diff --git a/default.nix b/default.nix
index e4f292f9..f0480e19 100644
--- a/default.nix
+++ b/default.nix
@@ -12,6 +12,7 @@ mkDerivation {
   src = ./.;
   isLibrary = true;
   isExecutable = true;
+  enableSeparateDataOutput = true;
   libraryHaskellDepends = [
     aeson aeson-pretty attoparsec base base64-bytestring bytestring
     cereal containers deepseq foldl haskell-src lens mtl
diff --git a/nix/aeson-pretty.nix b/nix/aeson-pretty.nix
deleted file mode 100644
index fe695fa7..00000000
--- a/nix/aeson-pretty.nix
+++ /dev/null
@@ -1,20 +0,0 @@
-{ mkDerivation, aeson, attoparsec, base, base-compat, bytestring
-, cmdargs, scientific, stdenv, text, unordered-containers, vector
-}:
-mkDerivation {
-  pname = "aeson-pretty";
-  version = "0.8.2";
-  sha256 = "1c5r1w1hcv297pmj9yjpz9al22k3mh61gimi37wddga02212kd3c";
-  isLibrary = true;
-  isExecutable = true;
-  libraryHaskellDepends = [
-    aeson base base-compat bytestring scientific text
-    unordered-containers vector
-  ];
-  executableHaskellDepends = [
-    aeson attoparsec base bytestring cmdargs
-  ];
-  homepage = "http://github.com/informatikr/aeson-pretty";
-  description = "JSON pretty-printing library and command-line tool";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/aeson.nix b/nix/aeson.nix
deleted file mode 100644
index da66e754..00000000
--- a/nix/aeson.nix
+++ /dev/null
@@ -1,32 +0,0 @@
-{ mkDerivation, attoparsec, base, base-compat, base-orphans
-, base16-bytestring, bytestring, containers, deepseq, directory
-, dlist, filepath, generic-deriving, ghc-prim, hashable
-, hashable-time, HUnit, integer-logarithms, QuickCheck
-, quickcheck-instances, scientific, stdenv, tagged
-, template-haskell, test-framework, test-framework-hunit
-, test-framework-quickcheck2, text, time, time-locale-compat
-, unordered-containers, uuid-types, vector
-}:
-mkDerivation {
-  pname = "aeson";
-  version = "1.1.1.0";
-  sha256 = "1mkj4a09x9psmgq9sg5nz9va76756zfm97ds2gk2qpgxc7nr2dq8";
-  revision = "2";
-  editedCabalFile = "10bc20f8807990e71f5db74a1b7029f81f888c6f9d1c03e93883555fd1291e84";
-  libraryHaskellDepends = [
-    attoparsec base base-compat bytestring containers deepseq dlist
-    ghc-prim hashable scientific tagged template-haskell text time
-    time-locale-compat unordered-containers uuid-types vector
-  ];
-  testHaskellDepends = [
-    attoparsec base base-compat base-orphans base16-bytestring
-    bytestring containers directory dlist filepath generic-deriving
-    ghc-prim hashable hashable-time HUnit integer-logarithms QuickCheck
-    quickcheck-instances scientific tagged template-haskell
-    test-framework test-framework-hunit test-framework-quickcheck2 text
-    time time-locale-compat unordered-containers uuid-types vector
-  ];
-  homepage = "https://github.com/bos/aeson";
-  description = "Fast JSON parsing and encoding";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/cabal-doctest.nix b/nix/cabal-doctest.nix
deleted file mode 100644
index 360c9a1c..00000000
--- a/nix/cabal-doctest.nix
+++ /dev/null
@@ -1,10 +0,0 @@
-{ mkDerivation, base, Cabal, directory, filepath, stdenv }:
-mkDerivation {
-  pname = "cabal-doctest";
-  version = "1.0.2";
-  sha256 = "0h3wsjf2mg8kw1zvxc0f9nzchj5kzvza9z0arcyixkd9rkgqq6sa";
-  libraryHaskellDepends = [ base Cabal directory filepath ];
-  homepage = "https://github.com/phadej/cabal-doctest";
-  description = "A Setup.hs helper for doctests running";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/insert-ordered-containers.nix b/nix/insert-ordered-containers.nix
deleted file mode 100644
index 5f957133..00000000
--- a/nix/insert-ordered-containers.nix
+++ /dev/null
@@ -1,23 +0,0 @@
-{ mkDerivation, aeson, base, base-compat, hashable, lens
-, QuickCheck, semigroupoids, semigroups, stdenv, tasty
-, tasty-quickcheck, text, transformers, unordered-containers
-}:
-mkDerivation {
-  pname = "insert-ordered-containers";
-  version = "0.2.1.0";
-  sha256 = "1612f455dw37da9g7bsd1s5kyi84mnr1ifnjw69892amyimi47fp";
-  revision = "3";
-  editedCabalFile = "6fdce987672b006226243aa17522b57ec7a9e1cab247802eddbdaa9dc5b06446";
-  libraryHaskellDepends = [
-    aeson base base-compat hashable lens semigroupoids semigroups text
-    transformers unordered-containers
-  ];
-  testHaskellDepends = [
-    aeson base base-compat hashable lens QuickCheck semigroupoids
-    semigroups tasty tasty-quickcheck text transformers
-    unordered-containers
-  ];
-  homepage = "https://github.com/phadej/insert-ordered-containers#readme";
-  description = "Associative containers retating insertion order for traversals";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/neat-interpolation.nix b/nix/neat-interpolation.nix
