diff --git a/src/test/run-pass-fulldeps/proc-macro/derive-test.rs b/src/test/run-pass-fulldeps/proc-macro/derive-test.rs
index a07e8b6cd7e6..5a53a4e8db34 100644
--- a/src/test/run-pass-fulldeps/proc-macro/derive-test.rs
+++ b/src/test/run-pass-fulldeps/proc-macro/derive-test.rs
@@ -17,6 +17,9 @@ extern crate proc_macro;
 
 use proc_macro::TokenStream;
 
+// ```
+// assert!(true);
+// ```
 #[proc_macro_derive(Foo)]
 pub fn derive_foo(_input: TokenStream) -> TokenStream {
     "".parse().unwrap()