How to check if every type in a parameter pack is unique? [duplicate]

Answer 1

You could do it like this:

#include 

template 
struct unique_types;

template 
struct unique_types
 : unique_types, unique_types, unique_types {};

template 
struct unique_types
{
    static_assert(!std::is_same::value, "Types must be unique");
};

int main()
{
    // OK.
    unique_types foo;

    // Should not compile.
    unique_types bar;
}