'rule_type': unknown override specifier. missing type specifier -int assumed

There is following class

template <template <class> class build_rules>
class data : public data_base
{
public:
typedef build_rules<build_type> build_rule_type;
typedef typename build_rule_type::rule rule_type;
// do some stuff 
};

Then the compiler reports an errors: 'rule_type': unknown override specifier. missing type specifier -int assumed.

The Visual Studio 2015 compiler reports: How to fix this?