Enum rustc_middle::infer::canonical::Certainty

pub enum Certainty {
    Proven,
    Ambiguous,
}

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 unifiations 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

impl Certainty

pub fn is_proven(&self) -> bool

Trait Implementations

impl Clone for Certainty

fn clone(&self) -> Certainty

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Certainty

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for Certainty

fn hash_stable(
    &self,
    __hcx: &mut StableHashingContext<'__ctx>,
    __hasher: &mut StableHasher
)

impl<'tcx> Lift<'tcx> for Certainty

type Lifted = Self

fn lift_to_tcx(self, _: TyCtxt<'tcx>) -> Option<Self>

impl<'tcx> TypeFoldable<'tcx> for Certainty

fn super_fold_with<F: TypeFolder<'tcx>>(self, _: &mut F) -> Certainty

fn super_visit_with<F: TypeVisitor<'tcx>>(
    &self,
    _: &mut F
) -> ControlFlow<F::BreakTy>

fn fold_with<F: TypeFolder<'tcx>>(self, folder: &mut F) -> Self

fn visit_with<V: TypeVisitor<'tcx>>(
    &self,
    visitor: &mut V
) -> ControlFlow<V::BreakTy>

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.

fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this self has any regions that escape binder (and hence are not bound by it).

fn has_escaping_bound_vars(&self) -> bool

fn has_type_flags(&self, flags: TypeFlags) -> bool

fn has_projections(&self) -> bool

fn has_opaque_types(&self) -> bool

fn references_error(&self) -> bool

fn has_param_types_or_consts(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_infer_types_or_consts(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&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

fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

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.

fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

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.

impl Copy for Certainty