pub enum ValTree<'tcx> {
Leaf(ScalarInt),
Branch(&'tcx [ValTree<'tcx>]),
}
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§
source§impl<'tcx> ValTree<'tcx>
impl<'tcx> ValTree<'tcx>
pub fn zst() -> Self
pub fn unwrap_leaf(self) -> ScalarInt
pub fn unwrap_branch(self) -> &'tcx [Self]
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>
pub fn try_to_scalar_int(self) -> Option<ScalarInt>
pub fn try_to_target_usize(self, tcx: TyCtxt<'tcx>) -> Option<u64>
Trait Implementations§
source§impl<'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, )
source§impl<'tcx> PartialEq for ValTree<'tcx>
impl<'tcx> PartialEq for ValTree<'tcx>
source§impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ValTree<'tcx>
impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ValTree<'tcx>
source§fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
self,
_: &mut F,
) -> Result<Self, F::Error>
fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F, ) -> Result<Self, F::Error>
source§impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ValTree<'tcx>
impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for ValTree<'tcx>
source§fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>(&self, _: &mut F) -> F::Result
fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>(&self, _: &mut F) -> F::Result
impl<'tcx> Copy for ValTree<'tcx>
impl<'tcx> Eq for ValTree<'tcx>
impl<'tcx> StructuralPartialEq for ValTree<'tcx>
Auto Trait Implementations§
impl<'tcx> Freeze for ValTree<'tcx>
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§
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]
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T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Copy,
impl<T> CloneToUninit for Twhere
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source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
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source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Tcx, T> DepNodeParams<Tcx> for T
impl<Tcx, T> DepNodeParams<Tcx> for T
default fn fingerprint_style() -> FingerprintStyle
source§default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_debug_str(&self, _: Tcx) -> String
source§default fn recover(_: Tcx, _: &DepNode) -> Option<T>
default fn recover(_: Tcx, _: &DepNode) -> 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.source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Filterable for T
impl<T> Filterable for T
source§fn filterable(
self,
filter_name: &'static str,
) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
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if into_left
is true
.
Converts self
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otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
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variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
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impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<'tcx, T> IsSuggestable<'tcx> for T
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source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<I, T> TypeVisitableExt<I> for Twhere
I: Interner,
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source§fn 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
.
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source§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
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fn has_escaping_bound_vars(&self) -> bool
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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 morefn has_aliases(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_coroutines(&self) -> bool
fn references_error(&self) -> bool
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 has_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn has_non_region_placeholders(&self) -> bool
fn has_param(&self) -> bool
source§fn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
source§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
source§fn is_global(&self) -> bool
fn is_global(&self) -> bool
source§fn has_bound_regions(&self) -> bool
fn has_bound_regions(&self) -> bool
source§fn has_non_region_bound_vars(&self) -> bool
fn has_non_region_bound_vars(&self) -> bool
source§fn has_bound_vars(&self) -> bool
fn has_bound_vars(&self) -> bool
source§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization.source§impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
source§impl<I, T> UpcastFrom<I, T> for T
impl<I, T> UpcastFrom<I, T> for T
fn upcast_from(from: T, _tcx: I) -> T
source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T
source§impl<T> WithSubscriber for T
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source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
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source§fn with_current_subscriber(self) -> WithDispatch<Self>
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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