deleted file mode 100644
index 06f6ba54..00000000
--- a/nix/neat-interpolation.nix
+++ /dev/null
@@ -1,15 +0,0 @@
-{ mkDerivation, base, base-prelude, HTF, parsec, stdenv
-, template-haskell, text
-}:
-mkDerivation {
-  pname = "neat-interpolation";
-  version = "0.3.2.1";
-  sha256 = "0550dy0vwh81byi9bxhdzqx5y9lnvkwj5rbks5rbj2fylhyf8c2m";
-  libraryHaskellDepends = [
-    base base-prelude parsec template-haskell text
-  ];
-  testHaskellDepends = [ base-prelude HTF ];
-  homepage = "https://github.com/nikita-volkov/neat-interpolation";
-  description = "A quasiquoter for neat and simple multiline text interpolation";
-  license = stdenv.lib.licenses.mit;
-}
diff --git a/nix/optparse-applicative.nix b/nix/optparse-applicative.nix
deleted file mode 100644
index bdfc252a..00000000
--- a/nix/optparse-applicative.nix
+++ /dev/null
@@ -1,15 +0,0 @@
-{ mkDerivation, ansi-wl-pprint, base, bytestring, process
-, QuickCheck, stdenv, transformers, transformers-compat
-}:
-mkDerivation {
-  pname = "optparse-applicative";
-  version = "0.14.0.0";
-  sha256 = "06iwp1qsq0gjhnhxwyhdhldwvhlgcik6lx5jxpbb40fispyk4nxm";
-  libraryHaskellDepends = [
-    ansi-wl-pprint base process transformers transformers-compat
-  ];
-  testHaskellDepends = [ base bytestring QuickCheck ];
-  homepage = "https://github.com/pcapriotti/optparse-applicative";
-  description = "Utilities and combinators for parsing command line options";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/optparse-generic.nix b/nix/optparse-generic.nix
deleted file mode 100644
index 42bc1302..00000000
--- a/nix/optparse-generic.nix
+++ /dev/null
@@ -1,14 +0,0 @@
-{ mkDerivation, base, bytestring, optparse-applicative, semigroups
-, stdenv, system-filepath, text, time, transformers, void
-}:
-mkDerivation {
-  pname = "optparse-generic";
-  version = "1.2.1";
-  sha256 = "1dk945dp98mwk1v4y0cky3z0ngmd29nbg6fbaaxnigcrgpbvkjml";
-  libraryHaskellDepends = [
-    base bytestring optparse-applicative semigroups system-filepath
-    text time transformers void
-  ];
-  description = "Auto-generate a command-line parser for your datatype";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nix/proto3-wire.nix b/nix/proto3-wire.nix
index 305b82e0..1fd3032d 100644
--- a/nix/proto3-wire.nix
+++ b/nix/proto3-wire.nix
@@ -6,9 +6,9 @@ mkDerivation {
   pname = "proto3-wire";
   version = "1.0.0";
   src = fetchgit {
-    url = "https://github.com/awakenetworks/proto3-wire";
-    sha256 = "14n0d16an782ayipirm5v2mvp58jgf65xvffqzp08p50sksil3gi";
-    rev = "a938330bf794cf3fa05591d03906915df98d157c";
+    url = "https://github.com/awakenetworks/proto3-wire.git";
+    sha256 = "0nlar9zwy7k47nm395h11ivmhhfhip5bhyazwa2gnffn5lhsyv3i";
+    rev = "d492fa3034724b46f23fb2c73780c9dd7ecb4d04";
   };
   libraryHaskellDepends = [
     base bytestring cereal containers deepseq hashable QuickCheck safe
diff --git a/nix/turtle.nix b/nix/turtle.nix
deleted file mode 100644
index 4f667138..00000000
--- a/nix/turtle.nix
+++ /dev/null
@@ -1,20 +0,0 @@
-{ mkDerivation, ansi-wl-pprint, async, base, bytestring, clock
-, directory, doctest, foldl, hostname, managed, optional-args
-, optparse-applicative, process, semigroups, stdenv, stm
-, system-fileio, system-filepath, temporary, text, time
-, transformers, unix, unix-compat
-}:
-mkDerivation {
-  pname = "turtle";
-  version = "1.3.6";
-  sha256 = "0fr8p6rnk2lrsgbfh60jlqcjr0nxrh3ywxsj5d4psck0kgyhvg1m";
-  libraryHaskellDepends = [
-    ansi-wl-pprint async base bytestring clock directory foldl hostname
-    managed optional-args optparse-applicative process semigroups stm
-    system-fileio system-filepath temporary text time transformers unix
-    unix-compat
-  ];
-  testHaskellDepends = [ base doctest system-filepath temporary ];
-  description = "Shell programming, Haskell-style";
-  license = stdenv.lib.licenses.bsd3;
-}
diff --git a/nixpkgs/17_09.nix b/nixpkgs/17_09.nix
new file mode 100644
index 00000000..5295b386
--- /dev/null
+++ b/nixpkgs/17_09.nix
@@ -0,0 +1,12 @@
+# Given a Git revision hash `<rev>`, you get the new SHA256 by running:
+#
+# ```bash
+# $ nix-prefetch-url "https://github.com/NixOS/nixpkgs/archive/<rev>.tar.gz"
+# ```
+#
+# The SHA256 will be printed as the last line of stdout.
+
+import ./fetch-nixpkgs.nix {
+   rev    = "74286ec9e76be7cd00c4247b9acb430c4bd9f1ce";
+   sha256 = "0njb3qd2wxj7gil8y61lwh7zacmvr6zklv67w5zmvifi1fvalvdg";
+}
diff --git a/fetch-nixpkgs.nix b/nixpkgs/fetch-nixpkgs.nix
similarity index 99%
rename from fetch-nixpkgs.nix
rename to nixpkgs/fetch-nixpkgs.nix
index 8b30bbc6..644b892c 100644
--- a/fetch-nixpkgs.nix
+++ b/nixpkgs/fetch-nixpkgs.nix
@@ -27,7 +27,7 @@ ifThenElse {
       };
 
       builtin-paths = import <nix/config.nix>;
-      
+
       script = builtins.toFile "nixpkgs-unpacker" ''
         "$coreutils/mkdir" "$out"
         cd "$out"
diff --git a/proto3-suite.cabal b/proto3-suite.cabal
index 09e34e0e..cafae14e 100644
--- a/proto3-suite.cabal
+++ b/proto3-suite.cabal
@@ -24,7 +24,7 @@ library
   other-modules:       Proto3.Suite.DotProto.Internal
                        Proto3.Suite.DotProto.Generate.Swagger
                        Proto3.Suite.JSONPB.Class
-  build-depends:       aeson == 1.1.1.0,
+  build-depends:       aeson >= 1.1.1.0 && < 1.2,
                        aeson-pretty,
                        attoparsec >= 0.13.0.1,
                        base >=4.8 && <5.0,
@@ -66,7 +66,7 @@ test-suite tests
   default-language:    Haskell2010
   build-depends:       base >=4.8 && <5.0,
                        QuickCheck >=2.8 && <2.10,
-                       aeson == 1.1.1.0,
+                       aeson >= 1.1.1.0 && < 1.2,
                        attoparsec >= 0.13.0.1,
                        base >=4.8 && <5.0,
                        base64-bytestring >= 1.0.0.1 && < 1.1,
diff --git a/release.nix b/release.nix
index 4a099071..be9e031a 100644
--- a/release.nix
+++ b/release.nix
@@ -1,99 +1,90 @@
-# To develop with this repository, open a Nix shell with:
+# To develop iteratively within this repository, open a Nix shell via:
 #
 #     $ nix-shell -A proto3-suite.env release.nix
 #
-# ... then run `cabal` commands as you would normally do:
+# ... and then use `cabal` to build and test:
 #
-#     [nix-shell]$ cabal configure --with-gcc=clang --enable-tests
+#     [nix-shell]$ cabal configure --enable-tests
 #     [nix-shell]$ cabal build
 #     [nix-shell]$ cabal test
 
 let
-  config = {
-    packageOverrides = pkgs:
-      let
-        python_protobuf3_0 =
-          (pkgs.pythonPackages.protobufBuild pkgs.protobuf3_0).override {
-            doCheck = false;
-          };
-      in
-        { haskellPackages = pkgs.haskellPackages.override {
-            overrides = haskellPackagesNew: haskellPackagesOld: rec {
-
-              aeson =
-                pkgs.haskell.lib.dontCheck (haskellPackagesNew.callPackage ./nix/aeson.nix { });
-
-              aeson-pretty =
-                haskellPackagesNew.callPackage ./nix/aeson-pretty.nix { };
-
-              cabal-doctest =
-                haskellPackagesNew.callPackage ./nix/cabal-doctest.nix { };
-
-              insert-ordered-containers =
-                haskellPackagesNew.callPackage ./nix/insert-ordered-containers.nix { };
-
-              neat-interpolation =
-                haskellPackagesNew.callPackage ./nix/neat-interpolation.nix { };
-
-              optparse-applicative =
-                haskellPackagesNew.callPackage ./nix/optparse-applicative.nix { } ;
-
-              optparse-generic =
-                haskellPackagesNew.callPackage ./nix/optparse-generic.nix { } ;
-
-              proto3-suite-no-tests =
-                pkgs.haskell.lib.dontCheck
-                  (haskellPackagesNew.callPackage ./default.nix { });
-
-              proto3-suite =
-                pkgs.haskell.lib.overrideCabal
-                  (haskellPackagesNew.callPackage ./default.nix { })
-                  (oldAttrs: {
-                      patches = [ tests/tests.patch ];
-
-                      postPatch = ''
-                        substituteInPlace tests/encode.sh --replace @ghc@ ${pkgs.ghc} --replace @bash@ ${pkgs.bash}
-                        substituteInPlace tests/decode.sh --replace @ghc@ ${pkgs.ghc} --replace @bash@ ${pkgs.bash}
-                      '';
-
-                      testHaskellDepends = oldAttrs.testHaskellDepends ++ [
-                        pkgs.ghc
-                        proto3-suite-no-tests
-                        pkgs.protobuf3_0
-                        pkgs.python
-                        python_protobuf3_0
-                      ];
-                    }
-                  );
-
-              proto3-wire =
-                haskellPackagesNew.callPackage ./nix/proto3-wire.nix { };
-
-              scientific =
-                pkgs.haskell.lib.dontCheck haskellPackagesOld.scientific;
-
-              swagger2 =
-                pkgs.haskell.lib.dontHaddock (haskellPackagesNew.callPackage ./nix/swagger2.nix { });
-
-              turtle =
-                haskellPackagesNew.callPackage ./nix/turtle.nix { } ;
-
-            };
-          };
-        };
+  nixpkgs = import ./nixpkgs/17_09.nix;
 
+  config = {
     allowUnfree = true;
-  };
 
-  nixpkgs = import ./fetch-nixpkgs.nix {
-    rev    = "7ae9da426924537755ce9164fd5b5f81ce16a1c3";
-    sha256 = "1zg1j2fsfj6qhh724nc8fnn3ig3rm6nd29zzhjrbjkszkjspc9pl";
+    packageOverrides = pkgs: {
+      haskellPackages = pkgs.haskellPackages.override {
+        overrides = self: super: rec {
+
+          # The test suite for proto3-suite requires:
+          #
+          #   - a GHC with `proto3-suite` installed, since our code generation
+          #     tests compile and run generated code; since this custom GHC is
+          #     also used inside the nix-shell environment for iterative
+          #     development, we ensure that it is available on $PATH and that
+          #     all test suite deps are available to it
+          #
+          #   - a Python interpreter with a protobuf package installed, which we
+          #     use as a reference implementation; we also put expose this on
+          #     the `nix-shell` $PATH
+          #
+          # Finally, we make `cabal` available in the `nix-shell`, intentionally
+          # occluding any globally-installed versions of the tool.
+
+          proto3-suite =
+            pkgs.haskell.lib.overrideCabal
+              (self.callPackage ./default.nix { })
+              (drv:
+                 let
+                   python = pkgs.python.withPackages (pkgs: [ pkgs.protobuf3_0 ]);
+                 in
+                   {
+                     shellHook = (drv.shellHook or "") +
+                       (let
+                          ghc = self.ghcWithPackages (pkgs:
+                            drv.testHaskellDepends ++ [ pkgs.proto3-suite-boot ]
+                          );
+                        in ''
+                          export PATH=${self.cabal-install}/bin:${ghc}/bin:${python}/bin''${PATH:+:}$PATH
+                        '');
+
+                     testHaskellDepends = drv.testHaskellDepends ++ [
+                       pkgs.ghc
+                       proto3-suite-boot
+                       python
+                     ];
+                   }
+              );
+
+          # A proto3-suite sans tests, for bootstrapping
+          proto3-suite-boot =
+            pkgs.haskell.lib.overrideCabal
+              (self.callPackage ./default.nix { })
+              (_: {
+                 configureFlags = [ "--disable-optimization" ];
+                 doCheck        = false;
+                 doHaddock      = false;
+               });
+
+          proto3-wire =
+            self.callPackage ./nix/proto3-wire.nix { };
+
+          swagger2 =
+            pkgs.haskell.lib.dontCheck
+              (pkgs.haskell.lib.dontHaddock
+                (self.callPackage ./nix/swagger2.nix { }));
+        };
+      };
+    };
   };
+in
 
+let
    linuxPkgs = import nixpkgs { inherit config; system = "x86_64-linux" ; };
   darwinPkgs = import nixpkgs { inherit config; system = "x86_64-darwin"; };
         pkgs = import nixpkgs { inherit config; };
-
 in
   { proto3-suite-linux    =     linuxPkgs.haskellPackages.proto3-suite;
     proto3-suite-darwin   =    darwinPkgs.haskellPackages.proto3-suite;
diff --git a/tests/TestCodeGen.hs b/tests/TestCodeGen.hs
index 3d0a3e0d..3a8f853e 100644
--- a/tests/TestCodeGen.hs
+++ b/tests/TestCodeGen.hs
@@ -67,21 +67,21 @@ don'tAlterEnumFieldNames
                  $ prefixedEnumFieldName enumName fieldName
                      @?= Right (enumName <> fieldName)
 
+setPythonPath :: IO ()
+setPythonPath = Turtle.export "PYTHONPATH" =<< do
+  maybe pyTmpDir ((pyTmpDir <> ":") <>) <$> Turtle.need "PYTHONPATH"
+
 simpleEncodeDotProto :: TestTree
 simpleEncodeDotProto =
     testCase "generate code for a simple .proto and then use it to encode messages" $
     do compileTestDotProtos
+       -- Compile our generated encoder
        (@?= ExitSuccess) =<< Turtle.proc "tests/encode.sh" [hsTmpDir] empty
 
-       m <- Turtle.need "PYTHONPATH"
-       pythonPath <- case m of
-           Nothing         -> fail "PYTHONPATH environment variable is not set"
-           Just pythonPath -> return pythonPath
-       Turtle.export "PYTHONPATH" (pythonPath <> ":" <> pyTmpDir)
-
-       let cmd = (hsTmpDir <> "/simpleEncodeDotProto | python tests/check_simple_dot_proto.py")
-       -- The python test exits with a special error code to indicate all tests
-       -- were successful
+       -- The python encoder test exits with a special error code to indicate
+       -- all tests were successful
+       setPythonPath
+       let cmd = hsTmpDir <> "/simpleEncodeDotProto | python tests/check_simple_dot_proto.py"
        (@?= ExitFailure 12) =<< Turtle.shell cmd empty
 
        -- Not using bracket so that we can inspect the output to fix the tests
@@ -92,14 +92,10 @@ simpleDecodeDotProto :: TestTree
 simpleDecodeDotProto =
     testCase "generate code for a simple .proto and then use it to decode messages" $
     do compileTestDotProtos
+       -- Compile our generated decoder
        (@?= ExitSuccess) =<< Turtle.proc "tests/decode.sh" [hsTmpDir] empty
 
-       m <- Turtle.need "PYTHONPATH"
-       pythonPath <- case m of
-           Nothing         -> fail "PYTHONPATH environment variable is not set"
-           Just pythonPath -> return pythonPath
-       Turtle.export "PYTHONPATH" (pythonPath <> ":" <> pyTmpDir)
-
+       setPythonPath
        let cmd = "python tests/send_simple_dot_proto.py | " <> hsTmpDir <> "/simpleDecodeDotProto "
        (@?= ExitSuccess) =<< Turtle.shell cmd empty
 
diff --git a/tests/decode.sh b/tests/decode.sh
index 9ae39191..516134b3 100755
--- a/tests/decode.sh
+++ b/tests/decode.sh
@@ -1,5 +1,5 @@
-#!/bin/bash -eu
-
+#!/usr/bin/env bash
+set -eu
 hsTmpDir=$1
 
 ghc                                         \
diff --git a/tests/encode.sh b/tests/encode.sh
index 91fbd17a..9e94a4a0 100755
--- a/tests/encode.sh
+++ b/tests/encode.sh
@@ -1,5 +1,5 @@
-#!/bin/bash -eu
-
+#!/usr/bin/env bash
+set -eu
 hsTmpDir=$1
 
 ghc                                         \
diff --git a/tests/tests.patch b/tests/tests.patch
deleted file mode 100644
index ab76588f..00000000
--- a/tests/tests.patch
+++ /dev/null
@@ -1,30 +0,0 @@
-diff --git a/tests/decode.sh b/tests/decode.sh
-index 59ad7cc..d1df62b 100755
---- a/tests/decode.sh
-+++ b/tests/decode.sh
-@@ -1,8 +1,8 @@
--#!/bin/bash -eu
-+#! @bash@/bin/bash -eu
-
- hsTmpDir=$1
-
--ghc                                         \
-+@ghc@/bin/ghc                               \
-     --make                                  \
-     -odir $hsTmpDir                         \
-     -hidir $hsTmpDir                        \
-diff --git a/tests/encode.sh b/tests/encode.sh
-index 8ebea7e..bc79de2 100755
---- a/tests/encode.sh
-+++ b/tests/encode.sh
-@@ -1,8 +1,8 @@
--#!/bin/bash -eu
-+#! @bash@/bin/bash -eu
-
- hsTmpDir=$1
-
--ghc                                         \
-+@ghc@/bin/ghc                               \
-     --make                                  \
-     -odir $hsTmpDir                         \
-     -hidir $hsTmpDir                        \