rustc_trait_selection::traits

Struct FulfillmentContext

Source
pub struct FulfillmentContext<'tcx, E: 'tcx> {
    predicates: ObligationForest<PendingPredicateObligation<'tcx>>,
    usable_in_snapshot: usize,
    _errors: PhantomData<E>,
}
Expand description

The fulfillment context is used to drive trait resolution. It consists of a list of obligations that must be (eventually) satisfied. The job is to track which are satisfied, which yielded errors, and which are still pending. At any point, users can call select_where_possible, and the fulfillment context will try to do selection, retaining only those obligations that remain ambiguous. This may be helpful in pushing type inference along. Once all type inference constraints have been generated, the method select_all_or_error can be used to report any remaining ambiguous cases as errors.

Fields§

§predicates: ObligationForest<PendingPredicateObligation<'tcx>>

A list of all obligations that have been registered with this fulfillment context.

§usable_in_snapshot: usize

The snapshot in which this context was created. Using the context outside of this snapshot leads to subtle bugs if the snapshot gets rolled back. Because of this we explicitly check that we only use the context in exactly this snapshot.

§_errors: PhantomData<E>

Implementations§

Source§

impl<'tcx, E> FulfillmentContext<'tcx, E>
where E: FromSolverError<'tcx, OldSolverError<'tcx>>,

Source

pub(super) fn new(infcx: &InferCtxt<'tcx>) -> FulfillmentContext<'tcx, E>

Creates a new fulfillment context.

Source

fn select(&mut self, selcx: SelectionContext<'_, 'tcx>) -> Vec<E>

Attempts to select obligations using selcx.

Trait Implementations§

Source§

impl<'tcx, E> TraitEngine<'tcx, E> for FulfillmentContext<'tcx, E>
where E: FromSolverError<'tcx, OldSolverError<'tcx>>,

Source§

fn register_predicate_obligation( &mut self, infcx: &InferCtxt<'tcx>, obligation: PredicateObligation<'tcx>, )

Source§

fn collect_remaining_errors(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E>

Source§

fn select_where_possible(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E>

Source§

fn drain_unstalled_obligations( &mut self, infcx: &InferCtxt<'tcx>, ) -> PredicateObligations<'tcx>

Among all pending obligations, collect those are stalled on a inference variable which has changed since the last call to select_where_possible. Those obligations are marked as successful and returned.
Source§

fn has_pending_obligations(&self) -> bool

Source§

fn pending_obligations(&self) -> PredicateObligations<'tcx>

Source§

fn register_bound( &mut self, infcx: &InferCtxt<'tcx>, param_env: ParamEnv<'tcx>, ty: Ty<'tcx>, def_id: DefId, cause: ObligationCause<'tcx>, )

Requires that ty must implement the trait with def_id in the given environment. This trait must not have any type parameters (except for Self).
Source§

fn register_predicate_obligations( &mut self, infcx: &InferCtxt<'tcx>, obligations: ThinVec<Obligation<'tcx, Predicate<'tcx>>>, )

Source§

fn select_all_or_error(&mut self, infcx: &InferCtxt<'tcx>) -> Vec<E>

Auto Trait Implementations§

§

impl<'tcx, E> DynSend for FulfillmentContext<'tcx, E>
where E: DynSend,

§

impl<'tcx, E> !DynSync for FulfillmentContext<'tcx, E>

§

impl<'tcx, E> Freeze for FulfillmentContext<'tcx, E>

§

impl<'tcx, E> !RefUnwindSafe for FulfillmentContext<'tcx, E>

§

impl<'tcx, E> Send for FulfillmentContext<'tcx, E>
where E: Send,

§

impl<'tcx, E> !Sync for FulfillmentContext<'tcx, E>

§

impl<'tcx, E> Unpin for FulfillmentContext<'tcx, E>
where E: Unpin,

§

impl<'tcx, E> !UnwindSafe for FulfillmentContext<'tcx, E>

Blanket Implementations§

Source§

impl<T> Aligned for T

Source§

const ALIGN: Alignment = _

Alignment of Self.
Source§

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

Source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
Source§

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

Source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

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

Source§

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

Mutably borrows from an owned value. Read more
Source§

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

Source§

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<_>>()).

Source§

type Output = R

Source§

impl<T> Filterable for T

Source§

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
Source§

impl<T> From<T> for T

Source§

fn from(t: T) -> T

Returns the argument unchanged.

Source§

impl<T> Instrument for T

Source§

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

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Source§

fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
Source§

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

Source§

fn into(self) -> U

Calls U::from(self).

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

Source§

impl<T> IntoEither for T

Source§

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
Source§

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
Source§

impl<P> IntoQueryParam<P> for P

Source§

impl<T> MaybeResult<T> for T

Source§

type Error = !

Source§

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

Source§

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

Source§

impl<T> Pointable for T

Source§

const ALIGN: usize = _

The alignment of pointer.
Source§

type Init = T

The type for initializers.
Source§

unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
Source§

unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
Source§

unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
Source§

unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
Source§

impl<T> Same for T

Source§

type Output = T

Should always be Self
Source§

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

Source§

type Error = Infallible

The type returned in the event of a conversion error.
Source§

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

Performs the conversion.
Source§

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

Source§

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

The type returned in the event of a conversion error.
Source§

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

Performs the conversion.
Source§

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

Source§

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

Source§

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

Source§

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

Source§

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

Source§

fn vzip(self) -> V

Source§

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

Source§

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

Source§

impl<T> WithSubscriber for T

Source§

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
Source§

fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
Source§

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

Source§

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

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: 160 bytes