Struct rustc_trait_selection::traits::FulfillmentContext
source · pub struct FulfillmentContext<'tcx> {
predicates: ObligationForest<PendingPredicateObligation<'tcx>>,
usable_in_snapshot: usize,
}
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.
Implementations§
source§impl<'tcx> FulfillmentContext<'tcx>
impl<'tcx> FulfillmentContext<'tcx>
sourcepub(super) fn new(infcx: &InferCtxt<'tcx>) -> FulfillmentContext<'tcx>
pub(super) fn new(infcx: &InferCtxt<'tcx>) -> FulfillmentContext<'tcx>
Creates a new fulfillment context.
sourcefn select(
&mut self,
selcx: SelectionContext<'_, 'tcx>
) -> Vec<FulfillmentError<'tcx>>
fn select( &mut self, selcx: SelectionContext<'_, 'tcx> ) -> Vec<FulfillmentError<'tcx>>
Attempts to select obligations using selcx
.
Trait Implementations§
source§impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx>
impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx>
fn register_predicate_obligation( &mut self, infcx: &InferCtxt<'tcx>, obligation: PredicateObligation<'tcx> )
fn collect_remaining_errors( &mut self, _infcx: &InferCtxt<'tcx> ) -> Vec<FulfillmentError<'tcx>>
fn select_where_possible( &mut self, infcx: &InferCtxt<'tcx> ) -> Vec<FulfillmentError<'tcx>>
source§fn drain_unstalled_obligations(
&mut self,
infcx: &InferCtxt<'tcx>
) -> Vec<PredicateObligation<'tcx>>
fn drain_unstalled_obligations( &mut self, infcx: &InferCtxt<'tcx> ) -> Vec<PredicateObligation<'tcx>>
select_where_possible
. Those obligations are marked as
successful and returned.fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>>
source§fn register_bound(
&mut self,
infcx: &InferCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
ty: Ty<'tcx>,
def_id: DefId,
cause: ObligationCause<'tcx>
)
fn register_bound( &mut self, infcx: &InferCtxt<'tcx>, param_env: ParamEnv<'tcx>, ty: Ty<'tcx>, def_id: DefId, cause: ObligationCause<'tcx> )
ty
must implement the trait with def_id
in
the given environment. This trait must not have any type
parameters (except for Self
).Auto Trait Implementations§
impl<'tcx> !RefUnwindSafe for FulfillmentContext<'tcx>
impl<'tcx> !Send for FulfillmentContext<'tcx>
impl<'tcx> !Sync for FulfillmentContext<'tcx>
impl<'tcx> Unpin for FulfillmentContext<'tcx>
impl<'tcx> !UnwindSafe for FulfillmentContext<'tcx>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<'tcx, T> TraitEngineExt<'tcx> for Twhere
T: TraitEngine<'tcx> + ?Sized,
impl<'tcx, T> TraitEngineExt<'tcx> for Twhere T: TraitEngine<'tcx> + ?Sized,
fn register_predicate_obligations( &mut self, infcx: &InferCtxt<'tcx>, obligations: impl IntoIterator<Item = Obligation<'tcx, Predicate<'tcx>>> )
fn select_all_or_error( &mut self, infcx: &InferCtxt<'tcx> ) -> Vec<FulfillmentError<'tcx>, Global>
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