Auto merge of #98206 - eggyal:align-to-chalk-folding-api, r=jackh726

Split TypeVisitable from TypeFoldable

Impl of rust-lang/compiler-team#520 following MCP approval.

r? `@ghost`

23 files changed, 27 insertions, 21 deletions

diff --git a/compiler/rustc_trait_selection/src/autoderef.rs b/compiler/rustc_trait_selection/src/autoderef.rs
index 5b88cff03d7..8b7e8984a8a 100644
--- a/compiler/rustc_trait_selection/src/autoderef.rs
+++ b/compiler/rustc_trait_selection/src/autoderef.rs
@@ -4,7 +4,7 @@ use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_infer::infer::InferCtxt;
 use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt};
-use rustc_middle::ty::{ToPredicate, TypeFoldable};
+use rustc_middle::ty::{ToPredicate, TypeVisitable};
 use rustc_session::Limit;
 use rustc_span::def_id::LOCAL_CRATE;
 use rustc_span::Span;
diff --git a/compiler/rustc_trait_selection/src/infer.rs b/compiler/rustc_trait_selection/src/infer.rs
index f135f0c1b13..9d30374f8b8 100644
--- a/compiler/rustc_trait_selection/src/infer.rs
+++ b/compiler/rustc_trait_selection/src/infer.rs
@@ -9,7 +9,7 @@ use rustc_middle::infer::canonical::{Canonical, CanonicalizedQueryResponse, Quer
 use rustc_middle::traits::query::Fallible;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::ToPredicate;
-use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Ty, TypeFoldable, TypeVisitable};
 use rustc_span::{Span, DUMMY_SP};
 
 use std::fmt::Debug;
diff --git a/compiler/rustc_trait_selection/src/opaque_types.rs b/compiler/rustc_trait_selection/src/opaque_types.rs
index 9dd8588cece..d290f7b074c 100644
--- a/compiler/rustc_trait_selection/src/opaque_types.rs
+++ b/compiler/rustc_trait_selection/src/opaque_types.rs
@@ -9,6 +9,7 @@ use rustc_infer::infer::{InferCtxt, TyCtxtInferExt as _};
 use rustc_infer::traits::{Obligation, ObligationCause, TraitEngine};
 use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, InternalSubsts};
+use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, ToPredicate, Ty, TyCtxt};
 use rustc_span::Span;
 
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 49434ec1428..65ff9ceb67e 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -8,6 +8,7 @@ use crate::infer::InferCtxt;
 use crate::traits::project::ProjectAndUnifyResult;
 use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{Region, RegionVid, Term};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
diff --git a/compiler/rustc_trait_selection/src/traits/chalk_fulfill.rs b/compiler/rustc_trait_selection/src/traits/chalk_fulfill.rs
index 592b0ab477a..9ef7ac9a8e0 100644
--- a/compiler/rustc_trait_selection/src/traits/chalk_fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/chalk_fulfill.rs
@@ -8,7 +8,7 @@ use crate::traits::{
     PredicateObligation, SelectionError, TraitEngine,
 };
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
-use rustc_middle::ty::{self, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Ty, TypeVisitable};
 
