Require T: TypeFoldable in Binder<T> visit

Author: compiler-errors

compiler/rustc_borrowck/src/type_check/opaque_types.rs

@@ -266,10 +266,6 @@ impl<'tcx, OP> TypeVisitor<TyCtxt<'tcx>> for ConstrainOpaqueTypeRegionVisitor<'t
 where
     OP: FnMut(ty::Region<'tcx>),
 {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
-        t.super_visit_with(self);
-    }
-
     fn visit_region(&mut self, r: ty::Region<'tcx>) {
         match r.kind() {
             // ignore bound regions, keep visiting

compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs

@@ -9,8 +9,8 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{AmbigArg, HirId};
 use rustc_middle::bug;
 use rustc_middle::ty::{
-    self as ty, IsSuggestable, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
-    TypeVisitor, Upcast,
+    self as ty, IsSuggestable, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable,
+    TypeVisitableExt, TypeVisitor, Upcast,
 };
 use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol, kw, sym};
 use rustc_trait_selection::traits;
@@ -996,7 +996,7 @@ struct GenericParamAndBoundVarCollector<'a, 'tcx> {
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'_, 'tcx> {
     type Result = ControlFlow<ErrorGuaranteed>;
 
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(
+    fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
         &mut self,
         binder: &ty::Binder<'tcx, T>,
     ) -> Self::Result {

compiler/rustc_infer/src/infer/outlives/for_liveness.rs

@@ -24,10 +24,6 @@ impl<'tcx, OP> TypeVisitor<TyCtxt<'tcx>> for FreeRegionsVisitor<'tcx, OP>
 where
     OP: FnMut(ty::Region<'tcx>),
 {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
-        t.super_visit_with(self);
-    }
-
     fn visit_region(&mut self, r: ty::Region<'tcx>) {
         match r.kind() {
             // ignore bound regions, keep visiting

compiler/rustc_lint/src/impl_trait_overcaptures.rs

@@ -15,7 +15,8 @@ use rustc_middle::ty::relate::{
     Relate, RelateResult, TypeRelation, structurally_relate_consts, structurally_relate_tys,
 };
 use rustc_middle::ty::{
-    self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
+    self, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
+    TypeVisitor,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint::FutureIncompatibilityReason;
@@ -209,7 +210,7 @@ where
     VarFn: FnOnce() -> FxHashMap<DefId, ty::Variance>,
     OutlivesFn: FnOnce() -> OutlivesEnvironment<'tcx>,
 {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
+    fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
         // When we get into a binder, we need to add its own bound vars to the scope.
         let mut added = vec![];
         for arg in t.bound_vars() {

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -2934,7 +2934,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
 
     fn prepare_region_info<T>(&mut self, value: &ty::Binder<'tcx, T>)
     where
-        T: TypeVisitable<TyCtxt<'tcx>>,
+        T: TypeFoldable<TyCtxt<'tcx>>,
     {
         struct RegionNameCollector<'tcx> {
             used_region_names: FxHashSet<Symbol>,

compiler/rustc_middle/src/ty/visit.rs

@@ -66,7 +66,7 @@ impl<'tcx> TyCtxt<'tcx> {
         {
             type Result = ControlFlow<()>;
 
-            fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(
+            fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
                 &mut self,
                 t: &Binder<'tcx, T>,
             ) -> Self::Result {
@@ -168,7 +168,7 @@ impl LateBoundRegionsCollector {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for LateBoundRegionsCollector {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &Binder<'tcx, T>) {
+    fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, t: &Binder<'tcx, T>) {
         self.current_index.shift_in(1);
         t.super_visit_with(self);
         self.current_index.shift_out(1);

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

@@ -9,7 +9,7 @@ use rustc_macros::extension;
 pub use rustc_middle::traits::query::NormalizationResult;
 use rustc_middle::ty::{
     self, FallibleTypeFolder, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeSuperVisitable,
-    TypeVisitable, TypeVisitableExt, TypeVisitor, TypingMode,
+    TypeVisitableExt, TypeVisitor, TypingMode,
 };
 use rustc_span::DUMMY_SP;
 use tracing::{debug, info, instrument};
@@ -127,7 +127,7 @@ struct MaxEscapingBoundVarVisitor {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxEscapingBoundVarVisitor {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
+    fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
         self.outer_index.shift_in(1);
         t.super_visit_with(self);
         self.outer_index.shift_out(1);

compiler/rustc_ty_utils/src/ty.rs

@@ -7,7 +7,8 @@ use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::bug;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{
-    self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor, Upcast, fold_regions,
+    self, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitor, Upcast,
+    fold_regions,
 };
 use rustc_span::DUMMY_SP;
 use rustc_span::def_id::{CRATE_DEF_ID, DefId, LocalDefId};
@@ -185,7 +186,7 @@ struct ImplTraitInTraitFinder<'a, 'tcx> {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, binder: &ty::Binder<'tcx, T>) {
+    fn visit_binder<T: TypeFoldable<TyCtxt<'tcx>>>(&mut self, binder: &ty::Binder<'tcx, T>) {
         self.depth.shift_in(1);
         binder.super_visit_with(self);
         self.depth.shift_out(1);

compiler/rustc_type_ir/src/binder.rs

@@ -128,7 +128,7 @@ impl<I: Interner, T: TypeFoldable<I>> TypeFoldable<I> for Binder<I, T> {
     }
 }
 
-impl<I: Interner, T: TypeVisitable<I>> TypeVisitable<I> for Binder<I, T> {
+impl<I: Interner, T: TypeFoldable<I>> TypeVisitable<I> for Binder<I, T> {
     fn visit_with<V: TypeVisitor<I>>(&self, visitor: &mut V) -> V::Result {
         visitor.visit_binder(self)
     }
@@ -147,7 +147,7 @@ impl<I: Interner, T: TypeFoldable<I>> TypeSuperFoldable<I> for Binder<I, T> {
     }
 }
 
-impl<I: Interner, T: TypeVisitable<I>> TypeSuperVisitable<I> for Binder<I, T> {
+impl<I: Interner, T: TypeFoldable<I>> TypeSuperVisitable<I> for Binder<I, T> {
     fn super_visit_with<V: TypeVisitor<I>>(&self, visitor: &mut V) -> V::Result {
         self.as_ref().skip_binder().visit_with(visitor)
     }
@@ -292,7 +292,7 @@ impl<I: Interner> ValidateBoundVars<I> {
 impl<I: Interner> TypeVisitor<I> for ValidateBoundVars<I> {
     type Result = ControlFlow<()>;
 
-    fn visit_binder<T: TypeVisitable<I>>(&mut self, t: &Binder<I, T>) -> Self::Result {
+    fn visit_binder<T: TypeFoldable<I>>(&mut self, t: &Binder<I, T>) -> Self::Result {
         self.binder_index.shift_in(1);
         let result = t.super_visit_with(self);
         self.binder_index.shift_out(1);

compiler/rustc_type_ir/src/ty_kind/closure.rs

@@ -342,7 +342,7 @@ struct HasRegionsBoundAt {
 // FIXME: Could be optimized to not walk into components with no escaping bound vars.
 impl<I: Interner> TypeVisitor<I> for HasRegionsBoundAt {
     type Result = ControlFlow<()>;
-    fn visit_binder<T: TypeVisitable<I>>(&mut self, t: &ty::Binder<I, T>) -> Self::Result {
+    fn visit_binder<T: TypeFoldable<I>>(&mut self, t: &ty::Binder<I, T>) -> Self::Result {
         self.binder.shift_in(1);
         t.super_visit_with(self)?;
         self.binder.shift_out(1);