diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,23 +14,23 @@
 
 matrix:
   include:
-    - env: CABALVER=1.16 GHCVER=7.4.2 BUILD=cabal
+    - env: CABALVER=1.18 GHCVER=7.4.2 BUILD=cabal
       compiler: ": #GHC 7.4.2"
-      addons: {apt: {packages: [cabal-install-1.16,ghc-7.4.2,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
+      addons: {apt: {packages: [cabal-install-1.18,ghc-7.4.2,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
 
-    - env: CABALVER=1.16 GHCVER=7.6.3 BUILD=cabal
+    - env: CABALVER=1.18 GHCVER=7.6.3 BUILD=cabal
       compiler: ": #GHC 7.6.3"
-      addons: {apt: {packages: [cabal-install-1.16,ghc-7.6.3,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
+      addons: {apt: {packages: [cabal-install-1.18,ghc-7.6.3,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
 
     - env: CABALVER=1.18 GHCVER=7.8.4 BUILD=cabal
       compiler: ": #GHC 7.8.4"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
 
-    - env: BUILD=stack STACK_YAML=stack-7.8.yaml STACK_OPTIONS=--skip-ghc-check
-      addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
+#    - env: BUILD=stack STACK_YAML=stack-7.8.yaml STACK_OPTIONS=--skip-ghc-check
+#      addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4,alex-3.1.4,happy-1.19.5], sources: [hvr-ghc]}}
 
-    - env: BUILD=stack STACK_YAML=stack-7.8.yaml
-      os: osx
+#    - env: BUILD=stack STACK_YAML=stack-7.8.yaml
+#      os: osx
 
     - env: CABALVER=1.22 GHCVER=7.10.1 BUILD=cabal
       compiler: ": #GHC 7.10.1"
diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.5.0.1
+-------
+* Fix builds on GHC 7.2
+
 0.5
 ---
 * Added flags for removing some dependencies.
diff --git a/distributive.cabal b/distributive.cabal
--- a/distributive.cabal
+++ b/distributive.cabal
@@ -1,6 +1,6 @@
 name:          distributive
 category:      Data Structures
-version:       0.5
+version:       0.5.0.1
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
@@ -38,7 +38,8 @@
     base                >= 4   && < 5,
     base-orphans        >= 0.5 && < 1,
     transformers        >= 0.2 && < 0.6,
-    transformers-compat >= 0.3 && < 1
+    transformers-compat >= 0.3 && < 1,
+    ghc-prim
 
   hs-source-dirs:  src
   exposed-modules:
diff --git a/src/Data/Distributive/Generic.hs b/src/Data/Distributive/Generic.hs
--- a/src/Data/Distributive/Generic.hs
+++ b/src/Data/Distributive/Generic.hs
@@ -45,7 +45,7 @@
     sndP (_ :*: r) = r
   {-# INLINE gdistribute #-}
 
-instance (Functor a, Functor b, GDistributive a, GDistributive b) => GDistributive (a :.: b) where
+instance (Functor a, GDistributive a, GDistributive b) => GDistributive (a :.: b) where
   gdistribute = Comp1 . fmap gdistribute . gdistribute . fmap unComp1
   {-# INLINE gdistribute #-}