diff --git a/src/ci/run.sh b/src/ci/run.sh
index 1ce54f9ecb342..3962c354c10e5 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -55,7 +55,7 @@ fi
 # If runner uses an incompatible option and `FORCE_CI_RUSTC` is not defined,
 # switch to in-tree rustc.
 if [ "$FORCE_CI_RUSTC" == "" ]; then
-    echo "debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured."
+    echo 'debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured.'
     DISABLE_CI_RUSTC_IF_INCOMPATIBLE=1
 fi