struct ProvisionalCacheEntry<X: Cx> {
    stack_depth: Option<StackDepth>,
    with_inductive_stack: Option<DetachedEntry<X>>,
    with_coinductive_stack: Option<DetachedEntry<X>>,
}
Expand description

Stores the stack depth of a currently evaluated goal and already computed results for goals which depend on other goals still on the stack.

The provisional result may depend on whether the stack above it is inductive or coinductive. Because of this, we store separate provisional results for each case. If an provisional entry is not applicable, it may be the case that we already have provisional result while computing a goal. In this case we prefer the provisional result to potentially avoid fixpoint iterations. See tests/ui/traits/next-solver/cycles/mixed-cycles-2.rs for an example.

The provisional cache can theoretically result in changes to the observable behavior, see tests/ui/traits/next-solver/cycles/provisional-cache-impacts-behavior.rs.

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§stack_depth: Option<StackDepth>§with_inductive_stack: Option<DetachedEntry<X>>§with_coinductive_stack: Option<DetachedEntry<X>>

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Trait Implementations§

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impl<X: Cx> Default for ProvisionalCacheEntry<X>

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fn default() -> Self

Returns the “default value” for a type. Read more

Auto Trait Implementations§

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impl<X> Freeze for ProvisionalCacheEntry<X>
where <X as Cx>::Result: Freeze,

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impl<X> RefUnwindSafe for ProvisionalCacheEntry<X>
where <X as Cx>::Result: RefUnwindSafe,

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impl<X> Send for ProvisionalCacheEntry<X>
where <X as Cx>::Result: Send,

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impl<X> Sync for ProvisionalCacheEntry<X>
where <X as Cx>::Result: Sync,

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impl<X> Unpin for ProvisionalCacheEntry<X>
where <X as Cx>::Result: Unpin,

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impl<X> UnwindSafe for ProvisionalCacheEntry<X>
where <X as Cx>::Result: UnwindSafe,

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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> 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<T> IntoEither for T

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

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. 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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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<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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

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

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

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

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impl<'a, T> Captures<'a> for T
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Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.