Fix test

Author: scalexm

src/ir/lowering/test.rs

@@ -413,7 +413,7 @@ fn duplicate_parameters() {
                 type Item<T>: forall<'a> Fn<Ref<'a, T>>;
             }
         } error_msg {
-            "duplicate parameters"
+            "duplicate or shadowed parameters"
         }
     }
 }

src/rules/wf/test.rs

@@ -549,6 +549,8 @@ fn higher_ranked_inline_bound_on_gat() {
 
             struct fn<T, U> { }
 
+            impl<T, U> Fn<T, U> for fn<T, U> { }
+
             trait Bar {
                 type Item<T>: forall<U> Fn<T, U>;
             }