diff --git a/example/mini_core.rs b/example/mini_core.rs
index ce07fe83df18f..10cba99205629 100644
--- a/example/mini_core.rs
+++ b/example/mini_core.rs
@@ -1,6 +1,6 @@
 #![feature(
     no_core, lang_items, intrinsics, unboxed_closures, type_ascription, extern_types,
-    untagged_unions, decl_macro, rustc_attrs, transparent_unions, optin_builtin_traits,
+    untagged_unions, decl_macro, rustc_attrs, transparent_unions, auto_traits,
     thread_local,
 )]
 #![no_core]