Enum rustc_middle::ty::PredicateKind

pub enum PredicateKind<'tcx> {
    Trait(TraitPredicate<'tcx>),
    RegionOutlives(RegionOutlivesPredicate<'tcx>),
    TypeOutlives(TypeOutlivesPredicate<'tcx>),
    Projection(ProjectionPredicate<'tcx>),
    WellFormed(GenericArg<'tcx>),
    ObjectSafe(DefId),
    ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind),
    Subtype(SubtypePredicate<'tcx>),
    Coerce(CoercePredicate<'tcx>),
    ConstEvaluatable(Unevaluated<'tcx, ()>),
    ConstEquate(Const<'tcx>, Const<'tcx>),
    TypeWellFormedFromEnv(Ty<'tcx>),
}

Variants

Trait(TraitPredicate<'tcx>)

Corresponds to where Foo: Bar<A, B, C>. Foo here would be the Self type of the trait reference and A, B, and C would be the type parameters.

RegionOutlives(RegionOutlivesPredicate<'tcx>)

where 'a: 'b

TypeOutlives(TypeOutlivesPredicate<'tcx>)

where T: 'a

Projection(ProjectionPredicate<'tcx>)

where <T as TraitRef>::Name == X, approximately. See the ProjectionPredicate struct for details.

WellFormed(GenericArg<'tcx>)

No syntax: T well-formed.

ObjectSafe(DefId)

Trait must be object-safe.

ClosureKind(DefId, SubstsRef<'tcx>, ClosureKind)

No direct syntax. May be thought of as where T: FnFoo<...> for some substitutions ... and T being a closure type. Satisfied (or refuted) once we know the closure’s kind.

Subtype(SubtypePredicate<'tcx>)

T1 <: T2

This obligation is created most often when we have two unresolved type variables and hence don’t have enough information to process the subtyping obligation yet.

Coerce(CoercePredicate<'tcx>)

T1 coerced to T2

Like a subtyping obligation, this is created most often when we have two unresolved type variables and hence don’t have enough information to process the coercion obligation yet. At the moment, we actually process coercions very much like subtyping and don’t handle the full coercion logic.

ConstEvaluatable(Unevaluated<'tcx, ()>)

Constant initializer must evaluate successfully.

ConstEquate(Const<'tcx>, Const<'tcx>)

Constants must be equal. The first component is the const that is expected.

TypeWellFormedFromEnv(Ty<'tcx>)

Represents a type found in the environment that we can use for implied bounds.

Only used for Chalk.

Trait Implementations

impl<'tcx> Clone for PredicateKind<'tcx>

fn clone(&self) -> PredicateKind<'tcx>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'tcx> Debug for PredicateKind<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for PredicateKind<'tcx>

fn decode(__decoder: &mut __D) -> Self

impl<'tcx> Display for PredicateKind<'tcx>

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

Formats the value using the given formatter.

impl<'tcx, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for PredicateKind<'tcx>

fn encode(&self, __encoder: &mut __E)

impl<'tcx, E: TyEncoder<I = TyCtxt<'tcx>>> EncodableWithShorthand<E> for PredicateKind<'tcx>

type Variant = PredicateKind<'tcx>

fn variant(&self) -> &Self::Variant

impl<'tcx> Hash for PredicateKind<'tcx>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,

Feeds a slice of this type into the given Hasher.

impl<'tcx, '__ctx> HashStable<StableHashingContext<'__ctx>> for PredicateKind<'tcx>

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

impl<'tcx, '__lifted> Lift<'__lifted> for PredicateKind<'tcx>

type Lifted = PredicateKind<'__lifted>

fn lift_to_tcx(
    self,
    __tcx: TyCtxt<'__lifted>
) -> Option<PredicateKind<'__lifted>>

impl<'tcx> PartialEq<PredicateKind<'tcx>> for PredicateKind<'tcx>

fn eq(&self, other: &PredicateKind<'tcx>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'tcx, P: PrettyPrinter<'tcx>> Print<'tcx, P> for PredicateKind<'tcx>

type Output = P

type Error = Error

fn print(&self, cx: P) -> Result<Self::Output, Self::Error>

impl<'tcx> TypeFoldable<'tcx> for PredicateKind<'tcx>

fn try_fold_with<__F: FallibleTypeFolder<'tcx>>(
    self,
    __folder: &mut __F
) -> Result<Self, __F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

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

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx> TypeVisitable<'tcx> for PredicateKind<'tcx>

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

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

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 error_reported(&self) -> Option<ErrorGuaranteed>

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<'tcx> Copy for PredicateKind<'tcx>

impl<'tcx> Eq for PredicateKind<'tcx>

impl<'tcx> StructuralEq for PredicateKind<'tcx>

impl<'tcx> StructuralPartialEq for PredicateKind<'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: 32 bytes

Size for each variant:

• Trait: 31 bytes
• RegionOutlives: 23 bytes
• TypeOutlives: 23 bytes
• Projection: 31 bytes
• WellFormed: 15 bytes
• ObjectSafe: 11 bytes
• ClosureKind: 23 bytes
• Subtype: 31 bytes
• Coerce: 23 bytes
• ConstEvaluatable: 31 bytes
• ConstEquate: 23 bytes
• TypeWellFormedFromEnv: 15 bytes