Enum rustc_target::abi::DiscriminantKind

pub enum DiscriminantKind {
    Tag,
    Niche {
        dataful_variant: VariantIdx,
        niche_variants: RangeInclusive<VariantIdx>,
        niche_start: u128,
    },
}

Variants

Tag

Integer tag holding the discriminant value itself.

Niche

Niche (values invalid for a type) encoding the discriminant: the variant dataful_variant contains a niche at an arbitrary offset (field discr_index of the enum), which for a variant with discriminant d is set to (d - niche_variants.start).wrapping_add(niche_start).

For example, Option<(usize, &T)> is represented such that None has a null pointer for the second tuple field, and Some is the identity function (with a non-null reference).

Fields of Niche

dataful_variant: VariantIdxniche_variants: RangeInclusive<VariantIdx>niche_start: u128

Trait Implementations

impl PartialEq<DiscriminantKind> for DiscriminantKind

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Eq for DiscriminantKind

impl Debug for DiscriminantKind

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

Formats the value using the given formatter.

impl Hash for DiscriminantKind

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, 

Feeds a slice of this type into the given [Hasher].