Auto merge of rust-lang#78779 - LeSeulArtichaut:ty-visitor-return, r=…

…oli-obk

Introduce `TypeVisitor::BreakTy`

Implements MCP rust-lang/compiler-team#383.
r? `@ghost`
cc `@lcnr` `@oli-obk`

~~Blocked on FCP in rust-lang/compiler-team#383.~~

clippy_lints/src/redundant_clone.rs

@@ -563,7 +563,9 @@ impl<'a, 'tcx> mir::visit::Visitor<'tcx> for PossibleBorrowerVisitor<'a, 'tcx> {
 struct ContainsRegion;
 
 impl TypeVisitor<'_> for ContainsRegion {
-    fn visit_region(&mut self, _: ty::Region<'_>) -> ControlFlow<()> {
+    type BreakTy = ();
+
+    fn visit_region(&mut self, _: ty::Region<'_>) -> ControlFlow<Self::BreakTy> {
         ControlFlow::BREAK
     }
 }