diff --git a/dhall-nix.cabal b/dhall-nix.cabal
--- a/dhall-nix.cabal
+++ b/dhall-nix.cabal
@@ -1,5 +1,5 @@
 Name: dhall-nix
-Version: 1.1.11
+Version: 1.1.12
 Cabal-Version: >=1.8.0.2
 Build-Type: Simple
 Tested-With: GHC == 8.0.1
@@ -30,9 +30,9 @@
         base                      >= 4.8.0.0 && < 5   ,
         containers                              < 0.7 ,
         data-fix                                < 0.3 ,
-        dhall                     >= 1.28    && < 1.30,
+        dhall                     >= 1.28    && < 1.31,
         hnix                      >= 0.6.1   && < 0.7 ,
-        neat-interpolation                      < 0.4 ,
+        neat-interpolation                      < 0.5 ,
         text                      >= 0.8.0.0 && < 1.3
     Exposed-Modules:
         Dhall.Nix
diff --git a/src/Dhall/Nix.hs b/src/Dhall/Nix.hs
--- a/src/Dhall/Nix.hs
+++ b/src/Dhall/Nix.hs
@@ -462,7 +462,7 @@
                 return (NamedVar [StaticKey k] v Nix.nullPos)
         return (Fix (NSet a''))
     loop (Union _) = return (Fix (NSet []))
-    loop (Combine a b) = do
+    loop (Combine _ a b) = do
         a' <- loop a
         b' <- loop b
         let e0 = Fix (NBinary NApp (Fix (NBinary NApp "map" "toKeyVals")) "ks")