pub struct FulfillmentContext<'tcx> {
    predicates: ObligationForest<PendingPredicateObligation<'tcx>>,
    relationships: FxHashMap<TyVid, FoundRelationships>,
    usable_in_snapshot: bool,
}
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>>relationships: FxHashMap<TyVid, FoundRelationships>usable_in_snapshot: bool

Implementations

Creates a new fulfillment context.

Attempts to select obligations using selcx.

Trait Implementations

“Normalize” a projection type <SomeType as SomeTrait>::X by creating a fresh type variable $0 as well as a projection predicate <SomeType as SomeTrait>::X == $0. When the inference engine runs, it will attempt to find an impl of SomeTrait or a where-clause that lets us unify $0 with something concrete. If this fails, we’ll unify $0 with projection_ty again.

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). Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

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: 200 bytes