Struct rustc_trait_selection::infer::at::At

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pub struct At<'a, 'tcx> {
    pub infcx: &'a InferCtxt<'tcx>,
    pub cause: &'a ObligationCause<'tcx>,
    pub param_env: ParamEnv<'tcx>,
}

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§infcx: &'a InferCtxt<'tcx>§cause: &'a ObligationCause<'tcx>§param_env: ParamEnv<'tcx>

Implementations§

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impl<'a, 'tcx> At<'a, 'tcx>

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pub fn sup<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, actual: T, ) -> Result<InferOk<'tcx, ()>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Makes actual <: expected. For example, if type-checking a call like foo(x), where foo: fn(i32), you might have sup(i32, x), since the “expected” type is the type that appears in the signature.

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pub fn sub<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, actual: T, ) -> Result<InferOk<'tcx, ()>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Makes expected <: actual.

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pub fn eq<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, actual: T, ) -> Result<InferOk<'tcx, ()>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Makes expected == actual.

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pub fn eq_structurally_relating_aliases<T>( self, expected: T, actual: T, ) -> Result<InferOk<'tcx, ()>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Equates expected and found while structurally relating aliases. This should only be used inside of the next generation trait solver when relating rigid aliases.

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pub fn relate<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, variance: Variance, actual: T, ) -> Result<InferOk<'tcx, ()>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

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pub fn relate_no_trace<T>( self, expected: T, variance: Variance, actual: T, ) -> Result<Vec<Goal<TyCtxt<'tcx>, Predicate<'tcx>>>, NoSolution>
where T: Relate<TyCtxt<'tcx>>,

Used in the new solver since we don’t care about tracking an ObligationCause.

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pub fn eq_structurally_relating_aliases_no_trace<T>( self, expected: T, actual: T, ) -> Result<Vec<Goal<TyCtxt<'tcx>, Predicate<'tcx>>>, NoSolution>
where T: Relate<TyCtxt<'tcx>>,

Used in the new solver since we don’t care about tracking an ObligationCause.

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pub fn lub<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, actual: T, ) -> Result<InferOk<'tcx, T>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Computes the least-upper-bound, or mutual supertype, of two values. The order of the arguments doesn’t matter, but since this can result in an error (e.g., if asked to compute LUB of u32 and i32), it is meaningful to call one of them the “expected type”.

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pub fn glb<T>( self, define_opaque_types: DefineOpaqueTypes, expected: T, actual: T, ) -> Result<InferOk<'tcx, T>, TypeError<TyCtxt<'tcx>>>
where T: ToTrace<'tcx>,

Computes the greatest-lower-bound, or mutual subtype, of two values. As with lub order doesn’t matter, except for error cases.

Trait Implementations§

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impl<'a, 'tcx> Clone for At<'a, 'tcx>

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fn clone(&self) -> At<'a, '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> NormalizeExt<'tcx> for At<'_, 'tcx>

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fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(&self, value: T) -> InferOk<'tcx, T>

Normalize a value using the AssocTypeNormalizer.

This normalization should be used when the type contains inference variables or the projection may be fallible.

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fn deeply_normalize<T, E>( self, value: T, fulfill_cx: &mut dyn TraitEngine<'tcx, E>, ) -> Result<T, Vec<E>>
where T: TypeFoldable<TyCtxt<'tcx>>, E: FromSolverError<'tcx, NextSolverError<'tcx>>,

Deeply normalizes value, replacing all aliases which can by normalized in the current environment. In the new solver this errors in case normalization fails or is ambiguous.

In the old solver this simply uses normalizes and adds the nested obligations to the fulfill_cx. This is necessary as we otherwise end up recomputing the same goals in both a temporary and the shared context which negatively impacts performance as these don’t share caching.

FIXME(-Znext-solver): For performance reasons, we currently reuse an existing fulfillment context in the old solver. Once we have removed the old solver, we can remove the fulfill_cx parameter on this function.

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impl<'cx, 'tcx> QueryNormalizeExt<'tcx> for At<'cx, 'tcx>

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fn query_normalize<T>(self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
where T: TypeFoldable<TyCtxt<'tcx>>,

Normalize value in the context of the inference context, yielding a resulting type, or an error if value cannot be normalized. If you don’t care about regions, you should prefer normalize_erasing_regions, which is more efficient.

If the normalization succeeds and is unambiguous, returns back the normalized value along with various outlives relations (in the form of obligations that must be discharged).

N.B., this will eventually be the main means of normalizing, but for now should be used only when we actually know that normalization will succeed, since error reporting and other details are still “under development”.

This normalization should only be used when the projection does not have possible ambiguity or may not be well-formed.

After codegen, when lifetimes do not matter, it is preferable to instead use TyCtxt::normalize_erasing_regions, which wraps this procedure.

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impl<'tcx> StructurallyNormalizeExt<'tcx> for At<'_, 'tcx>

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fn structurally_normalize<E: 'tcx>( &self, ty: Ty<'tcx>, fulfill_cx: &mut dyn TraitEngine<'tcx, E>, ) -> Result<Ty<'tcx>, Vec<E>>

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impl<'a, 'tcx> Copy for At<'a, 'tcx>

Auto Trait Implementations§

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impl<'a, 'tcx> Freeze for At<'a, 'tcx>

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impl<'a, 'tcx> !RefUnwindSafe for At<'a, 'tcx>

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impl<'a, 'tcx> !Send for At<'a, 'tcx>

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impl<'a, 'tcx> !Sync for At<'a, 'tcx>

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impl<'a, 'tcx> Unpin for At<'a, 'tcx>

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impl<'a, 'tcx> !UnwindSafe for At<'a, '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<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]

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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> CloneToUninit for T
where T: Clone,

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

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. 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<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<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> 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<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<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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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

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