12 files changed, 32 insertions, 30 deletions
diff --git a/compiler/rustc_middle/src/macros.rs b/compiler/rustc_middle/src/macros.rs
index b5f3a0e1482..b5befe70768 100644
--- a/compiler/rustc_middle/src/macros.rs
+++ b/compiler/rustc_middle/src/macros.rs
@@ -59,8 +59,8 @@ macro_rules! TrivialLiftImpls {
 macro_rules! TrivialTypeTraversalImpls {
     ($($ty:ty),+ $(,)?) => {
         $(
-            impl<'tcx> $crate::ty::fold::TypeFoldable<$crate::ty::TyCtxt<'tcx>> for $ty {
-                fn try_fold_with<F: $crate::ty::fold::FallibleTypeFolder<$crate::ty::TyCtxt<'tcx>>>(
+            impl<'tcx> $crate::ty::TypeFoldable<$crate::ty::TyCtxt<'tcx>> for $ty {
+                fn try_fold_with<F: $crate::ty::FallibleTypeFolder<$crate::ty::TyCtxt<'tcx>>>(
                     self,
                     _: &mut F,
                 ) -> ::std::result::Result<Self, F::Error> {
@@ -68,7 +68,7 @@ macro_rules! TrivialTypeTraversalImpls {
                 }
 
                 #[inline]
-                fn fold_with<F: $crate::ty::fold::TypeFolder<$crate::ty::TyCtxt<'tcx>>>(
+                fn fold_with<F: $crate::ty::TypeFolder<$crate::ty::TyCtxt<'tcx>>>(
                     self,
                     _: &mut F,
                 ) -> Self {
diff --git a/compiler/rustc_middle/src/mir/query.rs b/compiler/rustc_middle/src/mir/query.rs
index 50494355e3e..5a9fe10938a 100644
--- a/compiler/rustc_middle/src/mir/query.rs
+++ b/compiler/rustc_middle/src/mir/query.rs
@@ -13,8 +13,7 @@ use rustc_span::{Span, Symbol};
 use smallvec::SmallVec;
 
 use super::{ConstValue, SourceInfo};
-use crate::ty::fold::fold_regions;
-use crate::ty::{self, CoroutineArgsExt, OpaqueHiddenType, Ty, TyCtxt};
+use crate::ty::{self, CoroutineArgsExt, OpaqueHiddenType, Ty, TyCtxt, fold_regions};
 
 rustc_index::newtype_index! {
     #[derive(HashStable)]
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index a2472157d0e..f54dd2b0040 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -49,11 +49,10 @@ use rustc_session::{Limit, MetadataKind, Session};
 use rustc_span::def_id::{CRATE_DEF_ID, DefPathHash, StableCrateId};
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use rustc_type_ir::TyKind::*;
-use rustc_type_ir::fold::TypeFoldable;
 use rustc_type_ir::lang_items::TraitSolverLangItem;
 pub use rustc_type_ir::lift::Lift;
 use rustc_type_ir::{
-    CollectAndApply, Interner, TypeFlags, WithCachedTypeInfo, elaborate, search_graph,
+    CollectAndApply, Interner, TypeFlags, TypeFoldable, WithCachedTypeInfo, elaborate, search_graph,
 };
 use tracing::{debug, instrument};
 
diff --git a/compiler/rustc_middle/src/ty/erase_regions.rs b/compiler/rustc_middle/src/ty/erase_regions.rs
index ecca1d44907..f25c48cf42a 100644
--- a/compiler/rustc_middle/src/ty/erase_regions.rs
+++ b/compiler/rustc_middle/src/ty/erase_regions.rs
@@ -1,8 +1,9 @@
 use tracing::debug;
 
 use crate::query::Providers;
-use crate::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
-use crate::ty::{self, Ty, TyCtxt, TypeFlags, TypeVisitableExt};
+use crate::ty::{
+    self, Ty, TyCtxt, TypeFlags, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt,
+};
 
 pub(super) fn provide(providers: &mut Providers) {
     *providers = Providers { erase_regions_ty, ..*providers };
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index 4ea4050ed8b..dc2c9e3d9f1 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -1,12 +1,11 @@
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_hir::def_id::DefId;
 use rustc_type_ir::data_structures::DelayedMap;
-pub use rustc_type_ir::fold::{
-    FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable, fold_regions, shift_region,
-    shift_vars,
-};
 
