Revert TypeVisitor changes

Author: oli-obk

compiler/rustc_middle/src/infer/canonical.rs

@@ -44,15 +44,6 @@ pub struct Canonical<'tcx, V> {
 
 pub type CanonicalVarInfos<'tcx> = &'tcx List<CanonicalVarInfo<'tcx>>;
 
-impl<'tcx> ty::TypeFoldable<'tcx> for CanonicalVarInfos<'tcx> {
-    fn try_fold_with<F: ty::FallibleTypeFolder<'tcx>>(
-        self,
-        folder: &mut F,
-    ) -> Result<Self, F::Error> {
-        ty::util::fold_list(self, folder, |tcx, v| tcx.intern_canonical_var_infos(v))
-    }
-}
-
 /// A set of values corresponding to the canonical variables from some
 /// `Canonical`. You can give these values to
 /// `canonical_value.substitute` to substitute them into the canonical
@@ -314,6 +305,12 @@ TrivialTypeTraversalAndLiftImpls! {
     }
 }
 
+TrivialTypeTraversalImpls! {
+    for <'tcx> {
+        crate::infer::canonical::CanonicalVarInfos<'tcx>,
+    }
+}
+
 impl<'tcx> CanonicalVarValues<'tcx> {
     #[inline]
     pub fn len(&self) -> usize {

compiler/rustc_middle/src/mir/type_visitable.rs

@@ -8,6 +8,12 @@ impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.iter().try_for_each(|t| t.visit_with(visitor))
+    }
+}
+
 impl<'tcx> TypeVisitable<'tcx> for ConstantKind<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         visitor.visit_mir_const(*self)

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -602,12 +602,26 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Binder<'tcx, ty::Existentia
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx>
+    for &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>
+{
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.iter().try_for_each(|p| p.visit_with(visitor))
+    }
+}
+
 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ProjectionKind> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         ty::util::fold_list(self, folder, |tcx, v| tcx.intern_projs(v))
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<ProjectionKind> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.iter().try_for_each(|t| t.visit_with(visitor))
+    }
+}
+
 impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         folder.try_fold_ty(self)
@@ -783,6 +797,12 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ty::Predicate<'tcx>> {
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<ty::Predicate<'tcx>> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.iter().try_for_each(|p| p.visit_with(visitor))
+    }
+}
+
 impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         self.try_map_id(|x| x.try_fold_with(folder))

compiler/rustc_middle/src/ty/subst.rs

@@ -459,6 +459,12 @@ impl<'tcx> TypeFoldable<'tcx> for SubstsRef<'tcx> {
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx> for SubstsRef<'tcx> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.iter().try_for_each(|t| t.visit_with(visitor))
+    }
+}
+
 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
         // This code is fairly hot, though not as hot as `SubstsRef`.
@@ -491,7 +497,7 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
     }
 }
 
-impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for &'tcx ty::List<T> {
+impl<'tcx> TypeVisitable<'tcx> for &'tcx ty::List<Ty<'tcx>> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         self.iter().try_for_each(|t| t.visit_with(visitor))
     }