diff --git a/ci/style.sh b/ci/style.sh
index 9b7c1ed26b05e..4e425f8806000 100755
--- a/ci/style.sh
+++ b/ci/style.sh
@@ -58,7 +58,7 @@ rm "$tmpfile"
 
 # Run once from workspace root to get everything that wasn't handled as an
 # individual file.
-cargo fmt "$check"
+cargo fmt ${check:+"$check"}
 
 # Ensure that `sort` output is not locale-dependent
 export LC_ALL=C