Remove type-traversal trait aliases

compiler/rustc_trait_selection/src/infer.rs

@@ -6,7 +6,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_middle::arena::ArenaAllocatable;
 use rustc_middle::infer::canonical::{Canonical, CanonicalQueryResponse, QueryResponse};
 use rustc_middle::traits::query::Fallible;
-use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_middle::ty::{GenericArg, ToPredicate};
 use rustc_span::{Span, DUMMY_SP};
 
@@ -104,8 +104,8 @@ pub trait InferCtxtBuilderExt<'tcx> {
         operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>,
     ) -> Fallible<CanonicalQueryResponse<'tcx, R>>
     where
-        K: TypeFoldable<'tcx>,
-        R: Debug + TypeFoldable<'tcx>,
+        K: TypeFoldable<TyCtxt<'tcx>>,
+        R: Debug + TypeFoldable<TyCtxt<'tcx>>,
         Canonical<'tcx, QueryResponse<'tcx, R>>: ArenaAllocatable<'tcx>;
 }
 
@@ -125,15 +125,15 @@ impl<'tcx> InferCtxtBuilderExt<'tcx> for InferCtxtBuilder<'tcx> {
     /// In part because we would need a `for<'tcx>` sort of
     /// bound for the closure and in part because it is convenient to
     /// have `'tcx` be free on this function so that we can talk about
-    /// `K: TypeFoldable<'tcx>`.)
+    /// `K: TypeFoldable<TyCtxt<'tcx>>`.)
     fn enter_canonical_trait_query<K, R>(
         &mut self,
         canonical_key: &Canonical<'tcx, K>,
         operation: impl FnOnce(&ObligationCtxt<'_, 'tcx>, K) -> Fallible<R>,
     ) -> Fallible<CanonicalQueryResponse<'tcx, R>>
     where
-        K: TypeFoldable<'tcx>,
-        R: Debug + TypeFoldable<'tcx>,
+        K: TypeFoldable<TyCtxt<'tcx>>,
+        R: Debug + TypeFoldable<TyCtxt<'tcx>>,
         Canonical<'tcx, QueryResponse<'tcx, R>>: ArenaAllocatable<'tcx>,
     {
         let (infcx, key, canonical_inference_vars) =

compiler/rustc_trait_selection/src/solve/assembly.rs

@@ -82,7 +82,7 @@ pub(super) enum CandidateSource {
 }
 
 /// Methods used to assemble candidates for either trait or projection goals.
-pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy + Eq {
+pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq {
     fn self_ty(self) -> Ty<'tcx>;
 
     fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self;

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -6,7 +6,10 @@ use rustc_infer::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
-use rustc_middle::ty::{self, ir::TypeVisitor, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable};
+use rustc_middle::ty::{
+    self, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
+    TypeVisitor,
+};
 use rustc_span::DUMMY_SP;
 use std::ops::ControlFlow;
 
@@ -137,7 +140,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             })
     }
 
-    pub(super) fn instantiate_binder_with_infer<T: TypeFoldable<'tcx> + Copy>(
+    pub(super) fn instantiate_binder_with_infer<T: TypeFoldable<TyCtxt<'tcx>> + Copy>(
         &self,
         value: ty::Binder<'tcx, T>,
     ) -> T {
@@ -148,7 +151,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         )
     }
 
-    pub(super) fn instantiate_binder_with_placeholders<T: TypeFoldable<'tcx> + Copy>(
+    pub(super) fn instantiate_binder_with_placeholders<T: TypeFoldable<TyCtxt<'tcx>> + Copy>(
         &self,
         value: ty::Binder<'tcx, T>,
     ) -> T {
@@ -157,7 +160,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
 
     pub(super) fn resolve_vars_if_possible<T>(&self, value: T) -> T
     where
-        T: TypeFoldable<'tcx>,
+        T: TypeFoldable<TyCtxt<'tcx>>,
     {
         self.infcx.resolve_vars_if_possible(value)
     }

compiler/rustc_trait_selection/src/solve/project_goals.rs

@@ -14,7 +14,7 @@ use rustc_infer::traits::Reveal;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_middle::ty::ProjectionPredicate;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_middle::ty::{ToPredicate, TypeVisitable};
+use rustc_middle::ty::{ToPredicate, TypeVisitableExt};
 use rustc_span::{sym, DUMMY_SP};
 use std::iter;
 

