pub enum PredicateKind<'tcx> {
    Trait(TraitPredicate<'tcx>),
    RegionOutlives(RegionOutlivesPredicate<'tcx>),
    TypeOutlives(TypeOutlivesPredicate<'tcx>),
    Projection(ProjectionPredicate<'tcx>),
    WellFormed(GenericArg<'tcx>),
    ObjectSafe(DefId),
    ClosureKind(DefIdSubstsRef<'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(DefIdSubstsRef<'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

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Formats the value using the given formatter. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

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

This method tests for !=.

Traverses the type in question, typically by calling try_fold_with on each field/element. This is true even for types of interest such as Ty. This should only be called within TypeFolder methods, when non-custom traversals are desired for types of interest. Read more

Traverses the type in question, typically by calling visit_with on each field/element. This is true even for types of interest such as Ty. This should only be called within TypeVisitor methods, when non-custom traversals are desired for types of interest. Read more

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

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

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

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

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. Read more

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

“Free” regions in this context means that it has any region that is not (a) erased or (b) late-bound. Read more

True if there are any un-erased free regions.

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. Read more

True if there are any late-bound regions

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. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

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). Read more

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. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

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: 40 bytes

Size for each variant:

  • Trait: 31 bytes
  • RegionOutlives: 23 bytes
  • TypeOutlives: 23 bytes
  • Projection: 39 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