Trait rustc_middle::ty::fold::TypeFolder
source · [−]pub trait TypeFolder<'tcx>: Sized {
type 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>,
Self: TypeFolder<'tcx, Error = !>,
{ ... }
fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{ ... }
fn fold_region(&mut self, r: Region<'tcx>) -> Region<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{ ... }
fn fold_const(&mut self, c: &'tcx Const<'tcx>) -> &'tcx Const<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{ ... }
fn fold_predicate(&mut self, p: Predicate<'tcx>) -> Predicate<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{ ... }
fn fold_mir_const(&mut self, c: ConstantKind<'tcx>) -> ConstantKind<'tcx>
where
Self: TypeFolder<'tcx, Error = !>,
{ ... }
}Expand description
The TypeFolder trait defines the actual folding. There is a
method defined for every foldable type. Each of these has a
default implementation that does an “identity” fold. Within each
identity fold, it should invoke foo.fold_with(self) to fold each
sub-item.
If this folder is fallible (and therefore its Error
associated type is something other than the default, never),
FallibleTypeFolder should be implemented manually; otherwise,
a blanket implementation of FallibleTypeFolder will defer to
the infallible methods of this trait to ensure that the two APIs
are coherent.