From 9e9e99a42e136d4fde22f408438c6afa06e49a85 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 29 Apr 2009 14:57:18 +0000
Subject: [PATCH] casting to the same type no longer generates a CwiseUnaryOp

---
 Eigen/src/Core/CwiseUnaryOp.h | 6 +++++-
 Eigen/src/Core/MatrixBase.h   | 8 ++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Eigen/src/Core/CwiseUnaryOp.h b/Eigen/src/Core/CwiseUnaryOp.h
index 076d568e0..5915dad54 100644
--- a/Eigen/src/Core/CwiseUnaryOp.h
+++ b/Eigen/src/Core/CwiseUnaryOp.h
@@ -188,7 +188,11 @@ MatrixBase<Derived>::imag() const { return derived(); }
   */
 template<typename Derived>
 template<typename NewType>
-EIGEN_STRONG_INLINE const CwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived>
+EIGEN_STRONG_INLINE
+typename ei_cast_return_type<
+            const Derived&,
+            const CwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived>
+          >::type
 MatrixBase<Derived>::cast() const
 {
   return derived();
diff --git a/Eigen/src/Core/MatrixBase.h b/Eigen/src/Core/MatrixBase.h
index a4e4e15d7..7eb7c1eff 100644
--- a/Eigen/src/Core/MatrixBase.h
+++ b/Eigen/src/Core/MatrixBase.h
@@ -504,8 +504,12 @@ template<typename Derived> class MatrixBase
 
 
     template<typename NewType>
-    const CwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived> cast() const;
-
+    typename ei_cast_return_type<
+        const Derived&,
+        const CwiseUnaryOp<ei_scalar_cast_op<typename ei_traits<Derived>::Scalar, NewType>, Derived>
+      >::type
+    cast() const;
+           
     /** \returns the matrix or vector obtained by evaluating this expression.
       *
       * Notice that in the case of a plain matrix or vector (not an expression) this function just returns