Trait rustc_type_ir::fold::FallibleTypeFolder

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pub trait FallibleTypeFolder<I: Interner>: Sized {
    type Error;

    // Required method
    fn interner(&self) -> I;

    // Provided methods
    fn try_fold_binder<T>(
        &mut self,
        t: I::Binder<T>
    ) -> Result<I::Binder<T>, Self::Error>
       where T: TypeFoldable<I>,
             I::Binder<T>: TypeSuperFoldable<I> { ... }
    fn try_fold_ty(&mut self, t: I::Ty) -> Result<I::Ty, Self::Error> { ... }
    fn try_fold_region(
        &mut self,
        r: I::Region
    ) -> Result<I::Region, Self::Error> { ... }
    fn try_fold_const(&mut self, c: I::Const) -> Result<I::Const, Self::Error> { ... }
    fn try_fold_predicate(
        &mut self,
        p: I::Predicate
    ) -> Result<I::Predicate, Self::Error> { ... }
}
Expand description

This trait is implemented for every folding traversal. There is a fold method defined for every type of interest. Each such method has a default that does an “identity” fold.

A blanket implementation of this trait (that defers to the relevant method of TypeFolder) is provided for all infallible folders in order to ensure the two APIs are coherent.

Required Associated Types§

Required Methods§

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fn interner(&self) -> I

Provided Methods§

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fn try_fold_binder<T>( &mut self, t: I::Binder<T> ) -> Result<I::Binder<T>, Self::Error>
where T: TypeFoldable<I>, I::Binder<T>: TypeSuperFoldable<I>,

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fn try_fold_ty(&mut self, t: I::Ty) -> Result<I::Ty, Self::Error>

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fn try_fold_region(&mut self, r: I::Region) -> Result<I::Region, Self::Error>

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fn try_fold_const(&mut self, c: I::Const) -> Result<I::Const, Self::Error>

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fn try_fold_predicate( &mut self, p: I::Predicate ) -> Result<I::Predicate, Self::Error>

Object Safety§

This trait is not object safe.

Implementors§

source§

impl<I: Interner, F> FallibleTypeFolder<I> for F
where F: TypeFolder<I>,

§

type Error = !