From cf6366babafb3b08c3944ee0a25e398af2657ed5 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Fri, 16 Sep 2022 11:02:11 +0000
Subject: [PATCH] Revert TypeVisitor changes

---
 compiler/rustc_middle/src/infer/canonical.rs  | 15 ++++++--------
 .../rustc_middle/src/mir/type_visitable.rs    |  6 ++++++
 .../rustc_middle/src/ty/structural_impls.rs   | 20 +++++++++++++++++++
 compiler/rustc_middle/src/ty/subst.rs         |  8 +++++++-
 4 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index d3cf519b633..4bad0950451 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/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 @@ pub fn unchecked_map<W>(self, map_op: impl FnOnce(V) -> W) -> Canonical<'tcx, W>
     }
 }
 
+TrivialTypeTraversalImpls! {
+    for <'tcx> {
+        crate::infer::canonical::CanonicalVarInfos<'tcx>,
+    }
+}
+
 impl<'tcx> CanonicalVarValues<'tcx> {
     #[inline]
     pub fn len(&self) -> usize {
diff --git a/compiler/rustc_middle/src/mir/type_visitable.rs b/compiler/rustc_middle/src/mir/type_visitable.rs
index 27a251f2f56..56fa7f1ede3 100644
--- a/compiler/rustc_middle/src/mir/type_visitable.rs
+++ b/compiler/rustc_middle/src/mir/type_visitable.rs
@@ -8,6 +8,12 @@ fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy>
     }
 }
 
+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)
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index f5fd1f6ffaf..ecbb2a16b69 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -602,12 +602,26 @@ fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Se
     }
 }
 
+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 @@ fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Se
     }
 }
 
+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))
diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
index 8e69bf067d0..6262aa18075 100644
--- a/compiler/rustc_middle/src/ty/subst.rs
+++ b/compiler/rustc_middle/src/ty/subst.rs
@@ -459,6 +459,12 @@ fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Se
     }
 }
 
+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 @@ fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Se
     }
 }
 
-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))
     }