diff --git a/Twee/CP.hs b/Twee/CP.hs
--- a/Twee/CP.hs
+++ b/Twee/CP.hs
@@ -8,7 +8,6 @@
 import Twee.Index(Index)
 import qualified Data.Set as Set
 import Control.Monad
-import Data.Maybe
 import Data.List
 import qualified Data.ChurchList as ChurchList
 import Data.ChurchList (ChurchList(..))
diff --git a/Twee/Index.hs b/Twee/Index.hs
--- a/Twee/Index.hs
+++ b/Twee/Index.hs
@@ -25,7 +25,6 @@
 import Data.Maybe
 import Twee.Base hiding (var, fun, empty, size, singleton, prefix, funs, lookupList, lookup)
 import qualified Twee.Term as Term
-import Twee.Term.Core(TermList(..))
 import Data.DynamicArray
 import qualified Data.List as List
 
diff --git a/Twee/Term/Core.hs b/Twee/Term/Core.hs
--- a/Twee/Term/Core.hs
+++ b/Twee/Term/Core.hs
@@ -15,7 +15,7 @@
 import Control.Monad.ST.Strict
 import Data.Bits
 import Data.Int
-import GHC.Int(Int(..))
+import GHC.Types(Int(..))
 import GHC.Prim
 import GHC.ST hiding (liftST)
 import Data.Ord
diff --git a/twee-lib.cabal b/twee-lib.cabal
--- a/twee-lib.cabal
+++ b/twee-lib.cabal
@@ -1,5 +1,5 @@
 name:                twee-lib
-version:             2.1.1
+version:             2.1.2
 synopsis:            An equational theorem prover
 homepage:            http://github.com/nick8325/twee
 license:             BSD3
@@ -75,7 +75,7 @@
     containers,
     transformers,
     dlist,
-    pretty,
+    pretty >= 1.1.2.0,
     ghc-prim,
     primitive >= 0.6.2.0,
     vector