l = (_t1::[Maybe Integer])
Just 1
r = GHC.IORef.IORef (GHC.STRef.STRef
                       (GHC.Prim.MutVar# (Just 1 : (_t2::[Maybe Integer]))))
r = GHC.IORef.IORef (GHC.STRef.STRef
                       (GHC.Prim.MutVar# (Just 1 : _)))