minor tweaks in has_* helpers

1 files changed, 10 insertions, 13 deletions

diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index e69c78db2..96563962e 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -368,29 +368,26 @@ struct result_of<Func(ArgType0,ArgType1,ArgType2)> {
 };
 #endif
 
+struct meta_yes { char a[1]; };
+struct meta_no  { char a[2]; };
+
 // Check whether T::ReturnType does exist
 template <typename T>
 struct has_ReturnType
 {
-  typedef char yes[1];
-  typedef char no[2];
-
-  template <typename C> static yes& testFunctor(typename C::ReturnType const *);
-  template <typename C> static no& testFunctor(...);
+  template <typename C> static meta_yes testFunctor(typename C::ReturnType const *);
+  template <typename C> static meta_no testFunctor(...);
 
-  enum { value = sizeof(testFunctor<T>(0)) == sizeof(yes) };
+  enum { value = sizeof(testFunctor<T>(0)) == sizeof(meta_yes) };
 };
 
-template<int> struct any_int {};
+template<int Val> struct integral_constant { static const int value = Val; };
 template<typename T> const T& return_ref();
 
-struct meta_yes { char data[1]; };
-struct meta_no  { char data[2]; };
-
 template <typename T>
 struct has_nullary_operator
 {
-  template <typename C> static meta_yes testFunctor(C const *,any_int< sizeof(return_ref<C>()()) > * = 0);
+  template <typename C> static meta_yes testFunctor(C const *,integral_constant< sizeof(return_ref<C>()()) > * = 0);
   static meta_no testFunctor(...);
 
   enum { value = sizeof(testFunctor(static_cast<T*>(0))) == sizeof(meta_yes) };
@@ -399,7 +396,7 @@ struct has_nullary_operator
 template <typename T>
 struct has_unary_operator
 {
-  template <typename C> static meta_yes testFunctor(C const *,any_int< sizeof(return_ref<C>()(Index(0))) > * = 0);
+  template <typename C> static meta_yes testFunctor(C const *,integral_constant< sizeof(return_ref<C>()(Index(0))) > * = 0);
   static meta_no testFunctor(...);
 
   enum { value = sizeof(testFunctor(static_cast<T*>(0))) == sizeof(meta_yes) };
@@ -408,7 +405,7 @@ struct has_unary_operator
 template <typename T>
 struct has_binary_operator
 {
-  template <typename C> static meta_yes testFunctor(C const *,any_int< sizeof(return_ref<C>()(Index(0),Index(0))) > * = 0);
+  template <typename C> static meta_yes testFunctor(C const *,integral_constant< sizeof(return_ref<C>()(Index(0),Index(0))) > * = 0);
   static meta_no testFunctor(...);
 
   enum { value = sizeof(testFunctor(static_cast<T*>(0))) == sizeof(meta_yes) };