pub enum TyKind<I: Interner> {
Show 23 variants Adt(AdtId<I>, Substitution<I>), AssociatedType(AssocTypeId<I>, Substitution<I>), Scalar(Scalar), Tuple(usizeSubstitution<I>), Array(Ty<I>, Const<I>), Slice(Ty<I>), Raw(MutabilityTy<I>), Ref(MutabilityLifetime<I>, Ty<I>), OpaqueType(OpaqueTyId<I>, Substitution<I>), FnDef(FnDefId<I>, Substitution<I>), Str, Never, Closure(ClosureId<I>, Substitution<I>), Generator(GeneratorId<I>, Substitution<I>), GeneratorWitness(GeneratorId<I>, Substitution<I>), Foreign(ForeignDefId<I>), Error, Placeholder(PlaceholderIndex), Dyn(DynTy<I>), Alias(AliasTy<I>), Function(FnPointer<I>), BoundVar(BoundVar), InferenceVar(InferenceVarTyVariableKind),
Expand description

Type data, which holds the actual type information.


Adt(AdtId<I>, Substitution<I>)

Abstract data types, i.e., structs, unions, or enumerations. For example, a type like Vec<T>.

AssociatedType(AssocTypeId<I>, Substitution<I>)

an associated type like Iterator::Item; see AssociatedType for details


a scalar type like bool or u32


a tuple of the given arity

Array(Ty<I>, Const<I>)

an array type like [T; N]


a slice type like [T]


a raw pointer type like *const T or *mut T

Ref(MutabilityLifetime<I>, Ty<I>)

a reference type like &T or &mut T

OpaqueType(OpaqueTyId<I>, Substitution<I>)

a placeholder for opaque types like impl Trait

FnDef(FnDefId<I>, Substitution<I>)

a function definition


the string primitive type


the never type !

Closure(ClosureId<I>, Substitution<I>)

A closure.

Generator(GeneratorId<I>, Substitution<I>)

A generator.

GeneratorWitness(GeneratorId<I>, Substitution<I>)

A generator witness.


foreign types


This can be used to represent an error, e.g. during name resolution of a type. Chalk itself will not produce this, just pass it through when given.


instantiated from a universally quantified type, e.g., from forall<T> { .. }. Stands in as a representative of “some unknown type”.


A “dyn” type is a trait object type created via the “dyn Trait” syntax. In the chalk parser, the traits that the object represents is parsed as a QuantifiedInlineBound, and is then changed to a list of where clauses during lowering.

See the Opaque variant for a discussion about the use of binders here.


An “alias” type represents some form of type alias, such as:

  • An associated type projection like <T as Iterator>::Item
  • impl Trait types
  • Named type aliases like type Foo<X> = Vec<X>


A function type such as for<'a> fn(&'a u32). Note that “higher-ranked” types (starting with for<>) are either function types or dyn types, and do not appear otherwise in Rust surface syntax.


References the binding at the given depth. The index is a [de Bruijn index], so it counts back through the in-scope binders.


Inference variable defined in the current inference context.


Show debug output for the application type.

Casts the type data to a type.

Compute type flags for a TyKind

Trait Implementations

Cast a value to type T.

Cast a value to type T.

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

The interner associated with the type.

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 !=.

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

Cast a value to type U using CastTo.

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

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.