diff --git a/Eigen/src/Core/util/EmulateArray.h b/Eigen/src/Core/util/EmulateArray.h
index 2b1155245..4bfbbbab0 100644
--- a/Eigen/src/Core/util/EmulateArray.h
+++ b/Eigen/src/Core/util/EmulateArray.h
@@ -204,19 +204,19 @@ EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T& array_get(const array<T, N>& a) {
 
 template <class T, std::size_t N>
 struct array_size<array<T, N> > {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 template <class T, std::size_t N>
 struct array_size<array<T, N>&> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 template <class T, std::size_t N>
 struct array_size<const array<T, N> > {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 template <class T, std::size_t N>
 struct array_size<const array<T, N>&> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 
 }  // end namespace internal
diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index 859d2f18d..d2336ce5d 100644
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -303,30 +303,30 @@ class noncopyable {
  */
 template <typename T, typename EnableIf = void>
 struct array_size {
-  enum { value = Dynamic };
+  static constexpr Index value = Dynamic;
 };
 
 template <typename T>
 struct array_size<T, std::enable_if_t<((T::SizeAtCompileTime & 0) == 0)>> {
-  enum { value = T::SizeAtCompileTime };
+  static constexpr Index value = T::SizeAtCompileTime;
 };
 
 template <typename T, int N>
 struct array_size<const T (&)[N]> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 template <typename T, int N>
 struct array_size<T (&)[N]> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 
 template <typename T, std::size_t N>
 struct array_size<const std::array<T, N>> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 template <typename T, std::size_t N>
 struct array_size<std::array<T, N>> {
-  enum { value = N };
+  static constexpr Index value = N;
 };
 
 /** \internal