diff --git a/cabal.project b/cabal.project
index e50f806..97d114c 100644
--- a/cabal.project
+++ b/cabal.project
@@ -20,6 +20,9 @@ source-repository-package
   tag: 08138810946c7eae2254feeb33269cd962d5e0c8
   subdir: packages/base
 
+package hmatrix
+  ghc-options: "-w"
+
 -- adds MonadTrans Decoder instance to waargonaut Decoder
 source-repository-package
   type: git