Trait rustc_middle::ty::fold::TypeFolder

pub trait TypeFolder<'tcx>: FallibleTypeFolder<'tcx, Error = !> {
    fn tcx<'a>(&'a self) -> TyCtxt<'tcx>;

    fn fold_binder<T>(&mut self, t: Binder<'tcx, T>) -> Binder<'tcx, T>
    where
        T: TypeFoldable<'tcx>,
    { ... }
    fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> { ... }
    fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx> { ... }
    fn fold_const(&mut self, c: Const<'tcx>) -> Const<'tcx> { ... }
    fn fold_predicate(&mut self, p: Predicate<'tcx>) -> Predicate<'tcx> { ... }
}

This trait is implemented for every infallible folding traversal. There is a fold method defined for every type of interest. Each such method has a default that does an “identity” fold. Implementations of these methods often fall back to a super_fold_with method if the primary argument doesn’t satisfy a particular condition.

A blanket implementation of FallibleTypeFolder will defer to the infallible methods of this trait to ensure that the two APIs are coherent.

Required Methods

fn tcx<'a>(&'a self) -> TyCtxt<'tcx>

Provided Methods

fn fold_binder<T>(&mut self, t: Binder<'tcx, T>) -> Binder<'tcx, T>where
    T: TypeFoldable<'tcx>,

fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx>

fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx>

fn fold_const(&mut self, c: Const<'tcx>) -> Const<'tcx>

fn fold_predicate(&mut self, p: Predicate<'tcx>) -> Predicate<'tcx>

Implementors

impl<'a, 'tcx> TypeFolder<'tcx> for rustc_middle::ty::print::pretty::RegionFolder<'a, 'tcx>

impl<'a, 'tcx> TypeFolder<'tcx> for SubstFolder<'a, 'tcx>

impl<'a, 'tcx> TypeFolder<'tcx> for rustc_middle::ty::fold::RegionFolder<'a, 'tcx>

impl<'tcx> TypeFolder<'tcx> for RegionEraserVisitor<'tcx>

impl<'tcx> TypeFolder<'tcx> for NormalizeAfterErasingRegionsFolder<'tcx>

impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx>

impl<'tcx> TypeFolder<'tcx> for OpaqueTypeExpander<'tcx>

impl<'tcx> TypeFolder<'tcx> for Shifter<'tcx>

impl<'tcx, D> TypeFolder<'tcx> for BoundVarReplacer<'tcx, D>where
    D: BoundVarReplacerDelegate<'tcx>,

impl<'tcx, F, G, H> TypeFolder<'tcx> for BottomUpFolder<'tcx, F, G, H>where
    F: FnMut(Ty<'tcx>) -> Ty<'tcx>,
    G: FnMut(Region<'tcx>) -> Region<'tcx>,
    H: FnMut(Const<'tcx>) -> Const<'tcx>,