Trait FixedStorage 

pub trait FixedStorage { }

Marker trait asserting that a type owns no heap allocation.

Required by Fixed::new. See the module documentation for the contract, for what is already implemented, and for why this is an assertion rather than an enforcement.

No methods — its only purpose is to gate construction of a Fixed<T>.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl FixedStorage for ()

impl FixedStorage for NonZeroI8

impl FixedStorage for NonZeroI16

impl FixedStorage for NonZeroI32

impl FixedStorage for NonZeroI64

impl FixedStorage for NonZeroI128

impl FixedStorage for NonZeroIsize

impl FixedStorage for NonZeroU8

impl FixedStorage for NonZeroU16

impl FixedStorage for NonZeroU32

impl FixedStorage for NonZeroU64

impl FixedStorage for NonZeroU128

impl FixedStorage for NonZeroUsize

impl FixedStorage for bool

impl FixedStorage for char

impl FixedStorage for f32

impl FixedStorage for f64

impl FixedStorage for i8

impl FixedStorage for i16

impl FixedStorage for i32

impl FixedStorage for i64

impl FixedStorage for i128

impl FixedStorage for isize

impl FixedStorage for u8

impl FixedStorage for u16

impl FixedStorage for u32

impl FixedStorage for u64

impl FixedStorage for u128

impl FixedStorage for usize

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

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage, E: FixedStorage, F: FixedStorage, G: FixedStorage, H: FixedStorage, I: FixedStorage> FixedStorage for (A, B, C, D, E, F, G, H, I)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage, E: FixedStorage, F: FixedStorage, G: FixedStorage, H: FixedStorage> FixedStorage for (A, B, C, D, E, F, G, H)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage, E: FixedStorage, F: FixedStorage, G: FixedStorage> FixedStorage for (A, B, C, D, E, F, G)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage, E: FixedStorage, F: FixedStorage> FixedStorage for (A, B, C, D, E, F)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage, E: FixedStorage> FixedStorage for (A, B, C, D, E)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage, D: FixedStorage> FixedStorage for (A, B, C, D)

impl<A: FixedStorage, B: FixedStorage, C: FixedStorage> FixedStorage for (A, B, C)

impl<A: FixedStorage, B: FixedStorage> FixedStorage for (A, B)

impl<A: FixedStorage> FixedStorage for (A,)

impl<T: FixedStorage + Zeroize> FixedStorage for Zeroizing<T>

zeroize::Zeroizing<T> holds T inline and wipes it on drop, so it qualifies exactly when T does.

This one matters out of proportion to its size. Zeroizing is the idiomatic “wipe this on drop” wrapper from this crate’s only non-optional dependency, so Fixed<Zeroizing<[u8; 32]>> is a shape people reach for — and because both the trait and the type are foreign to the caller, the orphan rule leaves them no way to assert it. It has to be here or it is unavailable.

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

An array never reallocates, whatever its length, so it is FixedStorage exactly when its element type is. This is the impl that covers [u8; N] and the non-byte arrays the generic arm of fixed_newtype! exists for.

impl<T: FixedStorage> FixedStorage for MaybeUninit<T>

MaybeUninit<T> is T’s storage, initialised or not. No allocation either way.

impl<T: FixedStorage> FixedStorage for Option<T>

An Option adds a discriminant and no heap storage, so it qualifies exactly when its payload does. Option<[u8; 32]> is a legitimate fixed-size secret; Option<Vec<u8>> and Option<Box<[u8]>> are both rejected, which is the point.

impl<T: FixedStorage> FixedStorage for Wrapping<T>

Wrapping is a transparent arithmetic wrapper: same storage as its payload.

Implementors

impl<T: Zeroize + FixedStorage> FixedStorage for Fixed<T>

A Fixed<T> holds T inline, so the wrapper nests: Fixed<Fixed<[u8; 32]>> is legal exactly when the payload qualifies. Without this impl the crate’s own wrapper could not be used as its own inner type.