diff --git a/build-constraints.yaml b/build-constraints.yaml
index 41c4d365..aa838fd8 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -45,6 +45,7 @@ packages:
         - cereal-conduit
         - binary-conduit
         - lzma-conduit
+        - mutable-containers
 
     "FP Complete michael@fpcomplete.com @snoyberg":
         - alex