Enable use of evaluators for noalias and lazyProduct, add conversion to scalar for inner products

Eigen/src/Core/util/ForwardDeclarations.h

@@ -36,6 +36,12 @@ template<typename Derived> struct accessors_level
   };
 };
 
+template<typename T> struct evaluator_traits;
+
+template< typename T,
+          typename Kind = typename evaluator_traits<T>::Kind,
+          typename Scalar = typename T::Scalar> struct evaluator;
+
 } // end namespace internal
 
 template<typename T> struct NumTraits;

Eigen/src/Core/util/StaticAssert.h

@@ -90,7 +90,8 @@
         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
+        OBJECT_ALLOCATED_ON_STACK_IS_TOO_BIG,
+        IMPLICIT_CONVERSION_TO_SCALAR_IS_FOR_INNER_PRODUCT_ONLY
       };
     };