diff --git a/Eigen/src/Core/SelfAdjointView.h b/Eigen/src/Core/SelfAdjointView.h
index 92d58b9f8..0e9872bf5 100644
--- a/Eigen/src/Core/SelfAdjointView.h
+++ b/Eigen/src/Core/SelfAdjointView.h
@@ -46,14 +46,14 @@ template<typename MatrixType, unsigned int UpLo>
 struct traits<SelfAdjointView<MatrixType, UpLo> > : traits<MatrixType>
 {
   typedef typename nested<MatrixType>::type MatrixTypeNested;
-  typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
+  typedef typename remove_all<MatrixTypeNested>::type MatrixTypeNestedCleaned;
   typedef MatrixType ExpressionType;
   typedef typename MatrixType::PlainObject DenseMatrixType;
   enum {
     Mode = UpLo | SelfAdjoint,
-    Flags =  _MatrixTypeNested::Flags & (HereditaryBits)
+    Flags =  MatrixTypeNestedCleaned::Flags & (HereditaryBits)
            & (~(PacketAccessBit | DirectAccessBit | LinearAccessBit)), // FIXME these flags should be preserved
-    CoeffReadCost = _MatrixTypeNested::CoeffReadCost
+    CoeffReadCost = MatrixTypeNestedCleaned::CoeffReadCost
   };
 };
 }
@@ -69,6 +69,8 @@ template<typename MatrixType, unsigned int UpLo> class SelfAdjointView
   public:
 
     typedef TriangularBase<SelfAdjointView> Base;
+    typedef typename internal::traits<SelfAdjointView>::MatrixTypeNested MatrixTypeNested;
+    typedef typename internal::traits<SelfAdjointView>::MatrixTypeNestedCleaned MatrixTypeNestedCleaned;
 
     /** \brief The type of coefficients in this matrix */
     typedef typename internal::traits<SelfAdjointView>::Scalar Scalar; 
@@ -107,10 +109,10 @@ template<typename MatrixType, unsigned int UpLo> class SelfAdjointView
     }
 
     /** \internal */
-    const MatrixType& _expression() const { return m_matrix; }
+    const MatrixTypeNestedCleaned& _expression() const { return m_matrix; }
 
-    const MatrixType& nestedExpression() const { return m_matrix; }
-    MatrixType& nestedExpression() { return const_cast<MatrixType&>(m_matrix); }
+    const MatrixTypeNestedCleaned& nestedExpression() const { return m_matrix; }
+    MatrixTypeNestedCleaned& nestedExpression() { return *const_cast<MatrixTypeNestedCleaned*>(&m_matrix); }
 
     /** Efficient self-adjoint matrix times vector/matrix product */
     template<typename OtherDerived>
@@ -197,7 +199,7 @@ template<typename MatrixType, unsigned int UpLo> class SelfAdjointView
     #endif
 
   protected:
-    const typename MatrixType::Nested m_matrix;
+    const MatrixTypeNested m_matrix;
 };
 
 
diff --git a/Eigen/src/Core/TriangularMatrix.h b/Eigen/src/Core/TriangularMatrix.h
index 714d56a5b..62586058b 100644
--- a/Eigen/src/Core/TriangularMatrix.h
+++ b/Eigen/src/Core/TriangularMatrix.h
@@ -143,13 +143,14 @@ template<typename MatrixType, unsigned int _Mode>
 struct traits<TriangularView<MatrixType, _Mode> > : traits<MatrixType>
 {
   typedef typename nested<MatrixType>::type MatrixTypeNested;
-  typedef typename remove_reference<MatrixTypeNested>::type _MatrixTypeNested;
+  typedef typename remove_reference<MatrixTypeNested>::type MatrixTypeNestedNonRef;
+  typedef typename remove_all<MatrixTypeNested>::type MatrixTypeNestedCleaned;
   typedef MatrixType ExpressionType;
   typedef typename MatrixType::PlainObject DenseMatrixType;
   enum {
     Mode = _Mode,
-    Flags = (_MatrixTypeNested::Flags & (HereditaryBits) & (~(PacketAccessBit | DirectAccessBit | LinearAccessBit))) | Mode,
-    CoeffReadCost = _MatrixTypeNested::CoeffReadCost
+    Flags = (MatrixTypeNestedCleaned::Flags & (HereditaryBits) & (~(PacketAccessBit | DirectAccessBit | LinearAccessBit))) | Mode,
+    CoeffReadCost = MatrixTypeNestedCleaned::CoeffReadCost
   };
 };
 }
@@ -171,8 +172,10 @@ template<typename _MatrixType, unsigned int _Mode> class TriangularView
     typedef typename internal::traits<TriangularView>::DenseMatrixType DenseMatrixType;
 
