diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index f8893ae29f58e..878f31af00f07 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -445,10 +445,13 @@ impl<'a, 'tcx> TypeFolder<'tcx> for BoundVarReplacer<'a, 'tcx> {
                 let ct = (self.fld_c)(bound_const, ct.ty());
                 ty::fold::shift_vars(self.tcx, ct, self.current_index.as_u32())
             }
-            _ if ct.has_vars_bound_at_or_above(self.current_index) => ct.super_fold_with(self),
-            _ => ct,
+            _ => ct.super_fold_with(self),
         }
     }
+
+    fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> {
+        if p.has_vars_bound_at_or_above(self.current_index) { p.super_fold_with(self) } else { p }
+    }
 }
 
 impl<'tcx> TyCtxt<'tcx> {
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index b3e7fbb357828..9de4d3a646cb3 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -753,10 +753,13 @@ impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
                     .tcx
                     .mk_const(ty::ConstS { kind: ty::ConstKind::Placeholder(p), ty: ct.ty() })
             }
-            _ if ct.has_vars_bound_at_or_above(self.current_index) => ct.super_fold_with(self),
-            _ => ct,
+            _ => ct.super_fold_with(self),
         }
     }
+
+    fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> {
+        if p.has_vars_bound_at_or_above(self.current_index) { p.super_fold_with(self) } else { p }
+    }
 }
 
 // The inverse of `BoundVarReplacer`: replaces placeholders with the bound vars from which they came.