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -10,7 +10,7 @@ use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::util::supertraits;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
-use rustc_middle::ty::{TraitPredicate, TypeVisitable};
+use rustc_middle::ty::{TraitPredicate, TypeVisitableExt};
 use rustc_span::DUMMY_SP;
 
 pub mod structural_traits;

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -8,9 +8,8 @@ use crate::infer::region_constraints::{Constraint, RegionConstraintData};
 use crate::infer::InferCtxt;
 use crate::traits::project::ProjectAndUnifyResult;
 use rustc_middle::mir::interpret::ErrorHandled;
-use rustc_middle::ty::fold::{ir::TypeFolder, TypeSuperFoldable};
-#[cfg(not(bootstrap))]
-use rustc_middle::ty::visit::TypeVisitable;
+use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::{ImplPolarity, Region, RegionVid};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};

compiler/rustc_trait_selection/src/traits/chalk_fulfill.rs

@@ -8,7 +8,7 @@ use crate::traits::{
     SelectionError, TraitEngine,
 };
 use rustc_data_structures::fx::FxIndexSet;
-use rustc_middle::ty::TypeVisitable;
+use rustc_middle::ty::TypeVisitableExt;
 
 pub struct FulfillmentContext<'tcx> {
     obligations: FxIndexSet<PredicateObligation<'tcx>>,

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -21,8 +21,8 @@ use rustc_infer::infer::{DefiningAnchor, InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::util;
 use rustc_middle::traits::specialization_graph::OverlapMode;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
-use rustc_middle::ty::visit::TypeVisitable;
-use rustc_middle::ty::{self, ir::TypeVisitor, ImplSubject, Ty, TyCtxt};
+use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt};
+use rustc_middle::ty::{self, ImplSubject, Ty, TyCtxt, TypeVisitor};
 use rustc_span::symbol::sym;
 use rustc_span::DUMMY_SP;
 use std::fmt::Debug;

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -14,7 +14,7 @@ use rustc_middle::mir::interpret::ErrorHandled;
 
 use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
-use rustc_middle::ty::{self, ir::TypeVisitor, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, TyCtxt, TypeVisitable, TypeVisitableExt, TypeVisitor};
 
 use rustc_span::Span;
 use std::ops::ControlFlow;

compiler/rustc_trait_selection/src/traits/engine.rs

@@ -104,7 +104,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
         });
     }
 
-    pub fn normalize<T: TypeFoldable<'tcx>>(
+    pub fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(
         &self,
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
@@ -220,7 +220,7 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
         answer: T,
     ) -> Fallible<CanonicalQueryResponse<'tcx, T>>
     where
-        T: Debug + TypeFoldable<'tcx>,
+        T: Debug + TypeFoldable<TyCtxt<'tcx>>,
         Canonical<'tcx, QueryResponse<'tcx, T>>: ArenaAllocatable<'tcx>,
     {
         self.infcx.make_canonicalized_query_response(

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -34,10 +34,11 @@ use rustc_infer::infer::{InferOk, TypeTrace};
 use rustc_middle::traits::select::OverflowError;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
-use rustc_middle::ty::fold::{ir::TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::print::{with_forced_trimmed_paths, FmtPrinter, Print};
 use rustc_middle::ty::{
     self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
+    TypeVisitable, TypeVisitableExt,
 };
 use rustc_session::config::TraitSolver;
 use rustc_session::Limit;
@@ -108,7 +109,7 @@ pub trait TypeErrCtxtExt<'tcx> {
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
     where
         T: fmt::Display
-            + TypeFoldable<'tcx>
+            + TypeFoldable<TyCtxt<'tcx>>
             + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
         <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug;
 
