Workaround various "returning reference to temporary" warnings.

5 files changed, 9 insertions, 11 deletions

diff --git a/Eigen/SparseCore b/Eigen/SparseCore
index b68c8fa8a..d5c0f6271 100644
--- a/Eigen/SparseCore
+++ b/Eigen/SparseCore
@@ -26,13 +26,6 @@
   * This module depends on: Core.
   */
 
-namespace Eigen {
-
-/** The type used to identify a general sparse storage. */
-struct Sparse {};
-
-}
-
 #include "src/SparseCore/SparseUtil.h"
 #include "src/SparseCore/SparseMatrixBase.h"
 #include "src/SparseCore/SparseAssign.h"
diff --git a/Eigen/src/Core/CoreEvaluators.h b/Eigen/src/Core/CoreEvaluators.h
index a0dc72c4d..1c7123b85 100644
--- a/Eigen/src/Core/CoreEvaluators.h
+++ b/Eigen/src/Core/CoreEvaluators.h
@@ -1221,7 +1221,9 @@ struct evaluator<Diagonal<ArgType, DiagIndex> >
  
   typedef typename XprType::Index Index;
   typedef typename XprType::Scalar Scalar;
-  typedef typename XprType::CoeffReturnType CoeffReturnType;
+  // FIXME having to check whether ArgType is sparse here i not very nice.
+  typedef typename internal::conditional<!internal::is_same<typename ArgType::StorageKind,Sparse>::value,
+                                         typename XprType::CoeffReturnType,Scalar>::type CoeffReturnType;
 
   EIGEN_DEVICE_FUNC CoeffReturnType coeff(Index row, Index) const
   {
diff --git a/Eigen/src/Core/util/Constants.h b/Eigen/src/Core/util/Constants.h
index 5c7d70af6..9b40093f0 100644
--- a/Eigen/src/Core/util/Constants.h
+++ b/Eigen/src/Core/util/Constants.h
@@ -449,6 +449,9 @@ enum Action {GetAction, SetAction};
 /** The type used to identify a dense storage. */
 struct Dense {};
 
+/** The type used to identify a general sparse storage. */
+struct Sparse {};
+
 /** The type used to identify a permutation storage. */
 struct PermutationStorage {};
 
diff --git a/Eigen/src/SparseCore/CompressedStorage.h b/Eigen/src/SparseCore/CompressedStorage.h
index 2741f8292..99f741138 100644
--- a/Eigen/src/SparseCore/CompressedStorage.h
+++ b/Eigen/src/SparseCore/CompressedStorage.h
@@ -143,7 +143,7 @@ class CompressedStorage
     }
 
     /** Like at(), but the search is performed in the range [start,end) */
-    inline const Scalar& atInRange(size_t start, size_t end, Index key, const Scalar& defaultValue = Scalar(0)) const
+    inline Scalar atInRange(size_t start, size_t end, Index key, const Scalar &defaultValue = Scalar(0)) const
     {
       if (start>=end)
         return defaultValue;
diff --git a/Eigen/src/SparseCore/SparseMatrix.h b/Eigen/src/SparseCore/SparseMatrix.h
index 4c79c7dc3..93677c786 100644
--- a/Eigen/src/SparseCore/SparseMatrix.h
+++ b/Eigen/src/SparseCore/SparseMatrix.h
@@ -179,7 +179,7 @@ class SparseMatrix
 
     /** \returns the value of the matrix at position \a i, \a j
       * This function returns Scalar(0) if the element is an explicit \em zero */
-    inline const Scalar& coeff(Index row, Index col) const
+    inline Scalar coeff(Index row, Index col) const
     {
       eigen_assert(row>=0 && row<rows() && col>=0 && col<cols());
       
@@ -1297,7 +1297,7 @@ struct evaluator<SparseMatrix<_Scalar,_Options,_Index> >
   operator const SparseMatrixType&() const { return *m_matrix; }
   
   typedef typename DenseCoeffsBase<SparseMatrixType,ReadOnlyAccessors>::CoeffReturnType CoeffReturnType;
-  CoeffReturnType coeff(Index row, Index col) const
+  Scalar coeff(Index row, Index col) const
   { return m_matrix->coeff(row,col); }
   
   Scalar& coeffRef(Index row, Index col)