diff --git a/default.nix b/default.nix
index 12c3cf876186..c384a5bb6946 100644
--- a/default.nix
+++ b/default.nix
@@ -6,4 +6,4 @@ if ! builtins ? nixVersion || builtins.compareVersions requiredVersion builtins.
 
 else
 
-  import ./pkgs/top-level/all-packages.nix
+  import ./pkgs/top-level
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 769cae55406d..18fc8b958113 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1,143 +1,16 @@
-/* This file composes the Nix Packages collection.  That is, it
-   imports the functions that build the various packages, and calls
-   them with appropriate arguments.  The result is a set of all the
-   packages in the Nix Packages collection for some particular
-   platform. */
+{ system, bootStdenv, noSysDirs, gccWithCC, gccWithProfiling
+, config, crossSystem, platform, lib
+, pkgsWithOverrides, stdenvAdapters, helperFunctions
+, ... }:
+self: pkgs:
 
-
-{ # The system (e.g., `i686-linux') for which to build the packages.
-  system ? builtins.currentSystem
-
-, # The standard environment to use.  Only used for bootstrapping.  If
-  # null, the default standard environment is used.
-  bootStdenv ? null
-
-, # Non-GNU/Linux OSes are currently "impure" platforms, with their libc
-  # outside of the store.  Thus, GCC, GFortran, & co. must always look for
-  # files in standard system directories (/usr/include, etc.)
-  noSysDirs ? (system != "x86_64-freebsd" && system != "i686-freebsd"
-               && system != "x86_64-solaris"
-               && system != "x86_64-kfreebsd-gnu")
-
-  # More flags for the bootstrapping of stdenv.
-, gccWithCC ? true
-, gccWithProfiling ? true
-
-, # Allow a configuration attribute set to be passed in as an
-  # argument.  Otherwise, it's read from $NIXPKGS_CONFIG or
-  # ~/.nixpkgs/config.nix.
-  config ? null
-
-, crossSystem ? null
-, platform ? null
-}:
-
-
-let config_ = config; platform_ = platform; in # rename the function arguments
+with pkgs;
 
 let
+  defaultScope = pkgs // pkgs.xorg;
+in
 
-  lib = import ../../lib;
-
-  # The contents of the configuration file found at $NIXPKGS_CONFIG or
-  # $HOME/.nixpkgs/config.nix.
-  # for NIXOS (nixos-rebuild): use nixpkgs.config option
-  config =
-    let
-      toPath = builtins.toPath;
-      getEnv = x: if builtins ? getEnv then builtins.getEnv x else "";
-      pathExists = name:
-        builtins ? pathExists && builtins.pathExists (toPath name);
-
-      configFile = getEnv "NIXPKGS_CONFIG";
-      homeDir = getEnv "HOME";
-      configFile2 = homeDir + "/.nixpkgs/config.nix";
-
-      configExpr =
-        if config_ != null then config_
-        else if configFile != "" && pathExists configFile then import (toPath configFile)
-        else if homeDir != "" && pathExists configFile2 then import (toPath configFile2)
-        else {};
-
-    in
-      # allow both:
-      # { /* the config */ } and
-      # { pkgs, ... } : { /* the config */ }
-      if builtins.isFunction configExpr
-        then configExpr { inherit pkgs; }
-        else configExpr;
-
-  # Allow setting the platform in the config file. Otherwise, let's use a reasonable default (pc)
-
-  platformAuto = let
-      platforms = (import ./platforms.nix);
-    in
-      if system == "armv6l-linux" then platforms.raspberrypi
-      else if system == "armv7l-linux" then platforms.armv7l-hf-multiplatform
-      else if system == "armv5tel-linux" then platforms.sheevaplug
-      else if system == "mips64el-linux" then platforms.fuloong2f_n32
-      else if system == "x86_64-linux" then platforms.pc64
-      else if system == "i686-linux" then platforms.pc32
-      else platforms.pcBase;
-
-  platform = if platform_ != null then platform_
-    else config.platform or platformAuto;
-
-  topLevelArguments = {
-    inherit system bootStdenv noSysDirs gccWithCC gccWithProfiling config
-      crossSystem platform lib;
-  };
-
-  # Allow packages to be overriden globally via the `packageOverrides'
-  # configuration option, which must be a function that takes `pkgs'
-  # as an argument and returns a set of new or overriden packages.
-  # The `packageOverrides' function is called with the *original*
-  # (un-overriden) set of packages, allowing packageOverrides
-  # attributes to refer to the original attributes (e.g. "foo =
-  # ... pkgs.foo ...").
-  pkgs = pkgsWithOverrides (self: config.packageOverrides or (super: {}));
-
-  # stdenvOverrides is used to avoid circular dependencies for building the
-  # standard build environment. This mechanism use the override mechanism to
-  # implement some staged compilation of the stdenv.
-  #
-  # We don't want stdenv overrides in the case of cross-building, or
-  # otherwise the basic overrided packages will not be built with the
-  # crossStdenv adapter.
-  stdenvOverrides = pkgs:
-    lib.optionalAttrs (crossSystem == null && pkgs.stdenv ? overrides)
-      (pkgs.stdenv.overrides pkgs);
-
-  # Return the complete set of packages, after applying the overrides
-  # returned by the `overrider' function (see above).  Warning: this
-  # function is very expensive!
-  pkgsWithOverrides = overrider:
-    let
-      # The un-overriden packages, passed to `overrider'.
-      pkgs_6 = pkgsFun pkgs;
-
-      pkgs_7 = pkgs_6 // overrider pkgs pkgs_6;
-
-      # The overriden, final packages.
-      pkgs =   pkgs_7 // stdenvOverrides pkgs_6;
-    in pkgs;
-
-  # The package compositions.  Yes, this isn't properly indented.
-  pkgsFun = pkgs:
-    let
-      defaultScope = pkgs // pkgs.xorg;
-
-      # Helper functions that are exported through `pkgs'.
-      helperFunctions =
-        stdenvAdapters //
-        (import ../build-support/trivial-builders.nix { inherit lib; inherit (pkgs) stdenv; inherit (pkgs.xorg) lndir; });
-
-      stdenvAdapters =
-        import ../stdenv/adapters.nix pkgs;
-
-      stdenvDefault = (import ./stdenv.nix topLevelArguments) {} pkgs;
-
-      self = with pkgs; {
+{
 
