diff --git a/check_diff/src/main.rs b/check_diff/src/main.rs
index 02e34985de3..6d07c1b0df6 100644
--- a/check_diff/src/main.rs
+++ b/check_diff/src/main.rs
@@ -11,7 +11,7 @@ struct CliInputs {
     commit_hash: Option<String>,
     /// Optional comma separated list of rustfmt config options to
     /// pass when running the feature branch
-    #[arg(value_delimiter = ',', short, long,num_args = 1..)]
+    #[arg(value_delimiter = ',', short, long, num_args = 1..)]
     rustfmt_config: Option<Vec<String>>,
 }