diff --git a/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs b/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs
index 79f5f009f1..fdd2adf0b4 100644
--- a/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs
+++ b/examples/remove-emphasis/mdbook-remove-emphasis/src/main.rs
@@ -28,6 +28,7 @@ fn main() {
     }
 }
 
+#[derive(Clone)]
 struct RemoveEmphasis;
 
 impl Preprocessor for RemoveEmphasis {