Simple example for a throw trick in constexpr context

gistfile1.txt

In "C++Now 2017: Ben Deane & Jason Turner "constexpr ALL the things!"", Jason Turner talks about
constexpr vector which has a push back method allowing to detect range errors at compile time: 
https://youtu.be/HMB9oXFobJc?t=921

If you want to see how to reproduce this trick here is the code:

#include <stdexcept>

class vec {
public:
    constexpr void test(int n) const {
        if (n > 10)
            throw std::range_error("error");
    }
};

constexpr int foo() {
    vec v;
    v.test(10); // OK
    v.test(11); // causes compile error: expression '<throw-expression>' is not a constant expression
    return 123;
}

constexpr int ik = foo();

int main() {}