Trait rustc_middle::ty::fold::TypeFoldable

source ·

pub trait TypeFoldable<I>: TypeVisitable<I>where
    I: Interner,{
    // Required method
    fn try_fold_with<F>(
        self,
        folder: &mut F
    ) -> Result<Self, <F as FallibleTypeFolder<I>>::Error>
       where F: FallibleTypeFolder<I>;

    // Provided method
    fn fold_with<F>(self, folder: &mut F) -> Self
       where F: TypeFolder<I> { ... }
}

Expand description

This trait is implemented for every type that can be folded, providing the skeleton of the traversal.

To implement this conveniently, use the derive macro located in rustc_macros.

This trait is a sub-trait of TypeVisitable. This is because many TypeFolder instances use the methods in TypeVisitableExt while folding, which means in practice almost every foldable type needs to also be visitable. (However, there are some types that are visitable without being foldable.)

Required Methods§

source

fn try_fold_with<F>( self, folder: &mut F ) -> Result<Self, <F as FallibleTypeFolder<I>>::Error>where F: FallibleTypeFolder<I>,

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

For most types, this just traverses the value, calling try_fold_with on each field/element.

For types of interest (such as Ty), the implementation of this method calls a folder method specifically for that type (such as F::try_fold_ty). This is where control transfers from TypeFoldable to TypeFolder.

Provided Methods§

source

fn fold_with<F>(self, folder: &mut F) -> Selfwhere F: TypeFolder<I>,

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

Trait rustc_middle::ty::fold::TypeFoldable

Required Methods§

fn try_fold_with<F>( self, folder: &mut F ) -> Result<Self, <F as FallibleTypeFolder<I>>::Error>where F: FallibleTypeFolder<I>,

Provided Methods§

fn fold_with<F>(self, folder: &mut F) -> Selfwhere F: TypeFolder<I>,

Implementations on Foreign Types§

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for LocalDefId

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ErrorGuaranteed

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx [Span]

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _folder: &mut F ) -> Result<Self, F::Error>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for FieldIdx

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Symbol

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Size

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for MatchSource

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Res

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for DefId

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx [InlineAsmTemplatePiece]

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _folder: &mut F ) -> Result<Self, F::Error>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for InlineAsmTemplatePiece

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for GeneratorKind

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Movability

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Abi

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for InlineAsmOptions

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Unsafety

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for NodeId

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for VariantIdx

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for HirId

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for InlineAsmRegOrRegClass

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Ident

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for Span

fn try_fold_with<F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, _: &mut F ) -> Result<Self, F::Error>

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

Implementors§

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx List<Const<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx List<Clause<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx List<Ty<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx List<PlaceElem<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for &'tcx List<PolyExistentialPredicate<'tcx>>

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for PlaceBase

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for ProjectionKind

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for CanonicalTyVarKind

impl<'tcx> TypeFoldable<TyCtxt<'tcx>> for CanonicalVarKind<'tcx>