Struct rustc_middle::ty::adt::AdtDef

pub struct AdtDef {
    pub did: DefId,
    pub variants: IndexVec<VariantIdx, VariantDef>,
    flags: AdtFlags,
    pub repr: ReprOptions,
}

The definition of a user-defined type, e.g., a struct, enum, or union.

These are all interned (by alloc_adt_def) into the global arena.

The initialism ADT stands for an algebraic data type (ADT). This is slightly wrong because unions are not ADTs. Moreover, Rust only allows recursive data types through indirection.

Recursive types

It may seem impossible to represent recursive types using Ty, since TyKind::Adt includes AdtDef, which includes its fields, creating a cycle. However, AdtDef does not actually include the types of its fields; it includes just their DefIds.

For example, the following type:

struct S { x: Box<S> }

is essentially represented with Ty as the following pseudocode:

struct S { x }

where x here represents the DefId of S.x. Then, the DefId can be used with TyCtxt::type_of() to get the type of the field.

Fields

did: DefId

The DefId of the struct, enum or union item.

variants: IndexVec<VariantIdx, VariantDef>

Variants of the ADT. If this is a struct or union, then there will be a single variant.

flags: AdtFlags

Flags of the ADT (e.g., is this a struct? is this non-exhaustive?).

repr: ReprOptions

Repr options provided by the user.

Implementations

impl<'tcx> AdtDef

fn uninhabited_from(
    &self,
    tcx: TyCtxt<'tcx>,
    substs: SubstsRef<'tcx>,
    param_env: ParamEnv<'tcx>
) -> DefIdForest

Calculates the forest of DefIds from which this ADT is visibly uninhabited.

impl<'tcx> AdtDef

pub(super) fn new(
    tcx: TyCtxt<'_>,
    did: DefId,
    kind: AdtKind,
    variants: IndexVec<VariantIdx, VariantDef>,
    repr: ReprOptions
) -> Self

Creates a new AdtDef.

pub fn is_struct(&self) -> bool

Returns true if this is a struct.

pub fn is_union(&self) -> bool

Returns true if this is a union.

pub fn is_enum(&self) -> bool

Returns true if this is an enum.

pub fn is_variant_list_non_exhaustive(&self) -> bool

Returns true if the variant list of this ADT is #[non_exhaustive].

pub fn adt_kind(&self) -> AdtKind

Returns the kind of the ADT.

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

Returns a description of this abstract data type.

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

Returns a description of a variant of this abstract data type.

pub fn has_ctor(&self) -> bool

If this function returns true, it implies that is_struct must return true.

pub fn is_fundamental(&self) -> bool

Returns true if this type is #[fundamental] for the purposes of coherence checking.

pub fn is_phantom_data(&self) -> bool

Returns true if this is PhantomData<T>.

pub fn is_box(&self) -> bool

Returns true if this is Box.

pub fn is_manually_drop(&self) -> bool

Returns true if this is ManuallyDrop<T>.

pub fn has_dtor(&self, tcx: TyCtxt<'tcx>) -> bool

Returns true if this type has a destructor.

pub fn has_non_const_dtor(&self, tcx: TyCtxt<'tcx>) -> bool

pub fn non_enum_variant(&self) -> &VariantDef

Asserts this is a struct or union and returns its unique variant.

pub fn predicates(&self, tcx: TyCtxt<'tcx>) -> GenericPredicates<'tcx>

pub fn all_fields(&self) -> impl Iterator<Item = &FieldDef> + Clone

Returns an iterator over all fields contained by this ADT.

pub fn is_payloadfree(&self) -> bool

Whether the ADT lacks fields. Note that this includes uninhabited enums, e.g., enum Void {} is considered payload free as well.

pub fn variant_with_id(&self, vid: DefId) -> &VariantDef

Return a VariantDef given a variant id.

pub fn variant_with_ctor_id(&self, cid: DefId) -> &VariantDef

Return a VariantDef given a constructor id.

pub fn variant_index_with_id(&self, vid: DefId) -> VariantIdx

Return the index of VariantDef given a variant id.

pub fn variant_index_with_ctor_id(&self, cid: DefId) -> VariantIdx

Return the index of VariantDef given a constructor id.

pub fn variant_of_res(&self, res: Res) -> &VariantDef

pub fn eval_explicit_discr(
    &self,
    tcx: TyCtxt<'tcx>,
    expr_did: DefId
) -> Option<Discr<'tcx>>

pub fn discriminants(
    &'tcx self,
    tcx: TyCtxt<'tcx>
) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx>

pub fn variant_range(&self) -> Range<VariantIdx>

pub fn discriminant_for_variant(
    &self,
    tcx: TyCtxt<'tcx>,
    variant_index: VariantIdx
) -> Discr<'tcx>

Computes the discriminant value used by a specific variant. Unlike discriminants, this is (amortized) constant-time, only doing at most one query for evaluating an explicit discriminant (the last one before the requested variant), assuming there are no constant-evaluation errors there.

pub fn discriminant_def_for_variant(
    &self,
    variant_index: VariantIdx
) -> (Option<DefId>, u32)

Yields a DefId for the discriminant and an offset to add to it Alternatively, if there is no explicit discriminant, returns the inferred discriminant directly.

pub fn destructor(&self, tcx: TyCtxt<'tcx>) -> Option<Destructor>

pub fn sized_constraint(&self, tcx: TyCtxt<'tcx>) -> &'tcx [Ty<'tcx>]

Returns a list of types such that Self: Sized if and only if that type is Sized, or TyErr if this type is recursive.

