Add Traits::HasOperatorBool

misc/traits.h

@@ -131,6 +131,9 @@ CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsReservable, std::declval<T &>().reserve
 /// \brief Evaluates to Bool<true> if the specified type can has a resize() method; otherwise evaluates to Bool<false>.
 CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsResizable, std::declval<T &>().resize(0u));
 
+/// \brief Evaluates to Bool<true> if the specified type has operator bool(); otherwise evaluates to Bool<false>.
+CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(HasOperatorBool, std::declval<T &>() ? true : false);
+
 /// \brief Evaluates to Bool<true> if the specified type is iteratable (can be used in for-each loop); otherwise evaluates to Bool<false>.
 CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsIteratable,
     // begin/end and operator !=