diff --git a/pkgs/top-level/emacs-packages.nix b/pkgs/top-level/emacs-packages.nix
index 0adddf3d5d0..c5bb3a5f047 100644
--- a/pkgs/top-level/emacs-packages.nix
+++ b/pkgs/top-level/emacs-packages.nix
@@ -597,6 +597,7 @@ let self = _self // overrides;
     pname = "ghc";
     version = external.ghc-mod.version;
     src = external.ghc-mod.src;
+    packageRequires = [ haskell-mode ];
     propagatedUserEnvPkgs = [ external.ghc-mod ];
     fileSpecs = [ "elisp/*.el" ];
     meta = { license = bsd3; };