Move visitable bounds up into interner

compiler/rustc_middle/src/ty/context.rs

@@ -28,7 +28,7 @@ use crate::ty::{
     self, AdtDef, AdtDefData, AdtKind, Binder, Clause, Const, ConstData, GenericParamDefKind,
     ImplPolarity, List, ParamConst, ParamTy, PolyExistentialPredicate, PolyFnSig, Predicate,
     PredicateKind, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVid,
-    Visibility,
+    TypeVisitable, Visibility,
 };
 use crate::ty::{GenericArg, GenericArgs, GenericArgsRef};
 use rustc_ast::{self as ast, attr};
@@ -87,7 +87,7 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
     type GenericArg = ty::GenericArg<'tcx>;
     type Term = ty::Term<'tcx>;
 
-    type Binder<T> = Binder<'tcx, T>;
+    type Binder<T: TypeVisitable<TyCtxt<'tcx>>> = Binder<'tcx, T>;
     type BoundVars = &'tcx List<ty::BoundVariableKind>;
     type BoundVar = ty::BoundVariableKind;
     type CanonicalVars = CanonicalVarInfos<'tcx>;

compiler/rustc_next_trait_solver/src/canonicalizer.rs

@@ -1,7 +1,7 @@
 use std::cmp::Ordering;
 
 use rustc_type_ir::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
-use rustc_type_ir::visit::{Flags, TypeVisitableExt};
+use rustc_type_ir::visit::TypeVisitableExt;
 use rustc_type_ir::{
     self as ty, Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, ConstTy,
     InferCtxtLike, Interner, IntoKind, PlaceholderLike,
@@ -45,13 +45,7 @@ pub struct Canonicalizer<'a, Infcx: InferCtxtLike<Interner = I>, I: Interner> {
     binder_index: ty::DebruijnIndex,
 }
 
-impl<'a, Infcx: InferCtxtLike<Interner = I>, I: Interner> Canonicalizer<'a, Infcx, I>
+impl<'a, Infcx: InferCtxtLike<Interner = I>, I: Interner> Canonicalizer<'a, Infcx, I> {
-where
-    I::Ty: Flags,
-    I::Region: Flags,
-    I::Const: Flags,
-    I::Predicate: Flags,
-{
     pub fn canonicalize<T: TypeFoldable<I>>(
         infcx: &'a Infcx,
         canonicalize_mode: CanonicalizeMode,

compiler/rustc_type_ir/src/interner.rs

@@ -2,6 +2,7 @@ use smallvec::SmallVec;
 use std::fmt::Debug;
 use std::hash::Hash;
 
+use crate::visit::{Flags, TypeSuperVisitable, TypeVisitable};
 use crate::{
     BoundVar, BoundVars, CanonicalVarInfo, ConstKind, DebruijnIndex, DebugWithInfcx, RegionKind,
     TyKind, UniverseIndex,
@@ -19,7 +20,7 @@ pub trait Interner: Sized {
     type GenericArg: Copy + DebugWithInfcx<Self> + Hash + Ord;
     type Term: Copy + Debug + Hash + Ord;
 
-    type Binder<T>: BoundVars<Self>;
+    type Binder<T: TypeVisitable<Self>>: BoundVars<Self> + TypeSuperVisitable<Self>;
     type BoundVars: IntoIterator<Item = Self::BoundVar>;
     type BoundVar;
 
