Convert `TypeVisitor` and `DefIdVisitor` to use `VisitorResult`

8 files changed, 30 insertions, 45 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
index 98d28f10a54..22f52c27362 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
@@ -648,8 +648,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         }
 
         impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsTermOrNotNameable<'_, 'tcx> {
-            type BreakTy = ();
-            fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+            type Result = ControlFlow<()>;
+            fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
                 match *t.kind() {
                     ty::Infer(ty::TyVar(vid)) => {
                         if let ty::TermKind::Ty(term) = self.term.unpack()
@@ -672,7 +672,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
                 }
             }
 
-            fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+            fn visit_const(&mut self, c: ty::Const<'tcx>) -> Self::Result {
                 match c.kind() {
                     ty::ConstKind::Infer(ty::InferConst::Var(vid)) => {
                         if let ty::TermKind::Const(term) = self.term.unpack()
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index 68111c4cc1f..20af016eb00 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -474,7 +474,7 @@ fn plug_infer_with_placeholders<'tcx>(
     }
 
     impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for PlugInferWithPlaceholder<'_, 'tcx> {
-        fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_ty(&mut self, ty: Ty<'tcx>) {
             let ty = self.infcx.shallow_resolve(ty);
             if ty.is_ty_var() {
                 let Ok(InferOk { value: (), obligations }) =
@@ -496,13 +496,12 @@ fn plug_infer_with_placeholders<'tcx>(
                     bug!("we always expect to be able to plug an infer var with placeholder")
                 };
                 assert_eq!(obligations, &[]);
-                ControlFlow::Continue(())
             } else {
-                ty.super_visit_with(self)
+                ty.super_visit_with(self);
             }
         }
 
-        fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_const(&mut self, ct: ty::Const<'tcx>) {
             let ct = self.infcx.shallow_resolve(ct);
             if ct.is_ct_infer() {
                 let Ok(InferOk { value: (), obligations }) =
@@ -519,13 +518,12 @@ fn plug_infer_with_placeholders<'tcx>(
                     bug!("we always expect to be able to plug an infer var with placeholder")
                 };
                 assert_eq!(obligations, &[]);
-                ControlFlow::Continue(())
             } else {
-                ct.super_visit_with(self)
+                ct.super_visit_with(self);
             }
         }
 
-        fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_region(&mut self, r: ty::Region<'tcx>) {
             if let ty::ReVar(vid) = *r {
                 let r = self
                     .infcx
@@ -555,7 +553,6 @@ fn plug_infer_with_placeholders<'tcx>(
                     assert_eq!(obligations, &[]);
                 }
             }
-            ControlFlow::Continue(())
         }
     }
 
@@ -868,12 +865,12 @@ impl<'tcx, F, E> TypeVisitor<TyCtxt<'tcx>> for OrphanChecker<'tcx, F>
 where
     F: FnMut(Ty<'tcx>) -> Result<Ty<'tcx>, E>,
 {
-    type BreakTy = OrphanCheckEarlyExit<'tcx, E>;
-    fn visit_region(&mut self, _r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
+    type Result = ControlFlow<OrphanCheckEarlyExit<'tcx, E>>;
+    fn visit_region(&mut self, _r: ty::Region<'tcx>) -> Self::Result {
         ControlFlow::Continue(())
     }
 
-    fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
         // Need to lazily normalize here in with `-Znext-solver=coherence`.
         let ty = match (self.lazily_normalize_ty)(ty) {
             Ok(ty) => ty,
@@ -996,7 +993,7 @@ where
     /// As these should be quite rare as const arguments and especially rare as impl
     /// parameters, allowing uncovered const parameters in impls seems more useful
     /// than allowing `impl<T> Trait<local_fn_ptr, T> for i32` to compile.
-    fn visit_const(&mut self, _c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_const(&mut self, _c: ty::Const<'tcx>) -> Self::Result {
         ControlFlow::Continue(())
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 189e1ba54bc..7f0f9a12d6a 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -17,7 +17,6 @@ use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitable, TypeVisitableExt, TypeVisitor};
 
 use rustc_span::Span;
-use std::ops::ControlFlow;
 
 use crate::traits::ObligationCtxt;
 
@@ -170,8 +169,7 @@ fn satisfied_from_param_env<'tcx>(
     }
 
     impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for Visitor<'a, 'tcx> {
-        type BreakTy = ();
-        fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_const(&mut self, c: ty::Const<'tcx>) {
             debug!("is_const_evaluatable: candidate={:?}", c);
             if self.infcx.probe(|_| {
                 let ocx = ObligationCtxt::new(self.infcx);
@@ -187,7 +185,7 @@ fn satisfied_from_param_env<'tcx>(
             }
 
             if let ty::ConstKind::Expr(e) = c.kind() {
-                e.visit_with(self)
+                e.visit_with(self);
             } else {
                 // FIXME(generic_const_exprs): This doesn't recurse into `<T as Trait<U>>::ASSOC`'s args.
                 // This is currently unobservable as `<T as Trait<{ U + 1 }>>::ASSOC` creates an anon const
@@ -196,7 +194,6 @@ fn satisfied_from_param_env<'tcx>(
                 // If we start allowing directly writing `ConstKind::Expr` without an intermediate anon const
                 // this will be incorrect. It might be worth investigating making `predicates_of` elaborate
                 // all of the `ConstEvaluatable` bounds rather than having a visitor here.
-                ControlFlow::Continue(())
             }
         }
     }
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 0796cb57d97..0515b09ae46 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -152,9 +152,9 @@ impl ArgKind {
 struct HasNumericInferVisitor;
 
 impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for HasNumericInferVisitor {
-    type BreakTy = ();
+    type Result = ControlFlow<()>;
 