 pub struct FulfillmentContext<'tcx> {
     obligations: FxIndexSet<PredicateObligation<'tcx>>,
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index ae69f2f7eb3..f933f1c3c94 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -20,8 +20,8 @@ use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::{util, TraitEngine};
 use rustc_middle::traits::specialization_graph::OverlapMode;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
-use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::subst::Subst;
+use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, ImplSubject, Ty, TyCtxt};
 use rustc_span::symbol::sym;
 use rustc_span::DUMMY_SP;
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 424eff2f621..f9b4a1583cc 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -17,7 +17,7 @@ use rustc_middle::mir::interpret::{ErrorHandled, LitToConstError, LitToConstInpu
 use rustc_middle::thir;
 use rustc_middle::thir::abstract_const::{self, Node, NodeId, NotConstEvaluatable};
 use rustc_middle::ty::subst::{Subst, SubstsRef};
-use rustc_middle::ty::{self, DelaySpanBugEmitted, EarlyBinder, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, DelaySpanBugEmitted, EarlyBinder, TyCtxt, TypeVisitable};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::Span;
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 88b09f4de0a..8fd58f3ce1a 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -30,6 +30,7 @@ use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::{
     self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
+    TypeVisitable,
 };
 use rustc_span::symbol::{kw, sym};
 use rustc_span::{ExpnKind, Span, DUMMY_SP};
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index a8be6f74c99..31d54b5b403 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -24,7 +24,7 @@ use rustc_middle::hir::map;
 use rustc_middle::ty::{
     self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree,
     GeneratorDiagnosticData, GeneratorInteriorTypeCause, Infer, InferTy, IsSuggestable,
-    ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
+    ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitable,
 };
 use rustc_middle::ty::{TypeAndMut, TypeckResults};
 use rustc_session::Limit;
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index 6663ff6bbe9..78600652254 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -10,7 +10,7 @@ use rustc_middle::thir::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::ToPredicate;
-use rustc_middle::ty::{self, Binder, Const, Ty, TypeFoldable};
+use rustc_middle::ty::{self, Binder, Const, Ty, TypeVisitable};
 use std::marker::PhantomData;
 
 use super::const_evaluatable;
diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs
index f04f527ccb7..dd2769c7186 100644
--- a/compiler/rustc_trait_selection/src/traits/misc.rs
+++ b/compiler/rustc_trait_selection/src/traits/misc.rs
@@ -5,7 +5,7 @@ use crate::traits::{self, ObligationCause};
 
 use rustc_hir as hir;
 use rustc_infer::infer::TyCtxtInferExt;
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
 
 use crate::traits::error_reporting::InferCtxtExt;
 
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index b45f72e8748..74d2eb17b6b 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -32,6 +32,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
+use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, GenericParamDefKind, ToPredicate, Ty, TyCtxt, VtblEntry};
 use rustc_span::{sym, Span};
 use smallvec::SmallVec;
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 8d344591915..ac1811244ca 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/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, Subst};
 use rustc_middle::ty::{
-    self, EarlyBinder, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitor,
+    self, EarlyBinder, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
 };
 use rustc_middle::ty::{Predicate, ToPredicate};
 use rustc_session::lint::builtin::WHERE_CLAUSES_OBJECT_SAFETY;
@@ -731,7 +731,7 @@ fn receiver_is_dispatchable<'tcx>(
     })
 }
 
-fn contains_illegal_self_type_reference<'tcx, T: TypeFoldable<'tcx>>(
+fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
     tcx: TyCtxt<'tcx>,
     trait_def_id: DefId,
     value: T,
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index aba4f144d4b..b3e7fbb3578 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -29,8 +29,9 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_infer::infer::resolve::OpportunisticRegionResolver;
 use rustc_middle::traits::select::OverflowError;
-use rustc_middle::ty::fold::{MaxUniverse, TypeFoldable, TypeFolder, TypeSuperFoldable};
+use rustc_middle::ty::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_middle::ty::subst::Subst;
+use rustc_middle::ty::visit::{MaxUniverse, TypeVisitable};
 use rustc_middle::ty::{self, EarlyBinder, Term, ToPredicate, Ty, TyCtxt};
 use rustc_span::symbol::sym;
 
@@ -359,7 +360,7 @@ where
     result
 }
 
-pub(crate) fn needs_normalization<'tcx, T: TypeFoldable<'tcx>>(value: &T, reveal: Reveal) -> bool {
+pub(crate) fn needs_normalization<'tcx, T: TypeVisitable<'tcx>>(value: &T, reveal: Reveal) -> bool {
     match reveal {
         Reveal::UserFacing => value
             .has_type_flags(ty::TypeFlags::HAS_TY_PROJECTION | ty::TypeFlags::HAS_CT_PROJECTION),
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index 7f15b683fda..eccfb3477b9 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -14,6 +14,7 @@ use rustc_infer::traits::Normalized;
 use rustc_middle::mir;
 use rustc_middle::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use rustc_middle::ty::subst::Subst;
+use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitor};
 