   # Make some arguments passed to all-packages.nix available
   inherit system platform;
@@ -16443,13 +16316,5 @@ let
 
   mg = callPackage ../applications/editors/mg { };
 
-}; # self =
+}
 
-
-aliases = import ./aliases.nix self;
-
-in
-  helperFunctions // stdenvDefault // self // aliases;
-
-in
-  pkgs
diff --git a/pkgs/top-level/default.nix b/pkgs/top-level/default.nix
new file mode 100644
index 000000000000..39626a7485f7
--- /dev/null
+++ b/pkgs/top-level/default.nix
@@ -0,0 +1,147 @@
+/* This file composes the Nix Packages collection.  That is, it
+   imports the functions that build the various packages, and calls
+   them with appropriate arguments.  The result is a set of all the
+   packages in the Nix Packages collection for some particular
+   platform. */
+
+
+{ # The system (e.g., `i686-linux') for which to build the packages.
+  system ? builtins.currentSystem
+
+, # The standard environment to use.  Only used for bootstrapping.  If
+  # null, the default standard environment is used.
+  bootStdenv ? null
+
+, # Non-GNU/Linux OSes are currently "impure" platforms, with their libc
+  # outside of the store.  Thus, GCC, GFortran, & co. must always look for
+  # files in standard system directories (/usr/include, etc.)
+  noSysDirs ? (system != "x86_64-freebsd" && system != "i686-freebsd"
+               && system != "x86_64-solaris"
+               && system != "x86_64-kfreebsd-gnu")
+
+  # More flags for the bootstrapping of stdenv.
+, gccWithCC ? true
+, gccWithProfiling ? true
+
+, # Allow a configuration attribute set to be passed in as an
+  # argument.  Otherwise, it's read from $NIXPKGS_CONFIG or
+  # ~/.nixpkgs/config.nix.
+  config ? null
+
+, crossSystem ? null
+, platform ? null
+}:
+
+
+let config_ = config; platform_ = platform; in # rename the function arguments
+
+let
+
+  lib = import ../../lib;
+
+  # The contents of the configuration file found at $NIXPKGS_CONFIG or
+  # $HOME/.nixpkgs/config.nix.
+  # for NIXOS (nixos-rebuild): use nixpkgs.config option
+  config =
+    let
+      toPath = builtins.toPath;
+      getEnv = x: if builtins ? getEnv then builtins.getEnv x else "";
+      pathExists = name:
+        builtins ? pathExists && builtins.pathExists (toPath name);
+
+      configFile = getEnv "NIXPKGS_CONFIG";
+      homeDir = getEnv "HOME";
+      configFile2 = homeDir + "/.nixpkgs/config.nix";
+
+      configExpr =
+        if config_ != null then config_
+        else if configFile != "" && pathExists configFile then import (toPath configFile)
+        else if homeDir != "" && pathExists configFile2 then import (toPath configFile2)
+        else {};
+
+    in
+      # allow both:
+      # { /* the config */ } and
+      # { pkgs, ... } : { /* the config */ }
+      if builtins.isFunction configExpr
+        then configExpr { inherit pkgs; }
+        else configExpr;
+
+  # Allow setting the platform in the config file. Otherwise, let's use a reasonable default (pc)
+
+  platformAuto = let
+      platforms = (import ./platforms.nix);
+    in
+      if system == "armv6l-linux" then platforms.raspberrypi
+      else if system == "armv7l-linux" then platforms.armv7l-hf-multiplatform
+      else if system == "armv5tel-linux" then platforms.sheevaplug
+      else if system == "mips64el-linux" then platforms.fuloong2f_n32
+      else if system == "x86_64-linux" then platforms.pc64
+      else if system == "i686-linux" then platforms.pc32
+      else platforms.pcBase;
+
+  platform = if platform_ != null then platform_
+    else config.platform or platformAuto;
+
+  topLevelArguments = {
+    inherit system bootStdenv noSysDirs gccWithCC gccWithProfiling config
+      crossSystem platform lib;
+  };
+
+  # Allow packages to be overriden globally via the `packageOverrides'
+  # configuration option, which must be a function that takes `pkgs'
+  # as an argument and returns a set of new or overriden packages.
+  # The `packageOverrides' function is called with the *original*
+  # (un-overriden) set of packages, allowing packageOverrides
+  # attributes to refer to the original attributes (e.g. "foo =
+  # ... pkgs.foo ...").
+  pkgs = pkgsWithOverrides (self: config.packageOverrides or (super: {}));
+
+  # stdenvOverrides is used to avoid circular dependencies for building the
+  # standard build environment. This mechanism use the override mechanism to
+  # implement some staged compilation of the stdenv.
+  #
+  # We don't want stdenv overrides in the case of cross-building, or
+  # otherwise the basic overrided packages will not be built with the
+  # crossStdenv adapter.
+  stdenvOverrides = pkgs:
+    lib.optionalAttrs (crossSystem == null && pkgs.stdenv ? overrides)
+      (pkgs.stdenv.overrides pkgs);
+
+  # Return the complete set of packages, after applying the overrides
+  # returned by the `overrider' function (see above).  Warning: this
+  # function is very expensive!
+  pkgsWithOverrides = overrider:
+    let
+      # The un-overriden packages, passed to `overrider'.
+      pkgs_6 = pkgsFun pkgs;
+
+      pkgs_7 = pkgs_6 // overrider pkgs pkgs_6;
+
+      # The overriden, final packages.
+      pkgs =   pkgs_7 // stdenvOverrides pkgs_6;
+    in pkgs;
+
+  # The package compositions.  Yes, this isn't properly indented.
+  pkgsFun = pkgs:
+    let
+      # Helper functions that are exported through `pkgs'.
+      helperFunctions =
+        stdenvAdapters //
+        (import ../build-support/trivial-builders.nix { inherit lib; inherit (pkgs) stdenv; inherit (pkgs.xorg) lndir; });
+
+      stdenvAdapters =
+        import ../stdenv/adapters.nix pkgs;
+
+      stdenvDefault = (import ./stdenv.nix topLevelArguments) {} pkgs;
+
+      selfArgs = topLevelArguments // { inherit pkgsWithOverrides stdenvAdapters helperFunctions; };
+      self = (import ./all-packages.nix selfArgs) self pkgs;
+
+      aliases = import ./aliases.nix self;
+
+     in
+       helperFunctions // stdenvDefault // self // aliases;
+
+in
+  pkgs