diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 9711038a8f7..413cc0ae831 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -4630,9 +4630,9 @@ This error indicates that there is a mismatch between generic parameters and
 impl Trait parameters in a trait declaration versus its impl.
 
 ```compile_fail,E0642
-#![feature(conservative_impl_trait)]
+#![feature(universal_impl_trait)]
 trait Foo
-    fn foo(&self, &impl Iterator)
+    fn foo(&self, _: &impl Iterator)
 }
 impl Foo for () {
     fn foo<U: Iterator>(&self, _: &U) { } // error method `foo` has incompatible
diff --git a/src/test/compile-fail/impl-trait/impl-generic-mismatch.rs b/src/test/compile-fail/impl-trait/impl-generic-mismatch.rs
index 41583d3b795..a95da61aa4c 100644
--- a/src/test/compile-fail/impl-trait/impl-generic-mismatch.rs
+++ b/src/test/compile-fail/impl-trait/impl-generic-mismatch.rs
@@ -12,7 +12,7 @@
 use std::fmt::Debug;
 
 trait Foo {
-    fn foo(&self, &impl Debug);
+    fn foo(&self, _: &impl Debug);
 }
 
 impl Foo for () {
@@ -21,7 +21,7 @@ impl Foo for () {
 }
 
 trait Bar {
-    fn bar<U: Debug>(&self, &U);
+    fn bar<U: Debug>(&self, _: &U);
 }
 
 impl Bar for () {