Struct rustc_trait_selection::traits::FulfillmentContext
source · 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
sourceimpl<'a, 'tcx> FulfillmentContext<'tcx>
impl<'a, 'tcx> FulfillmentContext<'tcx>
sourcepub fn new() -> FulfillmentContext<'tcx>
pub fn new() -> FulfillmentContext<'tcx>
Creates a new fulfillment context.
pub fn new_in_snapshot() -> FulfillmentContext<'tcx>
sourcefn select(
&mut self,
selcx: &mut SelectionContext<'a, 'tcx>
) -> Vec<FulfillmentError<'tcx>>
fn select(
&mut self,
selcx: &mut SelectionContext<'a, 'tcx>
) -> Vec<FulfillmentError<'tcx>>
Attempts to select obligations using selcx
.
Trait Implementations
sourceimpl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx>
impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx>
sourcefn normalize_projection_type(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
param_env: ParamEnv<'tcx>,
projection_ty: ProjectionTy<'tcx>,
cause: ObligationCause<'tcx>
) -> Ty<'tcx>
fn normalize_projection_type(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
param_env: ParamEnv<'tcx>,
projection_ty: ProjectionTy<'tcx>,
cause: ObligationCause<'tcx>
) -> Ty<'tcx>
“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.
fn register_predicate_obligation(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
obligation: PredicateObligation<'tcx>
)
fn select_all_or_error(
&mut self,
infcx: &InferCtxt<'_, 'tcx>
) -> Vec<FulfillmentError<'tcx>>
fn select_where_possible(
&mut self,
infcx: &InferCtxt<'_, 'tcx>
) -> Vec<FulfillmentError<'tcx>>
fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>>
fn relationships(&mut self) -> &mut FxHashMap<TyVid, FoundRelationships>
sourcefn 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
). Read moreAuto 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
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
sourceimpl<'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>>>
)
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