Trait const_default::ConstDefault

pub trait ConstDefault: Sized {
    const DEFAULT: Self;
}

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

const DEFAULT: Self

The constant default value.

Implementations on Foreign Types

impl<T> ConstDefault for Option<T>

const DEFAULT: Self

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.

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for Cell<T>

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for UnsafeCell<T>

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for RefCell<T>

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for MaybeUninit<T>

const DEFAULT: Self

impl<T> ConstDefault for Vec<T>

This is supported on crate features std or alloc only.

const DEFAULT: Self

impl ConstDefault for String

This is supported on crate features std or alloc only.

const DEFAULT: Self

impl<K: Ord, V> ConstDefault for BTreeMap<K, V>

This is supported on (crate features std or alloc) and crate feature unstable only.

const DEFAULT: Self

impl<T: Ord> ConstDefault for BTreeSet<T>

This is supported on (crate features std or alloc) and crate feature unstable only.

const DEFAULT: Self

impl<T> ConstDefault for LinkedList<T>

This is supported on crate features std or alloc only.

const DEFAULT: Self

impl<'a, T: 'a> ConstDefault for &'a [T]

const DEFAULT: Self

impl<T> ConstDefault for *const T

const DEFAULT: Self

impl<T> ConstDefault for *mut T

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for ManuallyDrop<T>

const DEFAULT: Self

impl<T: ?Sized> ConstDefault for PhantomData<T>

const DEFAULT: Self

impl ConstDefault for PhantomPinned

const DEFAULT: Self

impl<T> ConstDefault for Empty<T>

const DEFAULT: Self

impl<T: ConstDefault> ConstDefault for Wrapping<T>

const DEFAULT: Self

impl ConstDefault for Duration

const DEFAULT: Self

impl ConstDefault for Once

This is supported on crate feature std only.

const DEFAULT: Self

impl ConstDefault for ()

const DEFAULT: Self

impl ConstDefault for &()

const DEFAULT: Self

impl ConstDefault for bool

const DEFAULT: Self

impl ConstDefault for &bool

const DEFAULT: Self

impl ConstDefault for f32

const DEFAULT: Self

impl ConstDefault for &f32

const DEFAULT: Self

impl ConstDefault for f64

const DEFAULT: Self

impl ConstDefault for &f64

const DEFAULT: Self

impl ConstDefault for char

const DEFAULT: Self

impl ConstDefault for &char

const DEFAULT: Self

impl ConstDefault for &str

const DEFAULT: Self

impl ConstDefault for &&str

const DEFAULT: Self

impl ConstDefault for u8

const DEFAULT: Self

impl ConstDefault for &u8

const DEFAULT: Self

impl ConstDefault for AtomicU8

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for u16

const DEFAULT: Self

impl ConstDefault for &u16

const DEFAULT: Self

impl ConstDefault for AtomicU16

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for u32

const DEFAULT: Self

impl ConstDefault for &u32

const DEFAULT: Self

impl ConstDefault for AtomicU32

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for u64

const DEFAULT: Self

impl ConstDefault for &u64

const DEFAULT: Self

impl ConstDefault for AtomicU64

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for usize

const DEFAULT: Self

impl ConstDefault for &usize

const DEFAULT: Self

impl ConstDefault for AtomicUsize

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for i8

const DEFAULT: Self

impl ConstDefault for &i8

const DEFAULT: Self

impl ConstDefault for AtomicI8

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for i16

const DEFAULT: Self

impl ConstDefault for &i16

const DEFAULT: Self

impl ConstDefault for AtomicI16

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for i32

const DEFAULT: Self

impl ConstDefault for &i32

const DEFAULT: Self

impl ConstDefault for AtomicI32

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for i64

const DEFAULT: Self

impl ConstDefault for &i64

const DEFAULT: Self

impl ConstDefault for AtomicI64

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for isize

const DEFAULT: Self

impl ConstDefault for &isize

const DEFAULT: Self

impl ConstDefault for AtomicIsize

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl ConstDefault for i128

const DEFAULT: Self

impl ConstDefault for &i128

const DEFAULT: Self

impl ConstDefault for u128

const DEFAULT: Self

impl ConstDefault for &u128

const DEFAULT: Self

impl ConstDefault for AtomicBool

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl<T> ConstDefault for AtomicPtr<T>

This is supported on crate features default or enable-atomics only.

const DEFAULT: Self

impl<A: ConstDefault, B: ConstDefault, C: ConstDefault, D: ConstDefault, E: ConstDefault, F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (A, B, C, D, E, F, G, H, I, J, K, L)

const DEFAULT: Self

impl<B: ConstDefault, C: ConstDefault, D: ConstDefault, E: ConstDefault, F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (B, C, D, E, F, G, H, I, J, K, L)

const DEFAULT: Self

impl<C: ConstDefault, D: ConstDefault, E: ConstDefault, F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (C, D, E, F, G, H, I, J, K, L)

const DEFAULT: Self

impl<D: ConstDefault, E: ConstDefault, F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (D, E, F, G, H, I, J, K, L)

const DEFAULT: Self

impl<E: ConstDefault, F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (E, F, G, H, I, J, K, L)

const DEFAULT: Self

impl<F: ConstDefault, G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (F, G, H, I, J, K, L)

const DEFAULT: Self

impl<G: ConstDefault, H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (G, H, I, J, K, L)

const DEFAULT: Self

impl<H: ConstDefault, I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (H, I, J, K, L)

const DEFAULT: Self

impl<I: ConstDefault, J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (I, J, K, L)

const DEFAULT: Self

impl<J: ConstDefault, K: ConstDefault, L: ConstDefault> ConstDefault for (J, K, L)

const DEFAULT: Self

impl<K: ConstDefault, L: ConstDefault> ConstDefault for (K, L)

const DEFAULT: Self

impl<L: ConstDefault> ConstDefault for (L,)

const DEFAULT: Self

impl<T: ConstDefault, const N: usize> ConstDefault for [T; N]

const DEFAULT: Self

Implementors