diff --git a/build-constraints.yaml b/build-constraints.yaml
index 27455058..67108c44 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -589,6 +589,7 @@ packages:
         - incremental-parser
         - monoid-subclasses
         - picoparsec
+        - rank2classes
 
     "Brent Yorgey <byorgey@gmail.com> @byorgey":
         - active