Trait Nullability 

pub trait Nullability:
    Sealed
    + Copy
    + Default
    + 'static {
    type Decoded<T>;
    type Or<Rhs: Nullability>: Nullability;
    type And<Rhs: Nullability>: Nullability;
}

Type-level marker saying whether an expression can be NULL.

Implemented only by NonNull and Null. The associated types compute the nullability of combined expressions.

Required Associated Types

type Decoded<T>

How a decoded value of Rust type T is wrapped: T for NonNull, MaybeNull<T> for Null.

type Or<Rhs: Nullability>: Nullability

NULL propagation: nullable when either side is (a + b, f(a, b)).

Self	Rhs	Or
NonNull	NonNull	NonNull
NonNull	Null	Null
Null	_	Null

type And<Rhs: Nullability>: Nullability

NULL absorption: nullable only when both sides are (COALESCE(a, b)).

Self	Rhs	And
NonNull	_	NonNull
Null	NonNull	NonNull
Null	Null	Null

Dyn Compatibility

This trait is not dyn compatible.

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

Implementors

impl Nullability for NonNull

type Decoded<T> = T

type Or<Rhs: Nullability> = Rhs

type And<Rhs: Nullability> = NonNull

impl Nullability for Null

type Decoded<T> = MaybeNull<T>

type Or<Rhs: Nullability> = Null

type And<Rhs: Nullability> = Rhs