diff --git a/HGE2D.cabal b/HGE2D.cabal
--- a/HGE2D.cabal
+++ b/HGE2D.cabal
@@ -2,7 +2,7 @@
 --  see http://haskell.org/cabal/users-guide/
 
 name:                HGE2D
-version:             0.1.6.0
+version:             0.1.6.1
 synopsis:            2D game engine written in Haskell
 description:         See README and examples/ for further information
 license:             MIT
@@ -39,7 +39,7 @@
   -- other-modules:
   -- other-extensions:
   build-depends:
-      base >= 4.8 && < 4.9,
+      base >= 4.9.0.0 && < 5.0,
       OpenGL >=3.0 && < 3.1,
       GLUT >= 2.7 && < 2.8,
       time >= 1.5.0.1 && < 1.7
@@ -50,27 +50,27 @@
 executable example1
   default-language:    Haskell2010
   main-is:             Example1.hs
-  build-depends:       base >= 4.8 && < 4.9, HGE2D
+  build-depends:       base >= 4.9.0.0 && < 5.0, HGE2D
   hs-source-dirs:      src/examples
   ghc-options:         -O2 -W -fwarn-incomplete-patterns
 
 executable example2
   default-language:    Haskell2010
   main-is:             Example2.hs
-  build-depends:       base >= 4.8 && < 4.9, HGE2D
+  build-depends:       base >= 4.9.0.0 && < 5.0, HGE2D
   hs-source-dirs:      src/examples
   ghc-options:         -O2 -W -fwarn-incomplete-patterns
 
 executable example3
   default-language:    Haskell2010
   main-is:             Example3.hs
-  build-depends:       base >= 4.8 && < 4.9, HGE2D
+  build-depends:       base >= 4.9.0.0 && < 5.0, HGE2D
   hs-source-dirs:      src/examples
   ghc-options:         -O2 -W -fwarn-incomplete-patterns
 
 executable example4
   default-language:    Haskell2010
   main-is:             Example4.hs
-  build-depends:       base >= 4.8 && < 4.9, HGE2D
+  build-depends:       base >= 4.9.0.0 && < 5.0, HGE2D
   hs-source-dirs:      src/examples
   ghc-options:         -O2 -W -fwarn-incomplete-patterns
diff --git a/src/HGE2D/Collision.hs b/src/HGE2D/Collision.hs
--- a/src/HGE2D/Collision.hs
+++ b/src/HGE2D/Collision.hs
@@ -48,17 +48,15 @@
 
 --------------------------------------------------------------------------------
 
----TODO use HasPosition?
-
 -- | Tests whether a position is within the bounding box
-isInsideRP :: (HasBoundingBox a) => RealPosition -> a -> Bool
+isInsideRP :: (Positioned a, HasBoundingBox b) => a -> b -> Bool
 isInsideRP pos hasBB =  (posX > bbLeft)
                      && (posX < bbRight)
                      && (posY > bbTop)
                      && (posY < bbBottom)
   where
-    posX     = fst pos
-    posY     = snd pos
+    posX     = fst $ getPos pos
+    posY     = snd $ getPos pos
     bbTop    = snd $ bbMin bb
     bbRight  = fst $ bbMax bb
     bbBottom = snd $ bbMax bb