Struct chalk_ir::DynTy

pub struct DynTy<I: Interner> {
    pub bounds: Binders<QuantifiedWhereClauses<I>>,
    pub lifetime: Lifetime<I>,
}

A “DynTy” represents a trait object (dyn Trait). Trait objects are conceptually very related to an “existential type” of the form exists<T> { T: Trait } (another example of such type is impl Trait). DynTy represents the bounds on that type.

The “bounds” here represents the unknown self type. So, a type like dyn for<'a> Fn(&'a u32) would be represented with two-levels of binder, as “depicted” here:

exists<type> {
   vec![
       // A QuantifiedWhereClause:
       forall<region> { ^1.0: Fn(&^0.0 u32) }
   ]
}

The outer exists<type> binder indicates that there exists some type that meets the criteria within, but that type is not known. It is referenced within the type using ^1.0, indicating a bound type with debruijn index 1 (i.e., skipping through one level of binder).

Fields

bounds: Binders<QuantifiedWhereClauses<I>>

The unknown self type.

lifetime: Lifetime<I>

Lifetime of the DynTy.

Trait Implementations

impl<I: Clone + Interner> Clone for DynTy<I>

fn clone(&self) -> DynTy<I>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<I: Interner> Debug for DynTy<I>

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

Formats the value using the given formatter.

impl<I: Interner> HasInterner for DynTy<I>

type Interner = I

The interner associated with the type.

impl<I: Hash + Interner> Hash for DynTy<I>

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<I: PartialEq + Interner> PartialEq for DynTy<I>

fn eq(&self, other: &DynTy<I>) -> 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<I: Interner> TypeFoldable<I> for DynTy<I>

fn try_fold_with<E>( self, folder: &mut dyn FallibleTypeFolder<I, Error = E>, outer_binder: DebruijnIndex, ) -> Result<Self, E>

Apply the given folder folder to self; binders is the number of binders that are in scope when beginning the folder. Typically binders starts as 0, but is adjusted when we encounter Binders<T> in the IR or other similar constructs.

fn fold_with( self, folder: &mut dyn TypeFolder<I>, outer_binder: DebruijnIndex, ) -> 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<I: Interner> TypeVisitable<I> for DynTy<I>

fn visit_with<B>( &self, visitor: &mut dyn TypeVisitor<I, BreakTy = B>, outer_binder: DebruijnIndex, ) -> ControlFlow<B>

Apply the given visitor visitor to self; binders is the number of binders that are in scope when beginning the visitor. Typically binders starts as 0, but is adjusted when we encounter Binders<T> in the IR or other similar constructs.

impl<I: Interner> Zip<I> for DynTy<I>

fn zip_with<Z: Zipper<I>>( zipper: &mut Z, variance: Variance, a: &Self, b: &Self, ) -> Fallible<()>

Uses the zipper to walk through two values, ensuring that they match.

impl<I: Interner> Copy for DynTy<I>

where I::InternedLifetime: Copy, I::InternedQuantifiedWhereClauses: Copy, I::InternedVariableKinds: Copy,

impl<I: Eq + Interner> Eq for DynTy<I>

impl<I: Interner> StructuralPartialEq for DynTy<I>