update has_ReturnType to be more consistent with other has_ helpers

1 files changed, 3 insertions, 3 deletions

diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index 90eda6e70..8de605500 100755
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -433,10 +433,10 @@ struct meta_no  { char a[2]; };
 template <typename T>
 struct has_ReturnType
 {
-  template <typename C> static meta_yes testFunctor(typename C::ReturnType const *);
-  template <typename C> static meta_no testFunctor(...);
+  template <typename C> static meta_yes testFunctor(C const *, typename C::ReturnType const * = 0);
+  template <typename C> static meta_no  testFunctor(...);
 
-  enum { value = sizeof(testFunctor<T>(0)) == sizeof(meta_yes) };
+  enum { value = sizeof(testFunctor<T>(static_cast<T*>(0))) == sizeof(meta_yes) };
 };
 
 template<typename T> const T* return_ptr();