Auto merge of #98542 - jackh726:coinductive-wf, r=oli-obk

Make empty bounds lower to `WellFormed` and make `WellFormed` coinductive

r? rust-lang/types

compiler/rustc_privacy/src/lib.rs

@@ -154,6 +154,7 @@ where
                 }
                 ControlFlow::CONTINUE
             }
+            ty::PredicateKind::WellFormed(arg) => arg.visit_with(self),
             _ => bug!("unexpected predicate: {:?}", predicate),
         }
     }