diff --git a/src/test/ui/rust-2021/reserved-prefixes.rs b/src/test/ui/rust-2021/reserved-prefixes.rs
index 5882c7d83d8..1994f25b6a5 100644
--- a/src/test/ui/rust-2021/reserved-prefixes.rs
+++ b/src/test/ui/rust-2021/reserved-prefixes.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z unstable-options --edition 2021
+// edition:2021
 
 macro_rules! demo2 {
     ( $a:tt $b:tt ) => { println!("two tokens") };