@@ -121,7 +122,7 @@ pub trait TypeErrCtxtExt<'tcx> {
     ) -> !
     where
         T: fmt::Display
-            + TypeFoldable<'tcx>
+            + TypeFoldable<TyCtxt<'tcx>>
             + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
         <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug;
 
@@ -491,7 +492,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) -> !
     where
         T: fmt::Display
-            + TypeFoldable<'tcx>
+            + TypeFoldable<TyCtxt<'tcx>>
             + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
         <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug,
     {
@@ -511,7 +512,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>
     where
         T: fmt::Display
-            + TypeFoldable<'tcx>
+            + TypeFoldable<TyCtxt<'tcx>>
             + Print<'tcx, FmtPrinter<'tcx, 'tcx>, Output = FmtPrinter<'tcx, 'tcx>>,
         <T as Print<'tcx, FmtPrinter<'tcx, 'tcx>>>::Error: std::fmt::Debug,
     {
@@ -2970,7 +2971,7 @@ impl ArgKind {
 
 struct HasNumericInferVisitor;
 
-impl<'tcx> ty::ir::TypeVisitor<TyCtxt<'tcx>> for HasNumericInferVisitor {
+impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for HasNumericInferVisitor {
     type BreakTy = ();
 
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -30,10 +30,10 @@ use rustc_middle::hir::map;
 use rustc_middle::ty::error::TypeError::{self, Sorts};
 use rustc_middle::ty::relate::TypeRelation;
 use rustc_middle::ty::{
-    self, ir::TypeFolder, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind,
-    DefIdTree, GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, InternalSubsts,
-    IsSuggestable, ToPredicate, Ty, TyCtxt, TypeAndMut, TypeFoldable, TypeSuperFoldable,
-    TypeckResults,
+    self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree,
+    GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, InternalSubsts,
+    IsSuggestable, ToPredicate, Ty, TyCtxt, TypeAndMut, TypeFoldable, TypeFolder,
+    TypeSuperFoldable, TypeVisitableExt, TypeckResults,
 };
 use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::{sym, Ident, Symbol};

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -8,7 +8,7 @@ use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, Binder, Const, TypeVisitable};
+use rustc_middle::ty::{self, Binder, Const, TypeVisitableExt};
 use std::marker::PhantomData;
 
 use super::const_evaluatable;

compiler/rustc_trait_selection/src/traits/misc.rs

@@ -8,7 +8,7 @@ use rustc_infer::infer::canonical::Canonical;
 use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt};
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::{infer::outlives::env::OutlivesEnvironment, traits::FulfillmentError};
-use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::DUMMY_SP;
 
 use super::outlives_bounds::InferCtxtExt;

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -27,7 +27,7 @@ use crate::traits::error_reporting::TypeErrCtxtExt as _;
 use crate::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_errors::ErrorGuaranteed;
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::visit::TypeVisitable;
+use rustc_middle::ty::visit::{TypeVisitable, TypeVisitableExt};
 use rustc_middle::ty::{self, DefIdTree, ToPredicate, Ty, TyCtxt, TypeSuperVisitable};
 use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_span::def_id::{DefId, CRATE_DEF_ID};
@@ -141,7 +141,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'tcx>(
 fn pred_known_to_hold_modulo_regions<'tcx>(
     infcx: &InferCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    pred: impl ToPredicate<'tcx> + TypeVisitable<'tcx>,
+    pred: impl ToPredicate<'tcx> + TypeVisitable<TyCtxt<'tcx>>,
     span: Span,
 ) -> bool {
     let has_non_region_infer = pred.has_non_region_infer();
@@ -371,7 +371,7 @@ pub fn fully_normalize<'tcx, T>(
     value: T,
 ) -> Result<T, Vec<FulfillmentError<'tcx>>>
 where
-    T: TypeFoldable<'tcx>,
+    T: TypeFoldable<TyCtxt<'tcx>>,
 {
     let ocx = ObligationCtxt::new(infcx);
     debug!(?value);
@@ -481,7 +481,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
         generics: &'tcx ty::Generics,
         trait_item_def_id: DefId,
     }
-    impl<'tcx> ty::ir::TypeVisitor<TyCtxt<'tcx>> for ReferencesOnlyParentGenerics<'tcx> {
+    impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for ReferencesOnlyParentGenerics<'tcx> {
         type BreakTy = ();
         fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
             // If this is a parameter from the trait item's own generics, then bail