-use crate::ty::{self, Binder, BoundTy, Ty, TyCtxt, TypeVisitableExt};
+use crate::ty::{
+    self, Binder, BoundTy, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
+    TypeVisitableExt,
+};
 
 ///////////////////////////////////////////////////////////////////////////
 // Some sample folders
@@ -129,7 +128,7 @@ where
             ty::Bound(debruijn, bound_ty) if debruijn == self.current_index => {
                 let ty = self.delegate.replace_ty(bound_ty);
                 debug_assert!(!ty.has_vars_bound_above(ty::INNERMOST));
-                ty::fold::shift_vars(self.tcx, ty, self.current_index.as_u32())
+                ty::shift_vars(self.tcx, ty, self.current_index.as_u32())
             }
             _ => {
                 if !t.has_vars_bound_at_or_above(self.current_index) {
@@ -169,7 +168,7 @@ where
             ty::ConstKind::Bound(debruijn, bound_const) if debruijn == self.current_index => {
                 let ct = self.delegate.replace_const(bound_const);
                 debug_assert!(!ct.has_vars_bound_above(ty::INNERMOST));
-                ty::fold::shift_vars(self.tcx, ct, self.current_index.as_u32())
+                ty::shift_vars(self.tcx, ct, self.current_index.as_u32())
             }
             _ => ct.super_fold_with(self),
         }
diff --git a/compiler/rustc_middle/src/ty/generic_args.rs b/compiler/rustc_middle/src/ty/generic_args.rs
index f24910477dc..4de851db7e6 100644
--- a/compiler/rustc_middle/src/ty/generic_args.rs
+++ b/compiler/rustc_middle/src/ty/generic_args.rs
@@ -8,16 +8,16 @@ use std::ptr::NonNull;
 use rustc_data_structures::intern::Interned;
 use rustc_errors::{DiagArgValue, IntoDiagArg};
 use rustc_hir::def_id::DefId;
-use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable, extension};
+use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeVisitable, extension};
 use rustc_serialize::{Decodable, Encodable};
 use rustc_type_ir::WithCachedTypeInfo;
 use smallvec::SmallVec;
 
 use crate::ty::codec::{TyDecoder, TyEncoder};
-use crate::ty::fold::{FallibleTypeFolder, TypeFoldable};
 use crate::ty::visit::{TypeVisitable, TypeVisitor, VisitorResult, walk_visitable_list};
 use crate::ty::{
-    self, ClosureArgs, CoroutineArgs, CoroutineClosureArgs, InlineConstArgs, Lift, List, Ty, TyCtxt,
+    self, ClosureArgs, CoroutineArgs, CoroutineClosureArgs, FallibleTypeFolder, InlineConstArgs,
+    Lift, List, Ty, TyCtxt, TypeFoldable,
 };
 
 pub type GenericArgKind<'tcx> = rustc_type_ir::GenericArgKind<TyCtxt<'tcx>>;
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index ad9d32fd6c1..8260c88c5dd 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -68,7 +68,7 @@ pub use self::context::{
     CtxtInterners, CurrentGcx, DeducedParamAttrs, Feed, FreeRegionInfo, GlobalCtxt, Lift, TyCtxt,
     TyCtxtFeed, tls,
 };
-pub use self::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder, TypeSuperFoldable};
+pub use self::fold::*;
 pub use self::instance::{Instance, InstanceKind, ReifyReason, ShortInstance, UnusedGenericParams};
 pub use self::list::{List, ListWithCachedTypeInfo};
 pub use self::opaque_types::OpaqueTypeKey;
@@ -116,7 +116,7 @@ pub mod codec;
 pub mod error;
 pub mod fast_reject;
 pub mod flags;
-pub mod fold;
+mod fold;
 pub mod inhabitedness;
 pub mod layout;
 pub mod normalize_erasing_regions;
diff --git a/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs b/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
index e86e01451fe..f2a4a5a4ecf 100644
--- a/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
+++ b/compiler/rustc_middle/src/ty/normalize_erasing_regions.rs
@@ -11,8 +11,10 @@ use rustc_macros::{HashStable, TyDecodable, TyEncodable};
 use tracing::{debug, instrument};
 
