diff --git a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
index eab612c5dfb45..2a5b687ac2947 100644
--- a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
@@ -43,7 +43,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
         NormalTT {
             expander: Box::new(Expander { args: args, }),
             def_info: None,
-            allow_internal_unstable: false,
+            allow_internal_unstable: Vec::new(),
             allow_internal_unsafe: false,
             local_inner_macros: false,
             unstable_feature: None,