Struct Const

pub struct Const<'tcx>(pub(super) Interned<'tcx, WithCachedTypeInfo<ConstKind<'tcx>>>);

Tuple Fields

0: Interned<'tcx, WithCachedTypeInfo<ConstKind<'tcx>>>

Implementations

impl<'tcx> Const<'tcx>

pub fn walk(self) -> TypeWalker<'tcx>

Iterator that walks self and any types reachable from self, in depth-first order. Note that just walks the types that appear in self, it does not descend into the fields of structs or variants. For example:

isize => { isize }
Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
[isize] => { [isize], isize }

impl<'tcx> Const<'tcx>

pub fn kind(self) -> ConstKind<'tcx>

pub fn flags(self) -> TypeFlags

pub fn outer_exclusive_binder(self) -> DebruijnIndex

pub fn new(tcx: TyCtxt<'tcx>, kind: ConstKind<'tcx>) -> Const<'tcx>

pub fn new_param(tcx: TyCtxt<'tcx>, param: ParamConst) -> Const<'tcx>

pub fn new_var(tcx: TyCtxt<'tcx>, infer: ConstVid) -> Const<'tcx>

pub fn new_fresh(tcx: TyCtxt<'tcx>, fresh: u32) -> Const<'tcx>

pub fn new_infer(tcx: TyCtxt<'tcx>, infer: InferConst) -> Const<'tcx>

pub fn new_bound( tcx: TyCtxt<'tcx>, debruijn: DebruijnIndex, var: BoundVar, ) -> Const<'tcx>

pub fn new_placeholder( tcx: TyCtxt<'tcx>, placeholder: PlaceholderConst, ) -> Const<'tcx>

pub fn new_unevaluated( tcx: TyCtxt<'tcx>, uv: UnevaluatedConst<'tcx>, ) -> Const<'tcx>

pub fn new_value( tcx: TyCtxt<'tcx>, val: ValTree<'tcx>, ty: Ty<'tcx>, ) -> Const<'tcx>

pub fn new_expr(tcx: TyCtxt<'tcx>, expr: Expr<'tcx>) -> Const<'tcx>

pub fn new_error(tcx: TyCtxt<'tcx>, e: ErrorGuaranteed) -> Const<'tcx>

pub fn new_misc_error(tcx: TyCtxt<'tcx>) -> Const<'tcx>

Like Ty::new_error but for constants.

pub fn new_error_with_message<S: Into<MultiSpan>>( tcx: TyCtxt<'tcx>, span: S, msg: &'static str, ) -> Const<'tcx>

Like Ty::new_error_with_message but for constants.

impl<'tcx> Const<'tcx>

pub fn from_const_arg( tcx: TyCtxt<'tcx>, const_arg: &'tcx ConstArg<'tcx>, feed: FeedConstTy, ) -> Self

Convert a hir::ConstArg to a ty::Const.

pub fn from_anon_const(tcx: TyCtxt<'tcx>, def: LocalDefId) -> Self

Literals and const generic parameters are eagerly converted to a constant, everything else becomes Unevaluated.

fn from_param(tcx: TyCtxt<'tcx>, qpath: QPath<'tcx>, hir_id: HirId) -> Self

Lower a const param to a Const.

IMPORTANT: qpath must be a const param, otherwise this will panic

fn try_from_lit_or_param( tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, expr: &'tcx Expr<'tcx>, ) -> Option<Self>

pub fn from_bits( tcx: TyCtxt<'tcx>, bits: u128, ty: ParamEnvAnd<'tcx, Ty<'tcx>>, ) -> Self

Creates a constant with the given integer value and interns it.

pub fn zero_sized(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Self

Creates an interned zst constant.

pub fn from_bool(tcx: TyCtxt<'tcx>, v: bool) -> Self

Creates an interned bool constant.

pub fn from_target_usize(tcx: TyCtxt<'tcx>, n: u64) -> Self

Creates an interned usize constant.

pub fn eval_valtree( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, span: Span, ) -> Result<(Ty<'tcx>, ValTree<'tcx>), Either<Ty<'tcx>, ErrorHandled>>

Returns the evaluated constant as a valtree; if that fails due to a valtree-incompatible type, indicate which type that is by returning Err(Left(bad_type)).

pub fn normalize_internal( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, ) -> Self

Normalizes the constant to a value or an error if possible.

pub fn to_valtree(self) -> (ValTree<'tcx>, Ty<'tcx>)

Panics if self.kind != ty::ConstKind::Value

pub fn try_to_valtree(self) -> Option<(ValTree<'tcx>, Ty<'tcx>)>

Attempts to convert to a ValTree

pub fn try_to_scalar(self) -> Option<(Scalar, Ty<'tcx>)>

pub fn try_to_bool(self) -> Option<bool>

pub fn try_to_target_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64>

pub fn try_to_bits( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, ) -> Option<u128>

Attempts to evaluate the given constant to bits. Can fail to evaluate in the presence of generics (or erroneous code) or if the value can’t be represented as bits (e.g. because it contains const generic parameters or pointers).