@@ -31,7 +32,9 @@ pub trait Interner: Sized {
         + Hash
         + Ord
         + Into<Self::GenericArg>
-        + IntoKind<Kind = TyKind<Self>>;
+        + IntoKind<Kind = TyKind<Self>>
+        + TypeSuperVisitable<Self>
+        + Flags;
     type Tys: Copy + Debug + Hash + Ord + IntoIterator<Item = Self::Ty>;
     type AliasTy: Copy + DebugWithInfcx<Self> + Hash + Ord;
     type ParamTy: Copy + Debug + Hash + Ord;
@@ -51,7 +54,9 @@ pub trait Interner: Sized {
         + Ord
         + Into<Self::GenericArg>
         + IntoKind<Kind = ConstKind<Self>>
-        + ConstTy<Self>;
+        + ConstTy<Self>
+        + TypeSuperVisitable<Self>
+        + Flags;
     type AliasConst: Copy + DebugWithInfcx<Self> + Hash + Ord;
     type PlaceholderConst: Copy + Debug + Hash + Ord + PlaceholderLike;
     type ParamConst: Copy + Debug + Hash + Ord;
@@ -65,7 +70,8 @@ pub trait Interner: Sized {
         + Hash
         + Ord
         + Into<Self::GenericArg>
-        + IntoKind<Kind = RegionKind<Self>>;
+        + IntoKind<Kind = RegionKind<Self>>
+        + Flags;
     type EarlyParamRegion: Copy + Debug + Hash + Ord;
     type LateParamRegion: Copy + Debug + Hash + Ord;
     type BoundRegion: Copy + Debug + Hash + Ord;
@@ -73,7 +79,7 @@ pub trait Interner: Sized {
     type PlaceholderRegion: Copy + Debug + Hash + Ord + PlaceholderLike;
 
     // Predicates
-    type Predicate: Copy + Debug + Hash + Eq;
+    type Predicate: Copy + Debug + Hash + Eq + TypeSuperVisitable<Self> + Flags;
     type TraitPredicate: Copy + Debug + Hash + Eq;
     type RegionOutlivesPredicate: Copy + Debug + Hash + Eq;
     type TypeOutlivesPredicate: Copy + Debug + Hash + Eq;

compiler/rustc_type_ir/src/visit.rs

@@ -87,38 +87,28 @@ pub trait TypeVisitor<I: Interner>: Sized {
     #[cfg(not(feature = "nightly"))]
     type BreakTy;
 
-    fn visit_binder<T: TypeVisitable<I>>(&mut self, t: &I::Binder<T>) -> ControlFlow<Self::BreakTy>
+    fn visit_binder<T: TypeVisitable<I>>(
-    where
+        &mut self,
-        I::Binder<T>: TypeSuperVisitable<I>,
+        t: &I::Binder<T>,
-    {
+    ) -> ControlFlow<Self::BreakTy> {
         t.super_visit_with(self)
     }
 
-    fn visit_ty(&mut self, t: I::Ty) -> ControlFlow<Self::BreakTy>
+    fn visit_ty(&mut self, t: I::Ty) -> ControlFlow<Self::BreakTy> {
-    where
-        I::Ty: TypeSuperVisitable<I>,
-    {
         t.super_visit_with(self)
     }
 
     // The default region visitor is a no-op because `Region` is non-recursive
-    // and has no `super_visit_with` method to call. That also explains the
+    // and has no `super_visit_with` method to call.
-    // lack of `I::Region: TypeSuperVisitable<I>` bound.
     fn visit_region(&mut self, _r: I::Region) -> ControlFlow<Self::BreakTy> {
         ControlFlow::Continue(())
     }
 
-    fn visit_const(&mut self, c: I::Const) -> ControlFlow<Self::BreakTy>
+    fn visit_const(&mut self, c: I::Const) -> ControlFlow<Self::BreakTy> {
-    where
-        I::Const: TypeSuperVisitable<I>,
-    {
         c.super_visit_with(self)
     }
 
-    fn visit_predicate(&mut self, p: I::Predicate) -> ControlFlow<Self::BreakTy>
+    fn visit_predicate(&mut self, p: I::Predicate) -> ControlFlow<Self::BreakTy> {
-    where
-        I::Predicate: TypeSuperVisitable<I>,
-    {
         p.super_visit_with(self)
     }
 }
@@ -327,13 +317,7 @@ pub trait TypeVisitableExt<I: Interner>: TypeVisitable<I> {
     }
 }
 
