diff --git a/lib/attrsets.nix b/lib/attrsets.nix
index 84f6cb3658b9..f5184af42309 100644
--- a/lib/attrsets.nix
+++ b/lib/attrsets.nix
@@ -364,5 +364,5 @@ rec {
   overrideExisting = old: new:
     old // listToAttrs (map (attr: nameValuePair attr (attrByPath [attr] old.${attr} new)) (attrNames old));
 
-  deepSeqAttrs = x: y: deepSeqList (attrValues x) y;
+  deepSeqAttrs = throw "removed 2016-02-29 because unused and broken";
 }
diff --git a/lib/lists.nix b/lib/lists.nix
index 3bcf366f0c27..9e4ab9e2d95d 100644
--- a/lib/lists.nix
+++ b/lib/lists.nix
@@ -246,9 +246,6 @@ rec {
   init = list: assert list != []; take (length list - 1) list;
 
 
-  deepSeqList = xs: y: if any (x: deepSeq x false) xs then y else y;
-
-
   crossLists = f: foldl (fs: args: concatMap (f: map f args) fs) [f];
 
 
@@ -270,4 +267,7 @@ rec {
   # Subtracts list 'e' from another list. O(nm) complexity.
   subtractLists = e: filter (x: !(elem x e));
 
+  deepSeqList = throw "removed 2016-02-29 because unused and broken";
+
+
 }