diff --git a/overlays/30-ghc.nix b/overlays/30-ghc.nix
index 40ca35c3..045cd854 100644
--- a/overlays/30-ghc.nix
+++ b/overlays/30-ghc.nix
@@ -13,6 +13,7 @@ let
     {
       inherit (p)
         brittany ormolu releaser cabal-fmt stack ghcid ghcide arbtt cabal-edit iCalendar
+        pretty-simple tz
         haskell-language-server cabal-install dhall taskwarrior pandoc hlint
         cabal2nix weeder reflex-dom password optics shh-extras neuron
         hspec-discover paths hmatrix postgresql-simple snap