 use crate::traits::query::NoSolution;
-use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder};
-use crate::ty::{self, EarlyBinder, GenericArgsRef, Ty, TyCtxt, TypeVisitableExt};
+use crate::ty::{
+    self, EarlyBinder, FallibleTypeFolder, GenericArgsRef, Ty, TyCtxt, TypeFoldable, TypeFolder,
+    TypeVisitableExt,
+};
 
 #[derive(Debug, Copy, Clone, HashStable, TyEncodable, TyDecodable)]
 pub enum NormalizationError<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/opaque_types.rs b/compiler/rustc_middle/src/ty/opaque_types.rs
index cf789807bb0..56c44c8a84c 100644
--- a/compiler/rustc_middle/src/ty/opaque_types.rs
+++ b/compiler/rustc_middle/src/ty/opaque_types.rs
@@ -4,8 +4,9 @@ use rustc_span::def_id::DefId;
 use tracing::{debug, instrument, trace};
 
 use crate::error::ConstNotUsedTraitAlias;
-use crate::ty::fold::{TypeFolder, TypeSuperFoldable};
-use crate::ty::{self, GenericArg, GenericArgKind, Ty, TyCtxt, TypeFoldable};
+use crate::ty::{
+    self, GenericArg, GenericArgKind, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
+};
 
 pub type OpaqueTypeKey<'tcx> = rustc_type_ir::OpaqueTypeKey<TyCtxt<'tcx>>;
 
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index f1d03d0a659..59512fc55f0 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -17,10 +17,12 @@ use rustc_type_ir::visit::{VisitorResult, try_visit};
 use super::print::PrettyPrinter;
 use super::{GenericArg, GenericArgKind, Pattern, Region};
 use crate::mir::PlaceElem;
-use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{FmtPrinter, Printer, with_no_trimmed_paths};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use crate::ty::{self, InferConst, Lift, Term, TermKind, Ty, TyCtxt};
+use crate::ty::{
+    self, FallibleTypeFolder, InferConst, Lift, Term, TermKind, Ty, TyCtxt, TypeFoldable,
+    TypeSuperFoldable,
+};
 
 impl fmt::Debug for ty::TraitDef {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index 0c68913904f..c0d4130336e 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -23,11 +23,10 @@ use super::TypingEnv;
 use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use crate::mir;
 use crate::query::Providers;
-use crate::ty::fold::fold_regions;
 use crate::ty::layout::{FloatExt, IntegerExt};
 use crate::ty::{
     self, Asyncness, FallibleTypeFolder, GenericArgKind, GenericArgsRef, Ty, TyCtxt, TypeFoldable,
-    TypeFolder, TypeSuperFoldable, TypeVisitableExt, Upcast,
+    TypeFolder, TypeSuperFoldable, TypeVisitableExt, Upcast, fold_regions,
 };
 
 #[derive(Copy, Clone, Debug)]
diff --git a/compiler/rustc_middle/src/ty/visit.rs b/compiler/rustc_middle/src/ty/visit.rs
index 95256b55bb4..1d912d67299 100644
--- a/compiler/rustc_middle/src/ty/visit.rs
+++ b/compiler/rustc_middle/src/ty/visit.rs
@@ -1,7 +1,7 @@
 use std::ops::ControlFlow;
 
 use rustc_data_structures::fx::FxIndexSet;
-use rustc_type_ir::fold::TypeFoldable;
+use rustc_type_ir::TypeFoldable;
 pub use rustc_type_ir::visit::*;
 
 use crate::ty::{self, Binder, Ty, TyCtxt, TypeFlags};