diff --git a/acc.cabal b/acc.cabal
--- a/acc.cabal
+++ b/acc.cabal
@@ -1,5 +1,5 @@
 name: acc
-version: 0.1.3.1
+version: 0.2
 synopsis: Sequence optimized for monoidal construction and folding
 description:
   Data structure intended for accumulating a sequence of elements
diff --git a/library/Acc.hs b/library/Acc.hs
--- a/library/Acc.hs
+++ b/library/Acc.hs
@@ -3,7 +3,6 @@
     cons,
     snoc,
     uncons,
-    unsnoc,
     toNonEmpty,
     toNeAcc,
     enumFromTo,
@@ -39,11 +38,16 @@
 data Acc a
   = EmptyAcc
   | TreeAcc !(NeAcc.NeAcc a)
-  deriving (Generic, Generic1)
 
-instance NFData a => NFData (Acc a)
+instance NFData a => NFData (Acc a) where
+  rnf = \case
+    TreeAcc tree -> rnf tree
+    EmptyAcc -> ()
 
-instance NFData1 Acc
+instance NFData1 Acc where
+  liftRnf rnfLeaf = \case
+    TreeAcc tree -> liftRnf rnfLeaf tree
+    EmptyAcc -> ()
 
 deriving instance Functor Acc
 
diff --git a/library/Acc/NeAcc/Def.hs b/library/Acc/NeAcc/Def.hs
--- a/library/Acc/NeAcc/Def.hs
+++ b/library/Acc/NeAcc/Def.hs
@@ -18,17 +18,24 @@
 --
 -- Relates to 'Acc.Acc' the same way as 'NonEmpty' to list.
 data NeAcc a
-  = Leaf !a
+  = Leaf a
   | Branch !(NeAcc a) !(NeAcc a)
-  deriving (Generic, Generic1)
 
 instance Show a => Show (NeAcc a) where
   show =
     show . toList
 
-instance NFData a => NFData (NeAcc a)
+instance NFData a => NFData (NeAcc a) where
+  rnf = \case
+    Leaf a -> rnf a
+    Branch l r -> seq (rnf l) (rnf r)
 
-instance NFData1 NeAcc
+instance NFData1 NeAcc where
+  liftRnf rnfLeaf = rnfTree
+    where
+      rnfTree = \case
+        Leaf a -> rnfLeaf a
+        Branch l r -> seq (rnfTree l) (rnfTree r)
 
 instance IsList (NeAcc a) where
   type Item (NeAcc a) = a