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -19,7 +19,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, InternalSubsts};
 use rustc_middle::ty::{
-    self, ir::TypeVisitor, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
+    self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
 use rustc_middle::ty::{Predicate, ToPredicate};
 use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
@@ -790,7 +790,7 @@ fn receiver_is_dispatchable<'tcx>(
     infcx.predicate_must_hold_modulo_regions(&obligation)
 }
 
-fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
+fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>(
     tcx: TyCtxt<'tcx>,
     trait_def_id: DefId,
     value: T,

compiler/rustc_trait_selection/src/traits/project.rs

@@ -30,8 +30,8 @@ use rustc_infer::infer::at::At;
 use rustc_infer::infer::resolve::OpportunisticRegionResolver;
 use rustc_infer::traits::ImplSourceBuiltinData;
 use rustc_middle::traits::select::OverflowError;
-use rustc_middle::ty::fold::{ir::TypeFolder, TypeFoldable, TypeSuperFoldable};
-use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable};
+use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable, TypeVisitableExt};
 use rustc_middle::ty::DefIdTree;
 use rustc_middle::ty::{self, Term, ToPredicate, Ty, TyCtxt};
 use rustc_span::symbol::sym;
@@ -53,11 +53,11 @@ pub trait NormalizeExt<'tcx> {
     ///
     /// This normalization should be used when the type contains inference variables or the
     /// projection may be fallible.
-    fn normalize<T: TypeFoldable<'tcx>>(&self, t: T) -> InferOk<'tcx, T>;
+    fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(&self, t: T) -> InferOk<'tcx, T>;
 }
 
 impl<'tcx> NormalizeExt<'tcx> for At<'_, 'tcx> {
-    fn normalize<T: TypeFoldable<'tcx>>(&self, value: T) -> InferOk<'tcx, T> {
+    fn normalize<T: TypeFoldable<TyCtxt<'tcx>>>(&self, value: T) -> InferOk<'tcx, T> {
         let mut selcx = SelectionContext::new(self.infcx);
         let Normalized { value, obligations } =
             normalize_with_depth(&mut selcx, self.param_env, self.cause.clone(), 0, value);
@@ -312,7 +312,7 @@ pub(crate) fn normalize_with_depth<'a, 'b, 'tcx, T>(
     value: T,
 ) -> Normalized<'tcx, T>
 where
-    T: TypeFoldable<'tcx>,
+    T: TypeFoldable<TyCtxt<'tcx>>,
 {
     let mut obligations = Vec::new();
     let value = normalize_with_depth_to(selcx, param_env, cause, depth, value, &mut obligations);
@@ -329,7 +329,7 @@ pub(crate) fn normalize_with_depth_to<'a, 'b, 'tcx, T>(
     obligations: &mut Vec<PredicateObligation<'tcx>>,
 ) -> T
 where
-    T: TypeFoldable<'tcx>,
+    T: TypeFoldable<TyCtxt<'tcx>>,
 {
     debug!(obligations.len = obligations.len());
     let mut normalizer = AssocTypeNormalizer::new(selcx, param_env, cause, depth, obligations);
@@ -349,7 +349,7 @@ pub(crate) fn try_normalize_with_depth_to<'a, 'b, 'tcx, T>(
     obligations: &mut Vec<PredicateObligation<'tcx>>,
 ) -> T
 where
-    T: TypeFoldable<'tcx>,
+    T: TypeFoldable<TyCtxt<'tcx>>,
 {
     debug!(obligations.len = obligations.len());
     let mut normalizer = AssocTypeNormalizer::new_without_eager_inference_replacement(
@@ -365,7 +365,10 @@ where
     result
 }
 
-pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<'tcx>>(value: &T, reveal: Reveal) -> bool {
+pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>(
+    value: &T,
+    reveal: Reveal,
+) -> bool {
     match reveal {
         Reveal::UserFacing => value
             .has_type_flags(ty::TypeFlags::HAS_TY_PROJECTION | ty::TypeFlags::HAS_CT_PROJECTION),
@@ -427,7 +430,7 @@ impl<'a, 'b, 'tcx> AssocTypeNormalizer<'a, 'b, 'tcx> {
         }
     }
 
-    fn fold<T: TypeFoldable<'tcx>>(&mut self, value: T) -> T {
+    fn fold<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, value: T) -> T {
         let value = self.selcx.infcx.resolve_vars_if_possible(value);
         debug!(?value);
 
@@ -450,7 +453,7 @@ impl<'a, 'b, 'tcx> TypeFolder<TyCtxt<'tcx>> for AssocTypeNormalizer<'a, 'b, 'tcx
         self.selcx.tcx()
     }
 
-    fn fold_binder<T: TypeFoldable<'tcx>>(
+    fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
         &mut self,
         t: ty::Binder<'tcx, T>,
     ) -> ty::Binder<'tcx, T> {
@@ -669,7 +672,12 @@ pub struct BoundVarReplacer<'me, 'tcx> {
 ///
 /// FIXME(@lcnr): We may even consider experimenting with eagerly replacing bound vars during
 /// normalization as well, at which point this function will be unnecessary and can be removed.
-pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: TypeFoldable<'tcx>>(
+pub fn with_replaced_escaping_bound_vars<
+    'a,
+    'tcx,
+    T: TypeFoldable<TyCtxt<'tcx>>,
+    R: TypeFoldable<TyCtxt<'tcx>>,
+>(
     infcx: &'a InferCtxt<'tcx>,
     universe_indices: &'a mut Vec<Option<ty::UniverseIndex>>,
     value: T,
@@ -695,7 +703,7 @@ pub fn with_replaced_escaping_bound_vars<'a, 'tcx, T: TypeFoldable<'tcx>, R: Typ
 impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
     /// Returns `Some` if we *were* able to replace bound vars. If there are any bound vars that
     /// use a binding level above `universe_indices.len()`, we fail.
-    pub fn replace_bound_vars<T: TypeFoldable<'tcx>>(
+    pub fn replace_bound_vars<T: TypeFoldable<TyCtxt<'tcx>>>(
         infcx: &'me InferCtxt<'tcx>,
         universe_indices: &'me mut Vec<Option<ty::UniverseIndex>>,
         value: T,
@@ -742,7 +750,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for BoundVarReplacer<'_, 'tcx> {
         self.infcx.tcx
     }
 
-    fn fold_binder<T: TypeFoldable<'tcx>>(
+    fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
         &mut self,
         t: ty::Binder<'tcx, T>,
     ) -> ty::Binder<'tcx, T> {
@@ -823,7 +831,7 @@ pub struct PlaceholderReplacer<'me, 'tcx> {
 }
 
 impl<'me, 'tcx> PlaceholderReplacer<'me, 'tcx> {
-    pub fn replace_placeholders<T: TypeFoldable<'tcx>>(
+    pub fn replace_placeholders<T: TypeFoldable<TyCtxt<'tcx>>>(
         infcx: &'me InferCtxt<'tcx>,
         mapped_regions: BTreeMap<ty::PlaceholderRegion, ty::BoundRegion>,
         mapped_types: BTreeMap<ty::PlaceholderType, ty::BoundTy>,
@@ -848,7 +856,7 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for PlaceholderReplacer<'_, 'tcx> {
         self.infcx.tcx
     }
 
