std:: same_as

The concept same_as<T, U> is satisfied if and only if T and U denote the same type.

std :: same_as < T, U > subsumes std :: same_as < U, T > and vice versa.

Possible implementation

namespace detail
{
    template< class T, class U >
    concept SameHelper = std::is_same_v<T, U>;
}
template< class T, class U >
concept same_as = detail::SameHelper<T, U> && detail::SameHelper<U, T>;

Example

#include <concepts>
#include <iostream>
template<typename T, typename ... U>
concept either = (std::same_as<T, U> || ...);
template<typename T>
concept is_printable = std::integral<T> || std::floating_point<T> ||
    either<std::remove_cvref_t<std::remove_pointer_t<std::decay_t<T>>>, char, wchar_t>;
void println(is_printable auto const ... arguments)
{
    (std::wcout << ... << arguments) << '\n';
}
int main()
{
    println("Example: ", 3.14, " : ", 42, " : [", 'a', L'-', L"Z]");
}

Example: 3.14 : 42 : [a-Z]

References

See also