diff --git a/build-constraints.yaml b/build-constraints.yaml
index fd434865..66b338e9 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4831,7 +4831,7 @@ skipped-tests:
     - http-media # base-4.13
 
     # fails with ghc 8.8
-    # alex # as of alex-3.2.4
+    - alex # as of alex-3.2.4
 
     # Cyclic dependencies
     - base-orphans # via hspec