-    fn fold_binder<T: TypeFoldable<'tcx>>(
+    fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
         &mut self,
         t: ty::Binder<'tcx, T>,
     ) -> ty::Binder<'tcx, T> {

compiler/rustc_trait_selection/src/traits/query/normalize.rs

@@ -11,9 +11,9 @@ use crate::traits::{ObligationCause, PredicateObligation, Reveal};
 use rustc_data_structures::sso::SsoHashMap;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_infer::traits::Normalized;
-use rustc_middle::ty::fold::{ir::FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
-use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable};
-use rustc_middle::ty::{self, ir::TypeVisitor, Ty, TyCtxt};
+use rustc_middle::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
+use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitableExt};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitor};
 use rustc_span::DUMMY_SP;
 
 use std::ops::ControlFlow;
@@ -32,7 +32,7 @@ pub trait QueryNormalizeExt<'tcx> {
     /// use [`TyCtxt::normalize_erasing_regions`], which wraps this procedure.
     fn query_normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
     where
-        T: TypeFoldable<'tcx>;
+        T: TypeFoldable<TyCtxt<'tcx>>;
 }
 
 impl<'cx, 'tcx> QueryNormalizeExt<'tcx> for At<'cx, 'tcx> {
@@ -51,7 +51,7 @@ impl<'cx, 'tcx> QueryNormalizeExt<'tcx> for At<'cx, 'tcx> {
     /// and other details are still "under development".
     fn query_normalize<T>(&self, value: T) -> Result<Normalized<'tcx, T>, NoSolution>
     where
-        T: TypeFoldable<'tcx>,
+        T: TypeFoldable<TyCtxt<'tcx>>,
     {
         debug!(
             "normalize::<{}>(value={:?}, param_env={:?}, cause={:?})",
@@ -116,7 +116,7 @@ struct MaxEscapingBoundVarVisitor {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxEscapingBoundVarVisitor {
-    fn visit_binder<T: TypeVisitable<'tcx>>(
+    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(
         &mut self,
         t: &ty::Binder<'tcx, T>,
     ) -> ControlFlow<Self::BreakTy> {
@@ -177,7 +177,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx>
         self.infcx.tcx
     }
 
-    fn try_fold_binder<T: TypeFoldable<'tcx>>(
+    fn try_fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
         &mut self,
         t: ty::Binder<'tcx, T>,
     ) -> Result<ty::Binder<'tcx, T>, Self::Error> {

compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs

@@ -54,8 +54,8 @@ pub struct TypeOpOutput<'tcx, Op: TypeOp<'tcx>> {
 /// which produces the resulting query region constraints.
 ///
 /// [c]: https://rust-lang.github.io/chalk/book/canonical_queries/canonicalization.html
-pub trait QueryTypeOp<'tcx>: fmt::Debug + Copy + TypeFoldable<'tcx> + 'tcx {
-    type QueryResponse: TypeFoldable<'tcx>;
+pub trait QueryTypeOp<'tcx>: fmt::Debug + Copy + TypeFoldable<TyCtxt<'tcx>> + 'tcx {
+    type QueryResponse: TypeFoldable<TyCtxt<'tcx>>;
 
     /// Give query the option for a simple fast path that never
     /// actually hits the tcx cache lookup etc. Return `Some(r)` with

compiler/rustc_trait_selection/src/traits/query/type_op/normalize.rs

@@ -1,7 +1,7 @@
 use crate::infer::canonical::{Canonical, CanonicalQueryResponse};
 use crate::traits::query::Fallible;
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt};
+use rustc_middle::ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
 use std::fmt;
 
 pub use rustc_middle::traits::query::type_op::Normalize;
@@ -24,7 +24,7 @@ where
     }
 }
 
