diff --git a/pkgs/development/libraries/haskell/fgl-visualize/default.nix b/pkgs/development/libraries/haskell/fgl-visualize/default.nix
index e2987351d0ad..279f25eaca20 100644
--- a/pkgs/development/libraries/haskell/fgl-visualize/default.nix
+++ b/pkgs/development/libraries/haskell/fgl-visualize/default.nix
@@ -9,5 +9,6 @@ cabal.mkDerivation (self: {
     description = "Convert FGL graphs to dot (graphviz) files";
     license = self.stdenv.lib.licenses.bsd3;
     platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.andres ];
   };
 })
diff --git a/pkgs/development/libraries/haskell/gtk2hs-buildtools/default.nix b/pkgs/development/libraries/haskell/gtk2hs-buildtools/0.12.1.nix
similarity index 100%
rename from pkgs/development/libraries/haskell/gtk2hs-buildtools/default.nix
rename to pkgs/development/libraries/haskell/gtk2hs-buildtools/0.12.1.nix
diff --git a/pkgs/development/libraries/haskell/gtk2hs-buildtools/0.12.3.nix b/pkgs/development/libraries/haskell/gtk2hs-buildtools/0.12.3.nix
new file mode 100644
index 000000000000..a9b5efe58779
--- /dev/null
+++ b/pkgs/development/libraries/haskell/gtk2hs-buildtools/0.12.3.nix
@@ -0,0 +1,18 @@
+{ cabal, alex, filepath, happy, random }:
+
+cabal.mkDerivation (self: {
+  pname = "gtk2hs-buildtools";
+  version = "0.12.3";
+  sha256 = "1129p2b0hvmin7zpq43ik670v2c63jv704bnmnh3cr0bw06qrrbi";
+  isLibrary = false;
+  isExecutable = true;
+  buildDepends = [ filepath random ];
+  buildTools = [ alex happy ];
+  meta = {
+    homepage = "http://projects.haskell.org/gtk2hs/";
+    description = "Tools to build the Gtk2Hs suite of User Interface libraries";
+    license = self.stdenv.lib.licenses.gpl2;
+    platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.andres ];
+  };
+})
diff --git a/pkgs/development/libraries/haskell/network-conduit/default.nix b/pkgs/development/libraries/haskell/network-conduit/default.nix
new file mode 100644
index 000000000000..e16610fe3482
--- /dev/null
+++ b/pkgs/development/libraries/haskell/network-conduit/default.nix
@@ -0,0 +1,18 @@
+{ cabal, conduit, liftedBase, monadControl, network, transformers
+}:
+
+cabal.mkDerivation (self: {
+  pname = "network-conduit";
+  version = "0.4.0";
+  sha256 = "0h0s33nxihd4zy9mvy2vpdrpvjapacbl69ndsw5zrbqhwbpz3mzs";
+  buildDepends = [
+    conduit liftedBase monadControl network transformers
+  ];
+  meta = {
+    homepage = "http://github.com/snoyberg/conduit";
+    description = "Stream socket data using conduits";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.andres ];
+  };
+})
diff --git a/pkgs/development/libraries/haskell/path-pieces/0.1.0.nix b/pkgs/development/libraries/haskell/path-pieces/0.1.0.nix
deleted file mode 100755
index ea66d1d54bdc..000000000000
--- a/pkgs/development/libraries/haskell/path-pieces/0.1.0.nix
+++ /dev/null
@@ -1,15 +0,0 @@
-{ cabal, text }:
-
-cabal.mkDerivation (self: {
-  pname = "path-pieces";
-  version = "0.1.0";
-  sha256 = "12dgiq2pz94pwa5v5wv96ps0nl5w23r44nnp4lm4cdhl063c9w8d";
-  buildDepends = [ text ];
-  meta = {
-    homepage = "http://github.com/snoyberg/path-pieces";
-    description = "Components of paths";
-    license = self.stdenv.lib.licenses.bsd3;
-    platforms = self.ghc.meta.platforms;
-    maintainers = [ self.stdenv.lib.maintainers.andres ];
-  };
-})
diff --git a/pkgs/development/libraries/haskell/path-pieces/0.0.0.nix b/pkgs/development/libraries/haskell/path-pieces/default.nix
old mode 100755
new mode 100644
similarity index 69%
rename from pkgs/development/libraries/haskell/path-pieces/0.0.0.nix
rename to pkgs/development/libraries/haskell/path-pieces/default.nix
index 6b5168e50c1a..d4f52aef58e9
--- a/pkgs/development/libraries/haskell/path-pieces/0.0.0.nix
+++ b/pkgs/development/libraries/haskell/path-pieces/default.nix
@@ -1,10 +1,10 @@
-{ cabal, text }:
+{ cabal, text, time }:
 
