Struct rustc_middle::ty::consts::Const

pub struct Const<'tcx> {
    pub ty: Ty<'tcx>,
    pub val: ConstKind<'tcx>,
}

Typed constant value.

Fields

ty: Ty<'tcx>

val: ConstKind<'tcx>

Implementations

impl<'tcx> Const<'tcx>

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

pub fn from_value(
    tcx: TyCtxt<'tcx>,
    val: ConstValue<'tcx>,
    ty: Ty<'tcx>
) -> &'tcx Self

Interns the given value as a constant.

pub fn from_scalar(tcx: TyCtxt<'tcx>, val: Scalar, ty: Ty<'tcx>) -> &'tcx Self

Interns the given scalar as a constant.

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

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

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

Creates an interned zst constant.

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

Creates an interned bool constant.

pub fn from_usize(tcx: TyCtxt<'tcx>, n: u64) -> &'tcx 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.

Trait Implementations

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

fn borrow<'a>(&'a self) -> &'a Const<'tcx>

Immutably borrows from an owned value.

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> Copy for Const<'tcx>

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

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

Formats the value using the given formatter.

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

fn decode(__decoder: &mut __D) -> Result<Self, <__D as Decoder>::Error>

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

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

Formats the value using the given formatter.

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

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

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

impl<'tcx> EqUnifyValue for &'tcx Const<'tcx>

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

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

Performs the conversion.

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, 

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 &'tcx Const<'tcx>

type CacheSelector = DefaultCacheSelector

fn query_crate(&self) -> CrateNum

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?

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

type Lifted = &'tcx 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.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

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: &Const<'tcx>) -> bool

This method tests for !=.

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: &Const<'tcx>) -> bool

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

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

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

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

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

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

type Output = P::Const

type Error = P::Error

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

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

fn decode(decoder: &mut D) -> Result<&'tcx Self, D::Error>

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

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

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

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

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

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

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

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

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

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 has_infer_consts(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&self) -> bool

fn has_re_placeholders(&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.

fn visit_tys_shallow(&self, visit: impl FnMut(Ty<'tcx>) -> bool) -> bool

A visitor that does not recurse into types, works like fn walk_shallow in Ty.