diff --git a/pkgs/development/libraries/haskell/final/default.nix b/pkgs/development/libraries/haskell/final/default.nix
new file mode 100644
index 00000000000..63226174118
--- /dev/null
+++ b/pkgs/development/libraries/haskell/final/default.nix
@@ -0,0 +1,14 @@
+{ cabal, stm, transformers }:
+
+cabal.mkDerivation (self: {
+  pname = "final";
+  version = "0.1";
+  sha256 = "189vby5ym6hcjpz6y9chlgkyzl8wnndqkhzk7s7qy8mksr3g66f9";
+  buildDepends = [ stm transformers ];
+  meta = {
+    homepage = "http://github.com/errge/final";
+    description = "utility to add extra safety to monadic returns";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+  };
+})
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index f4f5e1810ca..42107fdfb0b 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -64,7 +64,7 @@
 # modifyPrio argument can be set to lowPrio to make all Haskell packages have
 # low priority.
 
-let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
+let result = let callPackage = x : y : modifyPrio (newScope result.finalReturn x y);
                  self = (prefFun result) result; in
 
 # Indentation deliberately broken at this point to keep the bulk
@@ -72,7 +72,7 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
 {
 
-  final = self;
+  finalReturn = self;
 
   callPackage = callPackage;
 
@@ -962,6 +962,8 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   filesystemConduit = callPackage ../development/libraries/haskell/filesystem-conduit {};
 
+  final = callPackage ../development/libraries/haskell/final {};
+
   fgl_5_4_2_2 = callPackage ../development/libraries/haskell/fgl/5.4.2.2.nix {};
   fgl_5_4_2_3 = callPackage ../development/libraries/haskell/fgl/5.4.2.3.nix {};
   fgl_5_4_2_4 = callPackage ../development/libraries/haskell/fgl/5.4.2.4.nix {};
@@ -2383,4 +2385,4 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
 };
 
-in result.final
+in result.finalReturn