c++14 - Counterpart to std::enable_if_t -

std::enable_if_t gets type if value true. want thing gets type if expression well-formed. if type want void, can decltype((void)(expr)). should if want other void? want succinct , elegant solution.

you can use this:

template<typename t> struct well_formed : std::true_type{}; 

and combine enable_if_t