Struct rustc_middle::ty::consts::Const

pub struct Const<'tcx>(pub Interned<'tcx, ConstS<'tcx>>);

Use this rather than ConstS, whenever possible.

Tuple Fields

0: Interned<'tcx, ConstS<'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 ty(self) -> Ty<'tcx>

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

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

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

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

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

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

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

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_usize(tcx: TyCtxt<'tcx>, n: u64) -> Self

Creates an interned usize constant.

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

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

pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Const<'tcx>

Tries to evaluate the constant if it is Unevaluated. If that doesn’t succeed, return the unevaluated constant.

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

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

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

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

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> 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> 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> Key for Const<'tcx>

fn query_crate_is_local(&self) -> bool

Given an instance of this key, what crate is it referring to? This is used to find the provider.

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?

type CacheSelector = DefaultCacheSelector<Self>

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_adt_id(&self) -> Option<DefId>

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

type Lifted = Const<'tcx>

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

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

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

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParameterizedOverTcx for Const<'static>

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

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

fn eq(&self, other: &Const<'tcx>) -> 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 !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'tcx> PartialOrd<Const<'tcx>> for Const<'tcx>

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

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

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

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

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

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

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

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

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<'tcx> for Const<'tcx>

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

Provides a default fold for a 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: TypeFolder<'tcx>>(self, folder: &mut F) -> Self

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<'tcx> for Const<'tcx>

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

Provides a default visit for a 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<'tcx> for Const<'tcx>

fn visit_with<V: TypeVisitor<'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).

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 type has any regions that escape binder (and hence are not bound by it).

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.

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

fn has_non_region_param(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_non_region_infer(&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<'tcx> Copy for Const<'tcx>

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

impl<'tcx> StructuralEq 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