diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 3300e7a2..11f27337 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -35,3 +35,4 @@ jobs:
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
       - run: bundle exec standardrb
       - run: bundle exec rake
+      - run: "RUBYOPT='--enable=frozen-string-literal --debug=frozen-string-literal' bundle exec rake"