Enum ProjectionCacheEntry

source

pub enum ProjectionCacheEntry<'tcx> {
    InProgress,
    Ambiguous,
    Recur,
    Error,
    NormalizedTerm {
        ty: NormalizedTerm<'tcx>,
        complete: Option<EvaluationResult>,
    },
}

Variants§

§

NormalizedTerm

Fields

§ty: NormalizedTerm<'tcx>

§complete: Option<EvaluationResult>

If we were able to successfully evaluate the corresponding cache entry key during predicate evaluation, then this field stores the final result obtained from evaluating all of the projection sub-obligations. During evaluation, we will skip evaluating the cached sub-obligations in ty if this field is set. Evaluation only cares about the final result, so we don’t care about any region constraint side-effects produced by evaluating the sub-obligations.

Additionally, we will clear out the sub-obligations entirely if we ever evaluate the cache entry (along with all its sub obligations) to EvaluatedToOk. This affects all users of the cache, not just evaluation. Since a result of EvaluatedToOk means that there were no region obligations that need to be tracked, it’s fine to forget about the sub-obligations - they don’t provide any additional information. However, we do not discard any obligations when we see EvaluatedToOkModuloRegions - we don’t know which sub-obligations may introduce region constraints, so we keep them all to be safe.

When we are not performing evaluation (e.g. in FulfillmentContext), we ignore this field, and always re-process the cached sub-obligations (which may have been cleared out - see the above paragraph). This ensures that we do not lose any regions constraints that arise from processing the sub-obligations.

Enum ProjectionCacheEntryCopy item path

Variants§

InProgress

Ambiguous

Recur

Error

NormalizedTerm

Fields

Trait Implementations§

impl<'tcx> Clone for ProjectionCacheEntry<'tcx>

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

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

impl<'tcx> Debug for ProjectionCacheEntry<'tcx>

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

Auto Trait Implementations§

impl<'tcx> Freeze for ProjectionCacheEntry<'tcx>

impl<'tcx> !RefUnwindSafe for ProjectionCacheEntry<'tcx>

impl<'tcx> !Send for ProjectionCacheEntry<'tcx>

impl<'tcx> !Sync for ProjectionCacheEntry<'tcx>

impl<'tcx> Unpin for ProjectionCacheEntry<'tcx>

impl<'tcx> !UnwindSafe for ProjectionCacheEntry<'tcx>

Blanket Implementations§

impl<T> Aligned for T

const ALIGN: Alignment = _

impl<T> Any for Twhere T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for Twhere T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for Twhere T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> CloneToUninit for Twhere T: Clone,

unsafe fn clone_to_uninit(&self, dst: *mut T)

impl<T, R> CollectAndApply<T, R> for T

fn collect_and_apply<I, F>(iter: I, f: F) -> Rwhere I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

type Output = R

impl<T> Filterable for T

fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

impl<T> From<T> for T

fn from(t: T) -> T

impl<T> Instrument for T

fn instrument(self, span: Span) -> Instrumented<Self>

fn in_current_span(self) -> Instrumented<Self>

impl<T, U> Into<U> for Twhere U: From<T>,

fn into(self) -> U

impl<T> IntoEither for T

fn into_either(self, into_left: bool) -> Either<Self, Self>

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>where F: FnOnce(&Self) -> bool,

impl<P> IntoQueryParam<P> for P

fn into_query_param(self) -> P

impl<T> MaybeResult<T> for T

type Error = !

fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

impl<T> Same for T

type Output = T

impl<T> ToOwned for Twhere T: Clone,

type Owned = T

fn to_owned(&self) -> T

fn clone_into(&self, target: &mut T)

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

type Error = Infallible

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

impl<I, T, U> Upcast<I, U> for Twhere U: UpcastFrom<I, T>,

fn upcast(self, interner: I) -> U

impl<I, T> UpcastFrom<I, T> for T

fn upcast_from(from: T, _tcx: I) -> T

impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

fn vzip(self) -> V

impl<Tcx, T> Value<Tcx> for Twhere Tcx: DepContext,

default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T

impl<T> WithSubscriber for T

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>where S: Into<Dispatch>,

fn with_current_subscriber(self) -> WithDispatch<Self>

impl<'a, T> Captures<'a> for Twhere T: ?Sized,

impl<T> ErasedDestructor for Twhere T: 'static,

impl<T> MaybeSendSync for T

Layout§

Enum ProjectionCacheEntry

impl<T> Any for T
where T: 'static + ?Sized,

impl<T> Borrow<T> for T
where T: ?Sized,

impl<T> BorrowMut<T> for T
where T: ?Sized,

impl<T> CloneToUninit for T
where T: Clone,

fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

impl<T, U> Into<U> for T
where U: From<T>,

fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

impl<T> ToOwned for T
where T: Clone,

impl<T, U> TryFrom<U> for T
where U: Into<T>,

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

impl<V, T> VZip<V> for T
where V: MultiLane<T>,

impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

impl<'a, T> Captures<'a> for T
where T: ?Sized,

impl<T> ErasedDestructor for T
where T: 'static,