"static_assert(false)" is ill-formed in "if constexpr" before CWG2518.

[Yan-Zero]

Change "false" to "N > 4 || N < 0" in static_assert

Only the GCC version above 13.0 can compile the code like:

template<typename T>
void f()
{
    if constexpr ([std::is_arithmetic_v](http://en.cppreference.com/w/cpp/types/is_arithmetic)<T>)
        // ...
    else {
        using invalid_array = int[-1]; // ill-formed: invalid for every T
        static_assert(false, "Must be arithmetic"); // ill-formed before CWG2518
    }
}

(from cppreference)

Before CWG2518, we can code:

template<typename>
inline constexpr bool dependent_false_v = false;
 
template<typename T>
void f()
{
    if constexpr ([std::is_arithmetic_v](http://en.cppreference.com/w/cpp/types/is_arithmetic)<T>)
        // ...
    else {
        // workaround before CWG2518
        static_assert(dependent_false_v<T>, "Must be arithmetic");
    }
}