Expand description
This datastructure is used to represent the value of constants used in the type system.
We explicitly choose a different datastructure from the way values are processed within
CTFE, as in the type system equal values (according to their PartialEq
) must also have
equal representation (==
on the rustc data structure, e.g. ValTree
) and vice versa.
Since CTFE uses AllocId
to represent pointers, it often happens that two different
AllocId
s point to equal values. So we may end up with different representations for
two constants whose value is &42
. Furthermore any kind of struct that has padding will
have arbitrary values within that padding, even if the values of the struct are the same.
ValTree
does not have this problem with representation, as it only contains integers or
lists of (nested) ValTree
.
Variants
Leaf(ScalarInt)
integers, bool
, char
are represented as scalars.
See the ScalarInt
documentation for how ScalarInt
guarantees that equal values
of these types have the same representation.
Branch(&'tcx [ValTree<'tcx>])
The fields of any kind of aggregate. Structs, tuples and arrays are represented by listing their fields’ values in order.
Enums are represented by storing their discriminant as a field, followed by all the fields of the variant.
ZST types are represented as an empty slice.
Implementations
sourceimpl<'tcx> ValTree<'tcx>
impl<'tcx> ValTree<'tcx>
pub fn zst() -> Self
pub fn unwrap_leaf(self) -> ScalarInt
pub fn unwrap_branch(self) -> &'tcx [Self]ⓘNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]
pub fn from_raw_bytes<'a>(tcx: TyCtxt<'tcx>, bytes: &'a [u8]) -> Self
pub fn from_scalar_int(i: ScalarInt) -> Self
pub fn try_to_scalar(self) -> Option<Scalar<AllocId>>
pub fn try_to_scalar_int(self) -> Option<ScalarInt>
pub fn try_to_machine_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64>
Trait Implementations
sourceimpl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for ValTree<'tcx>
impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for ValTree<'tcx>
fn hash_stable(
&self,
__hcx: &mut StableHashingContext<'__ctx>,
__hasher: &mut StableHasher
)
sourceimpl<'tcx> Ord for ValTree<'tcx>
impl<'tcx> Ord for ValTree<'tcx>
1.21.0 · sourcefn max(self, other: Self) -> Self
fn max(self, other: Self) -> Self
1.21.0 · sourcefn min(self, other: Self) -> Self
fn min(self, other: Self) -> Self
1.50.0 · sourcefn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
fn clamp(self, min: Self, max: Self) -> Selfwhere
Self: PartialOrd<Self>,
sourceimpl<'tcx> PartialEq<ValTree<'tcx>> for ValTree<'tcx>
impl<'tcx> PartialEq<ValTree<'tcx>> for ValTree<'tcx>
sourceimpl<'tcx> PartialOrd<ValTree<'tcx>> for ValTree<'tcx>
impl<'tcx> PartialOrd<ValTree<'tcx>> for ValTree<'tcx>
sourcefn partial_cmp(&self, other: &ValTree<'tcx>) -> Option<Ordering>
fn partial_cmp(&self, other: &ValTree<'tcx>) -> Option<Ordering>
1.0.0 · sourcefn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moresourceimpl<'tcx> TypeFoldable<'tcx> for ValTree<'tcx>
impl<'tcx> TypeFoldable<'tcx> for ValTree<'tcx>
sourcefn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
_: &mut F
) -> Result<ValTree<'tcx>, F::Error>
fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
self,
_: &mut F
) -> Result<ValTree<'tcx>, F::Error>
sourcefn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self
fn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self
try_fold_with
for use with infallible
folders. Do not override this method, to ensure coherence with
try_fold_with
. Read moresourceimpl<'tcx> TypeVisitable<'tcx> for ValTree<'tcx>
impl<'tcx> TypeVisitable<'tcx> for ValTree<'tcx>
sourcefn visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> ControlFlow<F::BreakTy>
fn visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> ControlFlow<F::BreakTy>
sourcefn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
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. Read moresourcefn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
true
if this self
has any regions that escape binder
(and
hence are not bound by it). Read morefn 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 error_reported(&self) -> Option<ErrorGuaranteed>
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 needs_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn needs_subst(&self) -> bool
sourcefn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
sourcefn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
sourcefn is_global(&self) -> bool
fn is_global(&self) -> bool
sourcefn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
sourcefn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization. Read moreimpl<'tcx> Copy for ValTree<'tcx>
impl<'tcx> Eq for ValTree<'tcx>
impl<'tcx> StructuralEq for ValTree<'tcx>
impl<'tcx> StructuralPartialEq for ValTree<'tcx>
Auto Trait Implementations
impl<'tcx> RefUnwindSafe for ValTree<'tcx>
impl<'tcx> Send for ValTree<'tcx>
impl<'tcx> Sync for ValTree<'tcx>
impl<'tcx> Unpin for ValTree<'tcx>
impl<'tcx> UnwindSafe for ValTree<'tcx>
Blanket Implementations
sourceimpl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter(
arena: &'a Arena<'tcx>,
iter: impl IntoIterator<Item = T>
) -> &'a mut [T]ⓘNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<Ctxt, T> DepNodeParams<Ctxt> for Twhere
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Ctxt, T> DepNodeParams<Ctxt> for Twhere
Ctxt: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
sourcedefault fn to_fingerprint(&self, tcx: Ctxt) -> Fingerprint
default fn to_fingerprint(&self, tcx: Ctxt) -> Fingerprint
default fn to_debug_str(&self, Ctxt) -> String
sourcedefault fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> Option<T>
default fn recover(Ctxt, &DepNode<<Ctxt as DepContext>::DepKind>) -> Option<T>
DepNode
,
something which is needed when forcing DepNode
s 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. Read moresourceimpl<T, R> InternIteratorElement<T, R> for T
impl<T, R> InternIteratorElement<T, R> for T
type Output = R
fn intern_with<I, F>(iter: I, f: F) -> <T as InternIteratorElement<T, R>>::Outputwhere
I: Iterator<Item = T>,
F: FnOnce(&[T]) -> R,
sourceimpl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
sourceimpl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
impl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
default fn from_cycle_error(tcx: CTX) -> T
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
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: 24 bytes
Size for each variant:
Leaf
: 17 bytesBranch
: 23 bytes