diff --git a/Control/Cond.hs b/Control/Cond.hs
--- a/Control/Cond.hs
+++ b/Control/Cond.hs
@@ -94,11 +94,11 @@
 
 type CondR a m r = (Maybe r, Recursor a m r)
 
-accept' :: Monad m => r -> CondR a m r
+accept' :: r -> CondR a m r
 accept' x = (Just x, Continue)
 {-# INLINE accept' #-}
 
-recurse' :: Monad m => CondR a m r
+recurse' :: CondR a m r
 recurse' = (Nothing, Continue)
 {-# INLINE recurse' #-}
 
diff --git a/Pipes/Tree.hs b/Pipes/Tree.hs
--- a/Pipes/Tree.hs
+++ b/Pipes/Tree.hs
@@ -3,7 +3,6 @@
 
 module Pipes.Tree where
 
-import Control.Applicative
 import Control.Comonad.Trans.Cofree
 import Control.Cond
 import Pipes
diff --git a/hierarchy.cabal b/hierarchy.cabal
--- a/hierarchy.cabal
+++ b/hierarchy.cabal
@@ -1,7 +1,7 @@
 name:          hierarchy
-version:       0.3.1.2
+version:       0.3.1.3
 synopsis:      Pipes-based library for predicated traversal of generated trees
-description:   Pipes-based library for predicated traversal of generated trees
+description:   Pipes-based library for predicated traversal of generated trees.
 homepage:      https://github.com/jwiegley/hierarchy
 license:       BSD3
 license-file:  LICENSE
@@ -17,23 +17,23 @@
   location: git://github.com/jwiegley/hierarchy.git
 
 library
-  ghc-options:      -Wall -O2 -funbox-strict-fields
+  ghc-options:      -Wall -funbox-strict-fields
   include-dirs:     .
   exposed-modules:     
       Control.Cond
     , Pipes.Tree
   build-depends:       
-      base                >=4.7  && <4.10
+      base                >=4.7  && <4.11
     , transformers        >=0.3  && <0.6
     , transformers-base   >=0.3  && <0.6
     , transformers-compat >=0.3  && <0.6
     , exceptions          >=0.8  && <0.9
-    , mmorph              >=1.0  && <1.1
+    , mmorph              >=1.0  && <1.3
     , mtl                 >=2.1  && <2.3
     , monad-control       >=1.0  && <1.1
     , semigroups          >=0.16 && <0.19
-    , free                >=4.12 && <4.13
-    , pipes               >=4.1  && <4.2
+    , free                >=4.10 && <4.13
+    , pipes               >=4.1  && <4.5
   default-language:    Haskell2010
 
 Test-suite doctests
@@ -57,7 +57,7 @@
   build-depends: 
       base >=3
     , hierarchy
-    , pipes              >=4.1  && <4.2
+    , pipes              >=4.1  && <4.5
     , transformers       >=0.3  && <0.6
     , mtl                >=2.1  && <2.3
     , hspec              >=1.4.4
diff --git a/test/doctest.hs b/test/doctest.hs
--- a/test/doctest.hs
+++ b/test/doctest.hs
@@ -12,8 +12,6 @@
     "-iControl"
   : "-iPipes"
   : "-idist/build/autogen"
-  : "-optP-include"
-  : "-optPdist/build/autogen/cabal_macros.h"
   : sources
 
 getSources :: IO [FilePath]