diff --git a/pkgs/development/haskell-modules/configuration-ghcjs.nix b/pkgs/development/haskell-modules/configuration-ghcjs.nix
index aad0da0604e3..2f68095f44aa 100644
--- a/pkgs/development/haskell-modules/configuration-ghcjs.nix
+++ b/pkgs/development/haskell-modules/configuration-ghcjs.nix
@@ -7,7 +7,7 @@ self: super: {
   # LLVM is not supported on this GHC; use the latest one.
   inherit (pkgs) llvmPackages;
 
-  jailbreak-cabal = pkgs.haskell-ng.packages.ghc7101.jailbreak-cabal;
+  inherit (pkgs.haskell-ng.packages.ghc7101) jailbreak-cabal alex happy;
 
   # Many packages fail with:
   #   haddock: internal error: expectJust getPackageDetails