Oddly enough, checking that the sized-constraint is Sized is actually more expressive than checking all members: the Sized trait is inductive, so an associated type that references Self would prevent its containing ADT from being Sized.

Due to normalization being eager, this applies even if the associated type is behind a pointer (e.g., issue #31299).

Trait Implementations

impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for AdtDef

fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

fn allocate_from_iter<'a>(
    arena: &'a Arena<'tcx>,
    iter: impl IntoIterator<Item = Self>
) -> &'a mut [Self]

impl<'tcx> Borrow<AdtDef> for Interned<'tcx, AdtDef>

fn borrow<'a>(&'a self) -> &'a AdtDef

Immutably borrows from an owned value.

impl Debug for AdtDef

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

Formats the value using the given formatter.

impl<'tcx, D: TyDecoder<'tcx>> Decodable<D> for &'tcx AdtDef

fn decode(decoder: &mut D) -> Self

impl<'tcx, __D: TyDecoder<'tcx>> Decodable<__D> for AdtDef

fn decode(__decoder: &mut __D) -> Self

impl<'tcx, E: TyEncoder<'tcx>> Encodable<E> for &'tcx AdtDef

fn encode(&self, e: &mut E) -> Result<(), E::Error>

impl<'tcx, __E: TyEncoder<'tcx>> Encodable<__E> for AdtDef

fn encode(&self, __encoder: &mut __E) -> Result<(), <__E as Encoder>::Error>

impl Hash for AdtDef

There should be only one AdtDef for each did, therefore it is fine to implement Hash only based on did.

fn hash<H: Hasher>(&self, s: &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<'a> HashStable<StableHashingContext<'a>> for AdtDef

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

impl Ord for AdtDef

There should be only one AdtDef for each did, therefore it is fine to implement Ord only based on did.

fn cmp(&self, other: &AdtDef) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<AdtDef> for AdtDef

There should be only one AdtDef for each did, therefore it is fine to implement PartialEq only based on did.

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

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

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

This method tests for !=.

impl PartialOrd<AdtDef> for AdtDef

fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'tcx, D: TyDecoder<'tcx>> RefDecodable<'tcx, D> for AdtDef

fn decode(decoder: &mut D) -> &'tcx Self

impl<'tcx> TypeFoldable<'tcx> for &'tcx AdtDef

AdtDefs are basically the same as a DefId.

fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
    self,
    _folder: &mut F
) -> Result<Self, F::Error>

fn super_visit_with<V: TypeVisitor<'tcx>>(
    &self,
    _visitor: &mut V
) -> ControlFlow<V::BreakTy>

fn super_fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &mut F) -> Self

Consumers may find this more convenient to use with infallible folders than try_super_fold_with, to which the provided default definition delegates. Implementors should not override this provided default definition, to ensure that the two methods are coherent (provide a definition of try_super_fold_with instead).

fn fold_with<F: TypeFolder<'tcx, Error = !>>(self, folder: &mut F) -> Self

Consumers may find this more convenient to use with infallible folders than try_fold_with, to which the provided default definition delegates. Implementors should not override this provided default definition, to ensure that the two methods are coherent (provide a definition of try_fold_with instead).

fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
    self,
    folder: &mut F
) -> Result<Self, F::Error>

fn visit_with<V: TypeVisitor<'tcx>>(
    &self,
    visitor: &mut V
) -> ControlFlow<V::BreakTy>

fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool

Returns true if self has any late-bound regions that are either bound by binder or bound by some binder outside of binder. If binder is ty::INNERMOST, this indicates whether there are any late-bound regions that appear free.

fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this self has any regions that escape binder (and hence are not bound by it).

fn has_escaping_bound_vars(&self) -> bool

fn has_type_flags(&self, flags: TypeFlags) -> bool

fn has_projections(&self) -> bool

fn has_opaque_types(&self) -> bool

fn references_error(&self) -> bool

fn has_param_types_or_consts(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_infer_types_or_consts(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&self) -> bool

fn has_free_regions(&self) -> bool

“Free” regions in this context means that it has any region that is not (a) erased or (b) late-bound.

fn has_erased_regions(&self) -> bool

fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

fn is_global(&self) -> bool

Indicates whether this value references only ‘global’ generic parameters that are the same regardless of what fn we are in. This is used for caching.

fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

fn still_further_specializable(&self) -> bool

Indicates whether this value still has parameters/placeholders/inference variables which could be replaced later, in a way that would change the results of impl specialization.

impl Eq for AdtDef

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 56 bytes