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#include <utility>
#include <tuple>
 
template<typename T>
struct unqualified {
	typedef typename std::remove_cv< typename std::remove_reference<T>::type>::type type;
};
 
template <int...> 
struct indices_list { typedef indices_list type; };
 
template <int N, int... I>
struct indices : indices<N-1, N-1, I...> { };
 
template <int... I>
struct indices<0, I...> : indices_list<I...>{ };
 
template <typename T>
struct tuple_indices : indices<std::tuple_size<typename unqualified<T>::type>::value> { };
 
template <int ...I, int ...J, typename Tuple0, typename Tuple1>
auto awesome_tuple_dog( indices_list<I...>, indices_list<J...>, Tuple0&& t0, Tuple1&& t1 ) {
    return std::make_tuple( std::get<I>( std::forward<Tuple0>(t0) )..., std::get<J>( std::forward<Tuple1>(t1) )... );
}
 
template <typename Tuple0, typename Tuple1>
auto awesome_tuple_cat( Tuple0&& t0, Tuple1&& t1 ) {
    return awesome_tuple_dog( tuple_indices<Tuple0>(), tuple_indices<Tuple1>(), std::forward<Tuple0>( t0 ), std::forward<Tuple1>( t1 ) );
}
 
int main () {
    std::tuple<bool, char> a;
    std::tuple<short, int> b;
    struct {} _ = awesome_tuple_cat( a, b );
 
}

prog.cpp:22:90: warning: ‘awesome_tuple_dog’ function uses ‘auto’ type specifier without trailing return type [enabled by default]
 auto awesome_tuple_dog( indices_list<I...>, indices_list<J...>, Tuple0&& t0, Tuple1&& t1 ) {
                                                                                          ^
prog.cpp:27:50: warning: ‘awesome_tuple_cat’ function uses ‘auto’ type specifier without trailing return type [enabled by default]
 auto awesome_tuple_cat( Tuple0&& t0, Tuple1&& t1 ) {
                                                  ^
prog.cpp: In function ‘int main()’:
prog.cpp:34:43: error: conversion from ‘std::tuple<bool, char, short int, int>’ to non-scalar type ‘main()::<anonymous struct>’ requested
     struct {} _ = awesome_tuple_cat( a, b );
                                           ^

Standard output is empty