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

Variants§

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InProgress

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Ambiguous

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Recur

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Error

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NormalizedTy

Fields

§ty: Normalized<'tcx, Term<'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.

Trait Implementations§

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

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

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'tcx> Debug for ProjectionCacheEntry<'tcx>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'tcx> DynSend for ProjectionCacheEntry<'tcx>

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impl<'tcx> DynSync for ProjectionCacheEntry<'tcx>

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

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

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

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

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

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<T> Filterable for T

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

Creates a filterable data provider with the given name for debugging. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P> IntoQueryParam<P> for P

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impl<T> MaybeResult<T> for T

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type Error = !

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

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

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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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

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

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impl<T> WithSubscriber for T

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

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

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

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impl<T> MaybeSendSync for T
where T: Send + Sync,

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: 40 bytes

Size for each variant:

  • InProgress: 0 bytes
  • Ambiguous: 0 bytes
  • Recur: 0 bytes
  • Error: 0 bytes
  • NormalizedTy: 40 bytes