-pub trait Normalizable<'tcx>: fmt::Debug + TypeFoldable<'tcx> + Lift<'tcx> + Copy {
+pub trait Normalizable<'tcx>: fmt::Debug + TypeFoldable<TyCtxt<'tcx>> + Lift<'tcx> + Copy {
     fn type_op_method(
         tcx: TyCtxt<'tcx>,
         canonicalized: Canonical<'tcx, ParamEnvAnd<'tcx, Normalize<Self>>>,

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -9,7 +9,7 @@ use hir::LangItem;
 use rustc_hir as hir;
 use rustc_infer::traits::ObligationCause;
 use rustc_infer::traits::{Obligation, SelectionError, TraitObligation};
-use rustc_middle::ty::{self, Ty, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TypeVisitableExt};
 use rustc_target::spec::abi::Abi;
 
 use crate::traits;

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -12,7 +12,7 @@ use rustc_infer::infer::InferOk;
 use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType;
 use rustc_middle::ty::{
     self, Binder, GenericParamDefKind, InternalSubsts, SubstsRef, ToPolyTraitRef, ToPredicate,
-    TraitRef, Ty, TyCtxt, TypeVisitable,
+    TraitRef, Ty, TyCtxt, TypeVisitableExt,
 };
 use rustc_session::config::TraitSolver;
 use rustc_span::def_id::DefId;

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -49,7 +49,7 @@ use rustc_middle::ty::fold::BottomUpFolder;
 use rustc_middle::ty::relate::TypeRelation;
 use rustc_middle::ty::SubstsRef;
 use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
-use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_session::config::TraitSolver;
 use rustc_span::symbol::sym;
 
@@ -1406,7 +1406,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     /// The weird return type of this function allows it to be used with the `try` (`?`)
     /// operator within certain functions.
     #[inline(always)]
-    fn check_recursion_limit<T: Display + TypeFoldable<'tcx>, V>(
+    fn check_recursion_limit<T: Display + TypeFoldable<TyCtxt<'tcx>>, V>(
         &self,
         obligation: &Obligation<'tcx, T>,
         error_obligation: &Obligation<'tcx, V>,

compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs

@@ -4,7 +4,7 @@ use crate::traits;
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::fast_reject::{self, SimplifiedType, TreatParams};
-use rustc_middle::ty::{self, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 
 pub use rustc_middle::traits::specialization_graph::*;
 

compiler/rustc_trait_selection/src/traits/structural_match.rs

@@ -1,8 +1,6 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
-#[cfg(not(bootstrap))]
-use rustc_middle::ty::TypeVisitable;
-use rustc_middle::ty::{self, ir::TypeVisitor, Ty, TyCtxt, TypeSuperVisitable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
 use rustc_span::Span;
 use std::ops::ControlFlow;
 

compiler/rustc_trait_selection/src/traits/util.rs

@@ -4,7 +4,7 @@ use smallvec::SmallVec;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitableExt};
 use rustc_middle::ty::{GenericArg, SubstsRef};
 
 use super::NormalizeExt;

compiler/rustc_trait_selection/src/traits/vtable.rs

@@ -4,7 +4,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_infer::traits::util::PredicateSet;
 use rustc_infer::traits::ImplSource;
-use rustc_middle::ty::visit::TypeVisitable;
+use rustc_middle::ty::visit::TypeVisitableExt;
 use rustc_middle::ty::InternalSubsts;
 use rustc_middle::ty::{self, GenericParamDefKind, ToPredicate, Ty, TyCtxt, VtblEntry};
 use rustc_span::{sym, Span};

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -3,7 +3,7 @@ use crate::traits;
 use rustc_hir as hir;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
 use rustc_span::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
 use rustc_span::{Span, DUMMY_SP};