diff --git a/Math/Manifold/Core/PseudoAffine.hs b/Math/Manifold/Core/PseudoAffine.hs
--- a/Math/Manifold/Core/PseudoAffine.hs
+++ b/Math/Manifold/Core/PseudoAffine.hs
@@ -361,6 +361,7 @@
 instance ( Semimanifold (f p), Semimanifold (g p)
          , InnerSpace (Needle (f p)), InnerSpace (Needle (g p))
          , Scalar (Needle (f p)) ~ Scalar (Needle (g p))
+         , AdditiveGroup (Scalar (Needle (g p)))
          , Num (Scalar (Needle (f p))) )
     => InnerSpace (NeedleProductSpace f g p)
 instance (Semimanifold (f p), Semimanifold (g p))
@@ -402,7 +403,9 @@
 instance VectorSpace (Needle (VRep x)) => VectorSpace (GenericNeedle x) where
   type Scalar (GenericNeedle x) = Scalar (Needle (VRep x))
   (*^) μ = GenericNeedle . (*^) μ . getGenericNeedle
-instance InnerSpace (Needle (VRep x)) => InnerSpace (GenericNeedle x) where
+instance ( InnerSpace (Needle (VRep x))
+         , AdditiveGroup (Scalar (Needle (Gnrx.Rep x Void))) )
+            => InnerSpace (GenericNeedle x) where
   GenericNeedle v <.> GenericNeedle w = v <.> w
 instance AdditiveGroup (Needle (VRep x)) => AffineSpace (GenericNeedle x) where
   type Diff (GenericNeedle x) = GenericNeedle x
diff --git a/manifolds-core.cabal b/manifolds-core.cabal
--- a/manifolds-core.cabal
+++ b/manifolds-core.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                manifolds-core
-version:             0.6.1.0
+version:             0.6.1.1
 synopsis:            The basic classes for the manifolds hierarchy.
 description:         The basic classes for the
                      <http://hackage.haskell.org/package/manifolds manifolds> hierarchy.
@@ -25,7 +25,7 @@
   other-modules:       Math.Manifold.Core.Types.Internal
   other-extensions:    FlexibleInstances, UndecidableInstances, ExplicitNamespaces, TypeFamilies, FunctionalDependencies, FlexibleContexts, GADTs, RankNTypes, TupleSections, ConstraintKinds, PatternGuards, TypeOperators, ScopedTypeVariables, RecordWildCards, DataKinds, StandaloneDeriving, DefaultSignatures, UnicodeSyntax, MultiWayIf
   build-depends:       base >=4.5 && <5
-                       , vector-space >=0.11 && <0.17
+                       , vector-space >=0.11 && <0.20
                        , call-stack <0.5
                        , equational-reasoning >=0.6 && <0.8
   -- hs-source-dirs: