Merge branch 'staging'

lib/default.nix

@@ -1,8 +1,3 @@
-/* Library of low-level helper functions for nix expressions.
- *
- * Please implement (mostly) exhaustive unit tests
- * for new functions in `./tests.nix'.
- */
 let
 
   # trivial, often used functions

lib/tests.nix

@@ -277,14 +277,4 @@ runTests {
     expected = [ "2001" "db8" "0" "0042" "" "8a2e" "370" "" ];
   };
 
-  testComposeExtensions = {
-    expr = let obj = makeExtensible (self: { foo = self.bar; });
-               f = self: super: { bar = false; baz = true; };
-               g = self: super: { bar = super.baz or false; };
-               f_o_g = composeExtensions f g;
-               composed = obj.extend f_o_g;
-           in composed.foo;
-    expected = true;
-  };
-
 }

lib/trivial.nix

@@ -85,15 +85,6 @@ rec {
   # argument, but it's nice this way if several uses of `extends` are cascaded.
   extends = f: rattrs: self: let super = rattrs self; in super // f self super;
 
-  # Compose two extending functions of the type expected by 'extends'
-  # into one where changes made in the first are available in the
-  # 'super' of the second
-  composeExtensions =
-    f: g: self: super:
-      let fApplied = f self super;
-          super' = super // fApplied;
-      in fApplied // g self super';
-
   # Create an overridable, recursive attribute set. For example:
   #
   #     nix-repl> obj = makeExtensible (self: { })