Enum Nullability 

pub enum Nullability {
    Never,
    Maybe,
    Always,
}

Nullability lattice: NEVER < MAYBE < ALWAYS

Used to track whether a variable may be null/None at a program point.

Lattice Order

       MAYBE (top - unknown)
      /     \
  NEVER    ALWAYS
      \     /
       (bottom - contradiction, not representable)

Default

Defaults to Maybe (unknown nullability) per spec CAP-AI-01.

Variants

Never

Definitely not null - safe to dereference

Maybe

Could be null or non-null - requires null check

Always

Definitely null - will fail on dereference

Implementations

impl Nullability

pub fn as_str(&self) -> &'static str

Convert to string representation for JSON output

Trait Implementations

impl Clone for Nullability

fn clone(&self) -> Nullability

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Nullability

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

Formats the value using the given formatter.

impl Default for Nullability

fn default() -> Self

CAP-AI-01: Default is Maybe (unknown)

impl<'de> Deserialize<'de> for Nullability

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for Nullability

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Nullability

fn eq(&self, other: &Nullability) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Nullability

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for Nullability

impl Eq for Nullability

impl StructuralPartialEq for Nullability