diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
index 206808245..170dacb98 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorDimensionList.h
@@ -46,27 +46,27 @@ template<DenseIndex n, typename Index, std::size_t Rank> const Index array_get(c
 
 #if defined(EIGEN_HAS_CONSTEXPR)
 template <typename Index, std::size_t Rank>
-struct index_known_statically<DimensionList<Index, Rank> > {
-  constexpr bool operator() (const DenseIndex) const {
+struct index_known_statically_impl<DimensionList<Index, Rank> > {
+  static constexpr bool run(const DenseIndex) {
     return true;
   }
 };
 template <typename Index, std::size_t Rank>
-struct index_known_statically<const DimensionList<Index, Rank> > {
-  constexpr bool operator() (const DenseIndex) const {
+struct index_known_statically_impl<const DimensionList<Index, Rank> > {
+  static constexpr bool run(const DenseIndex) {
     return true;
   }
 };
 
 template <typename Index, std::size_t Rank>
-struct all_indices_known_statically<DimensionList<Index, Rank> > {
-  constexpr bool operator() () const {
+struct all_indices_known_statically_impl<DimensionList<Index, Rank> > {
+  static constexpr bool run() {
     return true;
   }
 };
 template <typename Index, std::size_t Rank>
-struct all_indices_known_statically<const DimensionList<Index, Rank> > {
-  constexpr bool operator() () const {
+struct all_indices_known_statically_impl<const DimensionList<Index, Rank> > {
+  static constexpr bool run() {
     return true;
   }
 };
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h b/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
index 472fad0da..859c16ab0 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorIndexList.h
@@ -294,47 +294,57 @@ template<DenseIndex N, typename FirstType, typename... OtherTypes> constexpr Den
 }
 
 template <typename T>
-struct index_known_statically {
-  constexpr bool operator() (DenseIndex) const {
+struct index_known_statically_impl {
+  static constexpr bool run(const DenseIndex) {
     return false;
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct index_known_statically<IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() (const DenseIndex i) const {
+struct index_known_statically_impl<IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run(const DenseIndex i) {
     return IndexList<FirstType, OtherTypes...>().value_known_statically(i);
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct index_known_statically<const IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() (const DenseIndex i) const {
+struct index_known_statically_impl<const IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run(const DenseIndex i) {
     return IndexList<FirstType, OtherTypes...>().value_known_statically(i);
   }
 };
 
 template <typename T>
-struct all_indices_known_statically {
-  constexpr bool operator() () const {
+static constexpr bool index_known_statically(const DenseIndex i) {
+  return index_known_statically_impl<T>::run(i);
+}
+
+template <typename T>
+struct all_indices_known_statically_impl {
+  static constexpr bool run() {
     return false;
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct all_indices_known_statically<IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() () const {
+struct all_indices_known_statically_impl<IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run() {
     return IndexList<FirstType, OtherTypes...>().all_values_known_statically();
   }
 };
 
 template <typename FirstType, typename... OtherTypes>
-struct all_indices_known_statically<const IndexList<FirstType, OtherTypes...> > {
-  constexpr bool operator() () const {
+struct all_indices_known_statically_impl<const IndexList<FirstType, OtherTypes...> > {
+  static constexpr bool run() {
     return IndexList<FirstType, OtherTypes...>().all_values_known_statically();
   }
 };
 
+template <typename T>
+static constexpr bool all_indices_known_statically() {
+  return all_indices_known_statically_impl<T>::run();
+}
+
 template <typename T>
 struct indices_statically_known_to_increase_impl {
   static constexpr bool run() {
@@ -491,18 +501,14 @@ namespace internal {
 
 // No C++11 support
 template <typename T>
-struct index_known_statically {
-  EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool operator() (DenseIndex) const{
-    return false;
-  }
-};
+static EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool index_known_statically(DenseIndex) {
+  return false;
+}
 
 template <typename T>
-struct all_indices_known_statically {
-  EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool operator() () const {
-    return false;
-  }
-};
+static EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool all_indices_known_statically() {
+  return false;
+}
 
 template <typename T>
 static EIGEN_ALWAYS_INLINE EIGEN_DEVICE_FUNC bool indices_statically_known_to_increase() {
diff --git a/unsupported/test/cxx11_tensor_index_list.cpp b/unsupported/test/cxx11_tensor_index_list.cpp
index 7100c1628..4ce8dea20 100644
--- a/unsupported/test/cxx11_tensor_index_list.cpp
+++ b/unsupported/test/cxx11_tensor_index_list.cpp
@@ -58,11 +58,11 @@ static void test_type2index_list()
   typedef Eigen::IndexList<Eigen::type2index<0>, Eigen::type2index<1>, Eigen::type2index<2>, Eigen::type2index<3>, Eigen::type2index<4>> Dims4;
 
 #if 0
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims0>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims1>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims2>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims3>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims4>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims0>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims1>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims2>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims3>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<Dims4>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
 #endif
 
   EIGEN_STATIC_ASSERT((internal::are_inner_most_dims<Dims0, 1, ColMajor>::value == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
@@ -216,24 +216,24 @@ static void test_mixed_index_list()
   reduction_indices.set(3, 3);
   EIGEN_STATIC_ASSERT((internal::array_get<0>(reduction_indices) == 0), YOU_MADE_A_PROGRAMMING_MISTAKE);
   EIGEN_STATIC_ASSERT((internal::array_get<2>(reduction_indices) == 2), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_known_statically<ReductionIndices>()(0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_known_statically<ReductionIndices>()(2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionIndices>()(0, 0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionIndices>()(2, 2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_known_statically<ReductionIndices>(0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_known_statically<ReductionIndices>(2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionIndices>(0, 0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionIndices>(2, 2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
 #if 0
-  EIGEN_STATIC_ASSERT((internal::all_indices_known_statically<ReductionIndices>()() == false), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<ReductionIndices>()() == false), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::all_indices_known_statically<ReductionIndices>() == false), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<ReductionIndices>() == false), YOU_MADE_A_PROGRAMMING_MISTAKE);
 #endif
 
   typedef IndexList<type2index<0>, type2index<1>, type2index<2>, type2index<3>> ReductionList;
   ReductionList reduction_list;
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>()(0, 0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>()(1, 1) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>()(2, 2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>()(3, 3) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>(0, 0) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>(1, 1) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>(2, 2) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::index_statically_eq<ReductionList>(3, 3) == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
 #if 0
-  EIGEN_STATIC_ASSERT((internal::all_indices_known_statically<ReductionList>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
-  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<ReductionList>()() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::all_indices_known_statically<ReductionList>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
+  EIGEN_STATIC_ASSERT((internal::indices_statically_known_to_increase<ReductionList>() == true), YOU_MADE_A_PROGRAMMING_MISTAKE);
 #endif
 
   Tensor<float, 0> result1 = tensor.sum(reduction_axis);