 use std::ops::ControlFlow;
@@ -108,7 +109,7 @@ struct MaxEscapingBoundVarVisitor {
 }
 
 impl<'tcx> TypeVisitor<'tcx> for MaxEscapingBoundVarVisitor {
-    fn visit_binder<T: TypeFoldable<'tcx>>(
+    fn visit_binder<T: TypeVisitable<'tcx>>(
         &mut self,
         t: &ty::Binder<'tcx, T>,
     ) -> ControlFlow<Self::BreakTy> {
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
index 46d6e973d4c..2a3319f0f26 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs
@@ -3,7 +3,7 @@ use crate::traits::query::Fallible;
 use rustc_infer::traits::query::OutlivesBound;
 use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt};
 
-#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, Lift)]
+#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct ImpliedOutlivesBounds<'tcx> {
     pub ty: Ty<'tcx>,
 }
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
index 82f147f8143..b63382429d0 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/outlives.rs
@@ -3,7 +3,7 @@ use crate::traits::query::dropck_outlives::{trivial_dropck_outlives, DropckOutli
 use crate::traits::query::Fallible;
 use rustc_middle::ty::{ParamEnvAnd, Ty, TyCtxt};
 
-#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, Lift)]
+#[derive(Copy, Clone, Debug, HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct DropckOutlives<'tcx> {
     dropped_ty: Ty<'tcx>,
 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index cfd50c1afb9..0f7af41cfe3 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -12,7 +12,7 @@ use rustc_infer::traits::TraitEngine;
 use rustc_infer::traits::{Obligation, SelectionError, TraitObligation};
 use rustc_lint_defs::builtin::DEREF_INTO_DYN_SUPERTRAIT;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, ToPredicate, Ty, TypeFoldable};
+use rustc_middle::ty::{self, ToPredicate, Ty, TypeVisitable};
 use rustc_target::spec::abi::Abi;
 
 use crate::traits;
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 4223cdb5dbb..596ee435622 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -39,7 +39,7 @@ use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::relate::TypeRelation;
 use rustc_middle::ty::subst::{Subst, SubstsRef};
 use rustc_middle::ty::{self, EarlyBinder, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
-use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, TypeVisitable};
 use rustc_span::symbol::sym;
 
 use std::cell::{Cell, RefCell};
diff --git a/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs b/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs
index 930c80e0abb..fcb73b43fa8 100644
--- a/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs
+++ b/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs
@@ -4,7 +4,7 @@ use crate::traits;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::fast_reject::{self, SimplifiedType, TreatParams};
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, TyCtxt, TypeVisitable};
 
 pub use rustc_middle::traits::specialization_graph::*;
 
diff --git a/compiler/rustc_trait_selection/src/traits/structural_match.rs b/compiler/rustc_trait_selection/src/traits/structural_match.rs
index bc2ce31df6d..f3ae34ce30a 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_match.rs
@@ -6,7 +6,7 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::query::Providers;
-use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitor};
+use rustc_middle::ty::{self, AdtDef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
 use rustc_span::Span;
 use std::ops::ControlFlow;
 
diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs
index 3a00c41d90a..3170b29ee69 100644
--- a/compiler/rustc_trait_selection/src/traits/util.rs
+++ b/compiler/rustc_trait_selection/src/traits/util.rs
@@ -6,7 +6,7 @@ use smallvec::SmallVec;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, Subst, SubstsRef};
-use rustc_middle::ty::{self, EarlyBinder, ImplSubject, ToPredicate, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, EarlyBinder, ImplSubject, ToPredicate, Ty, TyCtxt, TypeVisitable};
 
 use super::{Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext};
 pub use rustc_infer::traits::{self, util::*};
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index 8d666046ad9..d43b3c9091f 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -5,7 +5,7 @@ use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
-use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt, TypeVisitable};
 use rustc_span::Span;
 
 use std::iter;