How do I find out if a tuple contains a type?

Question

Suppose I want to create a compile-time heterogenous container of unique types from some sequence of non-unique types. In order to do this I need to iterate over th

Answer 1

#include 
#include 

template 
struct has_type;

template 
struct has_type> : std::false_type {};

template 
struct has_type> : has_type> {};

template 
struct has_type> : std::true_type {};

DEMO

And an additional alias, if the trait itself should be std::true_type or std::false_type :

template 
using tuple_contains_type = typename has_type::type;