Enum rustc_middle::mir::interpret::value::ConstValue

pub enum ConstValue<'tcx> {
    Scalar(Scalar),
    ZeroSized,
    Slice {
        data: ConstAllocation<'tcx>,
        start: usize,
        end: usize,
    },
    ByRef {
        alloc: ConstAllocation<'tcx>,
        offset: Size,
    },
}

Represents a constant value in Rust. Scalar and Slice are optimizations for array length computations, enum discriminants and the pattern matching logic.

Variants

Scalar(Scalar)

Used only for types with layout::abi::Scalar ABI.

Not using the enum Value to encode that this must not be Uninit.

ZeroSized

Only used for ZSTs.

Slice

Fields

data: ConstAllocation<'tcx>

start: usize

end: usize

Used only for &[u8] and &str

ByRef

Fields

alloc: ConstAllocation<'tcx>

The backing memory of the value, may contain more memory than needed for just the value in order to share ConstAllocations between values

offset: Size

Offset into alloc

A value not represented/representable by Scalar or Slice

Implementations

impl<'tcx> ConstValue<'tcx>

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

pub fn try_to_scalar_int(&self) -> Option<ScalarInt>

pub fn try_to_bits(&self, size: Size) -> Option<u128>

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

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

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

pub fn from_bool(b: bool) -> Self

pub fn from_u64(i: u64) -> Self

pub fn from_machine_usize(i: u64, cx: &impl HasDataLayout) -> Self

Trait Implementations

impl<'tcx> Clone for ConstValue<'tcx>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Debug for ConstValue<'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 ConstValue<'tcx>

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

impl<'tcx, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for ConstValue<'tcx>

fn encode(&self, __encoder: &mut __E)

impl<'tcx> Hash for ConstValue<'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 ConstValue<'tcx>

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

impl<'tcx, '__lifted> Lift<'__lifted> for ConstValue<'tcx>

type Lifted = ConstValue<'__lifted>

fn lift_to_tcx(self, __tcx: TyCtxt<'__lifted>) -> Option<ConstValue<'__lifted>>

impl<'tcx> PartialEq<ConstValue<'tcx>> for ConstValue<'tcx>

fn eq(&self, other: &ConstValue<'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> TypeFoldable<'tcx> for ConstValue<'tcx>

fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
    self,
    _: &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, _: &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> TypeVisitable<'tcx> for ConstValue<'tcx>

fn visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> ControlFlow<F::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 ConstValue<'tcx>

impl<'tcx> Eq for ConstValue<'tcx>

impl<'tcx> StructuralEq for ConstValue<'tcx>

impl<'tcx> StructuralPartialEq for ConstValue<'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: 32 bytes

Size for each variant:

• Scalar: 24 bytes
• ZeroSized: 0 bytes
• Slice: 24 bytes
• ByRef: 16 bytes