pub fn is_ct_infer(self) -> bool

Trait Implementations

impl<'tcx> Clone for Const<'tcx>

fn clone(&self) -> Const<'tcx>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Const<TyCtxt<'tcx>> for Const<'tcx>

fn try_to_target_usize(self, interner: TyCtxt<'tcx>) -> Option<u64>

fn new_infer(tcx: TyCtxt<'tcx>, infer: InferConst) -> Self

fn new_var(tcx: TyCtxt<'tcx>, vid: ConstVid) -> Self

fn new_bound( interner: TyCtxt<'tcx>, debruijn: DebruijnIndex, var: BoundVar, ) -> Self

fn new_anon_bound( tcx: TyCtxt<'tcx>, debruijn: DebruijnIndex, var: BoundVar, ) -> Self

fn new_unevaluated(interner: TyCtxt<'tcx>, uv: UnevaluatedConst<'tcx>) -> Self

fn new_expr(interner: TyCtxt<'tcx>, expr: Expr<'tcx>) -> Self

fn new_error(interner: TyCtxt<'tcx>, guar: ErrorGuaranteed) -> Self

fn new_error_with_message(interner: I, msg: impl ToString) -> Self

fn is_ct_var(self) -> bool

impl<'tcx> Debug for Const<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Const<'tcx>

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

impl<'tcx> Display for Const<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Const<'tcx>

fn encode(&self, e: &mut E)

impl<'tcx> EraseType for Const<'tcx>

type Result = [u8; 8]

impl<'tcx> Flags for Const<'tcx>

fn flags(&self) -> TypeFlags

fn outer_exclusive_binder(&self) -> DebruijnIndex

impl<'tcx> From<Const<'tcx>> for GenericArg<'tcx>

fn from(c: Const<'tcx>) -> GenericArg<'tcx>

Converts to this type from the input type.

impl<'tcx> From<Const<'tcx>> for Term<'tcx>

fn from(c: Const<'tcx>) -> Self

Converts to this type from the input type.

impl<'tcx> Hash for Const<'tcx>

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<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for Const<'tcx>

fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher, )

impl<'tcx> IntoKind for Const<'tcx>

type Kind = ConstKind<TyCtxt<'tcx>>

fn kind(self) -> ConstKind<'tcx>

impl<'tcx> Key for Const<'tcx>

type Cache<V> = DefaultCache<Const<'tcx>, V>

fn default_span(&self, _: TyCtxt<'_>) -> Span

In the event that a cycle occurs, if no explicit span has been given for a query with key self, what span should we use?

fn key_as_def_id(&self) -> Option<DefId>

If the key is a DefId or DefId–equivalent, return that DefId. Otherwise, return None.

fn ty_def_id(&self) -> Option<DefId>

impl<'a, 'tcx> Lift<TyCtxt<'tcx>> for Const<'a>

type Lifted = Const<'tcx>

fn lift_to_interner(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted>

impl ParameterizedOverTcx for Const<'static>

type Value<'tcx> = Const<'tcx>

impl<'tcx> PartialEq for Const<'tcx>

fn eq(&self, other: &Const<'tcx>) -> 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<'tcx, P: Printer<'tcx>> Print<'tcx, P> for Const<'tcx>

fn print(&self, cx: &mut P) -> Result<(), PrintError>

impl<'tcx> Relate<TyCtxt<'tcx>> for Const<'tcx>

fn relate<R: TypeRelation<TyCtxt<'tcx>>>( relation: &mut R, a: Const<'tcx>, b: Const<'tcx>, ) -> RelateResult<'tcx, Const<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Const<'tcx>

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

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

fn fold_with<F>(self, folder: &mut F) -> Self

where F: TypeFolder<I>,

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx> TypeSuperFoldable<TyCtxt<'tcx>> for Const<'tcx>

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

Provides a default fold for a recursive type of interest. This should only be called within TypeFolder methods, when a non-custom traversal is desired for the value of the type of interest passed to that method. For example, in MyFolder::try_fold_ty(ty), it is valid to call ty.try_super_fold_with(self), but any other folding should be done with xyz.try_fold_with(self).

fn super_fold_with<F>(self, folder: &mut F) -> Self

where F: TypeFolder<I>,

A convenient alternative to try_super_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_super_fold_with.

impl<'tcx> TypeSuperVisitable<TyCtxt<'tcx>> for Const<'tcx>

fn super_visit_with<V: TypeVisitor<TyCtxt<'tcx>>>( &self, visitor: &mut V, ) -> V::Result

Provides a default visit for a recursive type of interest. This should only be called within TypeVisitor methods, when a non-custom traversal is desired for the value of the type of interest passed to that method. For example, in MyVisitor::visit_ty(ty), it is valid to call ty.super_visit_with(self), but any other visiting should be done with xyz.visit_with(self).

impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Const<'tcx>

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

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

impl<'tcx> Copy for Const<'tcx>

impl<'tcx> Eq for Const<'tcx>

impl<'tcx> StructuralPartialEq for Const<'tcx>

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: 8 bytes