Enum rustc_trait_selection::infer::canonical::Certainty
source · pub enum Certainty {
Proven,
Ambiguous,
}
Expand description
Indicates whether or not we were able to prove the query to be true.
Variants§
Proven
The query is known to be true, presuming that you apply the
given var_values
and the region-constraints are satisfied.
Ambiguous
The query is not known to be true, but also not known to be
false. The var_values
represent either values that must
hold in order for the query to be true, or helpful tips that
might make it true. Currently rustc’s trait solver cannot
distinguish the two (e.g., due to our preference for where
clauses over impls).
After some unification and things have been done, it makes sense to try and prove again – of course, at that point, the canonical form will be different, making this a distinct query.
Implementations§
Trait Implementations§
source§impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for Certainty
impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for Certainty
fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher<SipHasher128>, )
source§impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Certainty
impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Certainty
source§fn try_fold_with<F>(
self,
_: &mut F,
) -> Result<Certainty, <F as FallibleTypeFolder<TyCtxt<'tcx>>>::Error>where
F: FallibleTypeFolder<TyCtxt<'tcx>>,
fn try_fold_with<F>(
self,
_: &mut F,
) -> Result<Certainty, <F as FallibleTypeFolder<TyCtxt<'tcx>>>::Error>where
F: FallibleTypeFolder<TyCtxt<'tcx>>,
source§impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Certainty
impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Certainty
source§fn visit_with<F>(&self, _: &mut F) -> <F as TypeVisitor<TyCtxt<'tcx>>>::Resultwhere
F: TypeVisitor<TyCtxt<'tcx>>,
fn visit_with<F>(&self, _: &mut F) -> <F as TypeVisitor<TyCtxt<'tcx>>>::Resultwhere
F: TypeVisitor<TyCtxt<'tcx>>,
impl Copy for Certainty
Auto Trait Implementations§
impl Freeze for Certainty
impl RefUnwindSafe for Certainty
impl Send for Certainty
impl Sync for Certainty
impl Unpin for Certainty
impl UnwindSafe for Certainty
Blanket Implementations§
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]
source§impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'a mut [T]
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<T> CloneToUninit for Twhere
T: Copy,
impl<T> CloneToUninit for Twhere
T: Copy,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Tcx, T> DepNodeParams<Tcx> for T
impl<Tcx, T> DepNodeParams<Tcx> for T
default fn fingerprint_style() -> FingerprintStyle
source§default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_debug_str(&self, _: Tcx) -> String
source§default fn recover(_: Tcx, _: &DepNode) -> Option<T>
default fn recover(_: Tcx, _: &DepNode) -> Option<T>
DepNode
,
something which is needed when forcing DepNode
s during red-green
evaluation. The query system will only call this method if
fingerprint_style()
is not FingerprintStyle::Opaque
.
It is always valid to return None
here, in which case incremental
compilation will treat the query as having changed instead of forcing it.source§impl<T> Filterable for T
impl<T> Filterable for T
source§fn filterable(
self,
filter_name: &'static str,
) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
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 moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
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 moresource§impl<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<'tcx, T> IsSuggestable<'tcx> for T
impl<'tcx, T> IsSuggestable<'tcx> for T
source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<I, T> TypeVisitableExt<I> for Twhere
I: Interner,
T: TypeVisitable<I>,
impl<I, T> TypeVisitableExt<I> for Twhere
I: Interner,
T: TypeVisitable<I>,
fn has_type_flags(&self, flags: TypeFlags) -> bool
source§fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
true
if self
has any late-bound regions that are either
bound by binder
or bound by some binder outside of binder
.
If binder
is ty::INNERMOST
, this indicates whether
there are any late-bound regions that appear free.fn error_reported(&self) -> Result<(), <I as Interner>::ErrorGuaranteed>
source§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
true
if this type has any regions that escape binder
(and
hence are not bound by it).source§fn has_escaping_bound_vars(&self) -> bool
fn has_escaping_bound_vars(&self) -> bool
true
if this type has regions that are not a part of the type.
For example, for<'a> fn(&'a i32)
return false
, while fn(&'a i32)
would return true
. The latter can occur when traversing through the
former. Read morefn has_aliases(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_coroutines(&self) -> bool
fn references_error(&self) -> bool
fn has_non_region_param(&self) -> bool
fn has_infer_regions(&self) -> bool
fn has_infer_types(&self) -> bool
fn has_non_region_infer(&self) -> bool
fn has_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn has_non_region_placeholders(&self) -> bool
fn has_param(&self) -> bool
source§fn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
fn has_erased_regions(&self) -> bool
source§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
source§fn is_global(&self) -> bool
fn is_global(&self) -> bool
source§fn has_bound_regions(&self) -> bool
fn has_bound_regions(&self) -> bool
source§fn has_non_region_bound_vars(&self) -> bool
fn has_non_region_bound_vars(&self) -> bool
source§fn has_bound_vars(&self) -> bool
fn has_bound_vars(&self) -> bool
source§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
impl
specialization.source§impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
impl<I, T, U> Upcast<I, U> for Twhere
U: UpcastFrom<I, T>,
source§impl<I, T> UpcastFrom<I, T> for T
impl<I, T> UpcastFrom<I, T> for T
fn upcast_from(from: T, _tcx: I) -> T
source§impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
impl<Tcx, T> Value<Tcx> for Twhere
Tcx: DepContext,
default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> T
source§impl<T> WithSubscriber for T
impl<T> WithSubscriber for T
source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
source§fn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
impl<T> ErasedDestructor for Twhere
T: 'static,
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: 1 byte
Size for each variant:
Proven
: 0 bytesAmbiguous
: 0 bytes