-impl<I: Interner, T: TypeVisitable<I>> TypeVisitableExt<I> for T
+impl<I: Interner, T: TypeVisitable<I>> TypeVisitableExt<I> for T {
-where
-    I::Ty: Flags,
-    I::Region: Flags,
-    I::Const: Flags,
-    I::Predicate: Flags,
-{
     fn has_type_flags(&self, flags: TypeFlags) -> bool {
         let res =
             self.visit_with(&mut HasTypeFlagsVisitor { flags }) == ControlFlow::Break(FoundFlags);
@@ -381,19 +365,13 @@ impl std::fmt::Debug for HasTypeFlagsVisitor {
 // are present, regardless of whether those bound variables are used. This
 // is important for anonymization of binders in `TyCtxt::erase_regions`. We
 // specifically detect this case in `visit_binder`.
-impl<I: Interner> TypeVisitor<I> for HasTypeFlagsVisitor
+impl<I: Interner> TypeVisitor<I> for HasTypeFlagsVisitor {
-where
-    I::Ty: Flags,
-    I::Region: Flags,
-    I::Const: Flags,
-    I::Predicate: Flags,
-{
     type BreakTy = FoundFlags;
 
-    fn visit_binder<T: TypeVisitable<I>>(&mut self, t: &I::Binder<T>) -> ControlFlow<Self::BreakTy>
+    fn visit_binder<T: TypeVisitable<I>>(
-    where
+        &mut self,
-        I::Binder<T>: TypeSuperVisitable<I>,
+        t: &I::Binder<T>,
-    {
+    ) -> ControlFlow<Self::BreakTy> {
         // If we're looking for the HAS_BINDER_VARS flag, check if the
         // binder has vars. This won't be present in the binder's bound
         // value, so we need to check here too.
@@ -480,19 +458,13 @@ struct HasEscapingVarsVisitor {
     outer_index: ty::DebruijnIndex,
 }
 
-impl<I: Interner> TypeVisitor<I> for HasEscapingVarsVisitor
+impl<I: Interner> TypeVisitor<I> for HasEscapingVarsVisitor {
-where
-    I::Ty: Flags,
-    I::Region: Flags,
-    I::Const: Flags,
-    I::Predicate: Flags,
-{
     type BreakTy = FoundEscapingVars;
 
-    fn visit_binder<T: TypeVisitable<I>>(&mut self, t: &I::Binder<T>) -> ControlFlow<Self::BreakTy>
+    fn visit_binder<T: TypeVisitable<I>>(
-    where
+        &mut self,
-        I::Binder<T>: TypeSuperVisitable<I>,
+        t: &I::Binder<T>,
-    {
+    ) -> ControlFlow<Self::BreakTy> {
         self.outer_index.shift_in(1);
         let result = t.super_visit_with(self);
         self.outer_index.shift_out(1);
@@ -550,19 +522,10 @@ where
 
 struct HasErrorVisitor;
 
-impl<I: Interner> TypeVisitor<I> for HasErrorVisitor
+impl<I: Interner> TypeVisitor<I> for HasErrorVisitor {
-where
-    I::Ty: Flags,
-    I::Region: Flags,
-    I::Const: Flags,
-    I::Predicate: Flags,
-{
     type BreakTy = I::ErrorGuaranteed;
 
-    fn visit_ty(&mut self, t: <I as Interner>::Ty) -> ControlFlow<Self::BreakTy>
+    fn visit_ty(&mut self, t: <I as Interner>::Ty) -> ControlFlow<Self::BreakTy> {
-    where
-        <I as Interner>::Ty: TypeSuperVisitable<I>,
-    {
         if let ty::Error(guar) = t.kind() {
             ControlFlow::Break(guar)
         } else {
@@ -570,10 +533,7 @@ where
         }
     }
 
-    fn visit_const(&mut self, c: <I as Interner>::Const) -> ControlFlow<Self::BreakTy>
+    fn visit_const(&mut self, c: <I as Interner>::Const) -> ControlFlow<Self::BreakTy> {
-    where
-        <I as Interner>::Const: TypeSuperVisitable<I>,
-    {
         if let ty::ConstKind::Error(guar) = c.kind() {
             ControlFlow::Break(guar)
         } else {