diff --git a/build-constraints.yaml b/build-constraints.yaml
index 143bdc8c..3d9aff62 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -5325,7 +5325,7 @@ packages:
 
     "Sebastian Graf <sgraf1337@gmail.com> @sgraf812":
         - happy-lib
-        - happy
+        - happy < 2.1.7 # https://github.com/haskell/happy/issues/343
 
     "Max Ulidtko <ulidtko@gmail.com> @ulidtko":
         - cabal-doctest