Enum rustc::ty::layout::Variants

pub enum Variants {
    Single {
        index: usize,
    },
    Tagged {
        discr: Scalar,
        variants: Vec<LayoutDetails>,
    },
    NicheFilling {
        dataful_variant: usize,
        niche_variants: RangeInclusive<usize>,
        niche: Scalar,
        niche_start: u128,
        variants: Vec<LayoutDetails>,
    },
}

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Variants

Single

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Single enum variants, structs/tuples, unions, and all non-ADTs.

Fields of Single

index: usize

🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Tagged

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

General-case enums: for each case there is a struct, and they all have all space reserved for the discriminant, and their first field starts at a non-0 offset, after where the discriminant would go.

Fields of Tagged

discr: Scalar	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?
variants: Vec<LayoutDetails>	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

NicheFilling

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Multiple cases distinguished by a niche (values invalid for a type): the variant dataful_variant contains a niche at an arbitrary offset (field 0 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 NicheFilling

dataful_variant: usize	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?
niche_variants: RangeInclusive<usize>	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?
niche: Scalar	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?
niche_start: u128	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?
variants: Vec<LayoutDetails>	🔬 This is a nightly-only experimental API. (rustc_private) this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Trait Implementations

impl PartialEq for Variants

fn eq(&self, __arg_0: &Variants) -> bool

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

fn ne(&self, __arg_0: &Variants) -> bool

This method tests for !=.

impl Eq for Variants

impl Hash for Variants

fn hash<__H: Hasher>(&self, __arg_0: &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].

impl Debug for Variants

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'gcx> HashStable<StableHashingContext<'gcx>> for Variants

fn hash_stable<W: StableHasherResult>(
    &self,
    hcx: &mut StableHashingContext<'gcx>,
    hasher: &mut StableHasher<W>
)

🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?