> ConstDefault for BTreeMap<K, V>
This is supported on (crate features std
or alloc
) and crate feature unstable
only.
impl<K: Ord, V> ConstDefault for BTreeMap<K, V>
This is supported on (crate features
std
or alloc
) and crate feature unstable
only.impl<T: Ord> ConstDefault for BTreeSet<T>
This is supported on (crate features std
or alloc
) and crate feature unstable
only.
impl<T: Ord> ConstDefault for BTreeSet<T>
This is supported on (crate features
std
or alloc
) and crate feature unstable
only.impl ConstDefault for AtomicUsize
This is supported on crate features default
or enable-atomics
only.
impl ConstDefault for AtomicUsize
This is supported on crate features
default
or enable-atomics
only.impl ConstDefault for AtomicIsize
This is supported on crate features default
or enable-atomics
only.
impl ConstDefault for AtomicIsize
This is supported on crate features
default
or enable-atomics
only.impl<T> ConstDefault for AtomicPtr<T>
This is supported on crate features default
or enable-atomics
only.
impl<T> ConstDefault for AtomicPtr<T>
This is supported on crate features
default
or enable-atomics
only.