 cabal.mkDerivation (self: {
   pname = "path-pieces";
-  version = "0.0.0";
-  sha256 = "09sk4wlzy37gaii7spisjy4a3pizis9si4kv389bki20gfwpaivf";
-  buildDepends = [ text ];
+  version = "0.1.1";
+  sha256 = "17ymk2azgz2c1hwnzqd9xy77hh51mvrgz4zs7lz4ik6rnvvihraz";
+  buildDepends = [ text time ];
   meta = {
     homepage = "http://github.com/snoyberg/path-pieces";
     description = "Components of paths";
diff --git a/pkgs/development/libraries/haskell/void/default.nix b/pkgs/development/libraries/haskell/void/default.nix
new file mode 100644
index 000000000000..585ac3df9fb5
--- /dev/null
+++ b/pkgs/development/libraries/haskell/void/default.nix
@@ -0,0 +1,15 @@
+{ cabal, semigroups }:
+
+cabal.mkDerivation (self: {
+  pname = "void";
+  version = "0.5.5";
+  sha256 = "011ji37d5f6xrvd6sq0zkzggaq11r7nyb2z5v3ix3kn14r5psfz3";
+  buildDepends = [ semigroups ];
+  meta = {
+    homepage = "http://github.com/ekmett/void";
+    description = "A Haskell 98 logically uninhabited data type";
+    license = self.stdenv.lib.licenses.bsd3;
+    platforms = self.ghc.meta.platforms;
+    maintainers = [ self.stdenv.lib.maintainers.andres ];
+  };
+})
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index cd616925f315..5830d9d150ad 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -753,7 +753,9 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
     libc = pkgs.stdenv.gcc.libc;
   };
 
-  gtk2hsBuildtools = callPackage ../development/libraries/haskell/gtk2hs-buildtools {};
+  gtk2hsBuildtools_0_12_1 = callPackage ../development/libraries/haskell/gtk2hs-buildtools/0.12.1.nix {};
+  gtk2hsBuildtools_0_12_3 = callPackage ../development/libraries/haskell/gtk2hs-buildtools/0.12.3.nix {};
+  gtk2hsBuildtools = self.gtk2hsBuildtools_0_12_1;
   gtk2hsC2hs = self.gtk2hsBuildtools;
 
   gtksourceview2 = callPackage ../development/libraries/haskell/gtksourceview2 {
@@ -1042,6 +1044,8 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
   network_2_3_0_11 = callPackage ../development/libraries/haskell/network/2.3.0.11.nix {};
   network = self.network_2_3_0_11;
 
+  networkConduit = callPackage ../development/libraries/haskell/network-conduit {};
+
   nonNegative = callPackage ../development/libraries/haskell/non-negative {};
 
   numericPrelude = callPackage ../development/libraries/haskell/numeric-prelude {};
@@ -1065,9 +1069,7 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   OpenGLRaw = callPackage ../development/libraries/haskell/OpenGLRaw {};
 
-  pathPieces_0_0_0 = callPackage ../development/libraries/haskell/path-pieces/0.0.0.nix {};
-  pathPieces_0_1_0 = callPackage ../development/libraries/haskell/path-pieces/0.1.0.nix {};
-  pathPieces = self.pathPieces_0_1_0;
+  pathPieces = callPackage ../development/libraries/haskell/path-pieces {};
 
   pandoc = callPackage ../development/libraries/haskell/pandoc {};
 
@@ -1427,6 +1429,8 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   vectorSpace = callPackage ../development/libraries/haskell/vector-space {};
 
+  void = callPackage ../development/libraries/haskell/void {};
+
   vty = callPackage ../development/libraries/haskell/vty {
     mtl = self.mtl2;
   };
@@ -1497,9 +1501,7 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   yesodAuth = callPackage ../development/libraries/haskell/yesod-auth {};
 
-  yesodCore = callPackage ../development/libraries/haskell/yesod-core {
-    pathPieces = self.pathPieces_0_0_0;
-  };
+  yesodCore = callPackage ../development/libraries/haskell/yesod-core {};
 
   yesodDefault = callPackage ../development/libraries/haskell/yesod-default {};