Struct rustc_middle::ty::Const

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pub struct Const<'tcx>(pub(super) Interned<'tcx, ConstData<'tcx>>);
Expand description

Use this rather than ConstData, whenever possible.

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§0: Interned<'tcx, ConstData<'tcx>>

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impl<'tcx> Const<'tcx>

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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 }
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impl<'tcx> Const<'tcx>

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pub fn ty(self) -> Ty<'tcx>

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

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

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

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

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

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

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

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

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

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

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

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

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

Like Ty::new_error but for constants.

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

Like Ty::new_error_with_message but for constants.

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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.

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

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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.

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

Creates an interned zst constant.

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

Creates an interned bool constant.

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

Creates an interned usize constant.

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

Returns the evaluated constant

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

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

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

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

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).

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pub fn try_eval_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).

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

Panics if the value cannot be evaluated or doesn’t contain a valid integer of the given type.

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pub fn try_eval_target_usize( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx> ) -> Option<u64>

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

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pub fn eval_target_usize( self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx> ) -> u64

Panics if the value cannot be evaluated or doesn’t contain a valid usize.

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

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

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

Attempts to convert to a ValTree

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pub fn try_to_scalar(self) -> Option<Scalar<AllocId>>

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

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pub fn is_ct_infer(self) -> bool

Trait Implementations§

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

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

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'tcx> Debug for Const<'tcx>

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

Formats the value using the given formatter. Read more
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impl<'tcx> DebugWithInfcx<TyCtxt<'tcx>> for Const<'tcx>

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fn fmt<InfCtx: InferCtxtLike<TyCtxt<'tcx>>>( this: OptWithInfcx<'_, TyCtxt<'tcx>, InfCtx, &Self>, f: &mut Formatter<'_> ) -> Result

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

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

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

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

Formats the value using the given formatter. Read more
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impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<E> for Const<'tcx>

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

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

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type Result = [u8; 8]

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

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

Converts to this type from the input type.
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impl<'tcx> From<Const<'tcx>> for Term<'tcx>

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

Converts to this type from the input type.
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impl<'tcx> Hash for Const<'tcx>

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for Const<'tcx>

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

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

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type CacheSelector = DefaultCacheSelector<Const<'tcx>>

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

If the key is a DefId or DefId–equivalent, return that DefId. Otherwise, return None.
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fn ty_adt_id(&self) -> Option<DefId>

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

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type Lifted = Const<'tcx>

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

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impl<'tcx> Ord for Const<'tcx>

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fn cmp(&self, other: &Const<'tcx>) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl ParameterizedOverTcx for Const<'static>

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

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

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fn eq(&self, other: &Const<'tcx>) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<'tcx> PartialOrd<Const<'tcx>> for Const<'tcx>

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fn partial_cmp(&self, other: &Const<'tcx>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'tcx, P: Printer<'tcx>> Print<'tcx, P> for Const<'tcx>

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type Output = <P as Printer<'tcx>>::Const

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type Error = <P as Printer<'tcx>>::Error

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fn print(&self, cx: P) -> Result<Self::Output, Self::Error>

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

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

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

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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). Read more
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fn fold_with<F>(self, folder: &mut F) -> Selfwhere 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.
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impl<'tcx> TypeSuperFoldable<TyCtxt<'tcx>> for Const<'tcx>

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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).
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fn super_fold_with<F>(self, folder: &mut F) -> Selfwhere 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.
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impl<'tcx> TypeSuperVisitable<TyCtxt<'tcx>> for Const<'tcx>

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

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

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

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v). Read more
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impl<'tcx> Copy for Const<'tcx>

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

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impl<'tcx> StructuralEq for Const<'tcx>

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

Auto Trait Implementations§

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impl<'tcx> !RefUnwindSafe for Const<'tcx>

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impl<'tcx> Send for Const<'tcx>

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impl<'tcx> Sync for Const<'tcx>

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impl<'tcx> Unpin for Const<'tcx>

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impl<'tcx> !UnwindSafe for Const<'tcx>

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]

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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> Rwhere I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<Tcx, T> DepNodeParams<Tcx> for Twhere Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,

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default fn fingerprint_style() -> FingerprintStyle

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default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint

This method turns the parameters of a DepNodeConstructor into an opaque Fingerprint to be used in DepNode. Not all DepNodeParams support being turned into a Fingerprint (they don’t need to if the corresponding DepNode is anonymous).
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default fn to_debug_str(&self, _: Tcx) -> String

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default fn recover(_: Tcx, _: &DepNode) -> Option<T>

This method tries to recover the query key from the given DepNode, something which is needed when forcing DepNodes during red-green evaluation. The query system will only call this method if fingerprint_style() is not FingerprintStyle::Opaque. It is always valid to return None here, in which case incremental compilation will treat the query as having changed instead of forcing it.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P> IntoQueryParam<P> for P

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impl<'tcx, T> IsSuggestable<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,

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fn is_suggestable(self, tcx: TyCtxt<'tcx>, infer_suggestable: bool) -> bool

Whether this makes sense to suggest in a diagnostic. Read more
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fn make_suggestable( self, tcx: TyCtxt<'tcx>, infer_suggestable: bool ) -> Option<T>

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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impl<T> ToString for Twhere T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>>,

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

Returns true if this type has any regions that escape binder (and hence are not bound by it).
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fn has_escaping_bound_vars(&self) -> bool

Return true if this type has regions that are not a part of the type. For example, for<'a> fn(&'a i32) return false, while fn(&'a i32) would return true. The latter can occur when traversing through the former. Read more
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fn has_type_flags(&self, flags: TypeFlags) -> bool

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fn has_projections(&self) -> bool

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fn has_inherent_projections(&self) -> bool

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fn has_opaque_types(&self) -> bool

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fn has_generators(&self) -> bool

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fn references_error(&self) -> bool

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fn error_reported(&self) -> Result<(), ErrorGuaranteed>

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fn has_non_region_param(&self) -> bool

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fn has_infer_regions(&self) -> bool

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fn has_infer_types(&self) -> bool

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fn has_non_region_infer(&self) -> bool

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fn has_infer(&self) -> bool

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fn has_placeholders(&self) -> bool

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fn has_non_region_placeholders(&self) -> bool

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fn has_param(&self) -> bool

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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.
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fn has_erased_regions(&self) -> bool

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fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.
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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.
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fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions
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fn has_non_region_late_bound(&self) -> bool

True if there are any late-bound non-region variables
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fn has_late_bound_vars(&self) -> bool

True if there are any late-bound variables
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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.
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impl<Tcx, T> Value<Tcx> for Twhere Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle: &[QueryInfo], _guar: ErrorGuaranteed ) -> T

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