diff --git a/stack.pkg.yaml b/stack.pkg.yaml
index 4823c3edc..d1843aae2 100644
--- a/stack.pkg.yaml
+++ b/stack.pkg.yaml
@@ -22,4 +22,5 @@ extra-deps:
 - cmark-gfm-0.1.1
 - QuickCheck-2.10.0.1
 - tasty-quickcheck-0.9.1
+- haddock-library-1.4.5
 resolver: lts-9.0
diff --git a/stack.yaml b/stack.yaml
index cda82013d..5ac569bfb 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -12,4 +12,5 @@ extra-deps:
 - cmark-gfm-0.1.1
 - QuickCheck-2.10.0.1
 - tasty-quickcheck-0.9.1
+- haddock-library-1.4.5
 resolver: lts-9.0