# HG changeset patch
# Parent cf8979c54d71c062ed5b7d970bb42896f54f4653
diff --git a/Eigen/src/Core/DenseCoeffsBase.h b/Eigen/src/Core/DenseCoeffsBase.h
--- a/Eigen/src/Core/DenseCoeffsBase.h
+++ b/Eigen/src/Core/DenseCoeffsBase.h
@@ -133,16 +133,19 @@ class DenseCoeffsBase<Derived,ReadOnlyAc
       *
       * \sa operator[](Index) const, coeffRef(Index), coeff(Index,Index) const
       */
 
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE CoeffReturnType
     coeff(Index index) const
     {
+      EIGEN_STATIC_ASSERT(Derived::Flags & LinearAccessBit,
+                    THIS_COEFFICIENT_ACCESSOR_TAKING_ONE_ACCESS_IS_ONLY_FOR_EXPRESSIONS_ALLOWING_LINEAR_ACCESS)
+
       eigen_internal_assert(index >= 0 && index < size());
       return typename internal::evaluator<Derived>::type(derived()).coeff(index);
     }
 
 
     /** \returns the coefficient at given index.
       *
       * This method is allowed only for vector expressions, and for matrix expressions having the LinearAccessBit.
@@ -363,16 +366,18 @@ class DenseCoeffsBase<Derived, WriteAcce
       *
       * \sa operator[](Index), coeff(Index) const, coeffRef(Index,Index)
       */
 
     EIGEN_DEVICE_FUNC
     EIGEN_STRONG_INLINE Scalar&
     coeffRef(Index index)
     {
+      EIGEN_STATIC_ASSERT(Derived::Flags & LinearAccessBit,
+                          THIS_COEFFICIENT_ACCESSOR_TAKING_ONE_ACCESS_IS_ONLY_FOR_EXPRESSIONS_ALLOWING_LINEAR_ACCESS)
       eigen_internal_assert(index >= 0 && index < size());
       return typename internal::evaluator<Derived>::type(derived()).coeffRef(index);
     }
 
     /** \returns a reference to the coefficient at given index.
       *
       * This method is allowed only for vector expressions, and for matrix expressions having the LinearAccessBit.
       *
diff --git a/Eigen/src/Core/util/StaticAssert.h b/Eigen/src/Core/util/StaticAssert.h
--- a/Eigen/src/Core/util/StaticAssert.h
+++ b/Eigen/src/Core/util/StaticAssert.h
@@ -88,17 +88,18 @@
         THIS_METHOD_IS_ONLY_FOR_EXPRESSIONS_OF_BOOL,
         THIS_METHOD_IS_ONLY_FOR_ARRAYS_NOT_MATRICES,
         YOU_PASSED_A_ROW_VECTOR_BUT_A_COLUMN_VECTOR_WAS_EXPECTED,
         YOU_PASSED_A_COLUMN_VECTOR_BUT_A_ROW_VECTOR_WAS_EXPECTED,
         THE_INDEX_TYPE_MUST_BE_A_SIGNED_TYPE,
         THE_STORAGE_ORDER_OF_BOTH_SIDES_MUST_MATCH,
         OBJECT_ALLOCATED_ON_STACK_IS_TOO_BIG,
         IMPLICIT_CONVERSION_TO_SCALAR_IS_FOR_INNER_PRODUCT_ONLY,
-        STORAGE_LAYOUT_DOES_NOT_MATCH
+        STORAGE_LAYOUT_DOES_NOT_MATCH,
+        THIS_COEFFICIENT_ACCESSOR_TAKING_ONE_ACCESS_IS_ONLY_FOR_EXPRESSIONS_ALLOWING_LINEAR_ACCESS
       };
     };
 
     } // end namespace internal
 
     } // end namespace Eigen
 
     // Specialized implementation for MSVC to avoid "conditional