diff --git a/Data/Eigen/Internal.hsc b/Data/Eigen/Internal.hsc
--- a/Data/Eigen/Internal.hsc
+++ b/Data/Eigen/Internal.hsc
@@ -54,7 +54,7 @@
         in return vs
 
 -- | Complex number for FFI with the same memory layout as std::complex\<T\>
-data CComplex a = CComplex !a !a
+data CComplex a = CComplex !a !a deriving Show
 
 instance Storable a => Storable (CComplex a) where
     sizeOf _ = sizeOf (undefined :: a) * 2
@@ -66,7 +66,7 @@
         <$> peekElemOff (castPtr p) 0
         <*> peekElemOff (castPtr p) 1
 
-data CTriplet a = CTriplet !CInt !CInt !a
+data CTriplet a = CTriplet !CInt !CInt !a deriving Show
 
 instance Storable a => Storable (CTriplet a) where
     sizeOf _ = sizeOf (undefined :: a) + sizeOf (undefined :: CInt) * 2
diff --git a/cbits/eigen-sparse-la.h b/cbits/eigen-sparse-la.h
--- a/cbits/eigen-sparse-la.h
+++ b/cbits/eigen-sparse-la.h
@@ -24,13 +24,6 @@
 
 extern "C" {
 
-enum Solver {
-	ConjugateGradient,
-	BiCGSTAB,
-	SparseLU,
-	SparseQR
-};
-
 const char* eigen_sparse_la_newSolver(int, int, void**);
 const char* eigen_sparse_la_freeSolver(int, int, void*);
 const char* eigen_sparse_la_factorize(int, int, void*, void*);
diff --git a/eigen.cabal b/eigen.cabal
--- a/eigen.cabal
+++ b/eigen.cabal
@@ -1,5 +1,5 @@
 name:           eigen
-version:        2.1.5
+version:        2.1.6
 homepage:       https://github.com/osidorkin/haskell-eigen
 synopsis:       Eigen C++ library (linear algebra: matrices, sparse matrices, vectors, numerical solvers).
 description:    This module provides Haskell binding for <http://eigen.tuxfamily.org/ Eigen C++ library>.