Struct Layout 

pub struct Layout {
    pub size: Option<ByteCount>,
    pub align: Option<ByteCount>,
    pub discriminator: Option<Discriminator>,
    pub uninhabited: bool,
    pub variant_layouts: IndexVec<VariantId, Option<VariantLayout>>,
    pub repr: ReprOptions,
}

Simplified type layout information.

Does not include information about niches. If the type does not have a fully known layout (e.g. it is ?Sized) some of the layout parts are not available.

Fields

size: Option<ByteCount>

The size of the type in bytes.

align: Option<ByteCount>

The alignment, in bytes.

discriminator: Option<Discriminator>

Decision tree that determines the active variant by reading memory. Only Some for enums.

uninhabited: bool

Whether the type is uninhabited, i.e. has any valid value at all. Note that uninhabited types can have arbitrary layouts: (u32, !) has space for the u32 and enum E2 { A, B(!), C(i32, !) } may have space for a discriminant.

variant_layouts: IndexVec<VariantId, Option<VariantLayout>>

Map from VariantId to the corresponding field layouts. Some variants don’t have a meaningful layout due to being uninhabited (though an uninhabited variant may have a layout). Structs and unions are modeled as having exactly one variant.

repr: ReprOptions

The representation options of this type declaration as annotated by the user.

Implementations

impl Layout

pub fn is_variant_uninhabited(&self, variant_id: VariantId) -> bool

pub fn is_c_repr(&self) -> bool

Trait Implementations

impl AstVisitable for Layout

fn drive<V: VisitAst>(&self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn drive_mut<V: VisitAstMut>(&mut self, v: &mut V) -> ControlFlow<V::Break>

Recursively visit this type with the provided visitor. This calls the visitor’s visit_$any method if it exists, otherwise visit_inner.

fn name(&self) -> &'static str

The name of the type, used for debug logging.

fn dyn_visit<T: AstVisitable>(&self, f: impl FnMut(&T))

Visit all occurrences of that type inside self, in pre-order traversal.

fn dyn_visit_mut<T: AstVisitable>(&mut self, f: impl FnMut(&mut T))

Visit all occurrences of that type inside self, in pre-order traversal.

impl Clone for Layout

fn clone(&self) -> Layout

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Layout

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Layout

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, __State: ?Sized> DeserializeState<'de, __State> for Layout

where Option<ByteCount>: Deserialize<'de>, Option<Discriminator>: Deserialize<'de>, bool: Deserialize<'de>, IndexVec<VariantId, Option<VariantLayout>>: Deserialize<'de>, ReprOptions: Deserialize<'de>,

fn deserialize_state<__D>( __state: &__State, __deserializer: __D, ) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

impl<'s, V> Drive<'s, V> for Layout

where V: Visitor + Visit<'s, IndexVec<VariantId, Option<VariantLayout>>>,

fn drive_inner(&'s self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl<'s, V> DriveMut<'s, V> for Layout

where V: Visitor + VisitMut<'s, IndexVec<VariantId, Option<VariantLayout>>>,

fn drive_inner_mut(&'s mut self, visitor: &mut V) -> ControlFlow<V::Break>

Call v.visit() on the immediate contents of self.

impl PartialEq for Layout

fn eq(&self, other: &Layout) -> 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 Layout

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<__State: ?Sized> SerializeState<__State> for Layout

where Option<ByteCount>: Serialize, Option<Discriminator>: Serialize, bool: Serialize, IndexVec<VariantId, Option<VariantLayout>>: Serialize, ReprOptions: Serialize,

fn serialize_state<__S>( &self, __state: &__State, __serializer: __S, ) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

impl Eq for Layout

impl StructuralPartialEq for Layout