Boost.Hana  1.2.0
Your standard library for metaprogramming
boost::hana::detail::std_common_type< T, U, typename > Struct Template Reference

Description

template<typename T, typename U, typename = void>
struct boost::hana::detail::std_common_type< T, U, typename >

Equivalent to std::common_type, except it is SFINAE-friendly and does not support custom specializations.