diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 43d09647..e5e7c8b1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -68,8 +68,8 @@ jobs:
     - name: Run make
       run: make -B
       
-    - name: diff
-      run: git diff
+    - name: Check no changes after rebuild of lexers and parsers
+      run: git diff --exit-code
 
     - name: Run tests with phpunit
       run: php ./vendor/phpunit/phpunit/phpunit