diff --git a/build-constraints.yaml b/build-constraints.yaml
index 0e224bfd..29ee426f 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1644,6 +1644,7 @@ packages:
         - slug
         - path-io
         - hspec-megaparsec
+        - plan-b
 
     "Thomas Bereknyei <tomberek@gmail.com>":
         - multiplate