   protected:
-    typedef typename MatrixType::Nested MatrixTypeNested;
-    typedef typename internal::remove_all<MatrixTypeNested>::type _MatrixTypeNested;
+    typedef typename internal::traits<TriangularView>::MatrixTypeNested MatrixTypeNested;
+    typedef typename internal::traits<TriangularView>::MatrixTypeNestedNonRef MatrixTypeNestedNonRef;
+    typedef typename internal::traits<TriangularView>::MatrixTypeNestedCleaned MatrixTypeNestedCleaned;
+
     typedef typename internal::remove_all<typename MatrixType::ConjugateReturnType>::type MatrixConjugateReturnType;
     
   public:
@@ -344,15 +347,15 @@ template<typename _MatrixType, unsigned int _Mode> class TriangularView
     void solveInPlace(const MatrixBase<OtherDerived>& other) const
     { return solveInPlace<OnTheLeft>(other); }
 
-    const SelfAdjointView<_MatrixTypeNested,Mode> selfadjointView() const
+    const SelfAdjointView<MatrixTypeNestedNonRef,Mode> selfadjointView() const
     {
       EIGEN_STATIC_ASSERT((Mode&UnitDiag)==0,PROGRAMMING_ERROR);
-      return SelfAdjointView<_MatrixTypeNested,Mode>(m_matrix);
+      return SelfAdjointView<MatrixTypeNestedNonRef,Mode>(m_matrix);
     }
-    SelfAdjointView<_MatrixTypeNested,Mode> selfadjointView()
+    SelfAdjointView<MatrixTypeNestedNonRef,Mode> selfadjointView()
     {
       EIGEN_STATIC_ASSERT((Mode&UnitDiag)==0,PROGRAMMING_ERROR);
-      return SelfAdjointView<_MatrixTypeNested,Mode>(m_matrix);
+      return SelfAdjointView<MatrixTypeNestedNonRef,Mode>(m_matrix);
     }
 
     template<typename OtherDerived>
@@ -694,7 +697,7 @@ void TriangularBase<Derived>::evalToLazy(MatrixBase<DenseDerived> &other) const
   eigen_assert(this->rows() == other.rows() && this->cols() == other.cols());
 
   internal::triangular_assignment_selector
-    <DenseDerived, typename internal::traits<Derived>::ExpressionType, Derived::Mode,
+    <DenseDerived, typename internal::traits<Derived>::MatrixTypeNestedCleaned, Derived::Mode,
     unroll ? int(DenseDerived::SizeAtCompileTime) : Dynamic,
     true // clear the opposite triangular part
     >::run(other.derived(), derived().nestedExpression());
diff --git a/test/selfadjoint.cpp b/test/selfadjoint.cpp
index a92ad96b5..622045f20 100644
--- a/test/selfadjoint.cpp
+++ b/test/selfadjoint.cpp
@@ -52,6 +52,11 @@ template<typename MatrixType> void selfadjoint(const MatrixType& m)
   VERIFY_IS_APPROX(m3, m3.adjoint());
 }
 
+void bug_159()
+{
+  Matrix3d m = Matrix3d::Random().selfadjointView<Lower>(); 
+}
+
 void test_selfadjoint()
 {
   for(int i = 0; i < g_repeat ; i++)
@@ -64,4 +69,6 @@ void test_selfadjoint()
     CALL_SUBTEST_4( selfadjoint(MatrixXcd(s,s)) );
     CALL_SUBTEST_5( selfadjoint(Matrix<float,Dynamic,Dynamic,RowMajor>(s, s)) );
   }
+  
+  CALL_SUBTEST_1( bug_159() );
 }