diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 92eb6fef1946..3af2cc540f0a 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -365,7 +365,7 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 10
     env:
-      RUSTFLAGS: # No need to check warnings on old MSRV, unset `-Dwarnings`
+      RUSTFLAGS: "" # No need to check warnings on old MSRV, clear `-Dwarnings`
     steps:
     - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       with: