diff --git a/default.nix b/default.nix
index d3a82782..84eb41b3 100644
--- a/default.nix
+++ b/default.nix
@@ -1,24 +1,13 @@
-{ compiler ? "ghc865", pkgs ? import nix/pkgs.nix }:
-
 let
-  hlib = pkgs.haskell.lib;
-  hpkg = pkgs.haskell.packages."${compiler}";
-  llvm-hs = import ./nix/llvm-hs.nix;
-in
-
-hpkg.developPackage {
-  root = ./grin;
-  overrides = self: super: {
-    llvm-hs = hlib.dontCheck (self.callCabal2nix "llvm-hs" "${llvm-hs}/llvm-hs" {
-      llvm-config = pkgs.llvm_7;
-    });
-    llvm-hs-pure = self.callCabal2nix "llvm-hs-pure" "${llvm-hs}/llvm-hs-pure" {};
-    llvm-hs-pretty = self.callPackage ./nix/llvm-hs-pretty.nix {};
+  haskell = import ./nix/haskell.nix;
+  llvm-overlay = self: super: {
+    llvm-config = self.llvm_7;
   };
-  modifier = drv: hlib.addBuildTools drv [
-    (import nix/llvm.nix {})
-    pkgs.clang_7
-    pkgs.llvm_7
-  ];
-  returnShellEnv = false;
-}
+  extra-overlays = [ llvm-overlay ];
+  pkgs = import ./nix/packages.nix (haskell // {
+    overlays = haskell.overlays ++ extra-overlays;
+  });
+in
+  pkgs.haskell-nix.stackProject {
+    src = pkgs.haskell-nix.haskellLib.cleanGit { src = ./.; };
+  }
diff --git a/nix/haskell-nix-src.json b/nix/haskell-nix-src.json
new file mode 100644
index 00000000..b7744e52
--- /dev/null
+++ b/nix/haskell-nix-src.json
@@ -0,0 +1,7 @@
+{
+  "url": "https://github.com/input-output-hk/haskell.nix",
+  "rev": "ebdc0030e6973629c1ed7dba53c1b1d154c3e75e",
+  "date": "2019-12-11T01:12:46+00:00",
+  "sha256": "1q25sw8kz7r0wwzq780qq1cgsiy1g7iwnywckixa28psim8rp2nw",
+  "fetchSubmodules": false
+}
diff --git a/nix/haskell.nix b/nix/haskell.nix
new file mode 100644
index 00000000..0770819d
--- /dev/null
+++ b/nix/haskell.nix
@@ -0,0 +1,8 @@
+let
+  spec = builtins.fromJSON (builtins.readFile ./haskell-nix-src.json);
+  haskell-nix-src = builtins.fetchGit {
+    name = "haskell-lib";
+    inherit (spec) url rev;
+  };
+in
+  import haskell-nix-src
diff --git a/nix/llvm-hs-pretty.nix b/nix/llvm-hs-pretty.nix
deleted file mode 100644
index 03b9bb35..00000000
--- a/nix/llvm-hs-pretty.nix
+++ /dev/null
@@ -1,19 +0,0 @@
-{ mkDerivation, array, base, bytestring, directory, filepath
-, llvm-hs, llvm-hs-pure, mtl, prettyprinter, tasty, tasty-golden
-, tasty-hspec, tasty-hunit, text, transformers, stdenv
-}:
-mkDerivation {
-  pname = "llvm-hs-pretty";
-  version = "0.6.1.0";
-  sha256 = "12w1rkkaf50jl2vdkyk4xpvjmsxzjbfkdyklaq5p6b8ykw872pda";
-  libraryHaskellDepends = [
-    array base bytestring llvm-hs-pure prettyprinter text
-  ];
-  testHaskellDepends = [
-    base directory filepath llvm-hs llvm-hs-pure mtl tasty tasty-golden
-    tasty-hspec tasty-hunit text transformers
-  ];
-  description = "A pretty printer for LLVM IR";
-  license = stdenv.lib.licenses.mit;
-  hydraPlatforms = stdenv.lib.platforms.none;
-}
diff --git a/nix/llvm-hs.nix b/nix/llvm-hs.nix
deleted file mode 100644
index ec6dea2c..00000000
--- a/nix/llvm-hs.nix
+++ /dev/null
@@ -1,7 +0,0 @@
-let
-  url = "https://github.com/csabahruska/llvm-hs";
-  ref = "llvm-7";
-  rev = "868e23a13942703255979369defdb49ac57b6866";
-  repo = builtins.fetchGit { inherit url ref rev; };
-in
-  repo
diff --git a/nix/llvm.nix b/nix/llvm.nix
index a8c389cc..19c19f6d 100644
--- a/nix/llvm.nix
+++ b/nix/llvm.nix
@@ -1,4 +1,4 @@
-{ pkgs ? import ./pkgs.nix }:
+{ pkgs ? import ./packages.nix {} }:
 
 pkgs.runCommand
   "llvm-7-links"
diff --git a/nix/packages.nix b/nix/packages.nix
new file mode 100644
index 00000000..d9a729f3
--- /dev/null
+++ b/nix/packages.nix
@@ -0,0 +1,10 @@
+let
+  commit = "4c6e9a553872366e485766fa8b574b54b15957f8";
+  nixpkgs = builtins.fetchTarball {
+    name = "nixpkgs-19.09";
+    url = "https://github.com/nixos/nixpkgs/archive/${commit}.tar.gz";
+    sha256 = "1az9yg2lwwfw3aypi6bdsk7ghld2963vqdp8ajkxciyxdfkaxb3b";
+  };
+  pkgs = import nixpkgs;
+in
+  pkgs
diff --git a/nix/pkgs.nix b/nix/pkgs.nix
deleted file mode 100644
index b8a8ec34..00000000
--- a/nix/pkgs.nix
+++ /dev/null
@@ -1,8 +0,0 @@
-let
-  commit = "2adf2d615cf8f6c6be49a0e54dc9ebf551dcf70f";
-  pinned = builtins.fetchTarball {
-    name   = "nixpkgs-19.09";
-    url = "https://github.com/nixos/nixpkgs/archive/${commit}.tar.gz";
-    sha256 = "0w8zgj38di4ssw6s0bxdb9rgksqfszsa3304863xic4bzsvkql9b";
-  };
-in import pinned {}
diff --git a/shell.nix b/shell.nix
index cc2da059..6cc8d1be 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,14 +1,12 @@
-{ pkgs ? import nix/pkgs.nix }:
-
 let
-  compiler = "ghc865";
-  hpkg = pkgs.haskell.packages."${compiler}";
-  grin = import ./. { inherit compiler pkgs; };
+  pkgs = import ./nix/packages.nix {};
+  llvm-links = import ./nix/llvm.nix { inherit pkgs; };
+  haskellPkgs = import ./.;
 in
-
-hpkg.shellFor {
-  withHoogle = true;
-  packages = p: [ grin ];
-  buildInputs = with hpkg; [ cabal-install ghcid ];
-  inherit (grin.env) nativeBuildInputs;
-}
+  haskellPkgs.shellFor {
+    buildInputs = with pkgs.haskellPackages; [
+      llvm-links
+      hlint
+      ghcid
+    ];
+  }