Enum rustc_middle::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 )
source§impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Certainty
impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Certainty
source§fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>(
self,
_: &mut F
) -> Result<Self, F::Error>
fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>
source§impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Certainty
impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for Certainty
source§fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>(
&self,
_: &mut F
) -> ControlFlow<F::BreakTy>
fn visit_with<F: TypeVisitor<TyCtxt<'tcx>>>( &self, _: &mut F ) -> ControlFlow<F::BreakTy>
impl Copy for Certainty
Auto Trait Implementations§
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<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
Mutably borrows from an owned value. Read more
source§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Tcx, T> DepNodeParams<Tcx> for Twhere
Tcx: DepContext,
T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
impl<Tcx, T> DepNodeParams<Tcx> for Twhere Tcx: DepContext, T: for<'a> HashStable<StableHashingContext<'a>> + Debug,
default fn fingerprint_style() -> FingerprintStyle
source§default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
default fn to_fingerprint(&self, tcx: Tcx) -> Fingerprint
This method turns the parameters of a DepNodeConstructor into an opaque
Fingerprint to be used in DepNode.
Not all DepNodeParams support being turned into a Fingerprint (they
don’t need to if the corresponding DepNode is anonymous).
default fn to_debug_str(&self, _: Tcx) -> String
source§default fn recover(_: Tcx, _: &DepNode) -> Option<T>
default fn recover(_: Tcx, _: &DepNode) -> Option<T>
This method tries to recover the query key from the given
DepNode,
something which is needed when forcing DepNodes 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<P> IntoQueryParam<P> for P
impl<P> IntoQueryParam<P> for P
fn into_query_param(self) -> P
source§impl<'tcx, T> IsSuggestable<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
impl<'tcx, T> IsSuggestable<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>> + TypeFoldable<TyCtxt<'tcx>>,
source§impl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
source§impl<'tcx, T> ToPredicate<'tcx, T> for T
impl<'tcx, T> ToPredicate<'tcx, T> for T
fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T
source§impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere
T: TypeVisitable<TyCtxt<'tcx>>,
impl<'tcx, T> TypeVisitableExt<'tcx> for Twhere T: TypeVisitable<TyCtxt<'tcx>>,
source§fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
Returns
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.source§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
Returns
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
Return
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_type_flags(&self, flags: TypeFlags) -> bool
fn has_projections(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_generators(&self) -> bool
fn references_error(&self) -> bool
fn error_reported(&self) -> Result<(), ErrorGuaranteed>
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
“Free” regions in this context means that it has any region
that is not (a) erased or (b) late-bound.
fn has_erased_regions(&self) -> bool
source§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
True if there are any un-erased free regions.
source§fn is_global(&self) -> bool
fn is_global(&self) -> bool
Indicates whether this value references only ‘global’
generic parameters that are the same regardless of what fn we are
in. This is used for caching.
source§fn has_late_bound_regions(&self) -> bool
fn has_late_bound_regions(&self) -> bool
True if there are any late-bound regions
source§fn has_non_region_late_bound(&self) -> bool
fn has_non_region_late_bound(&self) -> bool
True if there are any late-bound non-region variables
source§fn has_late_bound_vars(&self) -> bool
fn has_late_bound_vars(&self) -> bool
True if there are any late-bound variables
source§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
Indicates whether this value still has parameters/placeholders/inference variables
which could be replaced later, in a way that would change the results of
impl
specialization.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: &[QueryInfo], _guar: ErrorGuaranteed ) -> 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