#include <cstddef>
#include <assert.h>

size_t inc() {
	static size_t val = 0;
	++val;
	return val;
}

size_t bar(size_t num = inc()) {
	return num;
}

size_t line(size_t line = __LINE__) {
	return line;
}

int main() {
	int num = bar();
	assert(num == 1);
	num = bar();
	assert(num == 2);
	num = bar();
	num = bar();
	num = bar();
	assert(num == 5);

	// fails
	// I believe because __LINE__ is just a macro
	assert(line() == __LINE__);

	return 0;
}