core: fix check of user types

include/eigenpy/numpy-type.hpp

@@ -20,9 +20,12 @@ namespace eigenpy
   template<typename Scalar>
   bool np_type_is_convertible_into_scalar(const int np_type)
   {
+    if(NumpyEquivalentType<Scalar>::type_code >= NPY_USERDEF)
+      return np_type == Register::getTypeCode<Scalar>();
+
     if(NumpyEquivalentType<Scalar>::type_code == np_type)
       return true;
-    
+
     switch(np_type)
     {
       case NPY_INT: