Account for flags in ArgFolder

Author: compiler-errors

compiler/rustc_type_ir/src/binder.rs

@@ -697,12 +697,24 @@ impl<'a, I: Interner> TypeFolder<I> for ArgFolder<'a, I> {
     }
 
     fn fold_const(&mut self, c: I::Const) -> I::Const {
+        if !c.has_param() {
+            return c;
+        }
+
         if let ty::ConstKind::Param(p) = c.kind() {
             self.const_for_param(p, c)
         } else {
             c.super_fold_with(self)
         }
     }
+
+    fn fold_predicate(&mut self, p: I::Predicate) -> I::Predicate {
+        if !p.has_param() {
+            return p;
+        }
+
+        p.super_fold_with(self)
+    }
 }
 
 impl<'a, I: Interner> ArgFolder<'a, I> {