-    fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
         if matches!(ty.kind(), ty::Infer(ty::FloatVar(_) | ty::IntVar(_))) {
             ControlFlow::Break(())
         } else {
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 32447aca390..cc8b8f72cf3 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -435,8 +435,8 @@ fn is_impossible_associated_item(
         trait_item_def_id: DefId,
     }
     impl<'tcx> ty::TypeVisitor<TyCtxt<'tcx>> for ReferencesOnlyParentGenerics<'tcx> {
-        type BreakTy = ();
-        fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+        type Result = ControlFlow<()>;
+        fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
             // If this is a parameter from the trait item's own generics, then bail
             if let ty::Param(param) = t.kind()
                 && let param_def_id = self.generics.type_param(param, self.tcx).def_id
@@ -446,7 +446,7 @@ fn is_impossible_associated_item(
             }
             t.super_visit_with(self)
         }
-        fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_region(&mut self, r: ty::Region<'tcx>) -> Self::Result {
             if let ty::ReEarlyParam(param) = r.kind()
                 && let param_def_id = self.generics.region_param(&param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
@@ -455,7 +455,7 @@ fn is_impossible_associated_item(
             }
             ControlFlow::Continue(())
         }
-        fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_const(&mut self, ct: ty::Const<'tcx>) -> Self::Result {
             if let ty::ConstKind::Param(param) = ct.kind()
                 && let param_def_id = self.generics.const_param(&param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 7b715984c2b..1816b98a636 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -834,9 +834,9 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>(
     }
 
     impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for IllegalSelfTypeVisitor<'tcx> {
-        type BreakTy = ();
+        type Result = ControlFlow<()>;
 
-        fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
             match t.kind() {
                 ty::Param(_) => {
                     if t == self.tcx.types.self_param {
@@ -887,7 +887,7 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<TyCtxt<'tcx>>>(
             }
         }
 
-        fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_const(&mut self, ct: ty::Const<'tcx>) -> Self::Result {
             // Constants can only influence object safety if they are generic and reference `Self`.
             // This is only possible for unevaluated constants, so we walk these here.
             self.tcx.expand_abstract_consts(ct).super_visit_with(self)
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index e5f8e336860..c520e699bf5 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -18,8 +18,6 @@ use rustc_middle::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitableEx
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitor};
 use rustc_span::DUMMY_SP;
 
-use std::ops::ControlFlow;
-
 use super::NoSolution;
 
 pub use rustc_middle::traits::query::NormalizationResult;
@@ -123,28 +121,23 @@ struct MaxEscapingBoundVarVisitor {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxEscapingBoundVarVisitor {
-    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(
-        &mut self,
-        t: &ty::Binder<'tcx, T>,
-    ) -> ControlFlow<Self::BreakTy> {
+    fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(&mut self, t: &ty::Binder<'tcx, T>) {
         self.outer_index.shift_in(1);
-        let result = t.super_visit_with(self);
+        t.super_visit_with(self);
         self.outer_index.shift_out(1);
-        result
     }
 
     #[inline]
-    fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty(&mut self, t: Ty<'tcx>) {
         if t.outer_exclusive_binder() > self.outer_index {
             self.escaping = self
                 .escaping
                 .max(t.outer_exclusive_binder().as_usize() - self.outer_index.as_usize());
         }
-        ControlFlow::Continue(())
     }
 
     #[inline]
-    fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_region(&mut self, r: ty::Region<'tcx>) {
         match *r {
             ty::ReBound(debruijn, _) if debruijn > self.outer_index => {
                 self.escaping =
@@ -152,16 +145,14 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for MaxEscapingBoundVarVisitor {
             }
             _ => {}
         }
-        ControlFlow::Continue(())
     }
 
-    fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_const(&mut self, ct: ty::Const<'tcx>) {
         if ct.outer_exclusive_binder() > self.outer_index {
             self.escaping = self
                 .escaping
                 .max(ct.outer_exclusive_binder().as_usize() - self.outer_index.as_usize());
         }
-        ControlFlow::Continue(())
     }
 }
 
diff --git a/compiler/rustc_trait_selection/src/traits/structural_match.rs b/compiler/rustc_trait_selection/src/traits/structural_match.rs
index e6b42f15d51..b89406ca023 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_match.rs
@@ -53,9 +53,9 @@ impl<'tcx> Search<'tcx> {
 }
 
 impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for Search<'tcx> {
-    type BreakTy = Ty<'tcx>;
+    type Result = ControlFlow<Ty<'tcx>>;
 
-    fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
         debug!("Search visiting ty: {:?}", ty);
 
         let (adt_def, args) = match *ty.kind() {